From: Peilin Ye yepeilin.cs@gmail.com
commit 4ffb879ea648c2b42da4ca992ed3db87e564af69 upstream.
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: 1a6c0b36dd19 ("media: v4l2-core: fix VIDIOC_DQEVENT for time64 ABI") Fixes: 577c89b0ce72 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/media/v4l2-core/v4l2-ioctl.c | 50 ++++++++++++++++++----------------- 1 file changed, 27 insertions(+), 23 deletions(-)
--- a/drivers/media/v4l2-core/v4l2-ioctl.c +++ b/drivers/media/v4l2-core/v4l2-ioctl.c @@ -3186,14 +3186,16 @@ static int video_put_user(void __user *a #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)); @@ -3207,21 +3209,23 @@ static int video_put_user(void __user *a 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;