* KASAN: null-ptr-deref Write in video_usercopy
@ 2020-01-08 8:54 syzbot
2020-01-08 10:59 ` [PATCH] media: v4l2-core: Fix Oops in ioctl Dan Carpenter
0 siblings, 1 reply; 3+ messages in thread
From: syzbot @ 2020-01-08 8:54 UTC (permalink / raw)
To: arnd, hverkuil-cisco, linux-kernel, linux-media, mchehab+huawei,
mchehab, sakari.ailus, syzkaller-bugs
Hello,
syzbot found the following crash on:
HEAD commit: 26467385 Add linux-next specific files for 20200107
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14160915e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=2265a716722be976
dashboard link: https://syzkaller.appspot.com/bug?extid=9240c422be249a8422bd
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15d162aee00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b9c469e00000
The bug was bisected to:
commit c8ef1a6076bfb986052ff8fd8f5eb3b3a3f1048e
Author: Arnd Bergmann <arnd@arndb.de>
Date: Mon Dec 16 14:15:02 2019 +0000
media: v4l2-core: split out data copy from video_usercopy
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13442bc1e00000
final crash: https://syzkaller.appspot.com/x/report.txt?x=10c42bc1e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=17442bc1e00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9240c422be249a8422bd@syzkaller.appspotmail.com
Fixes: c8ef1a6076bf ("media: v4l2-core: split out data copy from
video_usercopy")
==================================================================
BUG: KASAN: null-ptr-deref in memset include/linux/string.h:411 [inline]
BUG: KASAN: null-ptr-deref in video_get_user+0x67f/0x890
drivers/media/v4l2-core/v4l2-ioctl.c:3053
Write of size 512 at addr 0000000000000000 by task syz-executor806/9573
CPU: 0 PID: 9573 Comm: syz-executor806 Not tainted
5.5.0-rc5-next-20200107-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
__kasan_report.cold+0x5/0x32 mm/kasan/report.c:510
kasan_report+0x12/0x20 mm/kasan/common.c:641
check_memory_region_inline mm/kasan/generic.c:185 [inline]
check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
memset+0x24/0x40 mm/kasan/common.c:108
memset include/linux/string.h:411 [inline]
video_get_user+0x67f/0x890 drivers/media/v4l2-core/v4l2-ioctl.c:3053
video_usercopy+0x21f/0x10b0 drivers/media/v4l2-core/v4l2-ioctl.c:3210
video_ioctl2+0x2d/0x35 drivers/media/v4l2-core/v4l2-ioctl.c:3274
v4l2_ioctl+0x1ac/0x230 drivers/media/v4l2-core/v4l2-dev.c:360
vfs_ioctl fs/ioctl.c:47 [inline]
ksys_ioctl+0x123/0x180 fs/ioctl.c:747
__do_sys_ioctl fs/ioctl.c:756 [inline]
__se_sys_ioctl fs/ioctl.c:754 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440189
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffffba225e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440189
RDX: 0000000000000000 RSI: 0000001002008914 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000401a10
R13: 0000000000401aa0 R14: 0000000000000000 R15: 0000000000000000
==================================================================
---
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.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH] media: v4l2-core: Fix Oops in ioctl 2020-01-08 8:54 KASAN: null-ptr-deref Write in video_usercopy syzbot @ 2020-01-08 10:59 ` Dan Carpenter 2020-01-08 11:12 ` Hans Verkuil 0 siblings, 1 reply; 3+ messages in thread From: Dan Carpenter @ 2020-01-08 10:59 UTC (permalink / raw) To: Mauro Carvalho Chehab, Arnd Bergmann Cc: Hans Verkuil, Sakari Ailus, Ezequiel Garcia, Boris Brezillon, Vandana BN, linux-media, linux-kernel, syzkaller-bugs Syzbot reported a crash in video_usercopy(). It turns out when we broke video_get_user() into a separate function then we accidentally moved it outside the if block so it tries to memset a user pointer. Reported-by: syzbot+9240c422be249a8422bd@syzkaller.appspotmail.com Fixes: c8ef1a6076bf ("media: v4l2-core: split out data copy from video_usercopy") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- Not actually tested. :( Sorry. drivers/media/v4l2-core/v4l2-ioctl.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c index b68ff06009cd..aaf83e254272 100644 --- a/drivers/media/v4l2-core/v4l2-ioctl.c +++ b/drivers/media/v4l2-core/v4l2-ioctl.c @@ -3205,12 +3205,12 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg, parg = mbuf; } + err = video_get_user((void __user *)arg, parg, orig_cmd, + &always_copy); + if (err) + goto out; } - err = video_get_user((void __user *)arg, parg, orig_cmd, &always_copy); - if (err) - goto out; - err = check_array_args(cmd, parg, &array_size, &user_ptr, &kernel_ptr); if (err < 0) goto out; -- 2.11.0 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] media: v4l2-core: Fix Oops in ioctl 2020-01-08 10:59 ` [PATCH] media: v4l2-core: Fix Oops in ioctl Dan Carpenter @ 2020-01-08 11:12 ` Hans Verkuil 0 siblings, 0 replies; 3+ messages in thread From: Hans Verkuil @ 2020-01-08 11:12 UTC (permalink / raw) To: Dan Carpenter, Mauro Carvalho Chehab, Arnd Bergmann Cc: Sakari Ailus, Ezequiel Garcia, Boris Brezillon, Vandana BN, linux-media, linux-kernel, syzkaller-bugs Hi Dan, Marking this as Obsoleted in patchwork since Arnd posted an identical patch for this already. Regards, Hans On 1/8/20 11:59 AM, Dan Carpenter wrote: > Syzbot reported a crash in video_usercopy(). It turns out when we > broke video_get_user() into a separate function then we accidentally > moved it outside the if block so it tries to memset a user pointer. > > Reported-by: syzbot+9240c422be249a8422bd@syzkaller.appspotmail.com > Fixes: c8ef1a6076bf ("media: v4l2-core: split out data copy from video_usercopy") > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > --- > Not actually tested. :( Sorry. > > drivers/media/v4l2-core/v4l2-ioctl.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c > index b68ff06009cd..aaf83e254272 100644 > --- a/drivers/media/v4l2-core/v4l2-ioctl.c > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c > @@ -3205,12 +3205,12 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg, > parg = mbuf; > } > > + err = video_get_user((void __user *)arg, parg, orig_cmd, > + &always_copy); > + if (err) > + goto out; > } > > - err = video_get_user((void __user *)arg, parg, orig_cmd, &always_copy); > - if (err) > - goto out; > - > err = check_array_args(cmd, parg, &array_size, &user_ptr, &kernel_ptr); > if (err < 0) > goto out; > ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-01-08 11:12 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-01-08 8:54 KASAN: null-ptr-deref Write in video_usercopy syzbot 2020-01-08 10:59 ` [PATCH] media: v4l2-core: Fix Oops in ioctl Dan Carpenter 2020-01-08 11:12 ` Hans Verkuil
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.