fbdev: fix potential OOB read in fast_imageblit()

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commit c2d22806ae upstream.

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@foxmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Zhang Shurong 2023-06-25 00:16:49 +08:00 • committed by Greg Kroah-Hartman

parent 00d5932e09

commit 14fdcf965d

1 changed files with 1 additions and 1 deletions

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drivers/video/fbdev/core/sysimgblt.c

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