[syzbot] [mm?] KASAN: out-of-bounds Read in copy_from_kernel_nofault

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syzbot

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Sep 30, 2024, 9:40:32 AMSep 30

to ak...@linux-foundation.org, linux-...@vger.kernel.org, linu...@kvack.org, syzkall...@googlegroups.com

Hello,

syzbot found the following issue on:

HEAD commit: cea5425829f7 Add linux-next specific files for 20240930
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14eccea9980000
kernel config: https://syzkaller.appspot.com/x/.config?x=41a28720ed564c6a
dashboard link: https://syzkaller.appspot.com/bug?extid=61123a5daeb9f7454599
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/566995596f19/disk-cea54258.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e7c506c1c71d/vmlinux-cea54258.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7fcb4468b8c0/bzImage-cea54258.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+61123a...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: out-of-bounds in instrument_memcpy_before include/linux/instrumented.h:163 [inline]
BUG: KASAN: out-of-bounds in copy_from_kernel_nofault+0x7a/0x2f0 mm/maccess.c:35
Read of size 6 at addr fffffffffffffffd by task syz.1.54/5558

CPU: 1 UID: 0 PID: 5558 Comm: syz.1.54 Not tainted 6.12.0-rc1-next-20240930-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
instrument_memcpy_before include/linux/instrumented.h:163 [inline]
copy_from_kernel_nofault+0x7a/0x2f0 mm/maccess.c:35
bpf_probe_read_kernel_common include/linux/bpf.h:2960 [inline]
____bpf_probe_read_kernel kernel/trace/bpf_trace.c:239 [inline]
bpf_probe_read_kernel+0x2a/0x70 kernel/trace/bpf_trace.c:236
bpf_prog_fe7b69aea4fa28bf+0x43/0x45
__bpf_prog_run include/linux/filter.h:701 [inline]
bpf_prog_run_xdp include/net/xdp.h:514 [inline]
bpf_test_run+0x4b1/0xa90 net/bpf/test_run.c:431
bpf_prog_test_run_xdp+0x7da/0x11e0 net/bpf/test_run.c:1319
bpf_prog_test_run+0x2e4/0x360 kernel/bpf/syscall.c:4247
__sys_bpf+0x48d/0x810 kernel/bpf/syscall.c:5652
__do_sys_bpf kernel/bpf/syscall.c:5741 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5739 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5739
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5e6c17dff9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5e6d02a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f5e6c335f80 RCX: 00007f5e6c17dff9
RDX: 000000000000003b RSI: 0000000020000240 RDI: 000000000000000a
RBP: 00007f5e6c1f0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5e6c335f80 R15: 00007ffdc493ae58
</TASK>

Memory state around the buggy address:
fffffffffffffe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffffffffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffffffffffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 5558 Comm: syz.1.54 Not tainted 6.12.0-rc1-next-20240930-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:kasan_metadata_fetch_row+0x12/0x30 mm/kasan/report_generic.c:186
Code: 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 48 c1 ee 03 48 b8 00 00 00 00 00 fc ff df <48> 8b 0c 06 48 8b 44 06 08 48 89 47 08 48 89 0f c3 cc cc cc cc 66
RSP: 0018:ffffc900049976d8 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 78f03800465e2000
RDX: ffffc900045d9000 RSI: 0000000000000000 RDI: ffffc90004997710
RBP: ffffc90004997758 R08: ffffffff8bc0f2d3 R09: 0000000000000020
R10: dffffc0000000000 R11: fffff52000932ee1 R12: ffffc90004997710
R13: 0000000000000080 R14: ffffffffffffff80 R15: ffffc900049976f0
FS: 00007f5e6d02a6c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558b7a5808 CR3: 000000003075e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
print_memory_metadata mm/kasan/report.c:464 [inline]
print_report+0x4df/0x550 mm/kasan/report.c:489
kasan_report+0x143/0x180 mm/kasan/report.c:601
kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
instrument_memcpy_before include/linux/instrumented.h:163 [inline]
copy_from_kernel_nofault+0x7a/0x2f0 mm/maccess.c:35
bpf_probe_read_kernel_common include/linux/bpf.h:2960 [inline]
____bpf_probe_read_kernel kernel/trace/bpf_trace.c:239 [inline]
bpf_probe_read_kernel+0x2a/0x70 kernel/trace/bpf_trace.c:236
bpf_prog_fe7b69aea4fa28bf+0x43/0x45
__bpf_prog_run include/linux/filter.h:701 [inline]
bpf_prog_run_xdp include/net/xdp.h:514 [inline]
bpf_test_run+0x4b1/0xa90 net/bpf/test_run.c:431
bpf_prog_test_run_xdp+0x7da/0x11e0 net/bpf/test_run.c:1319
bpf_prog_test_run+0x2e4/0x360 kernel/bpf/syscall.c:4247
__sys_bpf+0x48d/0x810 kernel/bpf/syscall.c:5652
__do_sys_bpf kernel/bpf/syscall.c:5741 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5739 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5739
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5e6c17dff9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5e6d02a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f5e6c335f80 RCX: 00007f5e6c17dff9
RDX: 000000000000003b RSI: 0000000020000240 RDI: 000000000000000a
RBP: 00007f5e6c1f0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5e6c335f80 R15: 00007ffdc493ae58
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:kasan_metadata_fetch_row+0x12/0x30 mm/kasan/report_generic.c:186
Code: 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 48 c1 ee 03 48 b8 00 00 00 00 00 fc ff df <48> 8b 0c 06 48 8b 44 06 08 48 89 47 08 48 89 0f c3 cc cc cc cc 66
RSP: 0018:ffffc900049976d8 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 78f03800465e2000
RDX: ffffc900045d9000 RSI: 0000000000000000 RDI: ffffc90004997710
RBP: ffffc90004997758 R08: ffffffff8bc0f2d3 R09: 0000000000000020
R10: dffffc0000000000 R11: fffff52000932ee1 R12: ffffc90004997710
R13: 0000000000000080 R14: ffffffffffffff80 R15: ffffc900049976f0
FS: 00007f5e6d02a6c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558b7a5808 CR3: 000000003075e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1)
7: 00
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 90 nop
15: 90 nop
16: 90 nop
17: 90 nop
18: 66 0f 1f 00 nopw (%rax)
1c: 48 c1 ee 03 shr $0x3,%rsi
20: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
27: fc ff df
* 2a: 48 8b 0c 06 mov (%rsi,%rax,1),%rcx <-- trapping instruction
2e: 48 8b 44 06 08 mov 0x8(%rsi,%rax,1),%rax
33: 48 89 47 08 mov %rax,0x8(%rdi)
37: 48 89 0f mov %rcx,(%rdi)
3a: c3 ret
3b: cc int3
3c: cc int3
3d: cc int3
3e: cc int3
3f: 66 data16

---
This report 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 syzk...@googlegroups.com.

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If the report is already addressed, let syzbot know by replying with:
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup

Sabyrzhan Tasbolatov

unread,

Sep 30, 2024, 9:55:49 AMSep 30

to syzbot, ak...@linux-foundation.org, linux-...@vger.kernel.org, linu...@kvack.org, syzkall...@googlegroups.com

On Mon, Sep 30, 2024 at 6:40 PM syzbot
<syzbot+61123a...@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: cea5425829f7 Add linux-next specific files for 20240930
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=14eccea9980000
> kernel config: https://syzkaller.appspot.com/x/.config?x=41a28720ed564c6a
> dashboard link: https://syzkaller.appspot.com/bug?extid=61123a5daeb9f7454599
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/566995596f19/disk-cea54258.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/e7c506c1c71d/vmlinux-cea54258.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/7fcb4468b8c0/bzImage-cea54258.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+61123a...@syzkaller.appspotmail.com
>
> ==================================================================
> BUG: KASAN: out-of-bounds in instrument_memcpy_before include/linux/instrumented.h:163 [inline]
> BUG: KASAN: out-of-bounds in copy_from_kernel_nofault+0x7a/0x2f0 mm/maccess.c:35
> Read of size 6 at addr fffffffffffffffd by task syz.1.54/5558

This is due to the recent commit in mm/maccess.c and
might be false-positive according to the report.
Fix for the proper arguments' check has been already sent.

See pending patch:
https://lore.kernel.org/linux-mm/20240930102405.22...@gmail.com/T/#u

syzbot

unread,

Oct 1, 2024, 12:22:23 AMOct 1

to ak...@linux-foundation.org, linux-...@vger.kernel.org, linu...@kvack.org, snov...@gmail.com, syzkall...@googlegroups.com

syzbot has found a reproducer for the following issue on:

HEAD commit: cea5425829f7 Add linux-next specific files for 20240930
git tree: linux-next

console+strace: https://syzkaller.appspot.com/x/log.txt?x=1250fd07980000

kernel config: https://syzkaller.appspot.com/x/.config?x=41a28720ed564c6a
dashboard link: https://syzkaller.appspot.com/bug?extid=61123a5daeb9f7454599
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=153c439f980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1603f127980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/566995596f19/disk-cea54258.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e7c506c1c71d/vmlinux-cea54258.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7fcb4468b8c0/bzImage-cea54258.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+61123a...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: out-of-bounds in instrument_memcpy_before include/linux/instrumented.h:163 [inline]
BUG: KASAN: out-of-bounds in copy_from_kernel_nofault+0x7a/0x2f0 mm/maccess.c:35

Read of size 6 at addr fffffffffffffffd by task syz-executor167/5229

CPU: 1 UID: 0 PID: 5229 Comm: syz-executor167 Not tainted 6.12.0-rc1-next-20240930-syzkaller #0

RIP: 0033:0x7f50ec364bb9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffed45c06d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f50ec364bb9

RDX: 000000000000003b RSI: 0000000020000240 RDI: 000000000000000a

RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000000006

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001

</TASK>

Memory state around the buggy address:
fffffffffffffe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffffffffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffffffffffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]

CPU: 1 UID: 0 PID: 5229 Comm: syz-executor167 Not tainted 6.12.0-rc1-next-20240930-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:kasan_metadata_fetch_row+0x12/0x30 mm/kasan/report_generic.c:186
Code: 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 48 c1 ee 03 48 b8 00 00 00 00 00 fc ff df <48> 8b 0c 06 48 8b 44 06 08 48 89 47 08 48 89 0f c3 cc cc cc cc 66

RSP: 0018:ffffc90002f5f6d8 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: cc1757ac84471d00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc90002f5f710
RBP: ffffc90002f5f758 R08: ffffffff8bc0f2d3 R09: 0000000000000020
R10: dffffc0000000000 R11: fffff520005ebee1 R12: ffffc90002f5f710
R13: 0000000000000080 R14: ffffffffffffff80 R15: ffffc90002f5f6f0
FS: 000055558e6ce380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f50ec3db0d0 CR3: 0000000073e8a000 CR4: 00000000003526f0

RDX: 000000000000003b RSI: 0000000020000240 RDI: 000000000000000a

RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000000006

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001

</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:kasan_metadata_fetch_row+0x12/0x30 mm/kasan/report_generic.c:186
Code: 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 48 c1 ee 03 48 b8 00 00 00 00 00 fc ff df <48> 8b 0c 06 48 8b 44 06 08 48 89 47 08 48 89 0f c3 cc cc cc cc 66

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f50ec3db0d0 CR3: 0000000073e8a000 CR4: 00000000003526f0

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

syzbot

unread,

Oct 1, 2024, 7:25:04 PMOct 1

to ak...@linux-foundation.org, andre...@gmail.com, dvy...@google.com, gli...@google.com, kasa...@googlegroups.com, linux-...@vger.kernel.org, linu...@kvack.org, ryabin...@gmail.com, snov...@gmail.com, syzkall...@googlegroups.com, vincenzo...@arm.com

syzbot has bisected this issue to:

commit 88ad9dc30bbf1b08bd1dddedf9ff39019f469b8f
Author: Sabyrzhan Tasbolatov <snov...@gmail.com>
Date: Fri Sep 27 15:14:38 2024 +0000

mm, kasan: instrument copy_from/to_kernel_nofault

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15848307980000
start commit: cea5425829f7 Add linux-next specific files for 20240930
git tree: linux-next
final oops: https://syzkaller.appspot.com/x/report.txt?x=17848307980000
console output: https://syzkaller.appspot.com/x/log.txt?x=13848307980000

kernel config: https://syzkaller.appspot.com/x/.config?x=41a28720ed564c6a
dashboard link: https://syzkaller.appspot.com/bug?extid=61123a5daeb9f7454599

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14dbf127980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12dbf127980000

Reported-by: syzbot+61123a...@syzkaller.appspotmail.com
Fixes: 88ad9dc30bbf ("mm, kasan: instrument copy_from/to_kernel_nofault")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

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