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From:   Ricardo Ribalda <ribalda@chromium.org>
To:     Tomasz Figa <tfiga@chromium.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Ricardo Ribalda <ribalda@chromium.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        stable@vger.kernel.org
Subject: [PATCH] media: videobuf2: Fix integer overrun in vb2_mmap
Date:   Wed, 10 Mar 2021 08:40:28 +0100
Message-Id: <20210310074028.1042475-1-ribalda@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The plane_length is an unsigned integer. So, if we have a size of
0xffffffff bytes we incorrectly allocate 0 bytes instead of 1 << 32.

Suggested-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: stable@vger.kernel.org
Fixes: 7f8414594e47 ("[media] media: videobuf2: fix the length check for mmap")
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 drivers/media/common/videobuf2/videobuf2-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 543da515c761..876db5886867 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -2256,7 +2256,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
 	 * The buffer length was page_aligned at __vb2_buf_mem_alloc(),
 	 * so, we need to do the same here.
 	 */
-	length = PAGE_ALIGN(vb->planes[plane].length);
+	length = PAGE_ALIGN((unsigned int)vb->planes[plane].length);
 	if (length < (vma->vm_end - vma->vm_start)) {
 		dprintk(q, 1,
 			"MMAP invalid, as it would overflow buffer length\n");
-- 
2.30.1.766.gb4fecdf3b7-goog