| 0/0 |
2026/08/27 02:24 |
flow |
assessment-security |
42m
Results: map[DenialOfService:true Explanation:Based on the analysis of the provided lockdep report and the kernel source code,
here is the assessment of the bug:
**Bug Mechanism and Impact:**
The bug is a lockdep warning indicating a possible circular locking dependency,
which represents a potential deadlock scenario. The dependency chain involves
the following locks: `pipe->mutex` -> `cb_lock` -> `ima_iint_mutex_key` ->
`buffer->mutex` -> `common->filesem` -> `pipe->mutex`.
This cycle is formed by the combination of four distinct operations:
1. **`pipe->mutex` -> `cb_lock`**: Splicing data from a pipe to a generic
netlink socket. `do_splice` acquires the `pipe->mutex` and eventually calls
`genl_rcv`, which acquires the generic netlink `cb_lock`.
2. **`cb_lock` -> `ima_iint_mutex_key`**: Processing a
`NL80211_CMD_RELOAD_REGDB` netlink message. The netlink handler holds `cb_lock`
and calls `request_firmware`. Opening the firmware file triggers the Integrity
Measurement Architecture (IMA), which acquires `ima_iint_mutex_key`.
3. **`ima_iint_mutex_key` -> `buffer->mutex`**: IMA measuring a `configfs` file.
IMA holds `ima_iint_mutex_key` and reads the file, acquiring the `configfs`
buffer mutex (`buffer->mutex`).
4. **`buffer->mutex` -> `common->filesem` -> `pipe->mutex`**: Writing to a USB
mass storage gadget `configfs` attribute (`file`). The `configfs` write handler
holds `buffer->mutex`, calls `fsg_store_file` (which acquires
`common->filesem`), and opens the backing file. If the backing file is a named
pipe (FIFO), `fifo_open` is called, which acquires `pipe->mutex`.
If these operations occur concurrently, they can deadlock the involved
subsystems (pipes, netlink, IMA, and USB gadgets), resulting in a **Denial of
Service (DoS)**. Deadlocks do not cause memory corruption and are **not
exploitable** for privilege escalation.
**Trigger Requirements:**
While splicing to a netlink socket can be done by an unprivileged user, the
other operations strictly require elevated privileges:
- Triggering `NL80211_CMD_RELOAD_REGDB` requires global `CAP_NET_ADMIN` (checked
via `netlink_capable(skb, CAP_NET_ADMIN)` against the initial user namespace).
- Writing to the USB gadget `configfs` or `sysfs` attributes requires root
privileges, as these files are owned by root and are not mountable/writable
within unprivileged user namespaces.
- IMA policy configuration (to measure `configfs` files) is also restricted to
root.
Therefore, this bug is **not accessible from unprivileged processes** and **not
accessible from user namespaces**. It requires a highly privileged user
(root/CAP_NET_ADMIN in the init namespace) to trigger the specific conditions
that lead to the deadlock. Exploitable:false FilesystemTrigger:false NetworkTrigger:false PeripheralTrigger:false RemoteTrigger:false Unprivileged:false UserNamespace:false VMGuestTrigger:false VMHostTrigger:false]
|
| 1/1 |
2026/08/27 02:24 |
action |
syz-repro-to-c-repro |
0m
Results:
|
| 2/1 |
2026/08/27 02:24 |
action |
kernel-checkouter |
0m
Results: map[KernelSrc:/app/workdir/cache/src/d3e5e845ea1e86991b96377ebe5c58374353a72c]
|
| 3/1 |
2026/08/27 02:24 |
action |
kernel-builder |
22m
Results: map[KernelObj:/app/workdir/cache/build/87aaa677bb09399630dfb39dc4dfd962f565d50c]
|
| 4/1 |
2026/08/27 02:46 |
action |
codesearch-prepare |
15m
Results: map[Index:codesearch-index]
|
| 5/1 |
2026/08/27 03:02 |
agent |
expert |
4m
Model:
Results: map[DenialOfService:true Exploitable:false FilesystemTrigger:false NetworkTrigger:false PeripheralTrigger:false RemoteTrigger:false Unprivileged:false UserNamespace:false VMGuestTrigger:false VMHostTrigger:false]
Instruction: You are an experienced Linux kernel security engineer. Your task is to analyze given kernel bug report
and determine its security impact based on the following dimensions.
Use the provided tools to examine the source code, check for capability checks (e.g., capable(), ns_capable()),
and understand the nature of the bug. Analyze the given kernel build and configuration.
You can check the kernel config by grepping ".config" file; you can check kernel cmdline by grepping
".config" file for "CONFIG_CMDLINE=". Assume sysctl parameters have default values.
But analyze for the corresponding production build w/o debugging tools enabled (like KASAN, KMSAN, UBSAN).
Try different strategies when analyzing the bug:
- think of ways in which the vulnerable code is unreachable
- or the other way around: try to come up with different ideas of how an unprivileged user can reach the bug
If still unsure err on the side of the bug being non-exploitable/not-accessible.
In the final reply, provide a reasoning for your assessment.
Analysis dimensions:
* Exploitable:
Determine if the bug can result in memory corruption, elevated privileges, or an information leak.
Memory safety issues are almost always exploitable (KASAN or UBSAN reports for use-after-free, out-of-bounds;
refcounting issues, corrupted lists, etc). When kernel is crashing on a completely wild pointer access
(e.g. user-space address, or non-canonical address, but not on NULL or address corresponding to KASAN shadow
for NULL address), including both data accesses and control transfers, that also usually implies possibility
of exploitation. Such reports usually say "unable to handle kernel paging request".
Uses of uninitialized values detected by KMSAN may be exploitable b/c attacker frequently can affect uninit
values with spraying techniques. However, for these exploitability depends on how exactly the uninit value
is used in the code, and what it affects.
Information leaks are exploitable on their own and should be classified as such. A bug that copies kernel
memory contents to userspace (e.g. an out-of-bounds read whose result is returned to the caller, or
uninitialized stack/heap bytes written to a user buffer) is exploitable: it can reveal kernel pointer
values and defeat KASLR, expose sensitive data such as cryptographic keys or other processes' memory, and
serves as a necessary building block in most modern kernel privilege-escalation exploit chains. Do not classify
an information leak as non-exploitable solely because it does not directly cause a memory write or control-flow
hijack; the leak itself is the exploit primitive.
Think of what happens after the bug is triggered. Some bugs cause kernel panic and halt execution,
they are harder to exploit. For example, BUG reports halts the kernel. However, WARNING reports don't halt
execution in production builds. Debug bug detection tools (like KASAN, KMSAN, KCSAN, UBSAN) are also not enabled
in production builds, so attacker can freely exploit these bugs w/o being detected by these tools.
If you see an integer overflow, think how the overflowed value used later (if it's used as allocation size,
or an array index). If you see an out-of-bounds read, think if it's followed by an out-of-bounds write as well.
Some KCSAN data-races may be exploitable by skilled attackers as well. Think what data structures got corrupted
as the result of data races and how. However, note that kernel has lots of "benign" data races that don't lead
to any runtime misbehavior at all.
* Denial Of Service:
Determine if the bug can result in denial-of-service. Most bugs can, since they cause system crash,
hangs, deadlocks, or resource leaks. This is mostly applicable to WARNING bugs that won't cause system crash
in production. For these think what will be consequences of the violation of the kernel assumptions flagged
by the WARNING. In some cases the unexpected condition is also properly handled by the normal control flow
(e.g. with "if (WARN_ON(...))"), these won't cause denial-of-service. If the condition is not handled,
then it may or may not cause denial-of-service.
* Accessible From Unprivileged Processes:
Determine if the bug can be reached from a typical (non-root) user process that does NOT have any special capabilities
(like CAP_SYS_ADMIN, CAP_NET_ADMIN, CAP_NET_RAW, CAP_PERFMON) or access to device nodes restricted to root.
Assume that unprivileged_bpf_disabled=1, that is eBPF loading is not accessible. However, cBPF (classical BPF)
is still accessible to non-root processes.
Assume that user namespaces are not accessible, that is, the process cannot get the mentioned capabilities even
within a new user namespace (checked by ns_capable() function in the kernel sources).
* Accessible From User Namespaces:
Determine if the bug can be reached within a user-namespace where the process has all capabilities
(including CAP_SYS_ADMIN, CAP_NET_ADMIN, CAP_NET_RAW, CAP_PERFMON). Such capabilities are checked with ns_capable()
function in the kernel sources.
* VM Guest Trigger:
Determine if the bug can be triggered from the context of a typical KVM guest (e.g., set up by a QEMU VMM).
Consider accesses to standard Linux host paravirtualized features (virtio-blk, virtio-net, etc.),
and handling of VM exits in the KVM code.
* VM Host Trigger in The Confidential Computing Context:
Determine if the bug can be triggered in a confidential computing guest kernel from the context of a KVM host.
Consider access to standard Linux guest paravirtualized features (virtio-blk, virtio-net, etc.).
* Ethernet Network Trigger:
Determine if the bug can be triggered by processing ingress network Ethernet traffic, either directly (network stack)
or via drivers exposed to network data.
* Other Remote Trigger:
Determine if the bug can be triggered by processing remote traffic other than Ethernet (Wifi, Bluetooth, NFC, etc).
* Peripheral Trigger:
Determine if the bug can be triggered via an untrusted peripheral device that can be physically plugged
into a system, such as a USB device or a niche hardware driver handling external hardware inputs.
This is particularly important for mobile and desktop environments where users can plug in unknown devices.
* Malicious Filesystem Trigger:
Determine if the bug can be triggered by the kernel mounting and parsing a malicious filesystem image.
This is highly critical for Desktop and Mobile environments where external media or downloaded images
might be auto-mounted.
Don't make assumptions about the kernel source code (it may be different from what you assume it is).
Extensively use the provided code access tools (codesearch-*, git-*, grepper, etc)
to examine the actual source code, and confirm any assumptions.
Prefer calling several tools at the same time to save round-trips.
Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.
Prompt:
The kernel bug report is:
9p: Bad value for 'version'
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L
------------------------------------------------------
syz.8.3362/18795 is trying to acquire lock:
ffff88805662e860 (&pipe->mutex){+.+.}-{4:4}, at: fifo_open+0x139/0xb40 fs/pipe.c:1235
but task is already holding lock:
ffff88802b41f920 (&common->filesem){++++}-{4:4}, at: fsg_store_file+0x193/0x450 drivers/usb/gadget/function/storage_common.c:452
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&common->filesem){++++}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
fsg_store_cdrom+0xe2/0x190 drivers/usb/gadget/function/storage_common.c:478
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6af/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (&p->frag_sem){++++}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
flush_write_buffer fs/configfs/file.c:205 [inline]
configfs_write_iter+0x218/0x4e0 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6af/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (&buffer->mutex#2){+.+.}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821
configfs_read_iter+0x79/0x6f0 fs/configfs/file.c:86
__kernel_read+0x397/0xad0 fs/read_write.c:532
integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222
ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280
ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
ima_file_check+0xc3/0x110 security/integrity/ima/ima_main.c:685
security_file_post_open+0xc4/0x210 security/security.c:2755
do_open fs/namei.c:4839 [inline]
path_openat+0x5cd/0x2440 fs/namei.c:5000
do_file_open+0x20e/0x430 fs/namei.c:5029
do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
do_sys_open fs/open.c:1423 [inline]
__do_sys_openat fs/open.c:1439 [inline]
__se_sys_openat fs/open.c:1434 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1434
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821
process_measurement+0x5ab/0x2350 security/integrity/ima/ima_main.c:319
ima_file_check+0xc3/0x110 security/integrity/ima/ima_main.c:685
security_file_post_open+0xc4/0x210 security/security.c:2755
do_open fs/namei.c:4839 [inline]
path_openat+0x5cd/0x2440 fs/namei.c:5000
do_file_open+0x20e/0x430 fs/namei.c:5029
file_open_name+0x1c3/0x3e0 fs/open.c:1375
filp_open+0x2e/0x50 fs/open.c:1392
kernel_read_file_from_path_initns+0xec/0x240 fs/kernel_read_file.c:159
fw_get_filesystem_firmware drivers/base/firmware_loader/main.c:549 [inline]
_request_firmware+0x733/0x13c0 drivers/base/firmware_loader/main.c:873
request_firmware+0x35/0x50 drivers/base/firmware_loader/main.c:948
reg_reload_regdb+0x85/0x460 net/wireless/reg.c:1067
genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec net/socket.c:800 [inline]
__sock_sendmsg net/socket.c:815 [inline]
____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2713
___sys_sendmsg+0x190/0x1e0 net/socket.c:2767
__sys_sendmsg+0x160/0x210 net/socket.c:2799
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (cb_lock){++++}-{4:4}:
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec net/socket.c:800 [inline]
__sock_sendmsg net/socket.c:815 [inline]
sock_sendmsg+0x394/0x410 net/socket.c:838
splice_to_socket+0xb3c/0x11a0 fs/splice.c:884
do_splice_from fs/splice.c:936 [inline]
do_splice+0x109c/0x1fa0 fs/splice.c:1349
__do_splice+0x33b/0x370 fs/splice.c:1431
__do_sys_splice fs/splice.c:1634 [inline]
__se_sys_splice fs/splice.c:1616 [inline]
__x64_sys_splice+0x187/0x250 fs/splice.c:1616
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&pipe->mutex){+.+.}-{4:4}:
check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
check_prevs_add kernel/locking/lockdep.c:3300 [inline]
validate_chain kernel/locking/lockdep.c:3924 [inline]
__lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5253
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821
fifo_open+0x139/0xb40 fs/pipe.c:1235
do_dentry_open+0x6ab/0x14d0 fs/open.c:996
vfs_open+0x82/0x3f0 fs/open.c:1101
do_open fs/namei.c:4837 [inline]
path_openat+0x19fa/0x2440 fs/namei.c:5000
do_file_open+0x20e/0x430 fs/namei.c:5029
file_open_name+0x1c3/0x3e0 fs/open.c:1375
filp_open+0x2e/0x50 fs/open.c:1392
fsg_lun_open+0x9e/0x7b0 drivers/usb/gadget/function/storage_common.c:199
fsg_store_file+0x1e7/0x450 drivers/usb/gadget/function/storage_common.c:455
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6af/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&pipe->mutex --> &p->frag_sem --> &common->filesem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&common->filesem);
lock(&p->frag_sem);
lock(&common->filesem);
lock(&pipe->mutex);
*** DEADLOCK ***
locks held by syz.8.3362/18795: 5, last CPU#0:
#0: ffff888034a2c9b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff8880238a2460 (sb_writers#18){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffff88803d2cde80 (&buffer->mutex#2){+.+.}-{4:4}, at: configfs_write_iter+0x76/0x4e0 fs/configfs/file.c:226
#3: ffff88803c8bd070 (&p->frag_sem){++++}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline]
#3: ffff88803c8bd070 (&p->frag_sem){++++}-{4:4}, at: configfs_write_iter+0x218/0x4e0 fs/configfs/file.c:229
#4: ffff88802b41f920 (&common->filesem){++++}-{4:4}, at: fsg_store_file+0x193/0x450 drivers/usb/gadget/function/storage_common.c:452
stack backtrace:
CPU: 0 UID: 0 PID: 18795 Comm: syz.8.3362 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2059
check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2191
check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
check_prevs_add kernel/locking/lockdep.c:3300 [inline]
validate_chain kernel/locking/lockdep.c:3924 [inline]
__lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5253
lock_acquire kernel/locking/lockdep.c:5886 [inline]
lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
__mutex_lock_common kernel/locking/mutex.c:646 [inline]
__mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821
fifo_open+0x139/0xb40 fs/pipe.c:1235
do_dentry_open+0x6ab/0x14d0 fs/open.c:996
vfs_open+0x82/0x3f0 fs/open.c:1101
do_open fs/namei.c:4837 [inline]
path_openat+0x19fa/0x2440 fs/namei.c:5000
do_file_open+0x20e/0x430 fs/namei.c:5029
file_open_name+0x1c3/0x3e0 fs/open.c:1375
filp_open+0x2e/0x50 fs/open.c:1392
fsg_lun_open+0x9e/0x7b0 drivers/usb/gadget/function/storage_common.c:199
fsg_store_file+0x1e7/0x450 drivers/usb/gadget/function/storage_common.c:455
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6af/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f485679e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4857660028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4856a25fa0 RCX: 00007f485679e0d9
RDX: 0000000000000005 RSI: 00002000000003c0 RDI: 0000000000000003
RBP: 00007f4856835024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4856a26038 R14: 00007f4856a25fa0 R15: 00007ffd7288fbb8
</TASK>
mass_storage.0/lun.0: unable to open backing file: file0
Reply: Based on the analysis of the provided lockdep report and the kernel source code, here is the assessment of the bug:
**Bug Mechanism and Impact:**
The bug is a lockdep warning indicating a possible circular locking dependency, which represents a potential deadlock scenario. The dependency chain involves the following locks: `pipe->mutex` -> `cb_lock` -> `ima_iint_mutex_key` -> `buffer->mutex` -> `common->filesem` -> `pipe->mutex`.
This cycle is formed by the combination of four distinct operations:
1. **`pipe->mutex` -> `cb_lock`**: Splicing data from a pipe to a generic netlink socket. `do_splice` acquires the `pipe->mutex` and eventually calls `genl_rcv`, which acquires the generic netlink `cb_lock`.
2. **`cb_lock` -> `ima_iint_mutex_key`**: Processing a `NL80211_CMD_RELOAD_REGDB` netlink message. The netlink handler holds `cb_lock` and calls `request_firmware`. Opening the firmware file triggers the Integrity Measurement Architecture (IMA), which acquires `ima_iint_mutex_key`.
3. **`ima_iint_mutex_key` -> `buffer->mutex`**: IMA measuring a `configfs` file. IMA holds `ima_iint_mutex_key` and reads the file, acquiring the `configfs` buffer mutex (`buffer->mutex`).
4. **`buffer->mutex` -> `common->filesem` -> `pipe->mutex`**: Writing to a USB mass storage gadget `configfs` attribute (`file`). The `configfs` write handler holds `buffer->mutex`, calls `fsg_store_file` (which acquires `common->filesem`), and opens the backing file. If the backing file is a named pipe (FIFO), `fifo_open` is called, which acquires `pipe->mutex`.
If these operations occur concurrently, they can deadlock the involved subsystems (pipes, netlink, IMA, and USB gadgets), resulting in a **Denial of Service (DoS)**. Deadlocks do not cause memory corruption and are **not exploitable** for privilege escalation.
**Trigger Requirements:**
While splicing to a netlink socket can be done by an unprivileged user, the other operations strictly require elevated privileges:
- Triggering `NL80211_CMD_RELOAD_REGDB` requires global `CAP_NET_ADMIN` (checked via `netlink_capable(skb, CAP_NET_ADMIN)` against the initial user namespace).
- Writing to the USB gadget `configfs` or `sysfs` attributes requires root privileges, as these files are owned by root and are not mountable/writable within unprivileged user namespaces.
- IMA policy configuration (to measure `configfs` files) is also restricted to root.
Therefore, this bug is **not accessible from unprivileged processes** and **not accessible from user namespaces**. It requires a highly privileged user (root/CAP_NET_ADMIN in the init namespace) to trigger the specific conditions that lead to the deadlock.
|
| 6/2 |
2026/08/27 03:02 |
llm |
expert |
0m
Model:
Tokens:
input: 11695
output: 35
thoughts: 907
Thoughts: **Analyzing a Potential Circular Locking Dependency**
Okay, so I've got a lockdep warning, meaning there's a possible circular dependency in the locking scheme. The report highlights three mutexes: `&pipe->mutex`, `&p->frag_sem`, and `&common->filesem`. The chain looks like this: `&pipe->mutex` depends on `&p->frag_sem`, which depends on `&common->filesem`.
Now, let's trace this back to the code. Specifically, the task is trying to acquire `&pipe->mutex` within `fifo_open`, but it's already holding `&common->filesem` from `fsg_store_file`. That's where it's starting to look problematic.
The backtrace shows an interesting sequence where `&common->filesem` is obtained via `fsg_store_file`, which leads into `flush_write_buffer` and all the way to `fifo_open` which is where the deadlock condition is present. This then goes through `configfs_write_iter`, which is usually only accessible by root.
So, I need to evaluate whether this represents a Denial of Service vulnerability. A circular locking dependency *can* lead to a deadlock, and a deadlock is definitely a form of DoS. The crucial question is whether this can be triggered by an unprivileged user. I need to focus on `fsg_store_file` and `configfs_write_iter`. Configfs, at `/sys/kernel/config`, is usually root-only. It's important to figure out if it's possible to mount configfs in a user namespace, but that's unlikely since configfs isn't generally designed to be mounted within a user namespace. Let's verify that.
|
| 7/2 |
2026/08/27 03:02 |
tool |
grepper |
0m
Error:
Args: map[Expression:fs_flags.*FS_USERNS_MOUNT PathPrefix:fs/configfs]
Results:
|
| 8/2 |
2026/08/27 03:02 |
llm |
expert |
0m
Model:
Tokens:
input: 13031
output: 44
thoughts: 75
Thoughts: **My Initial Thoughts on Configfs and USB Gadget Configuration**
Okay, so configfs isn't mountable within a user namespace, which is a key limitation to remember. That presents a problem. Since I need to access it for USB gadget configuration, and since that's typically done through configfs, I need to figure out an alternative approach. I know from experience that configuring USB gadgets via configfs typically demands root privileges, usually involving `CAP_SYS_ADMIN` or direct root access to the configfs mount point. Given this restriction, I'm going to have to dive deeper. I'm going to look closely at `fsg_store_file` to see if it unlocks the access I need.
|
| 9/2 |
2026/08/27 03:02 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/usb/gadget/function/storage_common.c Name:fsg_store_file]
Results: map[SourceCode: 437: ssize_t fsg_store_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
438: const char *buf, size_t count)
439: {
440: int rc = 0;
441:
442: if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
443: LDBG(curlun, "eject attempt prevented\n");
444: return -EBUSY; /* "Door is locked" */
445: }
446:
447: /* Remove a trailing newline */
448: if (count > 0 && buf[count-1] == '\n')
449: ((char *) buf)[count-1] = 0; /* Ugh! */
450:
451: /* Load new medium */
452: down_write(filesem);
453: if (count > 0 && buf[0]) {
454: /* fsg_lun_open() will close existing file if any. */
455: rc = fsg_lun_open(curlun, buf);
456: if (rc == 0)
457: curlun->unit_attention_data =
458: SS_NOT_READY_TO_READY_TRANSITION;
459: } else if (fsg_lun_is_open(curlun)) {
460: fsg_lun_close(curlun);
461: curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
462: }
463: up_write(filesem);
464: return (rc < 0 ? rc : count);
465: }
SourceFile:drivers/usb/gadget/function/storage_common.c]
|
| 10/2 |
2026/08/27 03:02 |
llm |
expert |
0m
Model:
Tokens:
input: 13829
output: 57
thoughts: 89
Thoughts: Okay, here's my take on those thoughts, framed as an expert's internal monologue:
**Investigating `fsg_store_file` in the ConfigFS Context**
Right, so `fsg_store_file` is the workhorse when we're writing to a USB mass storage LUN's `file` attribute within configfs. Understandably, that requires root access to the configfs mount, which makes sense. I need to figure out if there's any other way this thing can be triggered though. Itβs always good to be thorough. Wait a minute... I seem to recall `fsg_store_file` being accessible, at least in some capacity, via sysfs? I better check where `fsg_store_file` is actually getting used. I need to understand all potential entry points, particularly for any path that might bypass the normal security constraints.
|
| 11/2 |
2026/08/27 03:03 |
tool |
codesearch-find-references |
0m
Args: map[ContextFile:drivers/usb/gadget/function/storage_common.c IncludeSnippetLines:0 Name:fsg_store_file SourceTreePrefix:]
Results: map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:file_store SourceFile:drivers/usb/gadget/function/f_mass_storage.c SourceLine:2676] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:fsg_lun_opts_file_store SourceFile:drivers/usb/gadget/function/f_mass_storage.c SourceLine:3182] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:fsg_store_forced_eject SourceFile:drivers/usb/gadget/function/storage_common.c SourceLine:535] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:__UNIQUE_ID_addressable_fsg_store_file_972 SourceFile:drivers/usb/gadget/function/storage_common.c SourceLine:466] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:__gendwarfksyms_ptr_fsg_store_file SourceFile:drivers/usb/gadget/function/storage_common.c SourceLine:466] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:__gendwarfksyms_ptr_fsg_store_file SourceFile:drivers/usb/gadget/function/storage_common.c SourceLine:466]] TruncatedOutput:false]
|
| 12/2 |
2026/08/27 03:03 |
llm |
expert |
0m
Model:
Tokens:
input: 14584
output: 43
thoughts: 28
Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience:
**Diving into f_mass_storage.c**
Alright, time to troubleshoot this USB gadget issue. Let's start digging into the `f_mass_storage.c` file within the `drivers/usb/gadget/function` directory. The `file_store` variable in this file is a crucial piece of the puzzle, so it's a logical first point of investigation. Understanding how that particular variable is handled, initialized, and used will likely give me some important clues. I need to refresh my memory on the interactions within that code. Let me open the source.
|
| 13/2 |
2026/08/27 03:03 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/usb/gadget/function/f_mass_storage.c Name:file_store]
Results: map[SourceCode:2670: static ssize_t file_store(struct device *dev, struct device_attribute *attr,
2671: const char *buf, size_t count)
2672: {
2673: struct fsg_lun *curlun = fsg_lun_from_dev(dev);
2674: struct rw_semaphore *filesem = dev_get_drvdata(dev);
2675:
2676: return fsg_store_file(curlun, filesem, buf, count);
2677: }
SourceFile:drivers/usb/gadget/function/f_mass_storage.c]
|
| 14/2 |
2026/08/27 03:03 |
llm |
expert |
0m
Model:
Tokens:
input: 14981
output: 56
thoughts: 20
Thoughts: Here's my take on those thoughts, tailored for an expert audience:
**Analyzing Sysfs Attribute Permissions**
Right, this looks like a sysfs attribute we're dealing with here. My immediate thought is, before digging too deep into its function or the driver's intent, I need to get a solid handle on its security context. Permissions are critical in sysfs; a misconfigured attribute can open the door to all sorts of issues. Time to dig into the access control. Let's see who can read, write, or execute this thing. The usual tools like `stat` or direct examination of the `mode` field in the directory entry will be my starting point. Understanding the access restrictions is paramount for the overall security profile. I'll need to correlate the permissions to the driver's intended usage to ensure it aligns with the security posture.
|
| 15/2 |
2026/08/27 03:03 |
tool |
codesearch-find-references |
0m
Args: map[ContextFile:drivers/usb/gadget/function/f_mass_storage.c IncludeSnippetLines:2 Name:file_store SourceTreePrefix:]
Results: map[References:[map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:dev_attr_file SourceFile:drivers/usb/gadget/function/f_mass_storage.c SourceLine:2698 SourceSnippet:2698: static DEVICE_ATTR_RW(file);
] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:dev_attr_file SourceFile:drivers/usb/gadget/function/f_mass_storage.c SourceLine:2698 SourceSnippet:2698: static DEVICE_ATTR_RW(file);
] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:dev_attr_file SourceFile:drivers/usb/gadget/function/f_mass_storage.c SourceLine:2698 SourceSnippet:2698: static DEVICE_ATTR_RW(file);
]] TruncatedOutput:false]
|
| 16/2 |
2026/08/27 03:03 |
llm |
expert |
0m
Model:
Tokens:
input: 15516
output: 50
thoughts: 50
Thoughts: Okay, here's my interpretation of those thoughts, presented as my own thinking process:
**Sysfs Attribute Permissions Conundrum**
Right, `DEVICE_ATTR_RW(file)` sets up a sysfs attribute with permissions of `0644`. That means it's pretty much restricted to being writable only by root, which is the expected default. I've seen that behavior countless times in various sysfs implementations.
But hang on... what about `fsg_lun_opts_file_store`? Now, that throws a small wrench into the mix. I need to refresh my memory on that function specifically, and how its data flow. I should check how it handles write operations within the context of the filesystem globals. Is there an internal check, or is it directly using root write permissions? I need to clarify what the intent is there. Are there other access control mechanisms in place? It's important to understand the overall picture to be sure there isn't a vulnerability.
|
| 17/2 |
2026/08/27 03:03 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/usb/gadget/function/f_mass_storage.c Name:fsg_lun_opts_file_store]
Results: map[SourceCode:3176: static ssize_t fsg_lun_opts_file_store(struct config_item *item,
3177: const char *page, size_t len)
3178: {
3179: struct fsg_lun_opts *opts = to_fsg_lun_opts(item);
3180: struct fsg_opts *fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
3181:
3182: return fsg_store_file(opts->lun, &fsg_opts->common->filesem, page, len);
3183: }
SourceFile:drivers/usb/gadget/function/f_mass_storage.c]
|
| 18/2 |
2026/08/27 03:03 |
llm |
expert |
0m
Model:
Tokens:
input: 16032
output: 37
thoughts: 2548
Thoughts: **Analysis of a Potential Circular Locking Dependency in Configfs**
Okay, here's what I've gathered. This issue seems to involve a configfs attribute, which, as I know, requires root privileges to modify. My initial thought was, "Can an unprivileged user even trigger this?" The answer, as far as I can see, is no β modifying sysfs or configfs directly requires root. I considered user namespaces, but the restrictions on sysfs and configfs within them eliminate that possibility as well.
The core of the problem lies in a circular locking dependency, which lockdep flags. These warnings, while not leading to crashes by default, hint at a potential deadlock. Essentially, the code can get into a state where different threads are holding locks that they each need to acquire from each other, leading to a standstill β a Denial of Service.
I started analyzing the deadlock scenario, tracing the lock acquisition chain. It looks like: `&pipe->mutex` might depend on `&p->frag_sem`, and `&p->frag_sem` depends on `&common->filesem`, and `&common->filesem` depends on `&pipe->mutex`. I was looking for the execution paths, specifically checking how each lock is acquired in relation to others in each thread.
First, I examined CPU0's path, looking at how `&pipe->mutex` is acquired while holding `&common->filesem`. The code traces back to `fsg_store_file` holding `&common->filesem`, calling `fsg_lun_open` and then opening a file. If that file is a named pipe (FIFO), then `fifo_open` grabs `&pipe->mutex`. Yep, path is real.
I followed CPU1. `configfs_write_iter` acquires `&p->frag_sem`, and then it calls a function, which in the `fsg_store_cdrom` case, grabs `&common->filesem`. This confirmed that CPU1's sequence is also a real path.
For CPU2, I found out the chain starts from `&pipe->mutex`, leads to `&p->frag_sem` and then to `&common->filesem`. Then it turns out that all this chain is in one thread: from `configfs_write_iter` to `fsg_store_file`, and back, which isn't the circular dependency! That made me look at the lockdep report again.
I realized the circular dependency wasn't within *one* thread. There's a much more complex interaction. Here's what I finally understood:
* **Thread A (Splice to netlink socket):** `splice_to_socket` acquires `pipe->mutex` (by way of `do_splice`). It sends a netlink message, acquiring `cb_lock`.
* **Thread B (Firmware load via netlink):** `genl_rcv` acquires `cb_lock`. It triggers a firmware request, which opens a file.
* **Thread C (IMA measurement of configfs file):** The file open in Thread B triggers Integrity Measurement Architecture (IMA). IMA acquires `ima_iint_mutex_key` and attempts to read the file, which calls `configfs_read_iter` and acquires `buffer->mutex` (which is `p->frag_sem`).
* **Thread D (Writing to configfs USB gadget file):** `configfs_write_iter` acquires `buffer->mutex` (`p->frag_sem`), calls `fsg_store_file`, which gets `common->filesem`, and opens a FIFO, which acquires `pipe->mutex`.
This creates a full circle: `pipe->mutex` -> `cb_lock` -> `ima_iint_mutex_key` -> `buffer->mutex` -> `common->filesem` -> `pipe->mutex`.
Now, the crucial question: Is this a *real* deadlock? Could it actually happen? IMA is the key, and it does make a difference that it can measure *any* file if its policy says to. If IMA policy is configured to measure the configfs file being opened by root, this is possible. It can read a configfs file. With IMA in the mix, things get interesting. So, theoretically, it can happen.
The final question: Can an unprivileged user trigger this? I think the answer is **possibly, yes**. An unprivileged user can create pipes, and netlink sockets, and might be able to trigger `request_firmware` somehow. My next step will be to dive deeper into `reg_reload_regdb` to confirm how.
|
| 19/2 |
2026/08/27 03:03 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/wireless/reg.c Name:reg_reload_regdb]
Results: map[SourceCode:1059: int reg_reload_regdb(void)
1060: {
1061: const struct firmware *fw;
1062: void *db;
1063: int err;
1064: const struct ieee80211_regdomain *current_regdomain;
1065: struct regulatory_request *request;
1066:
1067: err = request_firmware(&fw, "regulatory.db", ®_fdev->dev);
1068: if (err)
1069: return err;
1070:
1071: if (!valid_regdb(fw->data, fw->size)) {
1072: err = -ENODATA;
1073: goto out;
1074: }
1075:
1076: db = kmemdup(fw->data, fw->size, GFP_KERNEL);
1077: if (!db) {
1078: err = -ENOMEM;
1079: goto out;
1080: }
1081:
1082: rtnl_lock();
1083: if (!IS_ERR_OR_NULL(regdb))
1084: kfree(regdb);
1085: regdb = db;
1086:
1087: /* reset regulatory domain */
1088: current_regdomain = get_cfg80211_regdom();
1089:
1090: request = kzalloc_obj(*request);
1091: if (!request) {
1092: err = -ENOMEM;
1093: goto out_unlock;
1094: }
1095:
1096: request->wiphy_idx = WIPHY_IDX_INVALID;
1097: request->alpha2[0] = current_regdomain->alpha2[0];
1098: request->alpha2[1] = current_regdomain->alpha2[1];
1099: request->initiator = NL80211_REGDOM_SET_BY_CORE;
1100: request->user_reg_hint_type = NL80211_USER_REG_HINT_USER;
1101:
1102: reg_process_hint(request);
1103:
1104: out_unlock:
1105: rtnl_unlock();
1106: out:
1107: release_firmware(fw);
1108: return err;
1109: }
SourceFile:net/wireless/reg.c]
|
| 20/2 |
2026/08/27 03:03 |
llm |
expert |
0m
Model:
Tokens:
input: 20340
output: 50
thoughts: 63
Thoughts: **Investigating the Regulator Reload**
Okay, so I'm seeing a lockdep report that points the finger at `reg_reload_regdb`. My immediate thought is, "Who's calling *that* function?" It's always crucial to understand the call stack. The report itself is helpful; it traces the problem back to `genl_family_rcv_msg_doit`, which then seems to trigger `reg_reload_regdb`. Now, this strongly suggests a Netlink interaction might be involved, so I need to find the specific handler, and I'll start by checking for likely suspects. I'll search for things like `nl80211_reload_regdb` or anything similar that might be handling this interaction. Time to dig in and see what's going on within the relevant Netlink family!
|
| 21/2 |
2026/08/27 03:03 |
tool |
codesearch-find-references |
0m
Args: map[ContextFile:net/wireless/reg.c IncludeSnippetLines:2 Name:reg_reload_regdb SourceTreePrefix:]
Results: map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:nl80211_reload_regdb SourceFile:net/wireless/nl80211.c SourceLine:10216 SourceSnippet:10214: static int nl80211_reload_regdb(struct sk_buff *skb, struct genl_info *info)
10215: {
10216: return reg_reload_regdb();
10217: }
]] TruncatedOutput:false]
|
| 22/2 |
2026/08/27 03:03 |
llm |
expert |
0m
Model:
Tokens:
input: 20792
output: 60
thoughts: 32
Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience:
**Diving into the Regulatory Database Reload**
Okay, so I need to understand what's happening with the regulatory database reload. The most likely place to start looking is `nl80211_reload_regdb` within the `net/wireless/nl80211.c` file. This function is the logical entry point for handling regulatory changes triggered via nl80211, so it's probably where the core logic resides. I'll need to dig into how it handles the interaction with the regulatory domain data structures, how it potentially calls into the core regulatory subsystem, and what error conditions it checks for. I'm especially interested in whether it handles any race conditions effectively, and how it deals with the transition between old and new regulatory information to avoid disrupting active wireless connections. It's also worth looking at what triggers this reload - is it solely user-space commands, or are there internal kernel events that also drive it? I'll probably also need to consider the broader context within the nl80211 framework to fully grasp the implementation. Time to dive in!
|
| 23/2 |
2026/08/27 03:03 |
tool |
codesearch-find-references |
0m
Args: map[ContextFile:net/wireless/nl80211.c IncludeSnippetLines:2 Name:nl80211_reload_regdb SourceTreePrefix:]
Results: map[References:[map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:nl80211_small_ops SourceFile:net/wireless/nl80211.c SourceLine:19924 SourceSnippet:19922: .cmd = NL80211_CMD_RELOAD_REGDB,
19923: .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
19924: .doit = nl80211_reload_regdb,
19925: .flags = GENL_ADMIN_PERM,
19926: },
]] TruncatedOutput:false]
|
| 24/2 |
2026/08/27 03:03 |
llm |
expert |
0m
Model:
Tokens:
input: 21337
output: 46
thoughts: 496
Thoughts: **Analyzing the CAP_NET_ADMIN Requirement for Reloading the Regulatory Database**
Okay, so I'm looking at this `.flags = GENL_ADMIN_PERM` thing. This tells me that the `NL80211_CMD_RELOAD_REGDB` command needs `CAP_NET_ADMIN`. Alright, so Thread B needs it too. My immediate question is whether this is doable within a user namespace. The good news is, I know that `CAP_NET_ADMIN` *is* possible within a user namespace.
Now, let's see if `nl80211` plays nice with user namespace `CAP_NET_ADMIN`. Typically, netlink families use `netlink_net_capable(skb, CAP_NET_ADMIN)` to check the user namespace of the network namespace. If you set up a new user namespace *and* a new network namespace, you inherently have `CAP_NET_ADMIN` within that new namespace.
But there's a wrinkle: `request_firmware` gets called. Does that play nice in a user namespace? Yes, thankfully, it just opens a file from the filesystem. But wait, is it using the global filesystem root or the process's root for that file? Aha! It uses `kernel_read_file_from_path_initns`, meaning it's using the init namespace's root.
So, the trigger for all of this (sending the netlink message) could be done from a user namespace *if* `nl80211` is accessible. Hmm, is `nl80211` accessible in a non-initial network namespace? I've got to check whether `nl80211` is a global netlink family or per-netns. Usually, `nl80211` is accessible across netns, although wiphy devices might only be visible in the init netns or the netns they are assigned to.
But...wait a second. `NL80211_CMD_RELOAD_REGDB` doesn't *seem* to need a wiphy device. It's just reloading the *global* regulatory database. So, does it check for the `capable(CAP_NET_ADMIN)` or does it use `ns_capable(net->user_ns, CAP_NET_ADMIN)`?
Right, `GENL_ADMIN_PERM` in generic netlink checks `netlink_net_capable(skb, CAP_NET_ADMIN)`. This points to the checking of `CAP_NET_ADMIN` in the network namespace where the message originated. Let me just take a look at `genl_family_rcv_msg_doit` to make sure I've got this right.
|
| 25/2 |
2026/08/27 03:04 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/netlink/genetlink.c Name:genl_family_rcv_msg_doit]
Results: map[SourceCode:1081: static int genl_family_rcv_msg_doit(const struct genl_family *family,
1082: struct sk_buff *skb,
1083: struct nlmsghdr *nlh,
1084: struct netlink_ext_ack *extack,
1085: const struct genl_split_ops *ops,
1086: int hdrlen, struct net *net)
1087: {
1088: struct nlattr **attrbuf;
1089: struct genl_info info;
1090: int err;
1091:
1092: attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
1093: ops, hdrlen,
1094: GENL_DONT_VALIDATE_STRICT);
1095: if (IS_ERR(attrbuf))
1096: return PTR_ERR(attrbuf);
1097:
1098: info.snd_seq = nlh->nlmsg_seq;
1099: info.snd_portid = NETLINK_CB(skb).portid;
1100: info.family = family;
1101: info.nlhdr = nlh;
1102: info.genlhdr = nlmsg_data(nlh);
1103: info.attrs = attrbuf;
1104: info.extack = extack;
1105: genl_info_net_set(&info, net);
1106: memset(&info.ctx, 0, sizeof(info.ctx));
1107:
1108: if (ops->pre_doit) {
1109: err = ops->pre_doit(ops, skb, &info);
1110: if (err)
1111: goto out;
1112: }
1113:
1114: err = ops->doit(skb, &info);
1115:
1116: if (ops->post_doit)
1117: ops->post_doit(ops, skb, &info);
1118:
1119: out:
1120: genl_family_rcv_msg_attrs_free(attrbuf);
1121:
1122: return err;
1123: }
SourceFile:net/netlink/genetlink.c]
|
| 26/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 23165
output: 37
thoughts: 17
Thoughts: Here's a summary of my thought process:
**Tracing the Permission Check**
Okay, time to get down to brass tacks. I need to understand how `GENL_ADMIN_PERM` is being utilized within the codebase. My immediate goal is to pinpoint every single location where that specific permission check is being performed. I need a comprehensive overview of where it's being evaluated, to assess its implications. This tracing exercise is crucial for understanding its scope and impact. Essentially, I'm going to follow the breadcrumbs of this permission check to get a clear picture of its role.
|
| 27/2 |
2026/08/27 03:04 |
tool |
grepper |
0m
Args: map[Expression:GENL_ADMIN_PERM PathPrefix:net/netlink/genetlink.c]
Results: map[Output:net/netlink/genetlink.c=1155=static int genl_family_rcv_msg(const struct genl_family *family,
--
net/netlink/genetlink.c-1181-
net/netlink/genetlink.c:1182: if ((op.flags & GENL_ADMIN_PERM) &&
net/netlink/genetlink.c-1183- !netlink_capable(skb, CAP_NET_ADMIN))
]
|
| 28/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 23478
output: 38
thoughts: 31
Thoughts: Okay, here's my interpretation of that thought process, assuming I'm deeply familiar with networking and Linux kernel internals:
**Checking Netlink Capability**
Alright, the code's using `netlink_capable(skb, CAP_NET_ADMIN)`. Good, that means we're evaluating whether the incoming socket buffer (`skb`) has the necessary privilege, specifically the `CAP_NET_ADMIN` capability, for a Netlink operation. It's the standard check for Netlink security. It's the first step - and a crucial one - to make sure this operation is allowed. Now, I should dive into the definition of `netlink_capable` itself to fully understand the authorization process. I'll need to remember the context of the operation that it's being used with.
|
| 29/2 |
2026/08/27 03:04 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/netlink/genetlink.c Name:netlink_capable]
Results: map[SourceCode: 874: /**
875: * netlink_capable - Netlink global message capability test
876: * @skb: socket buffer holding a netlink command from userspace
877: * @cap: The capability to use
878: *
879: * Test to see if the opener of the socket we received the message
880: * from had when the netlink socket was created and the sender of the
881: * message has the capability @cap in all user namespaces.
882: */
883: bool netlink_capable(const struct sk_buff *skb, int cap)
884: {
885: return netlink_ns_capable(skb, &init_user_ns, cap);
886: }
SourceFile:net/netlink/af_netlink.c]
|
| 30/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 23960
output: 47
thoughts: 459
Thoughts: **My Analysis of the Potential Vulnerability**
Okay, let me break this down. `netlink_capable` is the gatekeeper here, and it's looking at `&init_user_ns`. That immediately signals that a global `CAP_NET_ADMIN` is needed to get past it. So, that Thread B, the one that kicks off `NL80211_CMD_RELOAD_REGDB`, it definitely needs global `CAP_NET_ADMIN`. That means an unprivileged user is automatically blocked from triggering it. Good.
What about Thread D and that configfs USB gadget file? Right, we covered that earlier. Configfs is owned by root, and it's not mountable within user namespaces. So that's another roadblock. Thread D also requires global root access.
Thread C, the IMA measurement, is triggered by opening a file. Anyone *can* open a file, but for IMA to actually measure it, IMA needs to be configured to look at that specific file. Okay, so that's not automatically exploitable by everyone.
Thread A, the splice to the netlink socket, that's fine; an unprivileged user can do that. That doesn't seem to be a problem.
So, since Thread B and Thread D both require global root or `CAP_NET_ADMIN`, this whole thing isn't something an unprivileged user can just trip. But can it be triggered from a user namespace? Nope. `netlink_capable` and configfs being unmountable make sure of that.
Is this a denial-of-service? Yes, absolutely. It's a potential deadlock, and if it happens, those threads are going to hang. We're talking about a deadlock involving `pipe->mutex`, `cb_lock`, `ima_iint_mutex_key`, `buffer->mutex`, and `common->filesem`. That's bad news. It could hang netlink, IMA, pipes, and the USB gadget configuration. That's a significant DoS.
But wait, we're not talking about privilege escalation or memory corruption here. It's just a deadlock. Deadlocks are DoS, not an exploit.
Let me just double-check, is there *any* other way to hit `fsg_store_file`? We saw that it's used in `file_store` (sysfs) and `fsg_lun_opts_file_store` (configfs). Both require root to write to them. I'll need to research `fsg_store_forced_eject`, just to be certain.
|
| 31/2 |
2026/08/27 03:04 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/usb/gadget/function/storage_common.c Name:fsg_store_forced_eject]
Results: map[SourceCode: 525: ssize_t fsg_store_forced_eject(struct fsg_lun *curlun, struct rw_semaphore *filesem,
526: const char *buf, size_t count)
527: {
528: int ret;
529:
530: /*
531: * Forcibly detach the backing file from the LUN
532: * regardless of whether the host has allowed it.
533: */
534: curlun->prevent_medium_removal = 0;
535: ret = fsg_store_file(curlun, filesem, "", 0);
536: return ret < 0 ? ret : count;
537: }
SourceFile:drivers/usb/gadget/function/storage_common.c]
|
| 32/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 25259
output: 50
thoughts: 74
Thoughts: Here's my summary, as though I'm thinking through this myself:
**Investigating `reg_reload_regdb` Triggering**
Okay, so `fsg_store_forced_eject` is another sysfs/configfs attribute, also restricted to root users, which is important to remember. Now, I need to make sure I haven't missed any other potential triggers for `reg_reload_regdb`. I know it's called by `nl80211_reload_regdb`, that much is clear. The question is, are there *any* other callers of that function that I'm overlooking? I need to meticulously check the code for any alternate paths.
|
| 33/2 |
2026/08/27 03:04 |
tool |
codesearch-find-references |
0m
Args: map[ContextFile:net/wireless/reg.c IncludeSnippetLines:0 Name:reg_reload_regdb SourceTreePrefix:]
Results: map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:nl80211_reload_regdb SourceFile:net/wireless/nl80211.c SourceLine:10216]] TruncatedOutput:false]
|
| 34/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 25615
output: 44
thoughts: 278
Thoughts: **My Investigation into Firmware Loading via Netlink**
Okay, so I'm focusing on `nl80211_reload_regdb` as a potential firmware trigger. My initial thought is to explore whether other Netlink families could call `request_firmware` without needing global capabilities. There are quite a few Netlink families to consider. Could something like `ethtool` or `devlink` be a path?
If a user namespace has `CAP_NET_ADMIN` over its *own* network namespace, I'm thinking about virtual device creation like `veth` or `dummy`. Could I potentially exploit those to trigger the firmware request? Often, drivers call `request_firmware` when devices come up or when they're configured. The problem is that virtual devices rarely need firmware. Physical devices are usually in the init netns, and configuring them needs `CAP_NET_ADMIN` in the init netns.
But wait a minute... what about a `mac80211_hwsim` device? That can be created via Netlink. Now that's a new avenue of thought. Does that require global `CAP_NET_ADMIN`? That's what I need to check. Let's dig into `mac80211_hwsim` and see.
|
| 35/2 |
2026/08/27 03:04 |
tool |
grepper |
0m
Error:
Args: map[Expression:GENL_ADMIN_PERM PathPrefix:drivers/net/wireless/mac80211_hwsim.c]
Results:
|
| 36/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 26229
output: 44
thoughts: 13
Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience:
**Investigating `hwsim_genl_family`**
Okay, let's dive into this `hwsim_genl_family` business. I need to understand this module's interaction within the broader Genl framework, specifically how it's defined and registered. My immediate thought is to check its declaration, focusing on the key attributes and function pointers. I need to see how the family ID is assigned and whether it uses a static or dynamic allocation approach. Next, I need to check the command handlers; understanding their context and how they process requests is vital. I'll need to look at any associated permission checks and potential locking strategies implemented to see how it handles concurrency. I'm also interested in its initialization and cleanup routinesβhow it's brought up and taken downβto ensure proper resource management. I'll be looking for potential race conditions or other vulnerabilities.
|
| 37/2 |
2026/08/27 03:04 |
tool |
grepper |
0m
Error:
Args: map[Expression:hwsim_genl_family PathPrefix:drivers/net/wireless/mac80211_hwsim.c]
Results:
|
| 38/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 26501
output: 43
thoughts: 46
Thoughts: Okay, here's my interpretation of that thought process, as if I were having it:
**Digging into the `mac80211_hwsim` Code**
Alright, I'm diving back into this `mac80211_hwsim` thing. First things first, need to confirm the location of the core source. Ah, yes, it's definitely nestled in `drivers/net/wireless/mac80211_hwsim.c`. Now, where to begin my investigation? Let's zoom in on `hwsim_new_radio` β that seems like a logical entry point for understanding how new simulated radios are instantiated within this framework. That's the part that'll give me the most critical insights right now.
|
| 39/2 |
2026/08/27 03:04 |
tool |
grepper |
0m
Error:
Args: map[Expression:hwsim_new_radio PathPrefix:drivers/net/wireless/mac80211_hwsim.c]
Results:
|
| 40/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 26768
output: 41
thoughts: 41
Thoughts: Okay, here we go. Here's my take on those thoughts:
**Diving into the `mac80211_hwsim.c` Rabbit Hole**
Right, let's see. The first thing I'm doing is zeroing in on `drivers/net/wireless/mac80211_hwsim.c`. Ah, that rings a bell. It's a key part of the mac80211 hardware simulation, a pretty essential tool for testing and development within the wireless stack. Time to dig in and remind myself of the current state of this area.
|
| 41/2 |
2026/08/27 03:04 |
tool |
grepper |
0m
Error:
Args: map[Expression:hwsim_new_radio PathPrefix:drivers/net/wireless/mac80211_hwsim]
Results:
|
| 42/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 26993
output: 24
thoughts: 39
Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience:
**Investigating a Potentially Missing Module**
Okay, so I'm wondering if this `mac80211_hwsim.c` is actually a thing. Seems odd, or maybe I'm misremembering the exact path. The first step is to verify whether that module even exists. Right, so I'll quickly check the `drivers/net/wireless/` directory. That's where it *should* live, if it's part of the standard wireless subsystem. Let's see what's in there. I'll mentally map the possible filenames and get a feel for what the directory actually contains. This is just a quick sanity check before I start digging into any build logs or configuration options.
|
| 43/2 |
2026/08/27 03:04 |
tool |
codesearch-dir-index |
0m
Args: map[Dir:drivers/net/wireless/]
Results: map[Files:<nil> Subdirs:[admtek ath atmel broadcom intel intersil marvell mediatek microchip morsemicro nxp purelifi quantenna ralink realtek rsi silabs st ti virtual zydas]]
|
| 44/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 27343
output: 26
thoughts: 24
Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience:
**Diving into the Virtual Wireless World**
Right, so we're looking at `drivers/net/wireless/virtual/mac80211_hwsim.c`, are we? My mind immediately starts parsing this. This is where the magic happens, the virtualization layer for mac80211 in Linux's networking stack, specifically for simulating wireless hardware. I'm thinking about the implications instantly. This is crucial for testing, development, and debugging mac80211 without needing physical hardware. We're talking about emulating radio interfaces, creating virtual access points and stations, injecting frames, and managing channel behavior β all within the kernel.
I'm thinking about the challenges that come with this sort of simulation, like how accurately it models the complexities of real RF environments, and whether the simulation introduces its own bias into test results. I'm going through the different components. I wonder about how the hardware simulation layer interacts with the mac80211 core and whether the simulation accurately mimics the hardware interrupts and the timing of real drivers. I'm asking myself what aspects of real hardware the simulation attempts to mimic and what is purposefully simplified.
Let's see⦠I'm considering the core functions within that file. I'm thinking about the virtual device initialization, the handling of virtual hardware events, and the mapping of simulated hardware capabilities to mac80211's framework. I'm already anticipating the implementation details of packet injection, and how collision detection and contention are modeled. I'm also wondering about the degree of configurability offered by the simulation, such as different RF impairments. This file is probably the linchpin for a huge amount of wireless stack research and experimentation. I want to see the details.
|
| 45/2 |
2026/08/27 03:04 |
tool |
codesearch-dir-index |
0m
Args: map[Dir:drivers/net/wireless/virtual/]
Results: map[Files:[mac80211_hwsim.h mac80211_hwsim_i.h mac80211_hwsim_main.c mac80211_hwsim_nan.c mac80211_hwsim_nan.h virt_wifi.c] Subdirs:<nil>]
|
| 46/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 27875
output: 48
thoughts: 29
Thoughts: Here's a summary of my immediate thought process, focusing on the provided text, from the perspective of a seasoned expert:
**Investigating Potential Security Implications in mac80211_hwsim_main.c**
Okay, so the initial focus is on security, specifically, access control as it relates to the kernel's wireless simulation module. Immediately, I'm thinking of `mac80211_hwsim_main.c`. That file is a likely candidate for potential privilege escalation vulnerabilities given its core functionality. The key here is to determine whether it properly limits administrative functionality.
The phrase `GENL_ADMIN_PERM` has jumped out at me. This immediately indicates a potential area of concern. I need to quickly determine how that constant, `GENL_ADMIN_PERM`, is used within that file. Is it properly enforced? Are there any obvious bypasses or loopholes? Am I looking at standard access control checks? Are there missing checks? Does this module rely on the standard GENL mechanism and is that, in itself, a problem? I'll probably start scanning the file for uses of that specific permission flag and then examine the related code to see what the implications are in practice. It's a quick scan and a focused analysis. This is likely where the first interesting potential exploit vector might be. Let's see what we can find.
|
| 47/2 |
2026/08/27 03:04 |
tool |
grepper |
0m
Error:
Args: map[Expression:GENL_ADMIN_PERM PathPrefix:drivers/net/wireless/virtual/mac80211_hwsim_main.c]
Results:
|
| 48/2 |
2026/08/27 03:04 |
llm |
expert |
0m
Model:
Tokens:
input: 28254
output: 48
thoughts: 13
Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience and written in the first person:
**Diving into `hwsim_genl_ops`**
Okay, time to take a look at `hwsim_genl_ops`. Given what I know about the architecture, this likely relates to the handling of Generic Netlink operations within the hardware simulator. My first thought is to quickly identify the key functions within this structure. I'll be looking for handlers for different command IDs β the core routines that orchestrate interactions with the simulated hardware from userspace. I'll need to understand the data structures passed in and out, the error handling, and the overall flow of execution. I'm assuming it implements the common Generic Netlink pattern of request/response, but it's always good to verify and understand the specific semantics here. I also need to consider what underlying hardware it is emulating, as that will effect the expected interactions. Are we talking about simulating register accesses, interrupt generation, or something more complex? The goal is to get a solid grasp of how the simulator exposes its functionality and how control is provided. I'll be digging deep to understand how the simulation translates these Generic Netlink requests into emulated hardware behavior.
|
| 49/2 |
2026/08/27 03:05 |
tool |
grepper |
0m
Error:
Args: map[Expression:hwsim_genl_ops PathPrefix:drivers/net/wireless/virtual/mac80211_hwsim_main.c]
Results:
|
| 50/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 28589
output: 45
thoughts: 10
Thoughts: Okay, here's my attempt at summarizing that thought process, keeping in mind I'm speaking to a fellow expert and I'm treating the thought as my own:
**Checking `hwsim_ops`**
Alright, time to get down to brass tacks. "Let's check `hwsim_ops`." That's the core of it, isn't it? Something's nagging at me, or I'm on a hunch. It could be any number of things β maybe a recent bug report mentioned issues related to hardware simulation, perhaps I'm trying to optimize performance, or maybe I'm troubleshooting a specific error that points me in that direction. The beauty (and sometimes the frustration!) of this field is that a single keyword like "`hwsim_ops`" can unlock a whole chain of thought and analysis. I'm already mentally running through the different data structures, the function pointers, the potential race conditions, and all the delightful complexity that lies within that module. Let's see what we find!
|
| 51/2 |
2026/08/27 03:05 |
tool |
grepper |
0m
Args: map[Expression:hwsim_ops PathPrefix:drivers/net/wireless/virtual/mac80211_hwsim_main.c]
Results: map[Output:drivers/net/wireless/virtual/mac80211_hwsim_main.c=4274=static int mac80211_hwsim_set_radar_background(struct ieee80211_hw *hw,
--
drivers/net/wireless/virtual/mac80211_hwsim_main.c-4339-
drivers/net/wireless/virtual/mac80211_hwsim_main.c:4340:static const struct ieee80211_ops mac80211_hwsim_ops = {
drivers/net/wireless/virtual/mac80211_hwsim_main.c-4341- HWSIM_COMMON_OPS
--
drivers/net/wireless/virtual/mac80211_hwsim_main.c=5674=static int mac80211_hwsim_new_radio(struct genl_info *info,
--
drivers/net/wireless/virtual/mac80211_hwsim_main.c-5681- enum nl80211_band band;
drivers/net/wireless/virtual/mac80211_hwsim_main.c:5682: const struct ieee80211_ops *ops = &mac80211_hwsim_ops;
drivers/net/wireless/virtual/mac80211_hwsim_main.c-5683- struct net *net;
--
drivers/net/wireless/virtual/mac80211_hwsim_main.c=7053=static int hwsim_dump_radio_nl(struct sk_buff *skb,
--
drivers/net/wireless/virtual/mac80211_hwsim_main.c-7104-/* Generic Netlink operations array */
drivers/net/wireless/virtual/mac80211_hwsim_main.c:7105:static const struct genl_small_ops hwsim_ops[] = {
drivers/net/wireless/virtual/mac80211_hwsim_main.c-7106- {
--
drivers/net/wireless/virtual/mac80211_hwsim_main.c=7147=static struct genl_family hwsim_genl_family __ro_after_init = {
--
drivers/net/wireless/virtual/mac80211_hwsim_main.c-7153- .module = THIS_MODULE,
drivers/net/wireless/virtual/mac80211_hwsim_main.c:7154: .small_ops = hwsim_ops,
drivers/net/wireless/virtual/mac80211_hwsim_main.c:7155: .n_small_ops = ARRAY_SIZE(hwsim_ops),
drivers/net/wireless/virtual/mac80211_hwsim_main.c-7156- .resv_start_op = HWSIM_CMD_REPORT_PMSR + 1, // match with __HWSIM_CMD_MAX
]
|
| 52/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 29632
output: 49
thoughts: 12
Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience:
**Diving into the `hwsim_ops` Definition**
Alright, let's get down to brass tacks. I need to refresh my memory on the specifics of the `hwsim_ops` structure. It's been a while since I last deeply reviewed its definition, and given the nature of the task I'm about to embark on, a solid understanding is crucial. Specifically, I need to make sure I recall the intricacies of the driver's interface. No point in wasting time if it is not a part of the code I need to change. Grabbing the correct part of the code at the start will save me some time. So, let me quickly pull up the relevant header file or documentation and make sure I remember exactly what's in there. I'm especially interested in remembering the function pointers, and how they relate to the underlying hardware simulation.
|
| 53/2 |
2026/08/27 03:05 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/net/wireless/virtual/mac80211_hwsim_main.c Name:hwsim_ops]
Results: map[SourceCode:7104: /* Generic Netlink operations array */
7105: static const struct genl_small_ops hwsim_ops[] = {
7106: {
7107: .cmd = HWSIM_CMD_REGISTER,
7108: .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
7109: .doit = hwsim_register_received_nl,
7110: .flags = GENL_UNS_ADMIN_PERM,
7111: },
7112: {
7113: .cmd = HWSIM_CMD_FRAME,
7114: .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
7115: .doit = hwsim_cloned_frame_received_nl,
7116: },
7117: {
7118: .cmd = HWSIM_CMD_TX_INFO_FRAME,
7119: .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
7120: .doit = hwsim_tx_info_frame_received_nl,
7121: },
7122: {
7123: .cmd = HWSIM_CMD_NEW_RADIO,
7124: .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
7125: .doit = hwsim_new_radio_nl,
7126: .flags = GENL_UNS_ADMIN_PERM,
7127: },
7128: {
7129: .cmd = HWSIM_CMD_DEL_RADIO,
7130: .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
7131: .doit = hwsim_del_radio_nl,
7132: .flags = GENL_UNS_ADMIN_PERM,
7133: },
7134: {
7135: .cmd = HWSIM_CMD_GET_RADIO,
7136: .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
7137: .doit = hwsim_get_radio_nl,
7138: .dumpit = hwsim_dump_radio_nl,
7139: },
7140: {
7141: .cmd = HWSIM_CMD_REPORT_PMSR,
7142: .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
7143: .doit = hwsim_pmsr_report_nl,
7144: },
7145: };
SourceFile:drivers/net/wireless/virtual/mac80211_hwsim_main.c]
|
| 54/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 30688
output: 58
thoughts: 109
Thoughts: **Analyzing the Potential Security Implications of `HWSIM_CMD_NEW_RADIO`**
Okay, so I see this `GENL_UNS_ADMIN_PERM` and immediately my brain flags it: that means we're dealing with `CAP_NET_ADMIN` within a user namespace. That's a critical detail. So, in theory, an unprivileged user can create a user namespace and then try to send this `HWSIM_CMD_NEW_RADIO` command. The next question is, what happens when that command is triggered? My first line of investigation will be to figure out if `hwsim_new_radio_nl` leads to a `request_firmware` call. I need to trace the code path, so I'll start with `hwsim_new_radio_nl` and go from there, specifically looking at the function `mac80211_hwsim_new_radio`. This seems like the key entry point. I'll need to scrutinize the function. This warrants immediate attention.
|
| 55/2 |
2026/08/27 03:05 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/net/wireless/virtual/mac80211_hwsim_main.c Name:mac80211_hwsim_new_radio]
Results: map[SourceCode:5674: static int mac80211_hwsim_new_radio(struct genl_info *info,
5675: struct hwsim_new_radio_params *param)
5676: {
5677: int err;
5678: u8 addr[ETH_ALEN];
5679: struct mac80211_hwsim_data *data;
5680: struct ieee80211_hw *hw;
5681: enum nl80211_band band;
5682: const struct ieee80211_ops *ops = &mac80211_hwsim_ops;
5683: struct net *net;
5684: int idx, i;
5685: int n_limits = 0;
5686: int n_bands = 0;
5687:
5688: if (WARN_ON(param->channels > 1 && !param->use_chanctx))
5689: return -EINVAL;
5690:
5691: spin_lock_bh(&hwsim_radio_lock);
5692: idx = hwsim_radio_idx++;
5693: spin_unlock_bh(&hwsim_radio_lock);
5694:
5695: if (param->mlo)
5696: ops = &mac80211_hwsim_mlo_ops;
5697: else if (param->use_chanctx)
5698: ops = &mac80211_hwsim_mchan_ops;
5699: hw = ieee80211_alloc_hw_nm(sizeof(*data), ops, param->hwname);
5700: if (!hw) {
5701: pr_debug("mac80211_hwsim: ieee80211_alloc_hw failed\n");
5702: err = -ENOMEM;
5703: goto failed;
5704: }
5705:
5706: /* ieee80211_alloc_hw_nm may have used a default name */
5707: param->hwname = wiphy_name(hw->wiphy);
5708:
5709: if (info)
5710: net = genl_info_net(info);
5711: else
5712: net = &init_net;
5713: wiphy_net_set(hw->wiphy, net);
5714:
5715: data = hw->priv;
5716: data->hw = hw;
5717:
5718: data->dev = device_create(&hwsim_class, NULL, 0, hw, "hwsim%d", idx);
5719: if (IS_ERR(data->dev)) {
5720: printk(KERN_DEBUG
5721: "mac80211_hwsim: device_create failed (%ld)\n",
5722: PTR_ERR(data->dev));
5723: err = -ENOMEM;
5724: goto failed_drvdata;
5725: }
5726: data->dev->driver = &mac80211_hwsim_driver.driver;
5727: err = device_bind_driver(data->dev);
5728: if (err != 0) {
5729: pr_debug("mac80211_hwsim: device_bind_driver failed (%d)\n",
5730: err);
5731: goto failed_bind;
5732: }
5733:
5734: skb_queue_head_init(&data->pending);
5735:
5736: SET_IEEE80211_DEV(hw, data->dev);
5737: if (!param->perm_addr) {
5738: eth_zero_addr(addr);
5739: addr[0] = 0x02;
5740: addr[3] = idx >> 8;
5741: addr[4] = idx;
5742: memcpy(data->addresses[0].addr, addr, ETH_ALEN);
5743: /* Why need here second address ? */
5744: memcpy(data->addresses[1].addr, addr, ETH_ALEN);
5745: data->addresses[1].addr[0] |= 0x40;
5746: memcpy(data->addresses[2].addr, addr, ETH_ALEN);
5747: data->addresses[2].addr[0] |= 0x50;
5748:
5749: hw->wiphy->n_addresses = 3;
5750: hw->wiphy->addresses = data->addresses;
5751: /* possible address clash is checked at hash table insertion */
5752: } else {
5753: memcpy(data->addresses[0].addr, param->perm_addr, ETH_ALEN);
5754: /* compatibility with automatically generated mac addr */
5755: memcpy(data->addresses[1].addr, param->perm_addr, ETH_ALEN);
5756: memcpy(data->addresses[2].addr, param->perm_addr, ETH_ALEN);
5757: hw->wiphy->n_addresses = 3;
5758: hw->wiphy->addresses = data->addresses;
5759: }
5760:
5761: data->channels = param->channels;
5762: data->use_chanctx = param->use_chanctx;
5763: data->idx = idx;
5764: data->destroy_on_close = param->destroy_on_close;
5765: if (info)
5766: data->portid = info->snd_portid;
5767:
5768: /* setup interface limits, only on interface types we support */
5769: if (param->iftypes & BIT(NL80211_IFTYPE_ADHOC)) {
5770: data->if_limits[n_limits].max = 1;
5771: data->if_limits[n_limits].types = BIT(NL80211_IFTYPE_ADHOC);
5772: n_limits++;
5773: }
5774:
5775: if (param->iftypes & HWSIM_DEFAULT_IF_LIMIT) {
5776: data->if_limits[n_limits].max = 2048;
5777: /*
5778: * For this case, we may only support a subset of
5779: * HWSIM_DEFAULT_IF_LIMIT, therefore we only want to add the
5780: * bits that both param->iftype & HWSIM_DEFAULT_IF_LIMIT have.
5781: */
5782: data->if_limits[n_limits].types =
5783: HWSIM_DEFAULT_IF_LIMIT & param->iftypes;
5784: n_limits++;
5785: }
5786:
5787: if (param->iftypes & BIT(NL80211_IFTYPE_P2P_DEVICE)) {
5788: data->if_limits[n_limits].max = 1;
5789: data->if_limits[n_limits].types =
5790: BIT(NL80211_IFTYPE_P2P_DEVICE);
5791: n_limits++;
5792: }
5793:
5794: if (param->iftypes & BIT(NL80211_IFTYPE_NAN)) {
5795: data->if_limits[n_limits].max = 1;
5796: data->if_limits[n_limits].types = BIT(NL80211_IFTYPE_NAN);
5797: n_limits++;
5798:
5799: hw->wiphy->nan_supported_bands = BIT(NL80211_BAND_2GHZ) |
5800: BIT(NL80211_BAND_5GHZ);
5801:
5802: hw->wiphy->nan_capa.flags = WIPHY_NAN_FLAGS_CONFIGURABLE_SYNC |
5803: WIPHY_NAN_FLAGS_USERSPACE_DE;
5804: hw->wiphy->nan_capa.op_mode = NAN_OP_MODE_PHY_MODE_MASK |
5805: NAN_OP_MODE_80P80MHZ |
5806: NAN_OP_MODE_160MHZ;
5807:
5808: hw->wiphy->nan_capa.n_antennas = 0x22;
5809: hw->wiphy->nan_capa.max_channel_switch_time = 0;
5810:
5811: wiphy_ext_feature_set(hw->wiphy,
5812: NL80211_EXT_FEATURE_SECURE_NAN);
5813:
5814: hrtimer_setup(&data->nan.slot_timer,
5815: mac80211_hwsim_nan_slot_timer,
5816: CLOCK_BOOTTIME, HRTIMER_MODE_ABS_SOFT);
5817: hrtimer_setup(&data->nan.resume_txqs_timer,
5818: mac80211_hwsim_nan_resume_txqs_timer,
5819: CLOCK_BOOTTIME, HRTIMER_MODE_ABS_SOFT);
5820: hrtimer_setup(&data->nan.discovery_beacon_timer,
5821: mac80211_hwsim_nan_discovery_beacon_timer,
5822: CLOCK_BOOTTIME, HRTIMER_MODE_ABS_SOFT);
5823:
5824: spin_lock_init(&data->nan.state_lock);
5825: }
5826:
5827: if (param->iftypes & BIT(NL80211_IFTYPE_NAN_DATA)) {
5828: data->if_limits[n_limits].max = 2;
5829: data->if_limits[n_limits].types = BIT(NL80211_IFTYPE_NAN_DATA);
5830: n_limits++;
5831:
5832: hw->wiphy->nan_capa.phy.ht = hwsim_nan_ht_cap;
5833: hw->wiphy->nan_capa.phy.vht = hwsim_nan_vht_cap;
5834: hw->wiphy->nan_capa.phy.he = hwsim_nan_he_cap;
5835:
5836: /*
5837: * NAN switches between bands/channels per its schedule,
5838: * so mac80211 rate control can't work here.
5839: */
5840: ieee80211_hw_set(hw, HAS_RATE_CONTROL);
5841: }
5842:
5843: data->if_combination.radar_detect_widths =
5844: BIT(NL80211_CHAN_WIDTH_5) |
5845: BIT(NL80211_CHAN_WIDTH_10) |
5846: BIT(NL80211_CHAN_WIDTH_20_NOHT) |
5847: BIT(NL80211_CHAN_WIDTH_20) |
5848: BIT(NL80211_CHAN_WIDTH_40) |
5849: BIT(NL80211_CHAN_WIDTH_80) |
5850: BIT(NL80211_CHAN_WIDTH_160);
5851:
5852: if (data->use_chanctx) {
5853: hw->wiphy->max_scan_ssids = 255;
5854: hw->wiphy->max_scan_ie_len = IEEE80211_MAX_DATA_LEN;
5855: hw->wiphy->max_remain_on_channel_duration = 1000;
5856: data->if_combination.num_different_channels = data->channels;
5857: } else {
5858: data->if_combination.num_different_channels = 1;
5859: }
5860:
5861: if (!n_limits) {
5862: err = -EINVAL;
5863: goto failed_hw;
5864: }
5865:
5866: data->if_combination.max_interfaces = 0;
5867: for (i = 0; i < n_limits; i++)
5868: data->if_combination.max_interfaces +=
5869: data->if_limits[i].max;
5870:
5871: data->if_combination.n_limits = n_limits;
5872: data->if_combination.limits = data->if_limits;
5873:
5874: /*
5875: * If we actually were asked to support combinations,
5876: * advertise them - if there's only a single thing like
5877: * only IBSS then don't advertise it as combinations.
5878: */
5879: if (data->if_combination.max_interfaces > 1) {
5880: hw->wiphy->iface_combinations = &data->if_combination;
5881: hw->wiphy->n_iface_combinations = 1;
5882: }
5883:
5884: if (param->ciphers) {
5885: memcpy(data->ciphers, param->ciphers,
5886: param->n_ciphers * sizeof(u32));
5887: hw->wiphy->cipher_suites = data->ciphers;
5888: hw->wiphy->n_cipher_suites = param->n_ciphers;
5889: }
5890:
5891: hw->wiphy->mbssid_max_interfaces = 8;
5892: hw->wiphy->ema_max_profile_periodicity = 3;
5893:
5894: spin_lock_init(&data->tsf_offset_lock);
5895:
5896: data->rx_rssi = DEFAULT_RX_RSSI;
5897:
5898: INIT_DELAYED_WORK(&data->roc_start, hw_roc_start);
5899: INIT_DELAYED_WORK(&data->roc_done, hw_roc_done);
5900: INIT_DELAYED_WORK(&data->hw_scan, hw_scan_work);
5901:
5902: hw->queues = 5;
5903: hw->offchannel_tx_hw_queue = 4;
5904:
5905: ieee80211_hw_set(hw, SUPPORT_FAST_XMIT);
5906: ieee80211_hw_set(hw, CHANCTX_STA_CSA);
5907: ieee80211_hw_set(hw, SUPPORTS_HT_CCK_RATES);
5908: ieee80211_hw_set(hw, QUEUE_CONTROL);
5909: ieee80211_hw_set(hw, WANT_MONITOR_VIF);
5910: ieee80211_hw_set(hw, AMPDU_AGGREGATION);
5911: ieee80211_hw_set(hw, MFP_CAPABLE);
5912: ieee80211_hw_set(hw, SIGNAL_DBM);
5913: ieee80211_hw_set(hw, SUPPORTS_PS);
5914: ieee80211_hw_set(hw, REPORTS_TX_ACK_STATUS);
5915: ieee80211_hw_set(hw, TDLS_WIDER_BW);
5916: ieee80211_hw_set(hw, SUPPORTS_MULTI_BSSID);
5917: ieee80211_hw_set(hw, STRICT);
5918: ieee80211_hw_set(hw, BUFF_MMPDU_TXQ);
5919: ieee80211_hw_set(hw, STA_MMPDU_TXQ);
5920:
5921: if (param->mlo) {
5922: hw->wiphy->flags |= WIPHY_FLAG_SUPPORTS_MLO;
5923: ieee80211_hw_set(hw, HAS_RATE_CONTROL);
5924: ieee80211_hw_set(hw, SUPPORTS_DYNAMIC_PS);
5925: ieee80211_hw_set(hw, CONNECTION_MONITOR);
5926: ieee80211_hw_set(hw, AP_LINK_PS);
5927:
5928: hw->wiphy->iftype_ext_capab = mac80211_hwsim_iftypes_ext_capa;
5929: hw->wiphy->num_iftype_ext_capab =
5930: ARRAY_SIZE(mac80211_hwsim_iftypes_ext_capa);
5931: } else {
5932: ieee80211_hw_set(hw, HOST_BROADCAST_PS_BUFFERING);
5933: ieee80211_hw_set(hw, PS_NULLFUNC_STACK);
5934: if (rctbl)
5935: ieee80211_hw_set(hw, SUPPORTS_RC_TABLE);
5936: }
5937:
5938: hw->wiphy->flags &= ~WIPHY_FLAG_PS_ON_BY_DEFAULT;
5939: hw->wiphy->flags |= WIPHY_FLAG_SUPPORTS_TDLS |
5940: WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL |
5941: WIPHY_FLAG_AP_UAPSD |
5942: WIPHY_FLAG_HAS_CHANNEL_SWITCH;
5943: hw->wiphy->flags |= WIPHY_FLAG_IBSS_RSN;
5944: hw->wiphy->features |= NL80211_FEATURE_ACTIVE_MONITOR |
5945: NL80211_FEATURE_AP_MODE_CHAN_WIDTH_CHANGE |
5946: NL80211_FEATURE_STATIC_SMPS |
5947: NL80211_FEATURE_DYNAMIC_SMPS |
5948: NL80211_FEATURE_SCAN_RANDOM_MAC_ADDR |
5949: NL80211_FEATURE_AP_SCAN;
5950: wiphy_ext_feature_set(hw->wiphy, NL80211_EXT_FEATURE_VHT_IBSS);
5951: wiphy_ext_feature_set(hw->wiphy, NL80211_EXT_FEATURE_BEACON_PROTECTION);
5952: wiphy_ext_feature_set(hw->wiphy,
5953: NL80211_EXT_FEATURE_MULTICAST_REGISTRATIONS);
5954: wiphy_ext_feature_set(hw->wiphy,
5955: NL80211_EXT_FEATURE_BEACON_RATE_LEGACY);
5956: wiphy_ext_feature_set(hw->wiphy, NL80211_EXT_FEATURE_ENABLE_FTM_RESPONDER);
5957:
5958: wiphy_ext_feature_set(hw->wiphy,
5959: NL80211_EXT_FEATURE_SCAN_MIN_PREQ_CONTENT);
5960: wiphy_ext_feature_set(hw->wiphy,
5961: NL80211_EXT_FEATURE_BSS_COLOR);
5962: wiphy_ext_feature_set(hw->wiphy,
5963: NL80211_EXT_FEATURE_SPP_AMSDU_SUPPORT);
5964: wiphy_ext_feature_set(hw->wiphy,
5965: NL80211_EXT_FEATURE_CAN_REPLACE_PTK0);
5966: wiphy_ext_feature_set(hw->wiphy,
5967: NL80211_EXT_FEATURE_EXT_KEY_ID);
5968: wiphy_ext_feature_set(hw->wiphy,
5969: NL80211_EXT_FEATURE_ASSOC_FRAME_ENCRYPTION);
5970:
5971: hw->wiphy->interface_modes = param->iftypes;
5972:
5973: /* ask mac80211 to reserve space for magic */
5974: hw->vif_data_size = sizeof(struct hwsim_vif_priv);
5975: hw->sta_data_size = sizeof(struct hwsim_sta_priv);
5976: hw->chanctx_data_size = sizeof(struct hwsim_chanctx_priv);
5977: hw->txq_data_size = 0;
5978:
5979: memcpy(data->channels_2ghz, hwsim_channels_2ghz,
5980: sizeof(hwsim_channels_2ghz));
5981: memcpy(data->channels_5ghz, hwsim_channels_5ghz,
5982: sizeof(hwsim_channels_5ghz));
5983: memcpy(data->channels_6ghz, hwsim_channels_6ghz,
5984: sizeof(hwsim_channels_6ghz));
5985: memcpy(data->channels_s1g, hwsim_channels_s1g,
5986: sizeof(hwsim_channels_s1g));
5987: memcpy(data->rates, hwsim_rates, sizeof(hwsim_rates));
5988:
5989: for (band = NL80211_BAND_2GHZ; band < NUM_NL80211_BANDS; band++) {
5990: struct ieee80211_supported_band *sband = &data->bands[band];
5991: struct wiphy_radio_freq_range *radio_range;
5992: const struct ieee80211_channel *c;
5993: struct wiphy_radio *radio;
5994:
5995: sband->band = band;
5996:
5997: switch (band) {
5998: case NL80211_BAND_2GHZ:
5999: sband->channels = data->channels_2ghz;
6000: sband->n_channels = ARRAY_SIZE(hwsim_channels_2ghz);
6001: sband->bitrates = data->rates;
6002: sband->n_bitrates = ARRAY_SIZE(hwsim_rates);
6003: break;
6004: case NL80211_BAND_5GHZ:
6005: sband->channels = data->channels_5ghz;
6006: sband->n_channels = ARRAY_SIZE(hwsim_channels_5ghz);
6007: sband->bitrates = data->rates + 4;
6008: sband->n_bitrates = ARRAY_SIZE(hwsim_rates) - 4;
6009:
6010: sband->vht_cap.vht_supported = true;
6011: sband->vht_cap.cap =
6012: IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_11454 |
6013: IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ |
6014: IEEE80211_VHT_CAP_RXLDPC |
6015: IEEE80211_VHT_CAP_SHORT_GI_80 |
6016: IEEE80211_VHT_CAP_SHORT_GI_160 |
6017: IEEE80211_VHT_CAP_TXSTBC |
6018: IEEE80211_VHT_CAP_RXSTBC_4 |
6019: IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK;
6020: sband->vht_cap.vht_mcs.rx_mcs_map =
6021: cpu_to_le16(HWSIM_VHT_MCS_MAP);
6022: sband->vht_cap.vht_mcs.tx_mcs_map =
6023: sband->vht_cap.vht_mcs.rx_mcs_map;
6024: break;
6025: case NL80211_BAND_6GHZ:
6026: sband->channels = data->channels_6ghz;
6027: sband->n_channels = ARRAY_SIZE(hwsim_channels_6ghz);
6028: sband->bitrates = data->rates + 4;
6029: sband->n_bitrates = ARRAY_SIZE(hwsim_rates) - 4;
6030: break;
6031: case NL80211_BAND_S1GHZ:
6032: memcpy(&sband->s1g_cap, &hwsim_s1g_cap,
6033: sizeof(sband->s1g_cap));
6034: sband->channels = data->channels_s1g;
6035: sband->n_channels = ARRAY_SIZE(hwsim_channels_s1g);
6036: break;
6037: default:
6038: continue;
6039: }
6040:
6041: if (band != NL80211_BAND_6GHZ){
6042: sband->ht_cap.ht_supported = true;
6043: sband->ht_cap.cap = IEEE80211_HT_CAP_SUP_WIDTH_20_40 |
6044: IEEE80211_HT_CAP_GRN_FLD |
6045: IEEE80211_HT_CAP_SGI_20 |
6046: IEEE80211_HT_CAP_SGI_40 |
6047: IEEE80211_HT_CAP_DSSSCCK40 |
6048: IEEE80211_HT_CAP_TX_STBC |
6049: IEEE80211_HT_CAP_RX_STBC;
6050: sband->ht_cap.ampdu_factor = 0x3;
6051: sband->ht_cap.ampdu_density = 0x6;
6052: memset(&sband->ht_cap.mcs, 0,
6053: sizeof(sband->ht_cap.mcs));
6054: sband->ht_cap.mcs.rx_mask[0] = 0xff;
6055: sband->ht_cap.mcs.rx_mask[1] = 0xff;
6056: sband->ht_cap.mcs.tx_params = IEEE80211_HT_MCS_TX_DEFINED;
6057: }
6058:
6059: mac80211_hwsim_sband_capab(sband);
6060:
6061: hw->wiphy->bands[band] = sband;
6062:
6063: if (!param->multi_radio)
6064: continue;
6065:
6066: c = sband->channels;
6067: radio_range = &data->radio_range[n_bands];
6068: radio_range->start_freq = ieee80211_channel_to_khz(c) - 10000;
6069:
6070: c += sband->n_channels - 1;
6071: radio_range->end_freq = ieee80211_channel_to_khz(c) + 10000;
6072:
6073: radio = &data->radio[n_bands++];
6074: radio->freq_range = radio_range;
6075: radio->n_freq_range = 1;
6076: radio->iface_combinations = &data->if_combination_radio;
6077: radio->n_iface_combinations = 1;
6078: }
6079:
6080: if (param->multi_radio) {
6081: hw->wiphy->radio = data->radio;
6082: hw->wiphy->n_radio = n_bands;
6083:
6084: memcpy(&data->if_combination_radio, &data->if_combination,
6085: sizeof(data->if_combination));
6086: data->if_combination.num_different_channels *= n_bands;
6087: }
6088:
6089: if (data->use_chanctx)
6090: data->if_combination.radar_detect_widths = 0;
6091:
6092: /* By default all radios belong to the first group */
6093: data->group = 1;
6094: mutex_init(&data->mutex);
6095:
6096: data->netgroup = hwsim_net_get_netgroup(net);
6097: data->wmediumd = hwsim_net_get_wmediumd(net);
6098:
6099: /* Enable frame retransmissions for lossy channels */
6100: hw->max_rates = 4;
6101: hw->max_rate_tries = 11;
6102:
6103: hw->wiphy->vendor_commands = mac80211_hwsim_vendor_commands;
6104: hw->wiphy->n_vendor_commands =
6105: ARRAY_SIZE(mac80211_hwsim_vendor_commands);
6106: hw->wiphy->vendor_events = mac80211_hwsim_vendor_events;
6107: hw->wiphy->n_vendor_events = ARRAY_SIZE(mac80211_hwsim_vendor_events);
6108:
6109: if (param->reg_strict)
6110: hw->wiphy->regulatory_flags |= REGULATORY_STRICT_REG;
6111: if (param->regd) {
6112: data->regd = param->regd;
6113: hw->wiphy->regulatory_flags |= REGULATORY_CUSTOM_REG;
6114: wiphy_apply_custom_regulatory(hw->wiphy, param->regd);
6115: /* give the regulatory workqueue a chance to run */
6116: schedule_timeout_interruptible(1);
6117: }
6118:
6119: wiphy_ext_feature_set(hw->wiphy,
6120: NL80211_EXT_FEATURE_DFS_CONCURRENT);
6121: if (param->background_radar)
6122: wiphy_ext_feature_set(hw->wiphy,
6123: NL80211_EXT_FEATURE_RADAR_BACKGROUND);
6124:
6125: if (param->no_vif)
6126: ieee80211_hw_set(hw, NO_AUTO_VIF);
6127:
6128: wiphy_ext_feature_set(hw->wiphy, NL80211_EXT_FEATURE_CQM_RSSI_LIST);
6129: wiphy_ext_feature_set(hw->wiphy, NL80211_EXT_FEATURE_PUNCT);
6130: wiphy_ext_feature_set(hw->wiphy, NL80211_EXT_FEATURE_PROBE_AP);
6131:
6132: for (i = 0; i < ARRAY_SIZE(data->link_data); i++) {
6133: hrtimer_setup(&data->link_data[i].beacon_timer, mac80211_hwsim_beacon,
6134: CLOCK_MONOTONIC, HRTIMER_MODE_ABS_SOFT);
6135: data->link_data[i].link_id = i;
6136: }
6137:
6138: err = ieee80211_register_hw(hw);
6139: if (err < 0) {
6140: pr_debug("mac80211_hwsim: ieee80211_register_hw failed (%d)\n",
6141: err);
6142: goto failed_hw;
6143: }
6144:
6145: wiphy_dbg(hw->wiphy, "hwaddr %pM registered\n", hw->wiphy->perm_addr);
6146:
6147: if (param->reg_alpha2) {
6148: data->alpha2[0] = param->reg_alpha2[0];
6149: data->alpha2[1] = param->reg_alpha2[1];
6150: regulatory_hint(hw->wiphy, param->reg_alpha2);
6151: }
6152:
6153: data->debugfs = debugfs_create_dir("hwsim", hw->wiphy->debugfsdir);
6154: debugfs_create_file("ps", 0666, data->debugfs, data, &hwsim_fops_ps);
6155: debugfs_create_file("group", 0666, data->debugfs, data,
6156: &hwsim_fops_group);
6157: debugfs_create_file("rx_rssi", 0666, data->debugfs, data,
6158: &hwsim_fops_rx_rssi);
6159: if (!data->use_chanctx)
6160: debugfs_create_file("dfs_simulate_radar", 0222,
6161: data->debugfs,
6162: data, &hwsim_simulate_radar);
6163: if (param->background_radar)
6164: debugfs_create_file("dfs_background_cac", 0200,
6165: data->debugfs,
6166: data, &hwsim_background_cac_ops);
6167: debugfs_create_file("simulate_incumbent_signal_interference", 0200,
6168: data->debugfs,
6169: data, &hwsim_simulate_incumbent_signal_fops);
6170:
6171: if (param->pmsr_capa) {
6172: data->pmsr_capa = *param->pmsr_capa;
6173: hw->wiphy->pmsr_capa = &data->pmsr_capa;
6174: }
6175:
6176: spin_lock_bh(&hwsim_radio_lock);
6177: err = rhashtable_insert_fast(&hwsim_radios_rht, &data->rht,
6178: hwsim_rht_params);
6179: if (err < 0) {
6180: if (info) {
6181: GENL_SET_ERR_MSG(info, "perm addr already present");
6182: NL_SET_BAD_ATTR(info->extack,
6183: info->attrs[HWSIM_ATTR_PERM_ADDR]);
6184: }
6185: spin_unlock_bh(&hwsim_radio_lock);
6186: goto failed_final_insert;
6187: }
6188:
6189: list_add_tail(&data->list, &hwsim_radios);
6190: hwsim_radios_generation++;
6191: spin_unlock_bh(&hwsim_radio_lock);
6192:
6193: hwsim_mcast_new_radio(idx, info, param);
6194:
6195: return idx;
6196:
6197: failed_final_insert:
6198: debugfs_remove_recursive(data->debugfs);
6199: ieee80211_unregister_hw(data->hw);
6200: failed_hw:
6201: device_release_driver(data->dev);
6202: failed_bind:
6203: device_unregister(data->dev);
6204: failed_drvdata:
6205: ieee80211_free_hw(hw);
6206: failed:
6207: return err;
6208: }
SourceFile:drivers/net/wireless/virtual/mac80211_hwsim_main.c]
|
| 56/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 41332
output: 34
thoughts: 75
Thoughts: **Analyzing the Hardware Registration Process**
Okay, so I'm looking at this code and it's calling `ieee80211_register_hw`. My first thought is: does this registration function initiate a firmware request? Generally, that's not the typical behavior, so I need to dig deeper. Wait a minute... I see a call to `regulatory_hint(hw->wiphy, param->reg_alpha2)`. Aha! Now that's interesting. The `regulatory_hint` function could be the key here. It's a prime suspect for indirectly triggering some sort of firmware loading or regulatory domain setup. Time to dissect `regulatory_hint` and see what's really happening under the hood. I suspect that's where the control might lie, if it exists.
|
| 57/2 |
2026/08/27 03:05 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/wireless/reg.c Name:regulatory_hint]
Results: map[SourceCode:3318: /* Driver hints */
3319: int regulatory_hint(struct wiphy *wiphy, const char *alpha2)
3320: {
3321: struct regulatory_request *request;
3322:
3323: if (WARN_ON(!alpha2 || !wiphy))
3324: return -EINVAL;
3325:
3326: wiphy->regulatory_flags &= ~REGULATORY_CUSTOM_REG;
3327:
3328: request = kzalloc_obj(struct regulatory_request);
3329: if (!request)
3330: return -ENOMEM;
3331:
3332: request->wiphy_idx = get_wiphy_idx(wiphy);
3333:
3334: request->alpha2[0] = alpha2[0];
3335: request->alpha2[1] = alpha2[1];
3336: request->initiator = NL80211_REGDOM_SET_BY_DRIVER;
3337:
3338: /* Allow calling CRDA again */
3339: reset_crda_timeouts();
3340:
3341: queue_regulatory_request(request);
3342:
3343: return 0;
3344: }
SourceFile:net/wireless/reg.c]
|
| 58/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 42005
output: 36
thoughts: 24
Thoughts: Okay, here's my interpretation of that thought process, tailored for an expert audience, and written in the first person:
**Analyzing the Work Item Queue**
Alright, so the system is using `queue_regulatory_request` to, effectively, schedule tasks. My initial thought is to take a look at *that* function, specifically. I need to understand exactly how `queue_regulatory_request` is handling the intake, processing, and prioritization of these regulatory requests. What are the internal mechanics? Is it using a standard queue data structure, or something more sophisticated like a priority queue with custom ordering based on request type or deadline? Are there any obvious bottlenecks or potential concurrency issues I should be aware of within that function? Understanding this is key to assessing overall system performance and identifying areas for optimization or potential failure points. My next step will be to dive into the code for `queue_regulatory_request` directly.
|
| 59/2 |
2026/08/27 03:05 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/wireless/reg.c Name:queue_regulatory_request]
Results: map[SourceCode:3212: static void queue_regulatory_request(struct regulatory_request *request)
3213: {
3214: request->alpha2[0] = toupper(request->alpha2[0]);
3215: request->alpha2[1] = toupper(request->alpha2[1]);
3216:
3217: spin_lock(®_requests_lock);
3218: list_add_tail(&request->list, ®_requests_list);
3219: spin_unlock(®_requests_lock);
3220:
3221: schedule_work(®_work);
3222: }
SourceFile:net/wireless/reg.c]
|
| 60/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 42459
output: 38
thoughts: 29
Thoughts: Here's my summary, as if I were thinking these thoughts:
**Analyzing the Pending Hint Processing**
Okay, so `reg_work` is calling `reg_process_pending_hints`. That's the entry point I need to focus on. I need to understand how the system is handling and processing these hints, as that's clearly where `reg_work` is delegating this responsibility. Let's dive right into `reg_process_pending_hints` and see what's happening under the hood. I expect to find some critical path in here, probably some lock contention or something related to data integrity. Time to start digging!
|
| 61/2 |
2026/08/27 03:05 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/wireless/reg.c Name:reg_process_pending_hints]
Results: map[SourceCode:3082: /*
3083: * Processes regulatory hints, this is all the NL80211_REGDOM_SET_BY_*
3084: * Regulatory hints come on a first come first serve basis and we
3085: * must process each one atomically.
3086: */
3087: static void reg_process_pending_hints(void)
3088: {
3089: struct regulatory_request *reg_request, *lr;
3090:
3091: lr = get_last_request();
3092:
3093: /* When last_request->processed becomes true this will be rescheduled */
3094: if (lr && !lr->processed) {
3095: pr_debug("Pending regulatory request, waiting for it to be processed...\n");
3096: return;
3097: }
3098:
3099: spin_lock(®_requests_lock);
3100:
3101: if (list_empty(®_requests_list)) {
3102: spin_unlock(®_requests_lock);
3103: return;
3104: }
3105:
3106: reg_request = list_first_entry(®_requests_list,
3107: struct regulatory_request,
3108: list);
3109: list_del_init(®_request->list);
3110:
3111: spin_unlock(®_requests_lock);
3112:
3113: notify_self_managed_wiphys(reg_request);
3114:
3115: reg_process_hint(reg_request);
3116:
3117: lr = get_last_request();
3118:
3119: spin_lock(®_requests_lock);
3120: if (!list_empty(®_requests_list) && lr && lr->processed)
3121: schedule_work(®_work);
3122: spin_unlock(®_requests_lock);
3123: }
SourceFile:net/wireless/reg.c]
|
| 62/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 43272
output: 38
thoughts: 31
Thoughts: Here's my thinking process:
**Diving into the Hint Processing Core**
Okay, so `reg_process_hint` is calling `reg_process_hint_core`. That's a pretty standard pattern. It's likely `reg_process_hint` is the public-facing API, perhaps handling some initial setup or error checking, and then it offloads the actual heavy lifting to the `core` function. I need to understand what's happening at the fundamental level of hint processing, so my next logical step is to dig into the implementation of `reg_process_hint_core`. This is where the real interesting stuff should be. Let's see what's going on in there.
|
| 63/2 |
2026/08/27 03:05 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/wireless/reg.c Name:reg_process_hint_core]
Results: map[SourceCode:2668: /**
2669: * reg_process_hint_core - process core regulatory requests
2670: * @core_request: a pending core regulatory request
2671: *
2672: * The wireless subsystem can use this function to process
2673: * a regulatory request issued by the regulatory core.
2674: *
2675: * Returns: %REG_REQ_OK or %REG_REQ_IGNORE, indicating if the
2676: * hint was processed or ignored
2677: */
2678: static enum reg_request_treatment
2679: reg_process_hint_core(struct regulatory_request *core_request)
2680: {
2681: if (reg_query_database(core_request)) {
2682: core_request->intersect = false;
2683: core_request->processed = false;
2684: reg_update_last_request(core_request);
2685: return REG_REQ_OK;
2686: }
2687:
2688: return REG_REQ_IGNORE;
2689: }
SourceFile:net/wireless/reg.c]
|
| 64/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 43832
output: 37
thoughts: 48
Thoughts: Okay, let's see...
**Deconstructing the Firmware Retrieval Path**
Right, so `reg_query_database` is what's on my mind. I'm trying to figure out if that particular function might be the one that kicks off a call to `request_firmware`, which I'm trying to trace. It's a common pattern. But hold on, let me quickly review. I think `reg_query_database` actually goes through `reg_query_regdb` first. Okay, that's it. Time to dive into `reg_query_regdb` and see what it is actually doing.
|
| 65/2 |
2026/08/27 03:05 |
tool |
codesearch-definition-source |
0m
Error:
Args: map[ContextFile:net/wireless/reg.c Name:reg_query_regdb]
Results: map[SourceCode: SourceFile:]
|
| 66/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 44074
output: 36
thoughts: 11
Thoughts: Okay, here's my attempt at summarizing that thought process, keeping in mind I'm speaking to a fellow expert:
**Investigating `reg_query_database`**
Alright, time to dive in. My mind immediately goes to `reg_query_database`. It's the logical starting point for this investigation. Let's see what's what. We'll need to confirm what its doing. I'll need to go in and check its operation. Perhaps there's an issue with the parameters being passed, or maybe there's an unforeseen error in its return values. My thought process is to confirm that the code is working and what information it is looking at. I'll need to review the code.
|
| 67/2 |
2026/08/27 03:05 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/wireless/reg.c Name:reg_query_database]
Results: map[SourceCode:1111: static bool reg_query_database(struct regulatory_request *request)
1112: {
1113: if (query_regdb_file(request->alpha2) == 0)
1114: return true;
1115:
1116: if (call_crda(request->alpha2) == 0)
1117: return true;
1118:
1119: return false;
1120: }
SourceFile:net/wireless/reg.c]
|
| 68/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 44434
output: 37
thoughts: 17
Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience:
**Potential Firmware Dependency in `query_regdb_file`**
Okay, so I'm thinking about the flow here, specifically how `query_regdb_file` interacts with the firmware loading process. My initial assumption is that it's just a file lookup, but a little deeper thought reveals a potential complication. Could `query_regdb_file` potentially trigger a call to `request_firmware`? The regdb (regulatory database) often contains information crucial to firmware configuration, channel restrictions, and other driver aspects that might require a specific firmware to be loaded. It's not a given, but itβs a possible dependency that I need to investigate further. The question is, does the regdb file itself contain references to firmwares, or are they external dependencies? If it does, then the design of `query_regdb_file` needs to account for the possibility of a firmware request, error handling, and potential blocking behavior if the firmware isn't immediately available. Iβm going to need to look at the source code of both functions to understand the precise interaction and how any error conditions are managed. Otherwise, there might be a subtle but critical bug in certain situations.
|
| 69/2 |
2026/08/27 03:05 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/wireless/reg.c Name:query_regdb_file]
Results: map[SourceCode:1037: static int query_regdb_file(const char *alpha2)
1038: {
1039: int err;
1040:
1041: ASSERT_RTNL();
1042:
1043: if (regdb)
1044: return query_regdb(alpha2);
1045:
1046: alpha2 = kmemdup(alpha2, 2, GFP_KERNEL);
1047: if (!alpha2)
1048: return -ENOMEM;
1049:
1050: err = request_firmware_nowait(THIS_MODULE, true, "regulatory.db",
1051: ®_fdev->dev, GFP_KERNEL,
1052: (void *)alpha2, regdb_fw_cb);
1053: if (err)
1054: kfree(alpha2);
1055:
1056: return err;
1057: }
SourceFile:net/wireless/reg.c]
|
| 70/2 |
2026/08/27 03:05 |
llm |
expert |
0m
Model:
Tokens:
input: 45060
output: 39
thoughts: 3487
Thoughts: **Analysis of a Potential Kernel Deadlock**
Alright, let's break this down. My initial thought was triggered by the appearance of `request_firmware_nowait`, which usually implies asynchronous firmware loading. However, the Lockdep report reveals a synchronous `request_firmware` call, which immediately piqued my interest.
The Lockdep report, specifically the trace involving `reg_reload_regdb`, points towards a potential deadlock. `reg_reload_regdb` is called by `nl80211_reload_regdb`, which, in turn, requires `GENL_ADMIN_PERM`, and therefore, global `CAP_NET_ADMIN` privileges. This is key: Thread B necessitates root-level capabilities.
Now, let's consider Thread A. The report indicates it's a simple `splice` to a netlink socket, an operation accessible to unprivileged users. No immediate red flags there.
Next, Thread D. This thread is writing to configfs, which, by design, is a root-only operation. So, Thread D requires root as well.
Finally, Thread C is opening a configfs file. This operation itself may be done by unprivileged users depending on the file permissions, but configfs files are usually root-owned and are measured by IMA.
So, here's what it boils down to for this deadlock to occur:
1. **Thread B:** Calls `NL80211_CMD_RELOAD_REGDB`, which requires global `CAP_NET_ADMIN`.
2. **Thread D:** Writes to a USB gadget configfs file, which demands global root access.
3. **Thread C:** Opens a configfs file, triggering an IMA measurement.
4. **Thread A:** Splices to a netlink socket.
Given that Threads B and D require global root or `CAP_NET_ADMIN`, this bug is *not* accessible to unprivileged processes, nor from user namespaces. This is critical.
Is this a denial-of-service? Yes, a potential deadlock definitely falls under that. Is it exploitable for privilege escalation or memory corruption? No, this is just a lockdep warning, indicating a potential deadlock.
Let's summarize the key aspects:
* **Exploitable:** No.
* **Denial of Service:** Yes.
* **Unprivileged:** No.
* **User Namespace:** No.
* **VM Guest Trigger:** No.
* **VM Host Trigger (Confidential Computing):** No.
* **Network Trigger:** No.
* **Remote Trigger:** No.
* **Peripheral Trigger:** No.
* **Filesystem Trigger:** No.
A VM guest *could* trigger this if the guest has root, but thatβs not the typical definition of a "VM Guest Trigger". This is a general kernel issue, not specific to virtualized environments.
I then revisited other potential entry points for the relevant functions (such as `fsg_store_file` and `reg_reload_regdb`) to ensure there weren't any less-privileged paths. I confirmed that these critical functions are, indeed, protected by the root-level requirements.
Finally, I confirmed that `ima_iint_mutex_key` -> `buffer->mutex`, `buffer->mutex` -> `common->filesem`, and `common->filesem` -> `pipe->mutex`, and `pipe->mutex` -> `cb_lock` are valid dependencies in the context of the identified threads. This confirms the validity of the lock dependency cycle. The Lockdep warning is accurate: It's a real deadlock scenario.
|
| 71/2 |
2026/08/27 03:06 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/netlink/genetlink.c Name:genl_rcv]
Results: map[SourceCode:1215: static void genl_rcv(struct sk_buff *skb)
1216: {
1217: down_read(&cb_lock);
1218: netlink_rcv_skb(skb, &genl_rcv_msg);
1219: up_read(&cb_lock);
1220: }
SourceFile:net/netlink/genetlink.c]
|
| 72/2 |
2026/08/27 03:06 |
llm |
expert |
0m
Model:
Tokens:
input: 49498
output: 39
thoughts: 86
Thoughts: **Netlink Socket Splice Investigation**
Okay, so `genl_rcv` definitely grabs that `cb_lock`. That's the starting point. Now, what's got me thinking is the possibility of a `splice` operation triggering that lock acquisition. Hmm, `splice` to a *netlink* socket? I have to pause here because that feels odd. Can you even do that? `splice`, as I recall, requires the output file descriptor, the destination, to implement a `splice_write` method. So, the question becomes: does a netlink socket even *have* a `splice_write` method? That's what I need to dig into. Time to check the kernel code and verify if this is even a viable pathway.
|
| 73/2 |
2026/08/27 03:06 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/netlink/af_netlink.c Name:netlink_ops]
Results: map[SourceCode:2808: static const struct proto_ops netlink_ops = {
2809: .family = PF_NETLINK,
2810: .owner = THIS_MODULE,
2811: .release = netlink_release,
2812: .bind = netlink_bind,
2813: .connect = netlink_connect,
2814: .socketpair = sock_no_socketpair,
2815: .accept = sock_no_accept,
2816: .getname = netlink_getname,
2817: .poll = datagram_poll,
2818: .ioctl = netlink_ioctl,
2819: .listen = sock_no_listen,
2820: .shutdown = sock_no_shutdown,
2821: .setsockopt = netlink_setsockopt,
2822: .getsockopt_iter = netlink_getsockopt,
2823: .sendmsg = netlink_sendmsg,
2824: .recvmsg = netlink_recvmsg,
2825: .mmap = sock_no_mmap,
2826: };
SourceFile:net/netlink/af_netlink.c]
|
| 74/2 |
2026/08/27 03:06 |
llm |
expert |
0m
Model:
Tokens:
input: 50140
output: 34
thoughts: 45
Thoughts: **Investigating Netlink and Socket Operations**
Okay, wait a minute. I was pretty sure I saw `splice_write` somewhere in the netlink structure, but a quick check reveals that the `netlink_ops` structure *doesn't* actually have a direct `splice_write` function pointer. That's unexpected, but it doesn't necessarily mean it's impossible. Could `sock_splice_write` be used as a fallback mechanism somewhere down the line? It's a plausible design pattern in the kernel, so it's definitely worth checking. My next move is to go look at the `socket_file_ops` structure. That's the logical place to see if socket-specific operations are being leveraged when netlink doesn't provide a direct implementation, and to verify if `splice_write` is present and if it's being used within the socket framework.
|
| 75/2 |
2026/08/27 03:06 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:net/socket.c Name:socket_file_ops]
Results: map[SourceCode: 157: static const struct file_operations socket_file_ops = {
158: .owner = THIS_MODULE,
159: .read_iter = sock_read_iter,
160: .write_iter = sock_write_iter,
161: .poll = sock_poll,
162: .unlocked_ioctl = sock_ioctl,
163: #ifdef CONFIG_COMPAT
164: .compat_ioctl = compat_sock_ioctl,
165: #endif
166: .uring_cmd = io_uring_cmd_sock,
167: .mmap = sock_mmap,
168: .release = sock_close,
169: .fasync = sock_fasync,
170: .splice_write = splice_to_socket,
171: .splice_read = sock_splice_read,
172: .splice_eof = sock_splice_eof,
173: .show_fdinfo = sock_show_fdinfo,
174: };
SourceFile:net/socket.c]
|
| 76/2 |
2026/08/27 03:06 |
llm |
expert |
0m
Model:
Tokens:
input: 50736
output: 66
thoughts: 400
Thoughts: **My Analysis of the Potential Deadlock**
Okay, so `splice_to_socket` is indeed the standard `splice_write` implementation for all sockets. And that function ultimately leads to `sock_sendmsg`. That means, yes, we can absolutely use `splice` to a netlink socket β that dependency is valid and established.
Now, let's look at that crucial dependency chain: `cb_lock` -> `ima_iint_mutex_key`. Thread B's execution path goes like this: `genl_rcv` grabs the `cb_lock`. Then it goes through `netlink_rcv_skb`, `genl_family_rcv_msg`, `genl_family_rcv_msg_doit`, and finally lands on `reg_reload_regdb`. Within `reg_reload_regdb`, we have `request_firmware`, which calls `_request_firmware`. This leads to `fw_get_filesystem_firmware`, which then calls `kernel_read_file_from_path_initns`, which opens a file. That file opening triggers `security_file_post_open`, which in turn triggers `ima_file_check`, which triggers `process_measurement`. And finally, inside that, it acquires `ima_iint_mutex_key`. So, yep, that dependency chain is also completely valid.
Given these two valid dependency chains, we've got a circular dependency!
This deadlock, however, has several requirements:
* IMA needs to be enabled and configured to measure configfs files, specifically those under root.
* Someone needs to be writing to a USB gadget configfs (again, under root).
* The system needs to be sending `NL80211_CMD_RELOAD_REGDB` (requiring root).
* Finally, we need to be splicing data from a pipe to a netlink socket. (unprivileged)
Since three out of the four threads require root privileges, this isn't accessible to unprivileged users. It's a DoS (deadlock) but not a privilege escalation.
Okay, I'm ready to document these findings.
|
| 77/2 |
2026/08/27 03:06 |
tool |
set-results |
0m
Args: map[DenialOfService:true Exploitable:false FilesystemTrigger:false NetworkTrigger:false PeripheralTrigger:false RemoteTrigger:false Unprivileged:false UserNamespace:false VMGuestTrigger:false VMHostTrigger:false]
Results: map[DenialOfService:true Exploitable:false FilesystemTrigger:false NetworkTrigger:false PeripheralTrigger:false RemoteTrigger:false Unprivileged:false UserNamespace:false VMGuestTrigger:false VMHostTrigger:false]
|
| 78/2 |
2026/08/27 03:06 |
llm |
expert |
0m
Model:
Tokens:
input: 51733
output: 670
thoughts: 343
Thoughts: **Final Thoughts on the Lockdep Warning**
Okay, the results are in. Time to craft the definitive response. This lockdep warning is pointing to a nasty potential circular locking dependency β a classic deadlock scenario. Let's break down the chain. It's got four key players: `pipe->mutex`, `cb_lock`, `ima_iint_mutex_key`, `buffer->mutex`, and `common->filesem`.
The path to the deadlock unfolds like this: We've got a splice operation moving data from a pipe to a generic netlink socket (that's `pipe->mutex` to `cb_lock`). Then, triggering a `NL80211_CMD_RELOAD_REGDB` netlink message, which kicks off a firmware request and eventually an IMA measurement (moving from `cb_lock` to `ima_iint_mutex_key`). That IMA measurement, specifically of a configfs file, is where the third link comes in (`ima_iint_mutex_key` to `buffer->mutex`). Finally, the fourth operation, where writing to a USB gadget configfs file, which involves opening a FIFO and triggers the last lock (`buffer->mutex` to `common->filesem` and then back to `pipe->mutex`).
Now, here's the kicker: the first step in this chain can be done by an unprivileged user, but the other three demand root privileges. Specifically, that `NL80211_CMD_RELOAD_REGDB` netlink command needs `CAP_NET_ADMIN`, configuring IMA policy on configfs files needs root, and of course, writing to USB gadget configfs files requires root as well.
So, from an attack surface perspective, this isn't something a regular user can trigger, and it can't be exploited from within a user namespace. If a privileged user sets it off, it can result in a denial of service through the deadlock. This is not something that would allow for privilege escalation or memory corruption.
|
| 79/1 |
2026/08/27 03:06 |
action |
format-explanation |
0m
Results: map[Explanation:Based on the analysis of the provided lockdep report and the kernel source code,
here is the assessment of the bug:
**Bug Mechanism and Impact:**
The bug is a lockdep warning indicating a possible circular locking dependency,
which represents a potential deadlock scenario. The dependency chain involves
the following locks: `pipe->mutex` -> `cb_lock` -> `ima_iint_mutex_key` ->
`buffer->mutex` -> `common->filesem` -> `pipe->mutex`.
This cycle is formed by the combination of four distinct operations:
1. **`pipe->mutex` -> `cb_lock`**: Splicing data from a pipe to a generic
netlink socket. `do_splice` acquires the `pipe->mutex` and eventually calls
`genl_rcv`, which acquires the generic netlink `cb_lock`.
2. **`cb_lock` -> `ima_iint_mutex_key`**: Processing a
`NL80211_CMD_RELOAD_REGDB` netlink message. The netlink handler holds `cb_lock`
and calls `request_firmware`. Opening the firmware file triggers the Integrity
Measurement Architecture (IMA), which acquires `ima_iint_mutex_key`.
3. **`ima_iint_mutex_key` -> `buffer->mutex`**: IMA measuring a `configfs` file.
IMA holds `ima_iint_mutex_key` and reads the file, acquiring the `configfs`
buffer mutex (`buffer->mutex`).
4. **`buffer->mutex` -> `common->filesem` -> `pipe->mutex`**: Writing to a USB
mass storage gadget `configfs` attribute (`file`). The `configfs` write handler
holds `buffer->mutex`, calls `fsg_store_file` (which acquires
`common->filesem`), and opens the backing file. If the backing file is a named
pipe (FIFO), `fifo_open` is called, which acquires `pipe->mutex`.
If these operations occur concurrently, they can deadlock the involved
subsystems (pipes, netlink, IMA, and USB gadgets), resulting in a **Denial of
Service (DoS)**. Deadlocks do not cause memory corruption and are **not
exploitable** for privilege escalation.
**Trigger Requirements:**
While splicing to a netlink socket can be done by an unprivileged user, the
other operations strictly require elevated privileges:
- Triggering `NL80211_CMD_RELOAD_REGDB` requires global `CAP_NET_ADMIN` (checked
via `netlink_capable(skb, CAP_NET_ADMIN)` against the initial user namespace).
- Writing to the USB gadget `configfs` or `sysfs` attributes requires root
privileges, as these files are owned by root and are not mountable/writable
within unprivileged user namespaces.
- IMA policy configuration (to measure `configfs` files) is also restricted to
root.
Therefore, this bug is **not accessible from unprivileged processes** and **not
accessible from user namespaces**. It requires a highly privileged user
(root/CAP_NET_ADMIN in the init namespace) to trigger the specific conditions
that lead to the deadlock.]
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