ksmbd: add bounds check for create lease context

Add missing bounds check for create lease context.

Cc: stable@vger.kernel.org
Reported-by: Norbert Szetei <norbert@doyensec.com>
Tested-by: Norbert Szetei <norbert@doyensec.com>
Signed-off-by: Norbert Szetei <norbert@doyensec.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: nszetei

fs/smb/server/oplock.c

@@ -1505,6 +1505,10 @@ struct lease_ctx_info *parse_lease_state(void *open_req)
 	if (sizeof(struct lease_context_v2) == le32_to_cpu(cc->DataLength)) {
 		struct create_lease_v2 *lc = (struct create_lease_v2 *)cc;
 
+		if (le16_to_cpu(cc->DataOffset) + le32_to_cpu(cc->DataLength) <
+		    sizeof(struct create_lease_v2) - 4)
+			return NULL;
+
 		memcpy(lreq->lease_key, lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE);
 		lreq->req_state = lc->lcontext.LeaseState;
 		lreq->flags = lc->lcontext.LeaseFlags;
@@ -1517,6 +1521,10 @@ struct lease_ctx_info *parse_lease_state(void *open_req)
 	} else {
 		struct create_lease *lc = (struct create_lease *)cc;
 
+		if (le16_to_cpu(cc->DataOffset) + le32_to_cpu(cc->DataLength) <
+		    sizeof(struct create_lease))
+			return NULL;
+
 		memcpy(lreq->lease_key, lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE);
 		lreq->req_state = lc->lcontext.LeaseState;
 		lreq->flags = lc->lcontext.LeaseFlags;