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-rw-r--r--src/smtp/smtp_sasl_proto.c202
1 files changed, 202 insertions, 0 deletions
diff --git a/src/smtp/smtp_sasl_proto.c b/src/smtp/smtp_sasl_proto.c
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+/*++
+/* NAME
+/* smtp_sasl_proto 3
+/* SUMMARY
+/* Postfix SASL interface for SMTP client
+/* SYNOPSIS
+/* #include smtp_sasl.h
+/*
+/* void smtp_sasl_helo_auth(state, words)
+/* SMTP_STATE *state;
+/* const char *words;
+/*
+/* int smtp_sasl_helo_login(state)
+/* SMTP_STATE *state;
+/* DESCRIPTION
+/* This module contains random chunks of code that implement
+/* the SMTP protocol interface for SASL negotiation. The goal
+/* is to reduce clutter in the main SMTP client source code.
+/*
+/* smtp_sasl_helo_auth() processes the AUTH option in the
+/* SMTP server's EHLO response.
+/*
+/* smtp_sasl_helo_login() authenticates the SMTP client to the
+/* SMTP server, using the authentication mechanism information
+/* given by the server. The result is a Postfix delivery status
+/* code in case of trouble.
+/*
+/* Arguments:
+/* .IP state
+/* Session context.
+/* .IP words
+/* List of SASL authentication mechanisms (separated by blanks)
+/* DIAGNOSTICS
+/* All errors are fatal.
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Original author:
+/* Till Franke
+/* SuSE Rhein/Main AG
+/* 65760 Eschborn, Germany
+/*
+/* Adopted by:
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <string.h>
+#ifdef STRCASECMP_IN_STRINGS_H
+#include <strings.h>
+#endif
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <stringops.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+#include "smtp_sasl.h"
+
+#ifdef USE_SASL_AUTH
+
+/* smtp_sasl_compat_mechs - Trim server's mechanism list */
+
+static const char *smtp_sasl_compat_mechs(const char *words)
+{
+ static VSTRING *buf;
+ char *mech_list;
+ char *save_mech;
+ char *mech;
+
+ /*
+ * Use server's mechanisms if no filter specified
+ */
+ if (smtp_sasl_mechs == 0 || *words == 0)
+ return (words);
+
+ if (buf == 0)
+ buf = vstring_alloc(10);
+
+ VSTRING_RESET(buf);
+ VSTRING_TERMINATE(buf);
+
+ save_mech = mech_list = mystrdup(words);
+
+ while ((mech = mystrtok(&mech_list, " \t")) != 0) {
+ if (string_list_match(smtp_sasl_mechs, mech)) {
+ if (VSTRING_LEN(buf) > 0)
+ VSTRING_ADDCH(buf, ' ');
+ vstring_strcat(buf, mech);
+ } else if (smtp_sasl_mechs->error) {
+ msg_fatal("SASL mechanism filter failed for: '%s'", mech);
+ }
+ }
+ myfree(save_mech);
+
+ return (vstring_str(buf));
+}
+
+/* smtp_sasl_helo_auth - handle AUTH option in EHLO reply */
+
+void smtp_sasl_helo_auth(SMTP_SESSION *session, const char *words)
+{
+ const char *mech_list = smtp_sasl_compat_mechs(words);
+ char *junk;
+
+ /*
+ * XXX If the server offers no compatible authentication mechanisms, then
+ * pretend that the server doesn't support SASL authentication.
+ *
+ * XXX If the server offers multiple different lists, concatenate them. Let
+ * the SASL library worry about duplicates.
+ */
+ if (session->sasl_mechanism_list) {
+ if (strcasecmp(session->sasl_mechanism_list, mech_list) != 0
+ && strlen(mech_list) > 0
+ && strlen(session->sasl_mechanism_list) < var_line_limit) {
+ junk = concatenate(session->sasl_mechanism_list, " ", mech_list,
+ (char *) 0);
+ myfree(session->sasl_mechanism_list);
+ session->sasl_mechanism_list = junk;
+ }
+ return;
+ }
+ if (strlen(mech_list) > 0) {
+ session->sasl_mechanism_list = mystrdup(mech_list);
+ } else {
+ msg_warn(*words ? "%s offered no supported AUTH mechanisms: '%s'" :
+ "%s offered null AUTH mechanism list%s",
+ session->namaddrport, words);
+ }
+ session->features |= SMTP_FEATURE_AUTH;
+}
+
+/* smtp_sasl_helo_login - perform SASL login */
+
+int smtp_sasl_helo_login(SMTP_STATE *state)
+{
+ SMTP_SESSION *session = state->session;
+ DSN_BUF *why = state->why;
+ int ret;
+
+ /*
+ * Skip authentication when no authentication info exists for this
+ * server, so that we talk to each other like strangers.
+ */
+ if (smtp_sasl_passwd_lookup(session) == 0) {
+ session->features &= ~SMTP_FEATURE_AUTH;
+ return 0;
+ }
+
+ /*
+ * Otherwise, if authentication information exists, assume that
+ * authentication is required, and assume that an authentication error is
+ * recoverable from the message delivery point of view. An authentication
+ * error is unrecoverable from a session point of view - the session will
+ * not be reused.
+ */
+ ret = 0;
+ if (session->sasl_mechanism_list == 0) {
+ dsb_simple(why, "4.7.0", "SASL authentication failed: "
+ "server %s offered no compatible authentication mechanisms for this type of connection security",
+ session->namaddr);
+ ret = smtp_sess_fail(state);
+ /* Session reuse is disabled. */
+ } else {
+#ifndef USE_TLS
+ smtp_sasl_start(session, VAR_LMTP_SMTP(SASL_OPTS), var_smtp_sasl_opts);
+#else
+ if (session->tls_context == 0)
+ smtp_sasl_start(session, VAR_LMTP_SMTP(SASL_OPTS),
+ var_smtp_sasl_opts);
+ else if (TLS_CERT_IS_MATCHED(session->tls_context))
+ smtp_sasl_start(session, VAR_LMTP_SMTP(SASL_TLSV_OPTS),
+ var_smtp_sasl_tlsv_opts);
+ else
+ smtp_sasl_start(session, VAR_LMTP_SMTP(SASL_TLS_OPTS),
+ var_smtp_sasl_tls_opts);
+#endif
+ if (smtp_sasl_authenticate(session, why) <= 0) {
+ ret = smtp_sess_fail(state);
+ /* Session reuse is disabled. */
+ }
+ }
+ return (ret);
+}
+
+#endif