[PATCH 1/2] UDF: handle wrong superblock better

From: Jan Kara
Date: Wed Aug 22 2007 - 08:51:17 EST


Hello,

attached is a patch for UDF to better handle (i.e. don't Oops) the case when
we are not able to load table with extents of used / free space. This could
actually be considered a DOS... Andrew, please apply.
Honza

--
Jan Kara <jack@xxxxxxx>
SuSE CR Labs
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@xxxxxxx>

diff -rupX /home/jack/.kerndiffexclude linux-2.6.23-rc3-1-udf_fix/fs/udf/super.c linux-2.6.23-rc3-2-udf_mount_fix/fs/udf/super.c
--- linux-2.6.23-rc3-1-udf_fix/fs/udf/super.c 2007-08-21 14:11:44.000000000 +0200
+++ linux-2.6.23-rc3-2-udf_mount_fix/fs/udf/super.c 2007-08-21 18:29:40.000000000 +0200
@@ -89,7 +89,7 @@ static int udf_find_fileset(struct super
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 supe
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 sup

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 sup

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 sup
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 s
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);
}
}