4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicolas Pitre <nicolas.pi...@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.trosine...@gmail.com>
Signed-off-by: Nicolas Pitre <n...@linaro.org>
Cc: sta...@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
fs/cramfs/inode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -202,7 +202,8 @@ static void *cramfs_blkdev_read(struct s
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;
}
