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| author | Nicolas Pitre <nicolas.pitre@linaro.org> | 2018-10-30 13:26:15 -0400 |
|---|---|---|
| committer | Nicolas Pitre <nicolas.pitre@linaro.org> | 2018-10-30 14:24:19 -0400 |
| commit | 672ca9dd13f1aca0c17516f76fc5b0e8344b3e46 (patch) | |
| tree | d4cc70b2e65749144bb5992ca4c8a3232d444a64 | |
| parent | 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d (diff) | |
| download | lwn-672ca9dd13f1aca0c17516f76fc5b0e8344b3e46.tar.gz lwn-672ca9dd13f1aca0c17516f76fc5b0e8344b3e46.zip | |
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
| -rw-r--r-- | fs/cramfs/inode.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c index f408994fc632..6e000392e4a4 100644 --- a/fs/cramfs/inode.c +++ b/fs/cramfs/inode.c @@ -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; } |