[PATCH 6.1.y 2/2] udf: Make sure there's enough space for LVID implementation use field

[Sasha Levin <sashal@kernel.org>]

From: Jan Kara <jack@suse.cz>

[ Upstream commit a61fb39759d719a4f4966742b4d28387e33d81c4 ]

udf_lvid_valid() verifies that the LVID has enough space for all the
tables and the reported length of ImplementationUse field. However it
doesn't make sure the reported length is large enough to contain
logicalVolIntegrityDescImpUse structure which OSTA specification
requires. This can thus lead to accesses beyond the end of LVID buffer
for suitably corrupted UDF filesystem. Add the length check.

Reported-by: Yunpeng Tian <shionthanatos@gmail.com>
Reported-by: Gongming Wang <gmwgg05@gmail.com>
Reported-by: Mingda Zhang <npczmd@qq.com>
Reported-by: Qinrun Dai <jupmouse@gmail.com>
Cc: stable@vger.kernel.org
Fixes: 781d2a9a2fc7 ("udf: Check LVID earlier")
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/udf/super.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/udf/super.c b/fs/udf/super.c
index b091cc98406b4..f924a814874b3 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1581,7 +1581,10 @@ static bool udf_lvid_valid(struct super_block *sb,
 
 	parts = le32_to_cpu(lvid->numOfPartitions);
 	impuselen = le32_to_cpu(lvid->lengthOfImpUse);
-	if (parts >= sb->s_blocksize || impuselen >= sb->s_blocksize ||
+	if (sizeof(struct logicalVolIntegrityDescImpUse) > impuselen ||
+	    impuselen >= sb->s_blocksize)
+		return false;
+	if (parts >= sb->s_blocksize ||
 	    sizeof(struct logicalVolIntegrityDesc) + impuselen +
 	    2 * parts * sizeof(u32) > sb->s_blocksize)
 		return false;
-- 
2.53.0