linux-kernel - [PATCH 4.2.y-ckt 114/206] fs/cifs: correctly to anonymous authentication for the LANMAN authentication

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Message-Id: <1465507015-23052-115-git-send-email-kamal@canonical.com>
Date:	Thu,  9 Jun 2016 14:15:23 -0700
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Stefan Metzmacher <metze@...ba.org>,
	Steve French <smfrench@...il.com>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 4.2.y-ckt 114/206] fs/cifs: correctly to anonymous authentication for the LANMAN authentication

4.2.8-ckt12 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Stefan Metzmacher <metze@...ba.org>

commit fa8f3a354bb775ec586e4475bcb07f7dece97e0c upstream.

Only server which map unknown users to guest will allow
access using a non-null LMChallengeResponse.

For Samba it's the "map to guest = bad user" option.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11913

Signed-off-by: Stefan Metzmacher <metze@...ba.org>
Signed-off-by: Steve French <smfrench@...il.com>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 fs/cifs/sess.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index abaeeab..91dbaca 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -678,20 +678,24 @@ sess_auth_lanman(struct sess_data *sess_data)
 
 	pSMB->req.hdr.Flags2 &= ~SMBFLG2_UNICODE;
 
-	/* no capabilities flags in old lanman negotiation */
-	pSMB->old_req.PasswordLength = cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+	if (ses->user_name != NULL) {
+		/* no capabilities flags in old lanman negotiation */
+		pSMB->old_req.PasswordLength = cpu_to_le16(CIFS_AUTH_RESP_SIZE);
 
-	/* Calculate hash with password and copy into bcc_ptr.
-	 * Encryption Key (stored as in cryptkey) gets used if the
-	 * security mode bit in Negottiate Protocol response states
-	 * to use challenge/response method (i.e. Password bit is 1).
-	 */
-	rc = calc_lanman_hash(ses->password, ses->server->cryptkey,
-			      ses->server->sec_mode & SECMODE_PW_ENCRYPT ?
-			      true : false, lnm_session_key);
+		/* Calculate hash with password and copy into bcc_ptr.
+		 * Encryption Key (stored as in cryptkey) gets used if the
+		 * security mode bit in Negottiate Protocol response states
+		 * to use challenge/response method (i.e. Password bit is 1).
+		 */
+		rc = calc_lanman_hash(ses->password, ses->server->cryptkey,
+				      ses->server->sec_mode & SECMODE_PW_ENCRYPT ?
+				      true : false, lnm_session_key);
 
-	memcpy(bcc_ptr, (char *)lnm_session_key, CIFS_AUTH_RESP_SIZE);
-	bcc_ptr += CIFS_AUTH_RESP_SIZE;
+		memcpy(bcc_ptr, (char *)lnm_session_key, CIFS_AUTH_RESP_SIZE);
+		bcc_ptr += CIFS_AUTH_RESP_SIZE;
+	} else {
+		pSMB->old_req.PasswordLength = 0;
+	}
 
 	/*
 	 * can not sign if LANMAN negotiated so no need
-- 
2.7.4