CIFS: Only send SMB2_NEGOTIATE command on new TCP connections

Do not allow commands other than SMB2_NEGOTIATE to be sent over recently established TCP connections. Return -EAGAIN to let upper layers handle it properly. Signed-off-by: Pavel Shilovsky <[email protected]> Signed-off-by: Steve French <[email protected]>
tadfisher · Mar 6, 2019 · 2084ed5 · 2084ed5
1 parent 6dfbd84
commit 2084ed5
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
@@ -619,6 +619,10 @@ smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_sync_hdr *shdr,
 		return -EAGAIN;
 	}
 
+	if (ses->server->tcpStatus == CifsNeedNegotiate &&
+	   shdr->Command != SMB2_NEGOTIATE)
+		return -EAGAIN;
+
 	if (ses->status == CifsNew) {
 		if ((shdr->Command != SMB2_SESSION_SETUP) &&
 		    (shdr->Command != SMB2_NEGOTIATE))
@@ -702,6 +706,10 @@ smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 			(struct smb2_sync_hdr *)rqst->rq_iov[0].iov_base;
 	struct mid_q_entry *mid;
 
+	if (server->tcpStatus == CifsNeedNegotiate &&
+	   shdr->Command != SMB2_NEGOTIATE)
+		return ERR_PTR(-EAGAIN);
+
 	smb2_seq_num_into_buf(server, shdr);
 
 	mid = smb2_mid_entry_alloc(shdr, server);