* [syzbot] [media?] WARNING in dtv5100_i2c_msg
@ 2025-10-23 19:42 syzbot
2025-11-16 14:41 ` zzam
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2025-10-23 19:42 UTC (permalink / raw)
To: linux-kernel, linux-media, mchehab, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 1c64efcb083c Merge tag 'rust-rustfmt' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12a9752f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=9ad7b090a18654a7
dashboard link: https://syzkaller.appspot.com/bug?extid=a83ee2dae0e6cc6cd3aa
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5e186ec77007/disk-1c64efcb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6b834b72dada/vmlinux-1c64efcb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3ba22aa75c23/bzImage-1c64efcb.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a83ee2dae0e6cc6cd3aa@syzkaller.appspotmail.com
------------[ cut here ]------------
memcpy: detected field-spanning write (size 4096) of single field "st->data" at drivers/media/usb/dvb-usb/dtv5100.c:58 (size 80)
WARNING: CPU: 1 PID: 20467 at drivers/media/usb/dvb-usb/dtv5100.c:58 dtv5100_i2c_msg+0x2ac/0x330 drivers/media/usb/dvb-usb/dtv5100.c:58
Modules linked in:
CPU: 1 UID: 0 PID: 20467 Comm: syz.1.4196 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:dtv5100_i2c_msg+0x2ac/0x330 drivers/media/usb/dvb-usb/dtv5100.c:58
Code: d1 e8 d8 5c 0b fa c6 05 1c 33 d3 07 01 90 b9 50 00 00 00 48 c7 c7 e0 7b 32 8c 4c 89 e6 48 c7 c2 60 7c 32 8c e8 c5 79 ce f9 90 <0f> 0b 90 90 e9 34 ff ff ff 44 89 e9 80 e1 07 38 c1 0f 8c e2 fe ff
RSP: 0018:ffffc9000ff6f8a0 EFLAGS: 00010246
RAX: dd4b062c6f0c5d00 RBX: ffff88802fb10000 RCX: 0000000000080000
RDX: ffffc9000be3b000 RSI: 00000000000054be RDI: 00000000000054bf
RBP: 0000000000000102 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfa650 R12: 0000000000001000
R13: ffff8880543d4300 R14: 00000000000000c7 R15: 0000000080007700
FS: 0000000000000000(0000) GS:ffff888125e0d000(0063) knlGS:00000000f5436b40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000080000100 CR3: 0000000047562000 CR4: 00000000003526f0
Call Trace:
<TASK>
dtv5100_i2c_xfer+0x269/0x3c0 drivers/media/usb/dvb-usb/dtv5100.c:81
__i2c_transfer+0x874/0x2170 drivers/i2c/i2c-core-base.c:-1
i2c_transfer+0x25b/0x3a0 drivers/i2c/i2c-core-base.c:2317
i2cdev_ioctl_rdwr+0x460/0x740 drivers/i2c/i2c-dev.c:306
compat_i2cdev_ioctl+0x5a8/0x5c0 drivers/i2c/i2c-dev.c:575
__do_compat_sys_ioctl fs/ioctl.c:695 [inline]
__se_compat_sys_ioctl fs/ioctl.c:638 [inline]
__ia32_compat_sys_ioctl+0x543/0x840 fs/ioctl.c:638
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306
do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7f41539
Code: 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f543655c EFLAGS: 00000206 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000000707
RDX: 00000000800002c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
----------------
Code disassembly (best guess):
0: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi
4: 10 07 adc %al,(%rdi)
6: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
a: 10 08 adc %cl,(%rax)
c: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
20: 00 51 52 add %dl,0x52(%rcx)
23: 55 push %rbp
24: 89 e5 mov %esp,%ebp
26: 0f 34 sysenter
28: cd 80 int $0x80
* 2a: 5d pop %rbp <-- trapping instruction
2b: 5a pop %rdx
2c: 59 pop %rcx
2d: c3 ret
2e: 90 nop
2f: 90 nop
30: 90 nop
31: 90 nop
32: 90 nop
33: 90 nop
34: 90 nop
35: 90 nop
36: 90 nop
37: 90 nop
38: 90 nop
39: 90 nop
3a: 90 nop
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop
---
This report is generated by a bot. It may contain errors.
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] [media?] WARNING in dtv5100_i2c_msg
2025-10-23 19:42 [syzbot] [media?] WARNING in dtv5100_i2c_msg syzbot
@ 2025-11-16 14:41 ` zzam
0 siblings, 0 replies; 2+ messages in thread
From: zzam @ 2025-11-16 14:41 UTC (permalink / raw)
To: syzbot, linux-kernel, linux-media, mchehab, syzkaller-bugs
Am 23.10.25 um 21:42 schrieb syzbot:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 1c64efcb083c Merge tag 'rust-rustfmt' of git://git.kernel...
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12a9752f980000
> kernel config: https://syzkaller.appspot.com/x/.config?x=9ad7b090a18654a7
> dashboard link: https://syzkaller.appspot.com/bug?extid=a83ee2dae0e6cc6cd3aa
> compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> userspace arch: i386
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/5e186ec77007/disk-1c64efcb.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/6b834b72dada/vmlinux-1c64efcb.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/3ba22aa75c23/bzImage-1c64efcb.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+a83ee2dae0e6cc6cd3aa@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> memcpy: detected field-spanning write (size 4096) of single field "st->data" at drivers/media/usb/dvb-usb/dtv5100.c:58 (size 80)
> WARNING: CPU: 1 PID: 20467 at drivers/media/usb/dvb-usb/dtv5100.c:58 dtv5100_i2c_msg+0x2ac/0x330 drivers/media/usb/dvb-usb/dtv5100.c:58
> Modules linked in:
> CPU: 1 UID: 0 PID: 20467 Comm: syz.1.4196 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
> RIP: 0010:dtv5100_i2c_msg+0x2ac/0x330 drivers/media/usb/dvb-usb/dtv5100.c:58
> Code: d1 e8 d8 5c 0b fa c6 05 1c 33 d3 07 01 90 b9 50 00 00 00 48 c7 c7 e0 7b 32 8c 4c 89 e6 48 c7 c2 60 7c 32 8c e8 c5 79 ce f9 90 <0f> 0b 90 90 e9 34 ff ff ff 44 89 e9 80 e1 07 38 c1 0f 8c e2 fe ff
> RSP: 0018:ffffc9000ff6f8a0 EFLAGS: 00010246
> RAX: dd4b062c6f0c5d00 RBX: ffff88802fb10000 RCX: 0000000000080000
> RDX: ffffc9000be3b000 RSI: 00000000000054be RDI: 00000000000054bf
> RBP: 0000000000000102 R08: 0000000000000003 R09: 0000000000000004
> R10: dffffc0000000000 R11: fffffbfff1bfa650 R12: 0000000000001000
> R13: ffff8880543d4300 R14: 00000000000000c7 R15: 0000000080007700
> FS: 0000000000000000(0000) GS:ffff888125e0d000(0063) knlGS:00000000f5436b40
> CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
> CR2: 0000000080000100 CR3: 0000000047562000 CR4: 00000000003526f0
> Call Trace:
> <TASK>
> dtv5100_i2c_xfer+0x269/0x3c0 drivers/media/usb/dvb-usb/dtv5100.c:81
> __i2c_transfer+0x874/0x2170 drivers/i2c/i2c-core-base.c:-1
> i2c_transfer+0x25b/0x3a0 drivers/i2c/i2c-core-base.c:2317
> i2cdev_ioctl_rdwr+0x460/0x740 drivers/i2c/i2c-dev.c:306
> compat_i2cdev_ioctl+0x5a8/0x5c0 drivers/i2c/i2c-dev.c:575
> __do_compat_sys_ioctl fs/ioctl.c:695 [inline]
> __se_compat_sys_ioctl fs/ioctl.c:638 [inline]
> __ia32_compat_sys_ioctl+0x543/0x840 fs/ioctl.c:638
> do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
> __do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306
> do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
> entry_SYSENTER_compat_after_hwframe+0x84/0x8e
> RIP: 0023:0xf7f41539
> Code: 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
> RSP: 002b:00000000f543655c EFLAGS: 00000206 ORIG_RAX: 0000000000000036
> RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000000707
> RDX: 00000000800002c0 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> </TASK>
From the report above it looks like the i2c-read writes to
dtv5100_state->data:
struct dtv5100_state {
unsigned char data[80];
};
If the read is longer than 80 characters it writes after the end of
data. Limiting the read size to 80 bytes should fix this issue.
But I see more issues in that code so is it working at all?
1.
It seems to copy from the original read-target buffer (rbuf) to a
temporary buffer on the heap (in dtv5100_state->data). Then
usb_control_msg runs. But then the data itself seems not to be copied
back into rbuf.
25:static int dtv5100_i2c_msg(struct dvb_usb_device *d, u8 addr,
26: u8 *wbuf, u16 wlen, u8 *rbuf, u16 rlen)
27:{
[...]
58: memcpy(st->data, rbuf, rlen);
59: msleep(1); /* avoid I2C errors */
60: return usb_control_msg(d->udev, pipe, request,
61: type, value, index, st->data, rlen,
62: DTV5100_USB_TIMEOUT);
63:}
2. dtv5100_i2c_xfer: Single read-requests might be interpreted as single
writes.
Regards
Matthias
^ permalink raw reply [flat|nested] 2+ messages in thread
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2025-10-23 19:42 [syzbot] [media?] WARNING in dtv5100_i2c_msg syzbot
2025-11-16 14:41 ` zzam
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