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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 <snakebyte@gmx.de>
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Bob Copeland 15 anni fa
parent
commit
8800a044c7
2 ha cambiato i file con 7 aggiunte e 0 eliminazioni
  1. 6 0
      fs/omfs/inode.c
  2. 1 0
      fs/omfs/omfs_fs.h

+ 6 - 0
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)

+ 1 - 0
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];