diff --git a/fs/squashfs/fragment.c b/fs/squashfs/fragment.c
index 86ad9a4..0681fea 100644
--- a/fs/squashfs/fragment.c
+++ b/fs/squashfs/fragment.c
@@ -49,11 +49,16 @@ int squashfs_frag_lookup(struct super_block *sb, unsigned int fragment,
 				u64 *fragment_block)
 {
 	struct squashfs_sb_info *msblk = sb->s_fs_info;
-	int block = SQUASHFS_FRAGMENT_INDEX(fragment);
-	int offset = SQUASHFS_FRAGMENT_INDEX_OFFSET(fragment);
-	u64 start_block = le64_to_cpu(msblk->fragment_index[block]);
+	int block, offset, size;
 	struct squashfs_fragment_entry fragment_entry;
-	int size;
+	u64 start_block;
+
+	if (fragment >= msblk->fragments)
+		return -EIO;
+	block = SQUASHFS_FRAGMENT_INDEX(fragment);
+	offset = SQUASHFS_FRAGMENT_INDEX_OFFSET(fragment);
+
+	start_block = le64_to_cpu(msblk->fragment_index[block]);
 
 	size = squashfs_read_metadata(sb, &fragment_entry, &start_block,
 					&offset, sizeof(fragment_entry));