* KASAN: out-of-bounds Read in kvm_arch_hardware_setup
@ 2020-06-27 20:01 syzbot
2020-06-29 15:25 ` Paolo Bonzini
2020-06-30 6:12 ` Sean Christopherson
0 siblings, 2 replies; 5+ messages in thread
From: syzbot @ 2020-06-27 20:01 UTC (permalink / raw)
To: bp, hpa, jmattson, joro, kvm, linux-kernel, mingo, pbonzini,
sean.j.christopherson, syzkaller-bugs, tglx, vkuznets, wanpengli,
x86
Hello,
syzbot found the following crash on:
HEAD commit: 7ae77150 Merge tag 'powerpc-5.8-1' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1654e385100000
kernel config: https://syzkaller.appspot.com/x/.config?x=be4578b3f1083656
dashboard link: https://syzkaller.appspot.com/bug?extid=e0240f9c36530bda7130
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15f3abc9100000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=131b7bb5100000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e0240f9c36530bda7130@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: out-of-bounds in kvm_cpu_cap_get arch/x86/kvm/cpuid.h:292 [inline]
BUG: KASAN: out-of-bounds in kvm_cpu_cap_has arch/x86/kvm/cpuid.h:297 [inline]
BUG: KASAN: out-of-bounds in kvm_init_msr_list arch/x86/kvm/x86.c:5362 [inline]
BUG: KASAN: out-of-bounds in kvm_arch_hardware_setup+0xb05/0xf40 arch/x86/kvm/x86.c:9802
Read of size 4 at addr ffffffff896c3134 by task syz-executor614/6786
CPU: 1 PID: 6786 Comm: syz-executor614 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1e9/0x30e lib/dump_stack.c:118
print_address_description+0x66/0x5a0 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report+0x132/0x1d0 mm/kasan/report.c:530
kvm_cpu_cap_get arch/x86/kvm/cpuid.h:292 [inline]
kvm_cpu_cap_has arch/x86/kvm/cpuid.h:297 [inline]
kvm_init_msr_list arch/x86/kvm/x86.c:5362 [inline]
kvm_arch_hardware_setup+0xb05/0xf40 arch/x86/kvm/x86.c:9802
</IRQ>
The buggy address belongs to the variable:
kvm_cpu_caps+0x24/0x50
Memory state around the buggy address:
ffffffff896c3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffff896c3080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffffff896c3100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
ffffffff896c3180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffff896c3200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: KASAN: out-of-bounds Read in kvm_arch_hardware_setup 2020-06-27 20:01 KASAN: out-of-bounds Read in kvm_arch_hardware_setup syzbot @ 2020-06-29 15:25 ` Paolo Bonzini 2020-06-29 15:29 ` Andrey Konovalov 2020-06-30 6:12 ` Sean Christopherson 1 sibling, 1 reply; 5+ messages in thread From: Paolo Bonzini @ 2020-06-29 15:25 UTC (permalink / raw) To: syzbot, bp, hpa, jmattson, joro, kvm, linux-kernel, mingo, sean.j.christopherson, syzkaller-bugs, tglx, vkuznets, wanpengli, x86 The reproducer has nothing to do with KVM: # https://syzkaller.appspot.com/bug?id=c356395d480ca736b00443ad89cd76fd7d209013 # See https://goo.gl/kgGztJ for information about syzkaller reproducers. #{"repeat":true,"procs":1,"sandbox":"","fault_call":-1,"close_fds":false,"segv":true} r0 = openat$fb0(0xffffffffffffff9c, &(0x7f0000000180)='/dev/fb0\x00', 0x0, 0x0) ioctl$FBIOPUT_VSCREENINFO(r0, 0x4601, &(0x7f0000000000)={0x0, 0x80, 0xc80, 0x0, 0x2, 0x1, 0x4, 0x0, {0x0, 0x0, 0x1}, {0x0, 0x0, 0xfffffffc}, {}, {}, 0x0, 0x40}) but the stack trace does. On the other hand, the address seems okay: kvm_cpu_caps+0x24/0x50 and there are tons of other kvm_cpu_cap_get calls that aren't causing KASAN to complain. The variable is initialized from kvm_arch_hardware_setup hardware_setup (in arch/x86/kvm/vmx/vmx.c) vmx_set_cpu_caps kvm_set_cpu_caps with a simple memcpy that writes the entire array. Does anyone understand what is going on here? Paolo On 27/06/20 22:01, syzbot wrote: > BUG: KASAN: out-of-bounds in kvm_cpu_cap_get arch/x86/kvm/cpuid.h:292 [inline] > BUG: KASAN: out-of-bounds in kvm_cpu_cap_has arch/x86/kvm/cpuid.h:297 [inline] > BUG: KASAN: out-of-bounds in kvm_init_msr_list arch/x86/kvm/x86.c:5362 [inline] > BUG: KASAN: out-of-bounds in kvm_arch_hardware_setup+0xb05/0xf40 arch/x86/kvm/x86.c:9802 > Read of size 4 at addr ffffffff896c3134 by task syz-executor614/6786 > > CPU: 1 PID: 6786 Comm: syz-executor614 Not tainted 5.7.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > <IRQ> > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1e9/0x30e lib/dump_stack.c:118 > print_address_description+0x66/0x5a0 mm/kasan/report.c:383 > __kasan_report mm/kasan/report.c:513 [inline] > kasan_report+0x132/0x1d0 mm/kasan/report.c:530 > kvm_cpu_cap_get arch/x86/kvm/cpuid.h:292 [inline] > kvm_cpu_cap_has arch/x86/kvm/cpuid.h:297 [inline] > kvm_init_msr_list arch/x86/kvm/x86.c:5362 [inline] > kvm_arch_hardware_setup+0xb05/0xf40 arch/x86/kvm/x86.c:9802 > </IRQ> > > The buggy address belongs to the variable: > kvm_cpu_caps+0x24/0x50 > > Memory state around the buggy address: > ffffffff896c3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffffffff896c3080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >> ffffffff896c3100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ^ > ffffffff896c3180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffffffff896c3200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ================================================================== ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: KASAN: out-of-bounds Read in kvm_arch_hardware_setup 2020-06-29 15:25 ` Paolo Bonzini @ 2020-06-29 15:29 ` Andrey Konovalov 2020-06-29 15:35 ` Sean Christopherson 0 siblings, 1 reply; 5+ messages in thread From: Andrey Konovalov @ 2020-06-29 15:29 UTC (permalink / raw) To: Paolo Bonzini Cc: syzbot, Borislav Petkov, H. Peter Anvin, Jim Mattson, joro, KVM list, LKML, Ingo Molnar, sean.j.christopherson, syzkaller-bugs, Thomas Gleixner, vkuznets, wanpengli, the arch/x86 maintainers On Mon, Jun 29, 2020 at 5:25 PM Paolo Bonzini <pbonzini@redhat.com> wrote: > > The reproducer has nothing to do with KVM: > > # https://syzkaller.appspot.com/bug?id=c356395d480ca736b00443ad89cd76fd7d209013 > # See https://goo.gl/kgGztJ for information about syzkaller reproducers. > #{"repeat":true,"procs":1,"sandbox":"","fault_call":-1,"close_fds":false,"segv":true} > r0 = openat$fb0(0xffffffffffffff9c, &(0x7f0000000180)='/dev/fb0\x00', 0x0, 0x0) > ioctl$FBIOPUT_VSCREENINFO(r0, 0x4601, &(0x7f0000000000)={0x0, 0x80, 0xc80, 0x0, 0x2, 0x1, 0x4, 0x0, {0x0, 0x0, 0x1}, {0x0, 0x0, 0xfffffffc}, {}, {}, 0x0, 0x40}) > > but the stack trace does. On the other hand, the address seems okay: > > kvm_cpu_caps+0x24/0x50 > > and there are tons of other kvm_cpu_cap_get calls that aren't causing > KASAN to complain. The variable is initialized from > > kvm_arch_hardware_setup > hardware_setup (in arch/x86/kvm/vmx/vmx.c) > vmx_set_cpu_caps > kvm_set_cpu_caps > > with a simple memcpy that writes the entire array. Does anyone understand > what is going on here? Most likely a bug in /dev/fb handlers caused a memory corruption in kvm related memory. > > Paolo > > On 27/06/20 22:01, syzbot wrote: > > BUG: KASAN: out-of-bounds in kvm_cpu_cap_get arch/x86/kvm/cpuid.h:292 [inline] > > BUG: KASAN: out-of-bounds in kvm_cpu_cap_has arch/x86/kvm/cpuid.h:297 [inline] > > BUG: KASAN: out-of-bounds in kvm_init_msr_list arch/x86/kvm/x86.c:5362 [inline] > > BUG: KASAN: out-of-bounds in kvm_arch_hardware_setup+0xb05/0xf40 arch/x86/kvm/x86.c:9802 > > Read of size 4 at addr ffffffff896c3134 by task syz-executor614/6786 > > > > CPU: 1 PID: 6786 Comm: syz-executor614 Not tainted 5.7.0-syzkaller #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > Call Trace: > > <IRQ> > > __dump_stack lib/dump_stack.c:77 [inline] > > dump_stack+0x1e9/0x30e lib/dump_stack.c:118 > > print_address_description+0x66/0x5a0 mm/kasan/report.c:383 > > __kasan_report mm/kasan/report.c:513 [inline] > > kasan_report+0x132/0x1d0 mm/kasan/report.c:530 > > kvm_cpu_cap_get arch/x86/kvm/cpuid.h:292 [inline] > > kvm_cpu_cap_has arch/x86/kvm/cpuid.h:297 [inline] > > kvm_init_msr_list arch/x86/kvm/x86.c:5362 [inline] > > kvm_arch_hardware_setup+0xb05/0xf40 arch/x86/kvm/x86.c:9802 > > </IRQ> > > > > The buggy address belongs to the variable: > > kvm_cpu_caps+0x24/0x50 > > > > Memory state around the buggy address: > > ffffffff896c3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > ffffffff896c3080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> ffffffff896c3100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > ^ > > ffffffff896c3180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > ffffffff896c3200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > ================================================================== > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/04786ba2-4934-c544-63d1-4d5d36dc5822%40redhat.com. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: KASAN: out-of-bounds Read in kvm_arch_hardware_setup 2020-06-29 15:29 ` Andrey Konovalov @ 2020-06-29 15:35 ` Sean Christopherson 0 siblings, 0 replies; 5+ messages in thread From: Sean Christopherson @ 2020-06-29 15:35 UTC (permalink / raw) To: Andrey Konovalov Cc: Paolo Bonzini, syzbot, Borislav Petkov, H. Peter Anvin, Jim Mattson, joro, KVM list, LKML, Ingo Molnar, syzkaller-bugs, Thomas Gleixner, vkuznets, wanpengli, the arch/x86 maintainers On Mon, Jun 29, 2020 at 05:29:56PM +0200, Andrey Konovalov wrote: > On Mon, Jun 29, 2020 at 5:25 PM Paolo Bonzini <pbonzini@redhat.com> wrote: > > > > The reproducer has nothing to do with KVM: > > > > # https://syzkaller.appspot.com/bug?id=c356395d480ca736b00443ad89cd76fd7d209013 > > # See https://goo.gl/kgGztJ for information about syzkaller reproducers. > > #{"repeat":true,"procs":1,"sandbox":"","fault_call":-1,"close_fds":false,"segv":true} > > r0 = openat$fb0(0xffffffffffffff9c, &(0x7f0000000180)='/dev/fb0\x00', 0x0, 0x0) > > ioctl$FBIOPUT_VSCREENINFO(r0, 0x4601, &(0x7f0000000000)={0x0, 0x80, 0xc80, 0x0, 0x2, 0x1, 0x4, 0x0, {0x0, 0x0, 0x1}, {0x0, 0x0, 0xfffffffc}, {}, {}, 0x0, 0x40}) > > > > but the stack trace does. On the other hand, the address seems okay: > > > > kvm_cpu_caps+0x24/0x50 > > > > and there are tons of other kvm_cpu_cap_get calls that aren't causing > > KASAN to complain. The variable is initialized from > > > > kvm_arch_hardware_setup > > hardware_setup (in arch/x86/kvm/vmx/vmx.c) > > vmx_set_cpu_caps > > kvm_set_cpu_caps > > > > with a simple memcpy that writes the entire array. Does anyone understand > > what is going on here? > > Most likely a bug in /dev/fb handlers caused a memory corruption in > kvm related memory. That's my assumption as well. There's another syzbot failure[*] that points at KVM but whose reproducer is a single FBIOPUT_VSCREENINFO. In that case, the pointer from "&cpu_data(smp_processor_id())" is NULL, i.e. highly unlikely to be a KVM bug. [*] https://lkml.kernel.org/r/000000000000077a6505a8bf57b2@google.com > > Paolo > > > > On 27/06/20 22:01, syzbot wrote: > > > BUG: KASAN: out-of-bounds in kvm_cpu_cap_get arch/x86/kvm/cpuid.h:292 [inline] > > > BUG: KASAN: out-of-bounds in kvm_cpu_cap_has arch/x86/kvm/cpuid.h:297 [inline] > > > BUG: KASAN: out-of-bounds in kvm_init_msr_list arch/x86/kvm/x86.c:5362 [inline] > > > BUG: KASAN: out-of-bounds in kvm_arch_hardware_setup+0xb05/0xf40 arch/x86/kvm/x86.c:9802 > > > Read of size 4 at addr ffffffff896c3134 by task syz-executor614/6786 > > > > > > CPU: 1 PID: 6786 Comm: syz-executor614 Not tainted 5.7.0-syzkaller #0 > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > > Call Trace: > > > <IRQ> > > > __dump_stack lib/dump_stack.c:77 [inline] > > > dump_stack+0x1e9/0x30e lib/dump_stack.c:118 > > > print_address_description+0x66/0x5a0 mm/kasan/report.c:383 > > > __kasan_report mm/kasan/report.c:513 [inline] > > > kasan_report+0x132/0x1d0 mm/kasan/report.c:530 > > > kvm_cpu_cap_get arch/x86/kvm/cpuid.h:292 [inline] > > > kvm_cpu_cap_has arch/x86/kvm/cpuid.h:297 [inline] > > > kvm_init_msr_list arch/x86/kvm/x86.c:5362 [inline] > > > kvm_arch_hardware_setup+0xb05/0xf40 arch/x86/kvm/x86.c:9802 > > > </IRQ> > > > > > > The buggy address belongs to the variable: > > > kvm_cpu_caps+0x24/0x50 > > > > > > Memory state around the buggy address: > > > ffffffff896c3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > > ffffffff896c3080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > >> ffffffff896c3100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > > ^ > > > ffffffff896c3180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > > ffffffff896c3200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > > ================================================================== > > > > -- > > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/04786ba2-4934-c544-63d1-4d5d36dc5822%40redhat.com. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: KASAN: out-of-bounds Read in kvm_arch_hardware_setup 2020-06-27 20:01 KASAN: out-of-bounds Read in kvm_arch_hardware_setup syzbot 2020-06-29 15:25 ` Paolo Bonzini @ 2020-06-30 6:12 ` Sean Christopherson 1 sibling, 0 replies; 5+ messages in thread From: Sean Christopherson @ 2020-06-30 6:12 UTC (permalink / raw) To: syzbot Cc: bp, hpa, jmattson, joro, kvm, linux-kernel, mingo, pbonzini, syzkaller-bugs, tglx, vkuznets, wanpengli, x86 On Sat, Jun 27, 2020 at 01:01:13PM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 7ae77150 Merge tag 'powerpc-5.8-1' of git://git.kernel.org.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1654e385100000 > kernel config: https://syzkaller.appspot.com/x/.config?x=be4578b3f1083656 > dashboard link: https://syzkaller.appspot.com/bug?extid=e0240f9c36530bda7130 > compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15f3abc9100000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=131b7bb5100000 #syz dup: general protection fault in syscall_return_slowpath ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-06-30 6:12 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-06-27 20:01 KASAN: out-of-bounds Read in kvm_arch_hardware_setup syzbot 2020-06-29 15:25 ` Paolo Bonzini 2020-06-29 15:29 ` Andrey Konovalov 2020-06-29 15:35 ` Sean Christopherson 2020-06-30 6:12 ` Sean Christopherson
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