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Subject[ 092/180] udf: Avoid run away loop when partition table length is corrupted
2.6.32-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack@suse.cz>

commit adee11b2085bee90bd8f4f52123ffb07882d6256 upstream.

Check provided length of partition table so that (possibly maliciously)
corrupted partition table cannot cause accessing data beyond current buffer.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
fs/udf/super.c | 11 ++++++++++-
1 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/fs/udf/super.c b/fs/udf/super.c
index ee6b3af..0388d43 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1249,6 +1249,7 @@ 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);
@@ -1257,6 +1258,14 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
BUG_ON(ident != TAG_IDENT_LVD);
lvd = (struct logicalVolDesc *)bh->b_data;

+ table_len = le32_to_cpu(lvd->mapTableLength);
+ if (sizeof(*lvd) + table_len > sb->s_blocksize) {
+ udf_error(sb, __func__, "error loading logical volume descriptor: "
+ "Partition table too long (%u > %lu)\n", table_len,
+ sb->s_blocksize - sizeof(*lvd));
+ goto out_bh;
+ }
+
i = udf_sb_alloc_partition_maps(sb, le32_to_cpu(lvd->numPartitionMaps));
if (i != 0) {
ret = i;
@@ -1264,7 +1273,7 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
}

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 *)
--
1.7.2.1.45.g54fbc




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