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KMSAN: kernel-infoleak in kvm_vcpu_ioctl

Status: closed as invalid on 2018/11/13 16:57
Subsystems: kvm
[Documentation on labels]
First crash: 1991d, last: 1974d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: kernel-infoleak in kvm_vcpu_ioctl (2) kvm 1 1945d 1945d 0/26 auto-closed as invalid on 2019/05/29 02:07

Sample crash report:
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/l1tf.html for details.
==================================================================
BUG: KMSAN: kernel-infoleak in _copy_to_user+0x19a/0x230 lib/usercopy.c:31
CPU: 1 PID: 7757 Comm: syz-executor5 Not tainted 4.19.0+ #77
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+0x32d/0x480 lib/dump_stack.c:113
 kmsan_report+0x1a2/0x2e0 mm/kmsan/kmsan.c:911
 kmsan_internal_check_memory+0x2a1/0x430 mm/kmsan/kmsan.c:965
 kmsan_copy_to_user+0x85/0xe0 mm/kmsan/kmsan_hooks.c:552
 _copy_to_user+0x19a/0x230 lib/usercopy.c:31
 copy_to_user include/linux/uaccess.h:183 [inline]
 kvm_vcpu_ioctl+0x1829/0x1f90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2634
 do_vfs_ioctl+0xf77/0x2d30 fs/ioctl.c:46
 ksys_ioctl fs/ioctl.c:702 [inline]
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl+0x1da/0x270 fs/ioctl.c:707
 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:707
 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x4573d7
Code: 48 83 c4 08 48 89 d8 5b 5d c3 66 0f 1f 84 00 00 00 00 00 48 89 e8 48 f7 d8 48 39 c3 0f 92 c0 eb 92 66 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 5d b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f896ecf4098 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000018 RCX: 00000000004573d7
RDX: 00007f896ecf46f0 RSI: 000000008138ae83 RDI: 0000000000000005
RBP: 0000000020017000 R08: 0000000000000001 R09: 0000000000000048
R10: ffffffffffffffff R11: 0000000000000246 R12: 00000000fec00000
R13: 00000000ffffffff R14: 00000000004d8200 R15: 00000000ffffffff

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:252 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:267 [inline]
 kmsan_internal_chain_origin+0x136/0x240 mm/kmsan/kmsan.c:569
 __msan_chain_origin+0x6d/0xd0 mm/kmsan/kmsan_instr.c:292
 __get_sregs+0x976/0x1050 arch/x86/kvm/x86.c:8059
 kvm_arch_vcpu_ioctl_get_sregs+0x71/0xb0 arch/x86/kvm/x86.c:8077
 kvm_vcpu_ioctl+0x41a/0x1f90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2630
 do_vfs_ioctl+0xf77/0x2d30 fs/ioctl.c:46
 ksys_ioctl fs/ioctl.c:702 [inline]
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl+0x1da/0x270 fs/ioctl.c:707
 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:707
 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:252 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:267 [inline]
 kmsan_internal_chain_origin+0x136/0x240 mm/kmsan/kmsan.c:569
 __msan_chain_origin+0x6d/0xd0 mm/kmsan/kmsan_instr.c:292
 kvm_inject_page_fault+0x30a/0x740 arch/x86/kvm/x86.c:412
 handle_vmwrite+0xdcf/0x3310 arch/x86/kvm/vmx.c:8791
 vmx_handle_exit+0x1e81/0xbac0 arch/x86/kvm/vmx.c:10128
 vcpu_enter_guest arch/x86/kvm/x86.c:7667 [inline]
 vcpu_run arch/x86/kvm/x86.c:7730 [inline]
 kvm_arch_vcpu_ioctl_run+0xac32/0x11d80 arch/x86/kvm/x86.c:7930
 kvm_vcpu_ioctl+0xfb1/0x1f90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2590
 do_vfs_ioctl+0xf77/0x2d30 fs/ioctl.c:46
 ksys_ioctl fs/ioctl.c:702 [inline]
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl+0x1da/0x270 fs/ioctl.c:707
 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:707
 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Local variable description: ----e@handle_vmwrite
Variable was created at:
 handle_vmwrite+0x1f6/0x3310 arch/x86/kvm/vmx.c:8759
 vmx_handle_exit+0x1e81/0xbac0 arch/x86/kvm/vmx.c:10128

Bytes 232-239 of 312 are uninitialized
Memory access of size 312 starts at ffff88018d27b000
==================================================================

Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/11/01 12:40 https://github.com/google/kmsan.git master 88b95ef4c780 1f38e9ae .config console log report syz ci-upstream-kmsan-gce
2018/10/29 15:58 https://github.com/google/kmsan.git master 6b52a0ee6122 7df9db2e .config console log report syz ci-upstream-kmsan-gce
2018/10/26 02:45 https://github.com/google/kmsan.git master 4bb25354f0b0 a8292de9 .config console log report syz ci-upstream-kmsan-gce
2018/10/23 08:11 https://github.com/google/kmsan.git master 4bb25354f0b0 ecb386fe .config console log report syz ci-upstream-kmsan-gce
2018/10/20 18:04 https://github.com/google/kmsan.git master 4bb25354f0b0 ecb386fe .config console log report syz ci-upstream-kmsan-gce
2018/11/01 11:33 https://github.com/google/kmsan.git master 88b95ef4c780 1f38e9ae .config console log report ci-upstream-kmsan-gce
2018/10/29 13:56 https://github.com/google/kmsan.git master 6b52a0ee6122 7df9db2e .config console log report ci-upstream-kmsan-gce
2018/10/29 13:24 https://github.com/google/kmsan.git master 6b52a0ee6122 7df9db2e .config console log report ci-upstream-kmsan-gce
2018/10/27 18:58 https://github.com/google/kmsan.git master 4bb25354f0b0 8efba39a .config console log report ci-upstream-kmsan-gce
2018/10/27 06:58 https://github.com/google/kmsan.git master 4bb25354f0b0 a8292de9 .config console log report ci-upstream-kmsan-gce
2018/10/26 01:57 https://github.com/google/kmsan.git master 4bb25354f0b0 a8292de9 .config console log report ci-upstream-kmsan-gce
2018/10/23 07:11 https://github.com/google/kmsan.git master 4bb25354f0b0 ecb386fe .config console log report ci-upstream-kmsan-gce
2018/10/20 17:09 https://github.com/google/kmsan.git master 4bb25354f0b0 ecb386fe .config console log report ci-upstream-kmsan-gce
2018/10/20 03:44 https://github.com/google/kmsan.git master 4bb25354f0b0 ecb386fe .config console log report ci-upstream-kmsan-gce
2018/10/20 03:40 https://github.com/google/kmsan.git master 4bb25354f0b0 ecb386fe .config console log report ci-upstream-kmsan-gce
2018/10/19 01:50 https://github.com/google/kmsan.git master 4bb25354f0b0 9aba67b5 .config console log report ci-upstream-kmsan-gce
2018/10/15 13:53 https://github.com/google/kmsan.git master 22ec98c3e38f caf12900 .config console log report ci-upstream-kmsan-gce
* Struck through repros no longer work on HEAD.