SMB2: Separate Kerberos authentication from SMB2_sess_setup
Add helper functions and split Kerberos authentication off SMB2_sess_setup. Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
This commit is contained in:
Sachin Prabhu
Steve French
parent
cb978ac8b8
commit
3baf1a7b92
@ -593,6 +593,216 @@ vneg_out:
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return -EIO;
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}
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struct SMB2_sess_data {
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unsigned int xid;
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struct cifs_ses *ses;
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struct nls_table *nls_cp;
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void (*func)(struct SMB2_sess_data *);
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int result;
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u64 previous_session;
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/* we will send the SMB in three pieces:
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* a fixed length beginning part, an optional
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* SPNEGO blob (which can be zero length), and a
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* last part which will include the strings
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* and rest of bcc area. This allows us to avoid
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* a large buffer 17K allocation
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*/
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int buf0_type;
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struct kvec iov[2];
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};
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static int
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SMB2_sess_alloc_buffer(struct SMB2_sess_data *sess_data)
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{
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int rc;
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struct cifs_ses *ses = sess_data->ses;
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struct smb2_sess_setup_req *req;
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struct TCP_Server_Info *server = ses->server;
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rc = small_smb2_init(SMB2_SESSION_SETUP, NULL, (void **) &req);
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if (rc)
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return rc;
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req->hdr.SessionId = 0; /* First session, not a reauthenticate */
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/* if reconnect, we need to send previous sess id, otherwise it is 0 */
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req->PreviousSessionId = sess_data->previous_session;
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req->Flags = 0; /* MBZ */
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/* to enable echos and oplocks */
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req->hdr.CreditRequest = cpu_to_le16(3);
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/* only one of SMB2 signing flags may be set in SMB2 request */
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if (server->sign)
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req->SecurityMode = SMB2_NEGOTIATE_SIGNING_REQUIRED;
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else if (global_secflags & CIFSSEC_MAY_SIGN) /* one flag unlike MUST_ */
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req->SecurityMode = SMB2_NEGOTIATE_SIGNING_ENABLED;
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else
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req->SecurityMode = 0;
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req->Capabilities = 0;
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req->Channel = 0; /* MBZ */
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sess_data->iov[0].iov_base = (char *)req;
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/* 4 for rfc1002 length field and 1 for pad */
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sess_data->iov[0].iov_len = get_rfc1002_length(req) + 4 - 1;
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/*
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* This variable will be used to clear the buffer
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* allocated above in case of any error in the calling function.
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*/
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sess_data->buf0_type = CIFS_SMALL_BUFFER;
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return 0;
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}
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static void
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SMB2_sess_free_buffer(struct SMB2_sess_data *sess_data)
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{
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free_rsp_buf(sess_data->buf0_type, sess_data->iov[0].iov_base);
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sess_data->buf0_type = CIFS_NO_BUFFER;
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}
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static int
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SMB2_sess_sendreceive(struct SMB2_sess_data *sess_data)
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{
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int rc;
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struct smb2_sess_setup_req *req = sess_data->iov[0].iov_base;
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/* Testing shows that buffer offset must be at location of Buffer[0] */
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req->SecurityBufferOffset =
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cpu_to_le16(sizeof(struct smb2_sess_setup_req) -
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1 /* pad */ - 4 /* rfc1001 len */);
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req->SecurityBufferLength = cpu_to_le16(sess_data->iov[1].iov_len);
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inc_rfc1001_len(req, sess_data->iov[1].iov_len - 1 /* pad */);
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/* BB add code to build os and lm fields */
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rc = SendReceive2(sess_data->xid, sess_data->ses,
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sess_data->iov, 2,
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&sess_data->buf0_type,
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CIFS_LOG_ERROR | CIFS_NEG_OP);
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return rc;
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}
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static int
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SMB2_sess_establish_session(struct SMB2_sess_data *sess_data)
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{
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int rc = 0;
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struct cifs_ses *ses = sess_data->ses;
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mutex_lock(&ses->server->srv_mutex);
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if (ses->server->sign && ses->server->ops->generate_signingkey) {
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rc = ses->server->ops->generate_signingkey(ses);
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kfree(ses->auth_key.response);
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ses->auth_key.response = NULL;
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if (rc) {
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cifs_dbg(FYI,
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"SMB3 session key generation failed\n");
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mutex_unlock(&ses->server->srv_mutex);
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goto keygen_exit;
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}
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}
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if (!ses->server->session_estab) {
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ses->server->sequence_number = 0x2;
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ses->server->session_estab = true;
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}
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mutex_unlock(&ses->server->srv_mutex);
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cifs_dbg(FYI, "SMB2/3 session established successfully\n");
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spin_lock(&GlobalMid_Lock);
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ses->status = CifsGood;
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ses->need_reconnect = false;
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spin_unlock(&GlobalMid_Lock);
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keygen_exit:
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if (!ses->server->sign) {
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kfree(ses->auth_key.response);
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ses->auth_key.response = NULL;
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}
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return rc;
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}
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#ifdef CONFIG_CIFS_UPCALL
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static void
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SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
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{
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int rc;
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struct cifs_ses *ses = sess_data->ses;
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struct cifs_spnego_msg *msg;
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struct key *spnego_key = NULL;
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struct smb2_sess_setup_rsp *rsp = NULL;
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rc = SMB2_sess_alloc_buffer(sess_data);
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if (rc)
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goto out;
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spnego_key = cifs_get_spnego_key(ses);
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if (IS_ERR(spnego_key)) {
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rc = PTR_ERR(spnego_key);
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spnego_key = NULL;
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goto out;
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}
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msg = spnego_key->payload.data[0];
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/*
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* check version field to make sure that cifs.upcall is
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* sending us a response in an expected form
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*/
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if (msg->version != CIFS_SPNEGO_UPCALL_VERSION) {
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cifs_dbg(VFS,
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"bad cifs.upcall version. Expected %d got %d",
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CIFS_SPNEGO_UPCALL_VERSION, msg->version);
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rc = -EKEYREJECTED;
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goto out_put_spnego_key;
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}
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ses->auth_key.response = kmemdup(msg->data, msg->sesskey_len,
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GFP_KERNEL);
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if (!ses->auth_key.response) {
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cifs_dbg(VFS,
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"Kerberos can't allocate (%u bytes) memory",
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msg->sesskey_len);
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rc = -ENOMEM;
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goto out_put_spnego_key;
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}
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ses->auth_key.len = msg->sesskey_len;
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sess_data->iov[1].iov_base = msg->data + msg->sesskey_len;
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sess_data->iov[1].iov_len = msg->secblob_len;
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rc = SMB2_sess_sendreceive(sess_data);
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if (rc)
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goto out_put_spnego_key;
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rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;
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ses->Suid = rsp->hdr.SessionId;
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ses->session_flags = le16_to_cpu(rsp->SessionFlags);
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if (ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA)
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cifs_dbg(VFS, "SMB3 encryption not supported yet\n");
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rc = SMB2_sess_establish_session(sess_data);
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out_put_spnego_key:
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key_invalidate(spnego_key);
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key_put(spnego_key);
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out:
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sess_data->result = rc;
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sess_data->func = NULL;
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SMB2_sess_free_buffer(sess_data);
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}
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#else
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static void
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SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
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{
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cifs_dbg(VFS, "Kerberos negotiated but upcall support disabled!\n");
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sess_data->result = -EOPNOTSUPP;
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sess_data->func = NULL;
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}
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#endif
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int
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SMB2_sess_setup(const unsigned int xid, struct cifs_ses *ses,
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const struct nls_table *nls_cp)
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@ -605,11 +815,11 @@ SMB2_sess_setup(const unsigned int xid, struct cifs_ses *ses,
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__le32 phase = NtLmNegotiate; /* NTLMSSP, if needed, is multistage */
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struct TCP_Server_Info *server = ses->server;
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u16 blob_length = 0;
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struct key *spnego_key = NULL;
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char *security_blob = NULL;
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unsigned char *ntlmssp_blob = NULL;
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bool use_spnego = false; /* else use raw ntlmssp */
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u64 previous_session = ses->Suid;
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struct SMB2_sess_data *sess_data;
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cifs_dbg(FYI, "Session Setup\n");
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@ -618,6 +828,20 @@ SMB2_sess_setup(const unsigned int xid, struct cifs_ses *ses,
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return -EIO;
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}
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sess_data = kzalloc(sizeof(struct SMB2_sess_data), GFP_KERNEL);
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if (!sess_data)
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return -ENOMEM;
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sess_data->xid = xid;
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sess_data->ses = ses;
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sess_data->buf0_type = CIFS_NO_BUFFER;
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sess_data->nls_cp = (struct nls_table *) nls_cp;
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sess_data->previous_session = ses->Suid;
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if (ses->sectype == Kerberos) {
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SMB2_auth_kerberos(sess_data);
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goto out;
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}
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/*
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* If we are here due to reconnect, free per-smb session key
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* in case signing was required.
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@ -670,47 +894,7 @@ ssetup_ntlmssp_authenticate:
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/* 4 for rfc1002 length field and 1 for pad */
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iov[0].iov_len = get_rfc1002_length(req) + 4 - 1;
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if (ses->sectype == Kerberos) {
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#ifdef CONFIG_CIFS_UPCALL
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struct cifs_spnego_msg *msg;
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spnego_key = cifs_get_spnego_key(ses);
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if (IS_ERR(spnego_key)) {
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rc = PTR_ERR(spnego_key);
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spnego_key = NULL;
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goto ssetup_exit;
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}
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msg = spnego_key->payload.data[0];
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/*
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* check version field to make sure that cifs.upcall is
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* sending us a response in an expected form
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*/
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if (msg->version != CIFS_SPNEGO_UPCALL_VERSION) {
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cifs_dbg(VFS,
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"bad cifs.upcall version. Expected %d got %d",
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CIFS_SPNEGO_UPCALL_VERSION, msg->version);
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rc = -EKEYREJECTED;
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goto ssetup_exit;
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}
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ses->auth_key.response = kmemdup(msg->data, msg->sesskey_len,
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GFP_KERNEL);
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if (!ses->auth_key.response) {
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cifs_dbg(VFS,
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"Kerberos can't allocate (%u bytes) memory",
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msg->sesskey_len);
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rc = -ENOMEM;
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goto ssetup_exit;
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}
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ses->auth_key.len = msg->sesskey_len;
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blob_length = msg->secblob_len;
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iov[1].iov_base = msg->data + msg->sesskey_len;
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iov[1].iov_len = blob_length;
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#else
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rc = -EOPNOTSUPP;
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goto ssetup_exit;
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#endif /* CONFIG_CIFS_UPCALL */
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} else if (phase == NtLmNegotiate) { /* if not krb5 must be ntlmssp */
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if (phase == NtLmNegotiate) {
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ntlmssp_blob = kmalloc(sizeof(struct _NEGOTIATE_MESSAGE),
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GFP_KERNEL);
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if (ntlmssp_blob == NULL) {
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@ -853,12 +1037,12 @@ keygen_exit:
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kfree(ses->auth_key.response);
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ses->auth_key.response = NULL;
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}
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if (spnego_key) {
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key_invalidate(spnego_key);
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key_put(spnego_key);
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}
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kfree(ses->ntlmssp);
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return rc;
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out:
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rc = sess_data->result;
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kfree(sess_data);
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return rc;
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}
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