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Commit 9d9da6fe authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Greg Kroah-Hartman
Browse files

Cramfs: fix abad comparison when wrap-arounds occur 



commit 672ca9dd13f1aca0c17516f76fc5b0e8344b3e46 upstream.

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: default avatarAnatoly Trosinenko <anatoly.trosinenko@gmail.com>
Signed-off-by: default avatarNicolas Pitre <nico@linaro.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9632c033

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;

	}