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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Dr Silvio Cesare of InfoSect <silvio.cesare@gmail.com>,
        Kees Cook <keescook@chromium.org>
Subject: [PATCH 4.17 184/220] video: uvesafb: Fix integer overflow in allocation
Date:   Sun,  1 Jul 2018 18:23:28 +0200
Message-Id: <20180701160915.900637503@linuxfoundation.org>
In-Reply-To: <20180701160908.272447118@linuxfoundation.org>
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4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kees Cook <keescook@chromium.org>

commit 9f645bcc566a1e9f921bdae7528a01ced5bc3713 upstream.

cmap->len can get close to INT_MAX/2, allowing for an integer overflow in
allocation. This uses kmalloc_array() instead to catch the condition.

Reported-by: Dr Silvio Cesare of InfoSect <silvio.cesare@gmail.com>
Fixes: 8bdb3a2d7df48 ("uvesafb: the driver core")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/video/fbdev/uvesafb.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/video/fbdev/uvesafb.c
+++ b/drivers/video/fbdev/uvesafb.c
@@ -1044,7 +1044,8 @@ static int uvesafb_setcmap(struct fb_cma
 		    info->cmap.len || cmap->start < info->cmap.start)
 			return -EINVAL;
 
-		entries = kmalloc(sizeof(*entries) * cmap->len, GFP_KERNEL);
+		entries = kmalloc_array(cmap->len, sizeof(*entries),
+					GFP_KERNEL);
 		if (!entries)
 			return -ENOMEM;