omfs: sanity check cluster size

A corrupt filesystem could have a bad cluster size; this could result in the filesystem allocating too much space for files if too large, or getting stuck in omfs_allocate_block if too small. The proper range is 1-8 blocks. Reported-by: Eric Sesterhenn <[email protected]> Signed-off-by: Bob Copeland <[email protected]>
berg · Jul 10, 2010 · 8800a04 · 8800a04
1 parent 9442e54
commit 8800a04
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diff --git a/fs/omfs/inode.c b/fs/omfs/inode.c
@@ -517,6 +517,12 @@ static int omfs_fill_super(struct super_block *sb, void *data, int silent)
 			(unsigned long long) sbi->s_num_blocks);
 		goto out_brelse_bh2;
 	}
+	if (sbi->s_clustersize < 1 ||
+	    sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
+		printk(KERN_ERR "omfs: cluster size out of range (%d)",
+			sbi->s_clustersize);
+		goto out_brelse_bh2;
+	}
 
 	ret = omfs_get_imap(sb);
 	if (ret)

diff --git a/fs/omfs/omfs_fs.h b/fs/omfs/omfs_fs.h
@@ -17,6 +17,7 @@
 #define OMFS_EXTENT_CONT 0x40
 #define OMFS_XOR_COUNT 19
 #define OMFS_MAX_BLOCK_SIZE 8192
+#define OMFS_MAX_CLUSTER_SIZE 8
 
 struct omfs_super_block {
 	char s_fill1[256];