[PATCH 6.1.y 1/4] fs/ntfs3: Add more checks in mi_enum_attr (part 2)

[Nikita Nagornyi <nagornyi@amazon.de>]

From: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Add offset check before access to attr->non_res field as mentioned in [1].

[1] https://lore.kernel.org/ntfs3/20241010110005.42792-1-llfamsec@gmail.com/

Suggested-by: lei lu <llfamsec@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Nikita Nagornyi <nagornyi@amazon.de>
(cherry picked from commit a8f659ce14f8f734894227ba2c5ca78c8451501e)
---
 fs/ntfs3/record.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/fs/ntfs3/record.c b/fs/ntfs3/record.c
index bfb1f4c2f271..d8d43f6a96fd 100644
--- a/fs/ntfs3/record.c
+++ b/fs/ntfs3/record.c
@@ -206,7 +206,7 @@ struct ATTRIB *mi_enum_attr(struct mft_inode *mi, struct ATTRIB *attr)
 			return NULL;

 		if (off >= used || off < MFTRECORD_FIXUP_OFFSET_1 ||
-		    !IS_ALIGNED(off, 4)) {
+		    !IS_ALIGNED(off, 8)) {
 			return NULL;
 		}

@@ -230,8 +230,11 @@ struct ATTRIB *mi_enum_attr(struct mft_inode *mi, struct ATTRIB *attr)
 		off += asize;
 	}

-	/* Can we use the first field (attr->type). */
-	/* NOTE: this code also checks attr->size availability. */
+	/*
+	 * Can we use the first fields:
+	 * attr->type,
+	 * attr->size
+	 */
 	if (off + 8 > used) {
 		static_assert(ALIGN(sizeof(enum ATTR_TYPE), 8) == 8);
 		return NULL;
@@ -253,10 +256,17 @@ struct ATTRIB *mi_enum_attr(struct mft_inode *mi, struct ATTRIB *attr)

 	asize = le32_to_cpu(attr->size);

+	if (!IS_ALIGNED(asize, 8))
+		return NULL;
+
 	/* Check overflow and boundary. */
 	if (off + asize < off || off + asize > used)
 		return NULL;

+	/* Can we use the field attr->non_res. */
+	if (off + 9 > used)
+		return NULL;
+
 	/* Check size of attribute. */
 	if (!attr->non_res) {
 		/* Check resident fields. */

base-commit: 1a8763b93150b2c8f3992c27a5ce7857fee4ab0f
--
2.50.1