Hello,
syzbot has tested the proposed patch but the reproducer still triggered
crash:
general protection fault in vidioc_querycap
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
CPU: 0 PID: 2937 Comm: v4l_id Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:usb_make_path include/linux/usb.h:914 [inline]
RIP: 0010:vidioc_querycap+0x11c/0x320
drivers/media/usb/usbvision/usbvision-video.c:460
Code: 80 3c 02 00 0f 85 03 02 00 00 4c 8b ad f0 17 00 00 48 b8 00 00 00 00
00 fc ff df 49 8d 7d 48 4d 8d 45 04 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 c7 01 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b
RSP: 0018:ffff8881c045fa28 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8881c045fc18 RCX: 0000000000000000
RDX: 0000000000000009 RSI: 2e4c1f4252534d27 RDI: 0000000000000048
RBP: ffff8881d5172100 R08: 0000000000000004 R09: fffffbfff0c90220
R10: fffffbfff0c9021f R11: ffffffff864810f8 R12: ffff8881d517399c
R13: 0000000000000000 R14: ffff8881c045fc48 R15: 0000000080050000
FS: 00007fd17db9e700(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f28e2972518 CR3: 00000001d9a2b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
v4l_querycap+0x121/0x340 drivers/media/v4l2-core/v4l2-ioctl.c:1058
__video_do_ioctl+0x969/0xba0 drivers/media/v4l2-core/v4l2-ioctl.c:2878
video_usercopy+0x446/0xf40 drivers/media/v4l2-core/v4l2-ioctl.c:3060
v4l2_ioctl+0x1a2/0x220 drivers/media/v4l2-core/v4l2-dev.c:360
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fd17d6d1347
Code: 90 90 90 48 8b 05 f1 fa 2a 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff
ff c3 90 90 90 90 90 90 90 90 90 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 01 c3 48 8b 0d c1 fa 2a 00 31 d2 48 29 c2 64
RSP: 002b:00007ffd9397d098 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fd17d6d1347
RDX: 00007ffd9397d0a0 RSI: 0000000080685600 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000400884
R13: 00007ffd9397d1f0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace e95ba987ba08e9f8 ]---
RIP: 0010:usb_make_path include/linux/usb.h:914 [inline]
RIP: 0010:vidioc_querycap+0x11c/0x320
drivers/media/usb/usbvision/usbvision-video.c:460
Code: 80 3c 02 00 0f 85 03 02 00 00 4c 8b ad f0 17 00 00 48 b8 00 00 00 00
00 fc ff df 49 8d 7d 48 4d 8d 45 04 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 c7 01 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b
RSP: 0018:ffff8881c045fa28 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8881c045fc18 RCX: 0000000000000000
RDX: 0000000000000009 RSI: 2e4c1f4252534d27 RDI: 0000000000000048
RBP: ffff8881d5172100 R08: 0000000000000004 R09: fffffbfff0c90220
R10: fffffbfff0c9021f R11: ffffffff864810f8 R12: ffff8881d517399c
R13: 0000000000000000 R14: ffff8881c045fc48 R15: 0000000080050000
FS: 00007fd17db9e700(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f28e2972518 CR3: 00000001d9a2b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Tested on:
commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=12a52ac9600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=7fa38a608b1075dfd634
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=14e7f9c3600000
