This is a note to let you know that I've just added the patch titled
fbdev: zero-fill colormap in fbcmap.c
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the char-misc-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 19ab233989d0f7ab1de19a036e247afa4a0a1e9c Mon Sep 17 00:00:00 2001
From: Phillip Potter <phil@xxxxxxxxxxxxxxxx>
Date: Wed, 31 Mar 2021 23:07:19 +0100
Subject: fbdev: zero-fill colormap in fbcmap.c
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@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: stable <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Signed-off-by: Phillip Potter <phil@xxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210331220719.1499743-1-phil@xxxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/video/fbdev/core/fbcmap.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/video/fbdev/core/fbcmap.c b/drivers/video/fbdev/core/fbcmap.c
index 757d5c3f620b..ff09e57f3c38 100644
--- a/drivers/video/fbdev/core/fbcmap.c
+++ b/drivers/video/fbdev/core/fbcmap.c
@@ -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 {
--
2.31.1
