FS/OMFS: block number sanity check during fill_super operation

This patch defines maximum block number to 2^31.  It also converts
bitmap_size and array_size to unsigned int in omfs_get_imap

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Bob Copeland <me@bobcopeland.com>
Tested-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/omfs/inode.c

@@ -306,9 +306,7 @@ static const struct super_operations omfs_sops = {
  */
 static int omfs_get_imap(struct super_block *sb)
 {
-	int bitmap_size;
-	int array_size;
-	int count;
+	unsigned int bitmap_size, count, array_size;
 	struct omfs_sb_info *sbi = OMFS_SB(sb);
 	struct buffer_head *bh;
 	unsigned long **ptr;
@@ -473,6 +471,12 @@ static int omfs_fill_super(struct super_block *sb, void *data, int silent)
 	sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
 	mutex_init(&sbi->s_bitmap_lock);
 
+	if (sbi->s_num_blocks > OMFS_MAX_BLOCKS) {
+		printk(KERN_ERR "omfs: sysblock number (%llx) is out of range\n",
+		       (unsigned long long)sbi->s_num_blocks);
+		goto out_brelse_bh;
+	}
+
 	if (sbi->s_sys_blocksize > PAGE_SIZE) {
 		printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
 			sbi->s_sys_blocksize);

fs/omfs/omfs_fs.h

@@ -18,6 +18,7 @@
 #define OMFS_XOR_COUNT 19
 #define OMFS_MAX_BLOCK_SIZE 8192
 #define OMFS_MAX_CLUSTER_SIZE 8
+#define OMFS_MAX_BLOCKS (1ul << 31)
 
 struct omfs_super_block {
 	char s_fill1[256];