Added bounds checking to make sure that every attr don't stray beyond valid
memory region.
Signed-off-by: lei lu <llfamsec@xxxxxxxxx>
---
fs/ntfs3/record.c | 31 ++++++++++++++-----------------
1 file changed, 14 insertions(+), 17 deletions(-)
diff --git a/fs/ntfs3/record.c b/fs/ntfs3/record.c
index 6aa3a9d44df1..d47ca8ca270b 100644
--- a/fs/ntfs3/record.c
+++ b/fs/ntfs3/record.c
@@ -223,34 +223,35 @@ struct ATTRIB *mi_enum_attr(struct mft_inode *mi, struct ATTRIB *attr)
prev_type = 0;
attr = Add2Ptr(rec, off);
} else {
- /* Check if input attr inside record. */
+ /*
+ * We don't need to check previous attr here. There is
+ * a bounds checking in the previous round.
+ */
off = PtrOffset(rec, attr);
- if (off >= used)
- return NULL;
asize = le32_to_cpu(attr->size);
- if (asize < SIZEOF_RESIDENT) {
- /* Impossible 'cause we should not return such attribute. */
- return NULL;
- }
-
- /* Overflow check. */
- if (off + asize < off)
- return NULL;
prev_type = le32_to_cpu(attr->type);
attr = Add2Ptr(attr, asize);
off += asize;
}
- asize = le32_to_cpu(attr->size);
-
/* Can we use the first field (attr->type). */
if (off + 8 > used) {
static_assert(ALIGN(sizeof(enum ATTR_TYPE), 8) == 8);
return NULL;
}
+ asize = le32_to_cpu(attr->size);
+ if (asize < SIZEOF_RESIDENT) {
+ /* Impossible 'cause we should not return such attribute. */
+ return NULL;
+ }
+
+ /* Check overflow and boundary. */
+ if (off + asize < off || off + asize > used)
+ return NULL;
+
if (attr->type == ATTR_END) {
/* End of enumeration. */
return NULL;
@@ -265,10 +266,6 @@ struct ATTRIB *mi_enum_attr(struct mft_inode *mi, struct ATTRIB *attr)
if (t32 < prev_type)
return NULL;
- /* Check overflow and boundary. */
- if (off + asize < off || off + asize > used)
- return NULL;
-
/* Check size of attribute. */
if (!attr->non_res) {
/* Check resident fields. */
--
2.34.1
