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From: Phillip Potter <phil@philpotter.co.uk>
To: mchehab+huawei@kernel.org
Cc: daniel.vetter@ffwll.ch, dri-devel@lists.freedesktop.org,
	linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] zero-fill colormap in drivers/video/fbdev/core/fbcmap.c
Date: Wed, 31 Mar 2021 23:07:19 +0100	[thread overview]
Message-ID: <20210331220719.1499743-1-phil@philpotter.co.uk> (raw)

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
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
---
 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 {
-- 
2.30.2


             reply	other threads:[~2021-03-31 22:08 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-31 22:07 Phillip Potter [this message]
2021-04-01  9:55 ` Geert Uytterhoeven
2021-04-02  8:57   ` Phillip Potter
2021-04-02 15:37 ` Greg KH

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