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fbdev: zero-fill colormap in fbcmap.c

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Use kzalloc() rather than kmalloc() for the dynamically allocated parts
of the colormap in fb_alloc_cmap_gfp, to prevent a leak of random kernel
data to userspace under certain circumstances.

Fixes a KMSAN-found infoleak bug reported by syzbot at:
https://syzkaller.appspot.com/bug?id=741578659feabd108ad9e06696f0c1f2e69c4b6e

Reported-by: syzbot+47fa9c9c648b765305b9@syzkaller.appspotmail.com
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20210331220719.1499743-1-phil@philpotter.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Phillip Potter 2021-03-31 23:07:19 +01:00 committed by Greg Kroah-Hartman
parent 2954a6f12f
commit 19ab233989
1 changed files with 4 additions and 4 deletions
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8
drivers/video/fbdev/core/fbcmap.c
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@ -101,17 +101,17 @@ int fb_alloc_cmap_gfp(struct fb_cmap *cmap, int len, int transp, gfp_t flags)
if (!len)
return 0;
cmap->red = kmalloc(size, flags);
cmap->red = kzalloc(size, flags);
if (!cmap->red)
goto fail;
cmap->green = kmalloc(size, flags);
cmap->green = kzalloc(size, flags);
if (!cmap->green)
goto fail;
cmap->blue = kmalloc(size, flags);
cmap->blue = kzalloc(size, flags);
if (!cmap->blue)
goto fail;
if (transp) {
cmap->transp = kmalloc(size, flags);
cmap->transp = kzalloc(size, flags);
if (!cmap->transp)
goto fail;
} else {