2022-10-27 12:15:40

by Liu Shixin

[permalink] [raw]
Subject: [PATCH] media: vivid: fix compose size exceed boundary

syzkaller found a bug:

BUG: unable to handle page fault for address: ffffc9000a3b1000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 100000067 P4D 100000067 PUD 10015f067 PMD 1121ca067 PTE 0
Oops: 0002 [#1] PREEMPT SMP
CPU: 0 PID: 23489 Comm: vivid-000-vid-c Not tainted 6.1.0-rc1+ #512
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:memcpy_erms+0x6/0x10
[...]
Call Trace:
<TASK>
? tpg_fill_plane_buffer+0x856/0x15b0
vivid_fillbuff+0x8ac/0x1110
vivid_thread_vid_cap_tick+0x361/0xc90
vivid_thread_vid_cap+0x21a/0x3a0
kthread+0x143/0x180
ret_from_fork+0x1f/0x30
</TASK>

This is because we forget to check boundary after adjust compose->height
int V4L2_SEL_TGT_CROP case. Add v4l2_rect_map_inside() to fix this problem
for this case.

Fixes: ef834f7836ec ("vivid: add the video capture and output parts")
Signed-off-by: Liu Shixin <[email protected]>
---
drivers/media/test-drivers/vivid/vivid-vid-cap.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/media/test-drivers/vivid/vivid-vid-cap.c b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
index 86b158eeb2d8..b0cee26b9089 100644
--- a/drivers/media/test-drivers/vivid/vivid-vid-cap.c
+++ b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
@@ -957,6 +957,7 @@ int vivid_vid_cap_s_selection(struct file *file, void *fh, struct v4l2_selection
if (dev->has_compose_cap) {
v4l2_rect_set_min_size(compose, &min_rect);
v4l2_rect_set_max_size(compose, &max_rect);
+ v4l2_rect_map_inside(compose, &fmt);
}
dev->fmt_cap_rect = fmt;
tpg_s_buf_height(&dev->tpg, fmt.height);
--
2.25.1