Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Steve French <stfrench@microsoft.com>,
        Aurelien Aptel <aaptel@suse.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.18 123/197] smb3: if server does not support posix do not allow posix mount option
Date:   Thu, 13 Sep 2018 15:31:12 +0200
Message-Id: <20180913131846.465029010@linuxfoundation.org>
In-Reply-To: <20180913131841.568116777@linuxfoundation.org>
References: <20180913131841.568116777@linuxfoundation.org>
User-Agent: quilt/0.65
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Steve French <stfrench@microsoft.com>

[ Upstream commit 8505c8bfd85a260c9dc5c47e15bd8c5357fcbcd2 ]

If user specifies "posix" on an SMB3.11 mount, then fail the mount
if server does not return the POSIX negotiate context indicating
support for posix.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/cifs/connect.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3031,11 +3031,15 @@ cifs_get_tcon(struct cifs_ses *ses, stru
 	}
 
 #ifdef CONFIG_CIFS_SMB311
-	if ((volume_info->linux_ext) && (ses->server->posix_ext_supported)) {
-		if (ses->server->vals->protocol_id == SMB311_PROT_ID) {
+	if (volume_info->linux_ext) {
+		if (ses->server->posix_ext_supported) {
 			tcon->posix_extensions = true;
 			printk_once(KERN_WARNING
 				"SMB3.11 POSIX Extensions are experimental\n");
+		} else {
+			cifs_dbg(VFS, "Server does not support mounting with posix SMB3.11 extensions.\n");
+			rc = -EOPNOTSUPP;
+			goto out_fail;
 		}
 	}
 #endif /* 311 */