Merge tag 'v7.2-rc4-smb3-server-fixes' of git://git.samba.org/ksmbd

Pull smb server fixes from Steve French:
 "This contains eight ksmbd fixes covering POSIX ACL handling, SMB
  signing enforcement, DACL parsing and construction hardening, session
  lifetime handling, and validation of malformed transform and
  compressed SMB2 requests:

   - preserve inherited POSIX ACL mask when creating objects.

   - enforce the session signing requirement for plaintext SMB requests.

   - harden DACL/ACE processing against size overflows, incomplete ACE
     copies, and undersized SIDs.

   - defer teardown of a previous session until NTLM authentication
     succeeds.

   - reject undersized encryption-transform and decompressed SMB2
     requests before they can reach normal SMB2 request processing"

* tag 'v7.2-rc4-smb3-server-fixes' of git://git.samba.org/ksmbd:
  ksmbd: reject undersized decompressed SMB2 requests
  ksmbd: validate minimum PDU size for transform requests
  ksmbd: defer destroy_previous_session() until after NTLM authentication
  ksmbd: validate ACE size against SID sub-authorities
  ksmbd: restore DACL size on check_add_overflow() to avoid malformed ACL
  ksmbd: bound DACL dedup walk to copied ACEs
  ksmbd: enforce signing required by the session
  ksmbd: preserve VFS inherited POSIX ACL mask

1 files changed, 11 insertions, 5 deletions

diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c
index 9e8fdb39e5a2..dee8e4aced99 100644
--- a/fs/smb/server/connection.c
+++ b/fs/smb/server/connection.c
@@ -441,6 +441,8 @@ bool ksmbd_conn_alive(struct ksmbd_conn *conn)
 /* "+2" for BCC field (ByteCount, 2 bytes) */
 #define SMB1_MIN_SUPPORTED_PDU_SIZE (sizeof(struct smb_hdr) + 2)
 #define SMB2_MIN_SUPPORTED_PDU_SIZE (sizeof(struct smb2_pdu))
+#define SMB2_TRANSFORM_MIN_SUPPORTED_PDU_SIZE	\
+	(sizeof(struct smb2_transform_hdr) + sizeof(struct smb2_hdr))
 
 /**
  * ksmbd_conn_handler_loop() - session thread to listen on new smb requests
@@ -455,6 +457,7 @@ int ksmbd_conn_handler_loop(void *p)
 	struct ksmbd_conn *conn = (struct ksmbd_conn *)p;
 	struct ksmbd_transport *t = conn->transport;
 	unsigned int pdu_size, max_allowed_pdu_size, max_req;
+	__le32 proto;
 	char hdr_buf[4] = {0,};
 	int size;
 
@@ -546,11 +549,14 @@ recheck:
 		if (!ksmbd_smb_request(conn))
 			break;
 
-		if (((struct smb2_hdr *)smb_get_msg(conn->request_buf))->ProtocolId ==
-		    SMB2_PROTO_NUMBER) {
-			if (pdu_size < SMB2_MIN_SUPPORTED_PDU_SIZE)
-				break;
-		}
+		proto = *(__le32 *)smb_get_msg(conn->request_buf);
+		if (proto == SMB2_PROTO_NUMBER &&
+		    pdu_size < SMB2_MIN_SUPPORTED_PDU_SIZE)
+			break;
+
+		if (proto == SMB2_TRANSFORM_PROTO_NUM &&
+		    pdu_size < SMB2_TRANSFORM_MIN_SUPPORTED_PDU_SIZE)
+			break;
 
 		if (!default_conn_ops.process_fn) {
 			pr_err("No connection request callback\n");