Commit 672ca9dd authored Oct 30, 2018 by Nicolas Pitre

Cramfs: fix abad comparison when wrap-arounds occur



It is possible for corrupted filesystem images to produce very large
block offsets that may wrap when a length is added, and wrongly pass
the buffer size test.

Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Cc: stable@vger.kernel.org

parent 84df9525

fs/cramfs/inode.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -202,7 +202,8 @@ static void cramfs_blkdev_read(struct super_block sb, unsigned int offset,
		continue;
		blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_SHIFT;
		blk_offset += offset;
		if (blk_offset + len > BUFFER_SIZE)
		if (blk_offset > BUFFER_SIZE \|\|
		blk_offset + len > BUFFER_SIZE)
		continue;
		return read_buffers[i] + blk_offset;
		}

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