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authorNicolas Pitre <nicolas.pitre@linaro.org>2018-10-30 13:26:15 -0400
committerNicolas Pitre <nicolas.pitre@linaro.org>2018-10-30 14:24:19 -0400
commit672ca9dd13f1aca0c17516f76fc5b0e8344b3e46 (patch)
treed4cc70b2e65749144bb5992ca4c8a3232d444a64
parent84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d (diff)
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.c3
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;
}