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authorJan Kara <jack@suse.cz>2012-07-10 17:58:04 +0200
committerJan Kara <jack@suse.cz>2012-07-10 18:02:17 +0200
commit57b9655d01ef057a523e810d29c37ac09b80eead (patch)
tree2574c27c92170f6e580ac9d59c5719bffae994d1
parent44f4f729e7a143b08bd63c33cb78b3181d9f4716 (diff)
downloadlinux-57b9655d01ef057a523e810d29c37ac09b80eead.tar.bz2
udf: Improve table length check to avoid possible overflow
When a partition table length is corrupted to be close to 1 << 32, the check for its length may overflow on 32-bit systems and we will think the length is valid. Later on the kernel can crash trying to read beyond end of buffer. Fix the check to avoid possible overflow. CC: stable@vger.kernel.org Reported-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/udf/super.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/udf/super.c b/fs/udf/super.c
index 8a7583867811..dcbf98722afc 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1340,7 +1340,7 @@ 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) {
+ if (table_len > sb->s_blocksize - sizeof(*lvd)) {
udf_err(sb, "error loading logical volume descriptor: "
"Partition table too long (%u > %lu)\n", table_len,
sb->s_blocksize - sizeof(*lvd));