text[s] is a signed char, so using that as index into the font8x16 array
can result in negative indices. Cast it to u8 to be safe.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Reported-by: syzbot+ccf0a61ed12f2a7313ee@xxxxxxxxxxxxxxxxxxxxxxxxx
---
diff --git a/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c b/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c
index fa483b95bc5a..d9a590ae7545 100644
--- a/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c
+++ b/drivers/media/common/v4l2-tpg/v4l2-tpg-core.c
@@ -1769,7 +1769,7 @@ typedef struct { u16 __; u8 _; } __packed x24;
unsigned s; \
\
for (s = 0; s < len; s++) { \
- u8 chr = font8x16[text[s] * 16 + line]; \
+ u8 chr = font8x16[(u8)text[s] * 16 + line]; \
\
if (hdiv == 2 && tpg->hflip) { \
pos[3] = (chr & (0x01 << 6) ? fg : bg); \
