commit: 57b9655d01ef057a523e810d29c37ac09b80eead From: Jan Kara <[email protected]> Date: Tue, 10 Jul 2012 17:58:04 +0200 Subject: 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: [email protected] Reported-by: Ben Hutchings <[email protected]> Signed-off-by: Jan Kara <[email protected]> --- fs/udf/super.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/udf/super.c b/fs/udf/super.c index 8a75838..dcbf987 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)); -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
