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media: media/v4l2-core: Fix kernel-infoleak in video_put_user() 

video_put_user() is copying uninitialized stack memory to userspace due
to the compiler not initializing holes in the structures declared on the
stack. Fix it by initializing `ev32` and `vb32` using memset().

Reported-and-tested-by: syzbot+79d751604cb6f29fbf59@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=79d751604cb6f29fbf59

Cc: stable@vger.kernel.org
Fixes: 1a6c0b36dd ("media: v4l2-core: fix VIDIOC_DQEVENT for time64 ABI")
Fixes: 577c89b0ce ("media: v4l2-core: fix v4l2_buffer handling for time64 ABI")
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Peilin Ye 2020-07-27 10:00:02 +02:00 committed by Mauro Carvalho Chehab
parent bec2ddfd39
commit 4ffb879ea6
1 changed files with 27 additions and 23 deletions
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50
drivers/media/v4l2-core/v4l2-ioctl.c
View File

@ -3189,14 +3189,16 @@ static int video_put_user(void __user *arg, void *parg, unsigned int cmd)
#ifdef CONFIG_COMPAT_32BIT_TIME
case VIDIOC_DQEVENT_TIME32: {
struct v4l2_event *ev = parg;
struct v4l2_event_time32 ev32 = {
.type = ev->type,
.pending = ev->pending,
.sequence = ev->sequence,
.timestamp.tv_sec = ev->timestamp.tv_sec,
.timestamp.tv_nsec = ev->timestamp.tv_nsec,
.id = ev->id,
};
struct v4l2_event_time32 ev32;
memset(&ev32, 0, sizeof(ev32));
ev32.type = ev->type;
ev32.pending = ev->pending;
ev32.sequence = ev->sequence;
ev32.timestamp.tv_sec = ev->timestamp.tv_sec;
ev32.timestamp.tv_nsec = ev->timestamp.tv_nsec;
ev32.id = ev->id;
memcpy(&ev32.u, &ev->u, sizeof(ev->u));
memcpy(&ev32.reserved, &ev->reserved, sizeof(ev->reserved));
@ -3210,21 +3212,23 @@ static int video_put_user(void __user *arg, void *parg, unsigned int cmd)
case VIDIOC_DQBUF_TIME32:
case VIDIOC_PREPARE_BUF_TIME32: {
struct v4l2_buffer *vb = parg;
struct v4l2_buffer_time32 vb32 = {
.index = vb->index,
.type = vb->type,
.bytesused = vb->bytesused,
.flags = vb->flags,
.field = vb->field,
.timestamp.tv_sec = vb->timestamp.tv_sec,
.timestamp.tv_usec = vb->timestamp.tv_usec,
.timecode = vb->timecode,
.sequence = vb->sequence,
.memory = vb->memory,
.m.userptr = vb->m.userptr,
.length = vb->length,
.request_fd = vb->request_fd,
};
struct v4l2_buffer_time32 vb32;
memset(&vb32, 0, sizeof(vb32));
vb32.index = vb->index;
vb32.type = vb->type;
vb32.bytesused = vb->bytesused;
vb32.flags = vb->flags;
vb32.field = vb->field;
vb32.timestamp.tv_sec = vb->timestamp.tv_sec;
vb32.timestamp.tv_usec = vb->timestamp.tv_usec;
vb32.timecode = vb->timecode;
vb32.sequence = vb->sequence;
vb32.memory = vb->memory;
vb32.m.userptr = vb->m.userptr;
vb32.length = vb->length;
vb32.request_fd = vb->request_fd;
if (copy_to_user(arg, &vb32, sizeof(vb32)))
return -EFAULT;