1 files changed, 28 insertions, 5 deletions

diff --git a/fs/udf/balloc.c b/fs/udf/balloc.c
index fcda0fc97..0dc98bbad 100644
--- a/fs/udf/balloc.c
+++ b/fs/udf/balloc.c
@@ -36,18 +36,41 @@ static int read_block_bitmap(struct super_block *sb,
 			     unsigned long bitmap_nr)
 {
 	struct buffer_head *bh = NULL;
-	int retval = 0;
+	int i;
+	int max_bits, off, count;
 	struct kernel_lb_addr loc;
 
 	loc.logicalBlockNum = bitmap->s_extPosition;
 	loc.partitionReferenceNum = UDF_SB(sb)->s_partition;
 
 	bh = udf_tread(sb, udf_get_lb_pblock(sb, &loc, block));
+	bitmap->s_block_bitmap[bitmap_nr] = bh;
 	if (!bh)
-		retval = -EIO;
+		return -EIO;
 
-	bitmap->s_block_bitmap[bitmap_nr] = bh;
-	return retval;
+	/* Check consistency of Space Bitmap buffer. */
+	max_bits = sb->s_blocksize * 8;
+	if (!bitmap_nr) {
+		off = sizeof(struct spaceBitmapDesc) << 3;
+		count = min(max_bits - off, bitmap->s_nr_groups);
+	} else {
+		/*
+		 * Rough check if bitmap number is too big to have any bitmap
+		 * blocks reserved.
+		 */
+		if (bitmap_nr >
+		    (bitmap->s_nr_groups >> (sb->s_blocksize_bits + 3)) + 2)
+			return 0;
+		off = 0;
+		count = bitmap->s_nr_groups - bitmap_nr * max_bits +
+				(sizeof(struct spaceBitmapDesc) << 3);
+		count = min(count, max_bits);
+	}
+
+	for (i = 0; i < count; i++)
+		if (udf_test_bit(i + off, bh->b_data))
+			return -EFSCORRUPTED;
+	return 0;
 }
 
 static int __load_block_bitmap(struct super_block *sb,
@@ -555,7 +578,7 @@ static udf_pblk_t udf_table_new_block(struct super_block *sb,
 	udf_pblk_t newblock = 0;
 	uint32_t adsize;
 	uint32_t elen, goal_elen = 0;
-	struct kernel_lb_addr eloc, uninitialized_var(goal_eloc);
+	struct kernel_lb_addr eloc, goal_eloc;
 	struct extent_position epos, goal_epos;
 	int8_t etype;
 	struct udf_inode_info *iinfo = UDF_I(table);