UDF: handle wrong superblock better

If UDF superblock is incorrect, we can fail to find a table of free /
allocated space and consequently Oops.  Handle this situation more
gracefully by ignoring the broken UDF partition.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 4 deletions

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 382be7be5ae3..c68a6e730b97 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -89,7 +89,7 @@ static int udf_find_fileset(struct super_block *, kernel_lb_addr *,
 static void udf_load_pvoldesc(struct super_block *, struct buffer_head *);
 static void udf_load_fileset(struct super_block *, struct buffer_head *,
                              kernel_lb_addr *);
-static void udf_load_partdesc(struct super_block *, struct buffer_head *);
+static int udf_load_partdesc(struct super_block *, struct buffer_head *);
 static void udf_open_lvid(struct super_block *);
 static void udf_close_lvid(struct super_block *);
 static unsigned int udf_count_free(struct super_block *);
@@ -877,7 +877,7 @@ static void udf_load_fileset(struct super_block *sb, struct buffer_head *bh,
                   root->logicalBlockNum, root->partitionReferenceNum);
 }
 
-static void udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
+static int udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
 {
         struct partitionDesc *p;
         int i;
@@ -912,6 +912,11 @@ static void udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
 
                                         UDF_SB_PARTMAPS(sb)[i].s_uspace.s_table =
                                                 udf_iget(sb, loc);
+                                        if (!UDF_SB_PARTMAPS(sb)[i].s_uspace.s_table) {
+                                                udf_debug("cannot load unallocSpaceTable (part %d)\n",
+                                                        i);
+                                                return 1;
+                                        }
                                         UDF_SB_PARTFLAGS(sb,i) |= UDF_PART_FLAG_UNALLOC_TABLE;
                                         udf_debug("unallocSpaceTable (part %d) @ %ld\n",
                                                   i, UDF_SB_PARTMAPS(sb)[i].s_uspace.s_table->i_ino);
@@ -938,6 +943,11 @@ static void udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
 
                                         UDF_SB_PARTMAPS(sb)[i].s_fspace.s_table =
                                                 udf_iget(sb, loc);
+                                        if (!UDF_SB_PARTMAPS(sb)[i].s_fspace.s_table) {
+                                                udf_debug("cannot load freedSpaceTable (part %d)\n",
+                                                        i);
+                                                return 1;
+                                        }
                                         UDF_SB_PARTFLAGS(sb,i) |= UDF_PART_FLAG_FREED_TABLE;
                                         udf_debug("freedSpaceTable (part %d) @ %ld\n",
                                                   i, UDF_SB_PARTMAPS(sb)[i].s_fspace.s_table->i_ino);
@@ -966,6 +976,7 @@ static void udf_load_partdesc(struct super_block *sb, struct buffer_head *bh)
                           le16_to_cpu(p->partitionNumber), i, UDF_SB_PARTTYPE(sb,i),
                           UDF_SB_PARTROOT(sb,i), UDF_SB_PARTLEN(sb,i));
         }
+        return 0;
 }
 
 static int udf_load_logicalvol(struct super_block *sb, struct buffer_head *bh,
@@ -1177,12 +1188,19 @@ static int udf_process_sequence(struct super_block *sb, long block, long lastblo
                                 udf_load_logicalvol(sb, bh, fileset);
                         } else if (i == VDS_POS_PARTITION_DESC) {
                                 struct buffer_head *bh2 = NULL;
-                                udf_load_partdesc(sb, bh);
+                                if (udf_load_partdesc(sb, bh)) {
+                                        brelse(bh);
+                                        return 1;
+                                }
                                 for (j = vds[i].block + 1; j <  vds[VDS_POS_TERMINATING_DESC].block; j++) {
                                         bh2 = udf_read_tagged(sb, j, j, &ident);
                                         gd = (struct generic_desc *)bh2->b_data;
                                         if (ident == TAG_IDENT_PD)
-                                                udf_load_partdesc(sb, bh2);
+                                                if (udf_load_partdesc(sb, bh2)) {
+                                                        brelse(bh);
+                                                        brelse(bh2);
+                                                        return 1;
+                                                }
                                         brelse(bh2);
                                 }
                         }