KASAN: slab-out-of-bounds Read in __xfrm_decode_session

Status: auto-obsoleted due to no activity on 2024/02/16 23:16
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+98547f1ef754f8a551a0@syzkaller.appspotmail.com
First crash: 1186d, last: 999d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2023/06/20 upstream (ToT) 99ec1ed7c2ed C [report] KASAN: slab-use-after-free Read in __xfrm_decode_session
2023/09/19 upstream (ToT) 2cf0f7156238 C Didn't crash
▶ ▼ Similar bugs (14)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 KASAN: slab-use-after-free Read in __xfrm_decode_session 19 19 377d 398d 0/2 auto-obsoleted due to no activity on 2025/10/01 05:45
linux-5.15 KASAN: slab-out-of-bounds Read in __xfrm_decode_session (3) origin:lts-only 19 syz, C error 11 50d 114d 0/3 upstream: reported C repro on 2026/04/11 21:07
linux-6.1 KASAN: use-after-free Read in __xfrm_decode_session (2) origin:lts-only 19 syz, C inconclusive 9 251d 460d 0/3 upstream: reported C repro on 2025/04/30 13:03
upstream KASAN: slab-out-of-bounds Read in __xfrm_decode_session (2) net 19 7 1702d 1939d 0/29 auto-closed as invalid on 2022/04/04 17:22
upstream KMSAN: kernel-infoleak in copyout (2) net 17 syz, C 6723 1153d 2321d 22/29 fixed on 2023/06/08 14:41
linux-6.6 KASAN: slab-out-of-bounds Read in __xfrm_decode_session origin:lts-only 17 syz, C error 1 134d 134d 0/2 upstream: reported C repro on 2026/03/22 10:21
linux-6.1 KASAN: slab-out-of-bounds Read in __xfrm_decode_session 17 1 585d 585d 0/3 auto-obsoleted due to no activity on 2025/04/05 09:29
linux-5.15 KASAN: slab-out-of-bounds Read in __xfrm_decode_session (2) 19 4 363d 491d 0/3 auto-obsoleted due to no activity on 2025/11/13 13:37
upstream KASAN: slab-out-of-bounds Read in __xfrm_decode_session net 17 20 2154d 2439d 0/29 auto-closed as invalid on 2021/01/07 14:52
linux-6.1 KASAN: use-after-free Read in __xfrm_decode_session 19 4 1045d 1176d 0/3 auto-obsoleted due to no activity on 2024/01/01 21:03
linux-6.6 KASAN: slab-use-after-free Read in __xfrm_decode_session (2) 19 1 267d 267d 0/2 auto-obsoleted due to no activity on 2026/02/17 15:57
upstream KMSAN: kernel-infoleak in _copy_to_iter (7) net 21 syz, C 138977 1256d 1608d 22/29 fixed on 2023/02/24 13:50
upstream KMSAN: uninit-value in __xfrm_decode_session (4) net 19 syz, C 8 1016d 1063d 0/29 closed as invalid on 2023/12/14 11:46
upstream KASAN: use-after-free Read in __xfrm_decode_session net 19 12 2159d 2517d 0/29 auto-closed as invalid on 2021/01/03 02:25

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in decode_session6 net/xfrm/xfrm_policy.c:3377 [inline]
BUG: KASAN: slab-out-of-bounds in __xfrm_decode_session+0x1520/0x1d20 net/xfrm/xfrm_policy.c:3484
Read of size 1 at addr ffff0000d9b4158d by task swapper/1/0

CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.117-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description+0x7c/0x3f0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x174/0x1e4 mm/kasan/report.c:451
 __asan_report_load1_noabort+0x44/0x50 mm/kasan/report_generic.c:306
 decode_session6 net/xfrm/xfrm_policy.c:3377 [inline]
 __xfrm_decode_session+0x1520/0x1d20 net/xfrm/xfrm_policy.c:3484
 xfrm_decode_session include/net/xfrm.h:1155 [inline]
 xfrmi_xmit+0x1a0/0x12f8 net/xfrm/xfrm_interface.c:356
 __netdev_start_xmit include/linux/netdevice.h:5022 [inline]
 netdev_start_xmit include/linux/netdevice.h:5036 [inline]
 xmit_one net/core/dev.c:3594 [inline]
 dev_hard_start_xmit+0x2bc/0x92c net/core/dev.c:3610
 sch_direct_xmit+0x2e0/0x484 net/sched/sch_generic.c:342
 qdisc_restart net/sched/sch_generic.c:407 [inline]
 __qdisc_run+0x878/0x1fc0 net/sched/sch_generic.c:415
 __dev_xmit_skb net/core/dev.c:3879 [inline]
 __dev_queue_xmit+0x1068/0x2a6c net/core/dev.c:4190
 dev_queue_xmit+0x24/0x34 net/core/dev.c:4258
 neigh_connected_output+0x334/0x378 net/core/neighbour.c:1553
 neigh_output include/net/neighbour.h:516 [inline]
 ip6_finish_output2+0x1344/0x1c48 net/ipv6/ip6_output.c:126
 __ip6_finish_output+0x518/0x67c net/ipv6/ip6_output.c:191
 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:201
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x270/0x594 net/ipv6/ip6_output.c:224
 dst_output include/net/dst.h:449 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 ndisc_send_skb+0xbf8/0x1788 net/ipv6/ndisc.c:508
 ndisc_send_rs+0x494/0x5fc net/ipv6/ndisc.c:702
 addrconf_rs_timer+0x308/0x5a8 net/ipv6/addrconf.c:3932
 call_timer_fn+0x19c/0x8f0 kernel/time/timer.c:1421
 expire_timers kernel/time/timer.c:1466 [inline]
 __run_timers+0x554/0x718 kernel/time/timer.c:1737
 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1750
 __do_softirq+0x344/0xe20 kernel/softirq.c:558
 do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline]
 invoke_softirq kernel/softirq.c:439 [inline]
 __irq_exit_rcu+0x28c/0x534 kernel/softirq.c:636
 irq_exit+0x14/0x88 kernel/softirq.c:660
 handle_domain_irq+0xf4/0x178 kernel/irq/irqdesc.c:710
 gic_handle_irq+0x78/0x1c8 drivers/irqchip/irq-gic-v3.c:757
 call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:899
 do_interrupt_handler+0x74/0x94 arch/arm64/kernel/entry-common.c:267
 el1_interrupt+0x30/0x58 arch/arm64/kernel/entry-common.c:442
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:458
 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:580
 arch_local_irq_enable+0xc/0x18 arch/arm64/include/asm/irqflags.h:35
 default_idle_call+0xcc/0x4a8 kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:194 [inline]
 do_idle+0x1d4/0x4dc kernel/sched/idle.c:306
 cpu_startup_entry+0x24/0x28 kernel/sched/idle.c:403
 secondary_start_kernel+0x240/0x298 arch/arm64/kernel/smp.c:265
 __secondary_switched+0x94/0x98 arch/arm64/kernel/head.S:661

Allocated by task 5581:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc+0xbc/0xfc mm/kasan/common.c:513
 __kasan_kmalloc+0x10/0x1c mm/kasan/common.c:522
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 __kmalloc+0x29c/0x4c8 mm/slub.c:4407
 kmalloc include/linux/slab.h:596 [inline]
 tomoyo_realpath_from_path+0xd0/0x508 security/tomoyo/realpath.c:254
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x1dc/0x3f4 security/tomoyo/file.c:771
 tomoyo_file_open+0x138/0x1b0 security/tomoyo/tomoyo.c:311
 security_file_open+0x6c/0xb0 security/security.c:1650
 do_dentry_open+0x29c/0xed8 fs/open.c:813
 vfs_open+0x7c/0x90 fs/open.c:956
 do_open fs/namei.c:3538 [inline]
 path_openat+0x1f28/0x26f0 fs/namei.c:3672
 do_filp_open+0x1a8/0x3b4 fs/namei.c:3699
 do_sys_openat2+0x128/0x3d8 fs/open.c:1211
 do_sys_open fs/open.c:1227 [inline]
 __do_sys_openat fs/open.c:1243 [inline]
 __se_sys_openat fs/open.c:1238 [inline]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1238
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Freed by task 5581:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x84 mm/kasan/common.c:46
 kasan_set_free_info+0x28/0x4c mm/kasan/generic.c:360
 ____kasan_slab_free+0x118/0x164 mm/kasan/common.c:366
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0x128/0x1ec mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kfree+0x178/0x410 mm/slub.c:4559
 tomoyo_realpath_from_path+0x4c0/0x508 security/tomoyo/realpath.c:291
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x1dc/0x3f4 security/tomoyo/file.c:771
 tomoyo_file_open+0x138/0x1b0 security/tomoyo/tomoyo.c:311
 security_file_open+0x6c/0xb0 security/security.c:1650
 do_dentry_open+0x29c/0xed8 fs/open.c:813
 vfs_open+0x7c/0x90 fs/open.c:956
 do_open fs/namei.c:3538 [inline]
 path_openat+0x1f28/0x26f0 fs/namei.c:3672
 do_filp_open+0x1a8/0x3b4 fs/namei.c:3699
 do_sys_openat2+0x128/0x3d8 fs/open.c:1211
 do_sys_open fs/open.c:1227 [inline]
 __do_sys_openat fs/open.c:1243 [inline]
 __se_sys_openat fs/open.c:1238 [inline]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1238
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

The buggy address belongs to the object at ffff0000d9b40000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1421 bytes to the right of
 4096-byte region [ffff0000d9b40000, ffff0000d9b41000)
The buggy address belongs to the page:
page:00000000ff538ed2 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x119b40
head:00000000ff538ed2 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 dead000000000100 dead000000000122 ffff0000c0002a80
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d9b41480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d9b41500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000d9b41580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff0000d9b41600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d9b41680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/06/20 17:19 linux-5.15.y 471e639e59d1 09ffe269 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: slab-out-of-bounds Read in __xfrm_decode_session
2023/05/05 22:25 linux-5.15.y 8a7f2a5c5aa1 de870ca5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in __xfrm_decode_session
2023/08/09 07:13 linux-5.15.y c275eaaaa342 8ad1a287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: slab-out-of-bounds Read in __xfrm_decode_session
2023/06/20 00:51 linux-5.15.y 471e639e59d1 09ffe269 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: slab-out-of-bounds Read in __xfrm_decode_session
2023/11/08 23:15 linux-5.15.y 80529b4968a8 b93f63e8 .config console log report info ci2-linux-5-15-kasan KASAN: use-after-free Read in __xfrm_decode_session
2023/07/25 10:15 linux-5.15.y 5c6a716301d9 3b91ad04 .config console log report info ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in __xfrm_decode_session
2023/05/27 01:34 linux-5.15.y 1fe619a7d252 cf184559 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in __xfrm_decode_session
* Struck through repros no longer work on HEAD.