* 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.
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^ 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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