Merge tag '6.4-rc2-ksmbd-server-fixes' of git://git.samba.org/ksmbd

Pull ksmbd server fixes from Steve French:

 - two fixes for incorrect SMB3 message validation (one for client which
   uses 8 byte padding, and one for empty bcc)

 - two fixes for out of bounds bugs: one for username offset checks (in
   session setup) and the other for create context name length checks in
   open requests

* tag '6.4-rc2-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
  ksmbd: smb2: Allow messages padded to 8byte boundary
  ksmbd: allocate one more byte for implied bcc[0]
  ksmbd: fix wrong UserName check in session_user
  ksmbd: fix global-out-of-bounds in smb2_find_context_vals

fs/ksmbd/connection.c

@@ -351,7 +351,8 @@ int ksmbd_conn_handler_loop(void *p)
 			break;
 
 		/* 4 for rfc1002 length field */
-		size = pdu_size + 4;
+		/* 1 for implied bcc[0] */
+		size = pdu_size + 4 + 1;
 		conn->request_buf = kvmalloc(size, GFP_KERNEL);
 		if (!conn->request_buf)
 			break;

fs/ksmbd/oplock.c

@@ -1449,11 +1449,12 @@ struct lease_ctx_info *parse_lease_state(void *open_req)
  * smb2_find_context_vals() - find a particular context info in open request
  * @open_req:	buffer containing smb2 file open(create) request
  * @tag:	context name to search for
+ * @tag_len:	the length of tag
  *
  * Return:	pointer to requested context, NULL if @str context not found
  *		or error pointer if name length is invalid.
  */
-struct create_context *smb2_find_context_vals(void *open_req, const char *tag)
+struct create_context *smb2_find_context_vals(void *open_req, const char *tag, int tag_len)
 {
 	struct create_context *cc;
 	unsigned int next = 0;
@@ -1492,7 +1493,7 @@ struct create_context *smb2_find_context_vals(void *open_req, const char *tag)
 			return ERR_PTR(-EINVAL);
 
 		name = (char *)cc + name_off;
-		if (memcmp(name, tag, name_len) == 0)
+		if (name_len == tag_len && !memcmp(name, tag, name_len))
 			return cc;
 
 		remain_len -= next;

fs/ksmbd/oplock.h

@@ -118,7 +118,7 @@ void create_durable_v2_rsp_buf(char *cc, struct ksmbd_file *fp);
 void create_mxac_rsp_buf(char *cc, int maximal_access);
 void create_disk_id_rsp_buf(char *cc, __u64 file_id, __u64 vol_id);
 void create_posix_rsp_buf(char *cc, struct ksmbd_file *fp);
-struct create_context *smb2_find_context_vals(void *open_req, const char *str);
+struct create_context *smb2_find_context_vals(void *open_req, const char *tag, int tag_len);
 struct oplock_info *lookup_lease_in_table(struct ksmbd_conn *conn,
 					  char *lease_key);
 int find_same_lease_key(struct ksmbd_session *sess, struct ksmbd_inode *ci,

fs/ksmbd/smb2misc.c

@@ -416,8 +416,11 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work)
 
 		/*
 		 * Allow a message that padded to 8byte boundary.
+		 * Linux 4.19.217 with smb 3.0.2 are sometimes
+		 * sending messages where the cls_len is exactly
+		 * 8 bytes less than len.
 		 */
-		if (clc_len < len && (len - clc_len) < 8)
+		if (clc_len < len && (len - clc_len) <= 8)
 			goto validate_credit;
 
 		pr_err_ratelimited(

fs/ksmbd/smb2pdu.c

@@ -1356,7 +1356,7 @@ static struct ksmbd_user *session_user(struct ksmbd_conn *conn,
 	struct authenticate_message *authblob;
 	struct ksmbd_user *user;
 	char *name;
-	unsigned int auth_msg_len, name_off, name_len, secbuf_len;
+	unsigned int name_off, name_len, secbuf_len;
 
 	secbuf_len = le16_to_cpu(req->SecurityBufferLength);
 	if (secbuf_len < sizeof(struct authenticate_message)) {
@@ -1366,9 +1366,8 @@ static struct ksmbd_user *session_user(struct ksmbd_conn *conn,
 	authblob = user_authblob(conn, req);
 	name_off = le32_to_cpu(authblob->UserName.BufferOffset);
 	name_len = le16_to_cpu(authblob->UserName.Length);
-	auth_msg_len = le16_to_cpu(req->SecurityBufferOffset) + secbuf_len;
 
-	if (auth_msg_len < (u64)name_off + name_len)
+	if (secbuf_len < (u64)name_off + name_len)
 		return NULL;
 
 	name = smb_strndup_from_utf16((const char *)authblob + name_off,
@@ -2464,7 +2463,7 @@ static int smb2_create_sd_buffer(struct ksmbd_work *work,
 		return -ENOENT;
 
 	/* Parse SD BUFFER create contexts */
-	context = smb2_find_context_vals(req, SMB2_CREATE_SD_BUFFER);
+	context = smb2_find_context_vals(req, SMB2_CREATE_SD_BUFFER, 4);
 	if (!context)
 		return -ENOENT;
 	else if (IS_ERR(context))
@@ -2666,7 +2665,7 @@ int smb2_open(struct ksmbd_work *work)
 
 	if (req->CreateContextsOffset) {
 		/* Parse non-durable handle create contexts */
-		context = smb2_find_context_vals(req, SMB2_CREATE_EA_BUFFER);
+		context = smb2_find_context_vals(req, SMB2_CREATE_EA_BUFFER, 4);
 		if (IS_ERR(context)) {
 			rc = PTR_ERR(context);
 			goto err_out1;
@@ -2686,7 +2685,7 @@ int smb2_open(struct ksmbd_work *work)
 		}
 
 		context = smb2_find_context_vals(req,
-						 SMB2_CREATE_QUERY_MAXIMAL_ACCESS_REQUEST);
+						 SMB2_CREATE_QUERY_MAXIMAL_ACCESS_REQUEST, 4);
 		if (IS_ERR(context)) {
 			rc = PTR_ERR(context);
 			goto err_out1;
@@ -2697,7 +2696,7 @@ int smb2_open(struct ksmbd_work *work)
 		}
 
 		context = smb2_find_context_vals(req,
-						 SMB2_CREATE_TIMEWARP_REQUEST);
+						 SMB2_CREATE_TIMEWARP_REQUEST, 4);
 		if (IS_ERR(context)) {
 			rc = PTR_ERR(context);
 			goto err_out1;
@@ -2709,7 +2708,7 @@ int smb2_open(struct ksmbd_work *work)
 
 		if (tcon->posix_extensions) {
 			context = smb2_find_context_vals(req,
-							 SMB2_CREATE_TAG_POSIX);
+							 SMB2_CREATE_TAG_POSIX, 16);
 			if (IS_ERR(context)) {
 				rc = PTR_ERR(context);
 				goto err_out1;
@@ -3107,7 +3106,7 @@ int smb2_open(struct ksmbd_work *work)
 		struct create_alloc_size_req *az_req;
 
 		az_req = (struct create_alloc_size_req *)smb2_find_context_vals(req,
-					SMB2_CREATE_ALLOCATION_SIZE);
+					SMB2_CREATE_ALLOCATION_SIZE, 4);
 		if (IS_ERR(az_req)) {
 			rc = PTR_ERR(az_req);
 			goto err_out;
@@ -3134,7 +3133,7 @@ int smb2_open(struct ksmbd_work *work)
 					    err);
 		}
 
-		context = smb2_find_context_vals(req, SMB2_CREATE_QUERY_ON_DISK_ID);
+		context = smb2_find_context_vals(req, SMB2_CREATE_QUERY_ON_DISK_ID, 4);
 		if (IS_ERR(context)) {
 			rc = PTR_ERR(context);
 			goto err_out;