Old csum type check is wrong and can't catch csum_type 1(not supported).

Fix it to avoid hostile 0 division.

Reported-by: Lukas Lueg <lukas.l...@gmail.com>
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
Changelog:
v2:
   Fix existing codes other than adding new one.
---
 fs/btrfs/ctree.h   | 1 +
 fs/btrfs/disk-io.c | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f9c89ca..d6f3aa0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -173,6 +173,7 @@ struct btrfs_ordered_sum;
 
 /* csum types */
 #define BTRFS_CSUM_TYPE_CRC32  0
+#define BTRFS_CSUM_LAST_TYPE   0
 
 static int btrfs_csum_sizes[] = { 4, 0 };
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 639f266..e33a01b 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -426,9 +426,9 @@ static int btrfs_check_super_csum(char *raw_disk_sb)
                }
        }
 
-       if (csum_type >= ARRAY_SIZE(btrfs_csum_sizes)) {
+       if (csum_type > BTRFS_CSUM_LAST_TYPE) {
                printk(KERN_ERR "BTRFS: unsupported checksum algorithm %u\n",
-                               csum_type);
+                      csum_type);
                ret = 1;
        }
 
-- 
2.3.5

--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to