diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c
index 0d1be4da3e4f..66ead9db26ee 100644
--- a/fs/ntfs3/fslog.c
+++ b/fs/ntfs3/fslog.c
@@ -2599,11 +2599,12 @@ static int read_next_log_rec(struct ntfs_log *log, struct lcb *lcb, u64 *lsn)
 
 bool check_index_header(const struct INDEX_HDR *hdr, size_t bytes)
 {
+	const bool has_subnode = hdr_has_subnode(hdr);
 	__le16 mask;
 	u32 min_de, de_off, used, total;
 	const struct NTFS_DE *e;
 
-	if (hdr_has_subnode(hdr)) {
+	if (has_subnode) {
 		min_de = sizeof(struct NTFS_DE) + sizeof(u64);
 		mask = NTFS_IE_HAS_SUBNODES;
 	} else {
@@ -2620,20 +2621,33 @@ bool check_index_header(const struct INDEX_HDR *hdr, size_t bytes)
 		return false;
 	}
 
-	e = Add2Ptr(hdr, de_off);
+	e = (const struct NTFS_DE *)((const u8 *)hdr + de_off);
 	for (;;) {
 		u16 esize = le16_to_cpu(e->size);
-		struct NTFS_DE *next = Add2Ptr(e, esize);
+		u16 key_size = le16_to_cpu(e->key_size);
+		u16 data_size;
 
-		if (esize < min_de || PtrOffset(hdr, next) > used ||
+		if (!IS_ALIGNED(esize, 8) || esize < min_de ||
 		    (e->flags & NTFS_IE_HAS_SUBNODES) != mask) {
 			return false;
 		}
 
-		if (de_is_last(e))
-			break;
+		if (size_add(de_off, esize) > used)
+			return false;
 
-		e = next;
+		if (de_is_last(e)) {
+			if (key_size)
+				return false;
+
+			break;
+		}
+
+		data_size = esize - min_de;
+		if (key_size > data_size)
+			return false;
+
+		de_off += esize;
+		e = (const struct NTFS_DE *)((const u8 *)hdr + de_off);
 	}
 
 	return true;
diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c
index d65984d9dc07..85f674e9e361 100644
--- a/fs/ntfs3/index.c
+++ b/fs/ntfs3/index.c
@@ -611,16 +611,51 @@ static const struct NTFS_DE *hdr_insert_head(struct INDEX_HDR *hdr,
  */
 static bool index_hdr_check(const struct INDEX_HDR *hdr, u32 bytes)
 {
+	const bool has_subnode = hdr_has_subnode(hdr);
+	const u16 min_size = sizeof(struct NTFS_DE) +
+			     (has_subnode ? sizeof(u64) : 0);
 	u32 end = le32_to_cpu(hdr->used);
 	u32 tot = le32_to_cpu(hdr->total);
 	u32 off = le32_to_cpu(hdr->de_off);
+	const struct NTFS_DE *e;
 
 	if (!IS_ALIGNED(off, 8) || tot > bytes || end > tot ||
-	    size_add(off, sizeof(struct NTFS_DE)) > end) {
+	    size_add(off, min_size) > end) {
 		/* incorrect index buffer. */
 		return false;
 	}
 
+	/* Ensure every key stays inside its entry before lookup walks it. */
+	e = (const struct NTFS_DE *)((const u8 *)hdr + off);
+	for (;;) {
+		u16 e_size = le16_to_cpu(e->size);
+		u16 key_size = le16_to_cpu(e->key_size);
+		u16 data_size;
+
+		if (!IS_ALIGNED(e_size, 8) || e_size < min_size ||
+		    de_has_vcn(e) != has_subnode) {
+			/* incorrect index entry. */
+			return false;
+		}
+
+		if (size_add(off, e_size) > end)
+			return false;
+
+		if (de_is_last(e)) {
+			if (key_size)
+				return false;
+
+			break;
+		}
+
+		data_size = e_size - min_size;
+		if (key_size > data_size)
+			return false;
+
+		off += e_size;
+		e = (const struct NTFS_DE *)((const u8 *)hdr + off);
+	}
+
 	return true;
 }