udf: Avoid run away loop when partition table length is corrupted

[pandora-kernel.git] / fs / udf / super.c

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 87cb24a..800e839 100644 (file)
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1227,6 +1227,7 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
        struct genericPartitionMap *gpm;
        uint16_t ident;
        struct buffer_head *bh;
+       unsigned int table_len;
        int ret = 0;
 
        bh = udf_read_tagged(sb, block, block, &ident);
@@ -1234,15 +1235,20 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
                return 1;
        BUG_ON(ident != TAG_IDENT_LVD);
        lvd = (struct logicalVolDesc *)bh->b_data;
-
-       i = udf_sb_alloc_partition_maps(sb, le32_to_cpu(lvd->numPartitionMaps));
-       if (i != 0) {
-               ret = i;
+       table_len = le32_to_cpu(lvd->mapTableLength);
+       if (sizeof(*lvd) + table_len > sb->s_blocksize) {
+               udf_err(sb, "error loading logical volume descriptor: "
+                       "Partition table too long (%u > %lu)\n", table_len,
+                       sb->s_blocksize - sizeof(*lvd));
                goto out_bh;
        }
 
+       ret = udf_sb_alloc_partition_maps(sb, le32_to_cpu(lvd->numPartitionMaps));
+       if (ret)
+               goto out_bh;
+
        for (i = 0, offset = 0;
-            i < sbi->s_partitions && offset < le32_to_cpu(lvd->mapTableLength);
+            i < sbi->s_partitions && offset < table_len;
             i++, offset += gpm->partitionMapLength) {
                struct udf_part_map *map = &sbi->s_partmaps[i];
                gpm = (struct genericPartitionMap *)