| From | Ben Hutchings <> | Date | Sun, 03 Feb 2019 14:45:08 +0100 | Subject | [PATCH 3.16 128/305] Cramfs: fix abad comparison when wrap-arounds occur |
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3.16.63-rc1 review patch. If anyone has any objections, please let me know.
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From: Nicolas Pitre <nicolas.pitre@linaro.org>
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: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- fs/cramfs/inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/cramfs/inode.c +++ b/fs/cramfs/inode.c @@ -183,7 +183,8 @@ static void *cramfs_read(struct super_bl continue; blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_CACHE_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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