KMSAN: kernel-infoleak in __kvm_write_guest_page

Status: closed as dup on 2018/12/06 09:34
Subsystems: kvm
[Documentation on labels]
Reported-by: syzbot+af22f34edec5361fb143@syzkaller.appspotmail.com
First crash: 2796d, last: 2706d
▶ ▼ Duplicate of
Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported
KMSAN: kernel-infoleak in kvm_vcpu_write_guest_page kvm 9 syz, C 25 2797d 2825d
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
KMSAN: kernel-infoleak in __kvm_write_guest_page 1 (2) 2018/12/06 09:33
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: kernel-infoleak in __kvm_write_guest_page (2) kvm 9 syz, C 6 2589d 2652d 0/29 closed as invalid on 2019/07/03 16:46

Sample crash report:
==================================================================
BUG: KMSAN: kernel-infoleak in __copy_to_user include/linux/uaccess.h:118 [inline]
BUG: KMSAN: kernel-infoleak in __kvm_write_guest_page+0x2d5/0x470 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1930
CPU: 1 PID: 12545 Comm: syz-executor.5 Not tainted 5.0.0-rc1+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x173/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:600
 kmsan_internal_check_memory+0x9f4/0xb10 mm/kmsan/kmsan.c:694
 kmsan_copy_to_user+0xab/0xc0 mm/kmsan/kmsan_hooks.c:601
 __copy_to_user include/linux/uaccess.h:118 [inline]
 __kvm_write_guest_page+0x2d5/0x470 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1930
 kvm_vcpu_write_guest_page arch/x86/kvm/../../../virt/kvm/kvm_main.c:1951 [inline]
 kvm_vcpu_write_guest+0x77a/0x920 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1985
 kvm_write_guest_virt_helper arch/x86/kvm/x86.c:5161 [inline]
 emulator_write_std+0x391/0x4d0 arch/x86/kvm/x86.c:5185
 segmented_write_std arch/x86/kvm/emulate.c:853 [inline]
 em_fxsave+0x7c2/0x840 arch/x86/kvm/emulate.c:4073
 x86_emulate_insn+0x2d11/0xb400 arch/x86/kvm/emulate.c:5601
 x86_emulate_instruction+0x1105/0x73b0 arch/x86/kvm/x86.c:6442
 kvm_mmu_page_fault+0xcef/0x2860 arch/x86/kvm/mmu.c:5389
 handle_ept_violation+0x565/0x5a0 arch/x86/kvm/vmx/vmx.c:5104
 vmx_handle_exit+0x17a9/0x6690 arch/x86/kvm/vmx/vmx.c:5849
 vcpu_enter_guest arch/x86/kvm/x86.c:7908 [inline]
 vcpu_run arch/x86/kvm/x86.c:7971 [inline]
 kvm_arch_vcpu_ioctl_run+0xa556/0x11300 arch/x86/kvm/x86.c:8171
 kvm_vcpu_ioctl+0xfe9/0x1d20 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2673
 do_vfs_ioctl+0xebd/0x2bf0 fs/ioctl.c:46
 ksys_ioctl fs/ioctl.c:713 [inline]
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl+0x1da/0x270 fs/ioctl.c:718
 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:718
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457f29
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f31915a2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457f29
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f31915a36d4
R13: 00000000004c0e61 R14: 00000000004d2cb8 R15: 00000000ffffffff

Local variable description: ----fx_state@em_fxsave
Variable was created at:
 em_fxsave+0xcb/0x840 arch/x86/kvm/emulate.c:4060
 x86_emulate_insn+0x2d11/0xb400 arch/x86/kvm/emulate.c:5601

Bytes 8-159 of 160 are uninitialized
Memory access of size 160 starts at ffff888093b0edc0
Data copied to user address 0000000020000000
==================================================================

Crashes (29):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/03/06 02:21 https://github.com/google/kmsan.git master 6c55aa96dcda 16559f86 .config console log report ci-upstream-kmsan-gce
2019/03/03 23:43 https://github.com/google/kmsan.git master fa1981bee40f 1c0e457a .config console log report ci-upstream-kmsan-gce
2019/03/03 23:28 https://github.com/google/kmsan.git master fa1981bee40f 1c0e457a .config console log report ci-upstream-kmsan-gce
2019/03/02 13:20 https://github.com/google/kmsan.git master fa1981bee40f 1c0e457a .config console log report ci-upstream-kmsan-gce
2019/02/28 22:43 https://github.com/google/kmsan.git master fa1981bee40f 09aeeba4 .config console log report ci-upstream-kmsan-gce
2019/02/28 21:57 https://github.com/google/kmsan.git master fa1981bee40f 09aeeba4 .config console log report ci-upstream-kmsan-gce
2019/02/27 09:38 https://github.com/google/kmsan.git master fa1981bee40f f2468c12 .config console log report ci-upstream-kmsan-gce
2019/02/20 19:36 https://github.com/google/kmsan.git master fa1981bee40f c95f0707 .config console log report ci-upstream-kmsan-gce
2019/02/18 10:42 https://github.com/google/kmsan.git master fa1981bee40f 59f36113 .config console log report ci-upstream-kmsan-gce
2019/02/18 10:40 https://github.com/google/kmsan.git master fa1981bee40f 59f36113 .config console log report ci-upstream-kmsan-gce
2019/02/18 10:35 https://github.com/google/kmsan.git master fa1981bee40f 59f36113 .config console log report ci-upstream-kmsan-gce
2019/02/18 01:04 https://github.com/google/kmsan.git master fa1981bee40f 3e98cc30 .config console log report ci-upstream-kmsan-gce
2019/02/17 09:56 https://github.com/google/kmsan.git master fa1981bee40f f42dee6d .config console log report ci-upstream-kmsan-gce
2019/02/15 16:56 https://github.com/google/kmsan.git master fa1981bee40f f6f233c0 .config console log report ci-upstream-kmsan-gce
2019/02/07 20:16 https://github.com/google/kmsan.git master fa1981bee40f aa4feb03 .config console log report ci-upstream-kmsan-gce
2019/01/17 02:37 https://github.com/google/kmsan.git master 02f2d5aea531 c2faf9b2 .config console log report ci-upstream-kmsan-gce
2019/01/09 05:05 https://github.com/google/kmsan.git master 48128c3ca084 010ed08b .config console log report ci-upstream-kmsan-gce
2019/01/02 18:21 https://github.com/google/kmsan.git master 8ba10281f9e5 f0491811 .config console log report ci-upstream-kmsan-gce
2018/12/28 08:21 https://github.com/google/kmsan.git master 79fc24ff6184 af317504 .config console log report ci-upstream-kmsan-gce
2018/12/27 20:31 https://github.com/google/kmsan.git master 79fc24ff6184 43cf01dd .config console log report ci-upstream-kmsan-gce
2018/12/25 17:46 https://github.com/google/kmsan.git master 79fc24ff6184 8a41a0ad .config console log report ci-upstream-kmsan-gce
2018/12/25 09:20 https://github.com/google/kmsan.git master 79fc24ff6184 8a41a0ad .config console log report ci-upstream-kmsan-gce
2018/12/24 07:03 https://github.com/google/kmsan.git master 75b3ad224f19 be79df56 .config console log report ci-upstream-kmsan-gce
2018/12/23 07:31 https://github.com/google/kmsan.git master 75b3ad224f19 e3bd7ab8 .config console log report ci-upstream-kmsan-gce
2018/12/22 19:59 https://github.com/google/kmsan.git master 75b3ad224f19 e3bd7ab8 .config console log report ci-upstream-kmsan-gce
2018/12/15 05:38 https://github.com/google/kmsan.git master 0a602458c72c 7624ddd6 .config console log report ci-upstream-kmsan-gce
2018/12/15 01:54 https://github.com/google/kmsan.git master 0a602458c72c 7624ddd6 .config console log report ci-upstream-kmsan-gce
2018/12/14 15:23 https://github.com/google/kmsan.git master 0a602458c72c 7624ddd6 .config console log report ci-upstream-kmsan-gce
2018/12/06 02:14 https://github.com/google/kmsan.git master 6f0597832d81 764b42c4 .config console log report ci-upstream-kmsan-gce
* Struck through repros no longer work on HEAD.