From: Steve French <stfrench@microsoft.com>
Date: Sat, 8 May 2021 01:00:41 +0000 (-0500)
Subject: smb3: do not attempt multichannel to server which does not support it
X-Git-Tag: microblaze-v5.14~6^2~1
X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=9c2dc11df50d1c8537075ff6b98472198e24438e;p=linux-2.6-microblaze.git

smb3: do not attempt multichannel to server which does not support it

We were ignoring CAP_MULTI_CHANNEL in the server response - if the
server doesn't support multichannel we should not be attempting it.

See MS-SMB2 section 3.2.5.2

Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-By: Tom Talpey <tom@talpey.com>
Cc: <stable@vger.kernel.org> # v5.8+
Signed-off-by: Steve French <stfrench@microsoft.com>
---

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 63d517b9f2ff..a92a1fb7cb52 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -97,6 +97,12 @@ int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)
 		return 0;
 	}
 
+	if (!(ses->server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL)) {
+		cifs_dbg(VFS, "server %s does not support multichannel\n", ses->server->hostname);
+		ses->chan_max = 1;
+		return 0;
+	}
+
 	/*
 	 * Make a copy of the iface list at the time and use that
 	 * instead so as to not hold the iface spinlock for opening