This is a note to let you know that I've just added the patch titled
fbdev: fix potential OOB read in fast_imageblit()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fbdev-fix-potential-oob-read-in-fast_imageblit.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 67b037969ccb2a91211b435cbb1e9ae7eb512bdd
Author: Zhang Shurong <zhang_shurong@xxxxxxxxxxx>
Date: Sun Jun 25 00:16:49 2023 +0800
fbdev: fix potential OOB read in fast_imageblit()
[ Upstream commit c2d22806aecb24e2de55c30a06e5d6eb297d161d ]
There is a potential OOB read at fast_imageblit, for
"colortab[(*src >> 4)]" can become a negative value due to
"const char *s = image->data, *src".
This change makes sure the index for colortab always positive
or zero.
Similar commit:
https://patchwork.kernel.org/patch/11746067
Potential bug report:
https://groups.google.com/g/syzkaller-bugs/c/9ubBXKeKXf4/m/k-QXy4UgAAAJ
Signed-off-by: Zhang Shurong <zhang_shurong@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/video/fbdev/core/sysimgblt.c b/drivers/video/fbdev/core/sysimgblt.c
index 335e92b813fc4..665ef7a0a2495 100644
--- a/drivers/video/fbdev/core/sysimgblt.c
+++ b/drivers/video/fbdev/core/sysimgblt.c
@@ -189,7 +189,7 @@ static void fast_imageblit(const struct fb_image *image, struct fb_info *p,
u32 fgx = fgcolor, bgx = bgcolor, bpp = p->var.bits_per_pixel;
u32 ppw = 32/bpp, spitch = (image->width + 7)/8;
u32 bit_mask, eorx, shift;
- const char *s = image->data, *src;
+ const u8 *s = image->data, *src;
u32 *dst;
const u32 *tab;
size_t tablen;
