From 57b9655d01ef057a523e810d29c37ac09b80eead Mon Sep 17 00:00:00 2001 From: Jan Kara 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: stable@vger.kernel.org Reported-by: Ben Hutchings Signed-off-by: Jan Kara --- fs/udf/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/udf/super.c') 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)); -- cgit v1.2.3