| From 672ca9dd13f1aca0c17516f76fc5b0e8344b3e46 Mon Sep 17 00:00:00 2001 |
| From: Nicolas Pitre <nicolas.pitre@linaro.org> |
| Date: Tue, 30 Oct 2018 13:26:15 -0400 |
| Subject: Cramfs: fix abad comparison when wrap-arounds occur |
| |
| 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> |
| Cc: stable@vger.kernel.org |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/cramfs/inode.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/fs/cramfs/inode.c |
| +++ b/fs/cramfs/inode.c |
| @@ -186,7 +186,8 @@ static void *cramfs_read(struct super_bl |
| 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; |
| } |
