[PATCH 4.4 15/86] fs/cifs: correctly to anonymous authentication for the LANMAN authentication

Greg Kroah-Hartman
2016-05-30T22:06:49Z

From: Stefan Metzmacher <metze@samba.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@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/cifs/sess.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)

--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -678,20 +678,24 @@ sess_auth_lanman(struct sess_data *sess_

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