[syzbot] [can?] WARNING in ucan_probe

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 496659003dac Merge tag 'i2c-for-6.14-rc3' of git://git.ker..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11012bf8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c776e555cfbdb82d
dashboard link: https://syzkaller.appspot.com/bug?extid=d7d8c418e8317899e88c
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=14f7b9b0580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=155602e4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c1675d5fc116/disk-49665900.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0342ce7d0bc9/vmlinux-49665900.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5ce5b4978fc4/bzImage-49665900.xz

The issue was bisected to:

commit b3e40fc85735b787ce65909619fcd173107113c2
Author: Oliver Neukum <one...@suse.com>
Date: Thu May 2 11:51:40 2024 +0000

USB: usb_parse_endpoint: ignore reserved bits

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=11c65bf8580000
final oops: https://syzkaller.appspot.com/x/report.txt?x=13c65bf8580000
console output: https://syzkaller.appspot.com/x/log.txt?x=15c65bf8580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d7d8c4...@syzkaller.appspotmail.com
Fixes: b3e40fc85735 ("USB: usb_parse_endpoint: ignore reserved bits")

------------[ cut here ]------------
strnlen: detected buffer overflow: 129 byte read of buffer size 128
WARNING: CPU: 0 PID: 9 at lib/string_helpers.c:1033 __fortify_report+0x9d/0xb0 lib/string_helpers.c:1032
Modules linked in:
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.14.0-rc2-syzkaller-00281-g496659003dac #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: usb_hub_wq hub_event
RIP: 0010:__fortify_report+0x9d/0xb0 lib/string_helpers.c:1032
Code: 84 ed 48 8b 33 48 c7 c0 a0 ae 80 8c 48 c7 c1 c0 ae 80 8c 48 0f 44 c8 48 c7 c7 20 ac 80 8c 4c 89 fa 4d 89 f0 e8 04 dd 8b fc 90 <0f> 0b 90 90 5b 41 5e 41 5f 5d c3 cc cc cc cc 0f 1f 40 00 90 90 90
RSP: 0018:ffffc900000e6b50 EFLAGS: 00010246
RAX: e8edca93825f5800 RBX: ffffffff8c80ab68 RCX: ffff88801c2f8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff81817e32 R09: fffffbfff1d3a614
R10: dffffc0000000000 R11: fffffbfff1d3a614 R12: dffffc0000000000
R13: 1ffff9200001cd84 R14: 0000000000000080 R15: 0000000000000081
FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d6c3b85e50 CR3: 0000000078508000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__fortify_panic+0x9/0x10 lib/string_helpers.c:1039
_Z7strnlenPKcU25pass_dynamic_object_size1m include/linux/fortify-string.h:235 [inline]
_Z13sized_strscpyPcU25pass_dynamic_object_size1PKcU25pass_dynamic_object_size1m include/linux/fortify-string.h:309 [inline]
ucan_probe+0x195e/0x1980 drivers/net/can/usb/ucan.c:1535
usb_probe_interface+0x641/0xbb0 drivers/usb/core/driver.c:396
really_probe+0x2b9/0xad0 drivers/base/dd.c:658
__driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
driver_probe_device+0x50/0x430 drivers/base/dd.c:830
__device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:462
__device_attach+0x333/0x520 drivers/base/dd.c:1030
bus_probe_device+0x189/0x260 drivers/base/bus.c:537
device_add+0x856/0xbf0 drivers/base/core.c:3665
usb_set_configuration+0x1976/0x1fb0 drivers/usb/core/message.c:2210
usb_generic_driver_probe+0x88/0x140 drivers/usb/core/generic.c:250
usb_probe_device+0x1b8/0x380 drivers/usb/core/driver.c:291
really_probe+0x2b9/0xad0 drivers/base/dd.c:658
__driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
driver_probe_device+0x50/0x430 drivers/base/dd.c:830
__device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:462
__device_attach+0x333/0x520 drivers/base/dd.c:1030
bus_probe_device+0x189/0x260 drivers/base/bus.c:537
device_add+0x856/0xbf0 drivers/base/core.c:3665
usb_new_device+0x104a/0x19a0 drivers/usb/core/hub.c:2652
hub_port_connect drivers/usb/core/hub.c:5523 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5663 [inline]
port_event drivers/usb/core/hub.c:5823 [inline]
hub_event+0x2d6d/0x5150 drivers/usb/core/hub.c:5905
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3317
worker_thread+0x870/0xd30 kernel/workqueue.c:3398
kthread+0x7a9/0x920 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>


---
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.

syzbot will keep track of this issue. See:
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

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.

If you want to overwrite report's subsystems, reply with:
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#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[Marc Kleine-Budde]

On 17.02.2025 03:55:16, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 496659003dac Merge tag 'i2c-for-6.14-rc3' of git://git.ker..
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=11012bf8580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=c776e555cfbdb82d
> dashboard link: https://syzkaller.appspot.com/bug?extid=d7d8c418e8317899e88c
> 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=14f7b9b0580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=155602e4580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/c1675d5fc116/disk-49665900.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/0342ce7d0bc9/vmlinux-49665900.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/5ce5b4978fc4/bzImage-49665900.xz
>
> The issue was bisected to:
>
> commit b3e40fc85735b787ce65909619fcd173107113c2
> Author: Oliver Neukum <one...@suse.com>
> Date: Thu May 2 11:51:40 2024 +0000
>
> USB: usb_parse_endpoint: ignore reserved bits

I think the issue was introduced in: 7fdaf8966aae ("can: ucan: use
strscpy() to instead of strncpy()"). I'm preparing a fix.

regards,
Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung Nürnberg | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject:
Author: qasd...@gmail.com

#syz test

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: [PATCH] can: ucan: Correct the size parameter
Author: zoo...@gmail.com

According to the comment, the size parameter is only required when
@dst is not an array, or when the copy needs to be smaller than
sizeof(@dst). Since the source is a `union ucan_ctl_payload`, the
correct size should be sizeof(union ucan_ctl_payload).

#syz test

Signed-off-by: Matt Jan <zoo...@gmail.com>
---
drivers/net/can/usb/ucan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/ucan.c b/drivers/net/can/usb/ucan.c
index 39a63b7313a4..1ccef00388ae 100644
--- a/drivers/net/can/usb/ucan.c
+++ b/drivers/net/can/usb/ucan.c
@@ -1533,7 +1533,7 @@ static int ucan_probe(struct usb_interface *intf,
if (ret > 0) {
/* copy string while ensuring zero termination */
strscpy(firmware_str, up->ctl_msg_buffer->raw,
- sizeof(union ucan_ctl_payload) + 1);
+ sizeof(union ucan_ctl_payload));
} else {
strcpy(firmware_str, "unknown");
}
--
2.25.1

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in ucan_probe

firmware_str size: 129 bytes
union ucan_ctl_payload size: 128 bytes
ip->ctl_msg_buffer->raw size: 128 bytes
usb 1-1: ucan: probing device on interface #0

------------[ cut here ]------------
strnlen: detected buffer overflow: 129 byte read of buffer size 128

WARNING: CPU: 1 PID: 25 at lib/string_helpers.c:1033 __fortify_report+0x9d/0xb0 lib/string_helpers.c:1032
Modules linked in:
CPU: 1 UID: 0 PID: 25 Comm: kworker/1:0 Not tainted 6.14.0-rc3-syzkaller-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: usb_hub_wq hub_event
RIP: 0010:__fortify_report+0x9d/0xb0 lib/string_helpers.c:1032

Code: 84 ed 48 8b 33 48 c7 c0 e0 ad 80 8c 48 c7 c1 00 ae 80 8c 48 0f 44 c8 48 c7 c7 60 ab 80 8c 4c 89 fa 4d 89 f0 e8 e4 d9 8b fc 90 <0f> 0b 90 90 5b 41 5e 41 5f 5d c3 cc cc cc cc 0f 1f 40 00 90 90 90
RSP: 0018:ffffc900001f6b50 EFLAGS: 00010246
RAX: ae09b98519e5a900 RBX: ffffffff8c80aaa8 RCX: ffff88801da81e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000

RBP: 0000000000000000 R08: ffffffff81817e32 R09: fffffbfff1d3a614
R10: dffffc0000000000 R11: fffffbfff1d3a614 R12: dffffc0000000000

R13: 1ffff9200003ed84 R14: 0000000000000080 R15: 0000000000000081
FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000

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

CR2: 00005630540fd131 CR3: 00000000630a8000 CR4: 00000000003526f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__fortify_panic+0x9/0x10 lib/string_helpers.c:1039
_Z7strnlenPKcU25pass_dynamic_object_size1m include/linux/fortify-string.h:235 [inline]
_Z13sized_strscpyPcU25pass_dynamic_object_size1PKcU25pass_dynamic_object_size1m include/linux/fortify-string.h:309 [inline]

ucan_probe+0x1991/0x19c0 drivers/net/can/usb/ucan.c:1537

usb_probe_interface+0x641/0xbb0 drivers/usb/core/driver.c:396
really_probe+0x2b9/0xad0 drivers/base/dd.c:658
__driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
driver_probe_device+0x50/0x430 drivers/base/dd.c:830
__device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:462
__device_attach+0x333/0x520 drivers/base/dd.c:1030
bus_probe_device+0x189/0x260 drivers/base/bus.c:537
device_add+0x856/0xbf0 drivers/base/core.c:3665
usb_set_configuration+0x1976/0x1fb0 drivers/usb/core/message.c:2210
usb_generic_driver_probe+0x88/0x140 drivers/usb/core/generic.c:250
usb_probe_device+0x1b8/0x380 drivers/usb/core/driver.c:291
really_probe+0x2b9/0xad0 drivers/base/dd.c:658
__driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
driver_probe_device+0x50/0x430 drivers/base/dd.c:830
__device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:462
__device_attach+0x333/0x520 drivers/base/dd.c:1030
bus_probe_device+0x189/0x260 drivers/base/bus.c:537
device_add+0x856/0xbf0 drivers/base/core.c:3665

usb_new_device+0x104a/0x19a0 drivers/usb/core/hub.c:2663
hub_port_connect drivers/usb/core/hub.c:5533 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5673 [inline]
port_event drivers/usb/core/hub.c:5833 [inline]
hub_event+0x2d6d/0x5150 drivers/usb/core/hub.c:5915

process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3317
worker_thread+0x870/0xd30 kernel/workqueue.c:3398
kthread+0x7a9/0x920 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

Tested on:

commit: 0ad2507d Linux 6.14-rc3
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=152f75a4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b7bde34acd8f53b1

dashboard link: https://syzkaller.appspot.com/bug?extid=d7d8c418e8317899e88c
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=15e775a4580000

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+d7d8c4...@syzkaller.appspotmail.com
Tested-by: syzbot+d7d8c4...@syzkaller.appspotmail.com

Tested on:

commit: 0ad2507d Linux 6.14-rc3
git tree: upstream

console output: https://syzkaller.appspot.com/x/log.txt?x=11723bf8580000

kernel config: https://syzkaller.appspot.com/x/.config?x=b7bde34acd8f53b1
dashboard link: https://syzkaller.appspot.com/bug?extid=d7d8c418e8317899e88c
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=160f75a4580000

Note: testing is done by a robot and is best-effort only.