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>

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 382be7be5ae34e66b6619d5c7bab8e20852edd48..c68a6e730b97918f041819f055492193b10869ab 100644 (file)
--- 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);
                                }
                        }