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-rw-r--r--src/smtp/smtp_sasl_auth_cache.c272
1 files changed, 272 insertions, 0 deletions
diff --git a/src/smtp/smtp_sasl_auth_cache.c b/src/smtp/smtp_sasl_auth_cache.c
new file mode 100644
index 0000000..f3104ca
--- /dev/null
+++ b/src/smtp/smtp_sasl_auth_cache.c
@@ -0,0 +1,272 @@
+/*++
+/* NAME
+/* smtp_sasl_auth_cache 3
+/* SUMMARY
+/* Postfix SASL authentication reply cache
+/* SYNOPSIS
+/* #include "smtp.h"
+/* #include "smtp_sasl_auth_cache.h"
+/*
+/* SMTP_SASL_AUTH_CACHE *smtp_sasl_auth_cache_init(map, ttl)
+/* const char *map
+/* int ttl;
+/*
+/* void smtp_sasl_auth_cache_store(auth_cache, session, resp)
+/* SMTP_SASL_AUTH_CACHE *auth_cache;
+/* const SMTP_SESSION *session;
+/* const SMTP_RESP *resp;
+/*
+/* int smtp_sasl_auth_cache_find(auth_cache, session)
+/* SMTP_SASL_AUTH_CACHE *auth_cache;
+/* const SMTP_SESSION *session;
+/*
+/* char *smtp_sasl_auth_cache_dsn(auth_cache)
+/* SMTP_SASL_AUTH_CACHE *auth_cache;
+/*
+/* char *smtp_sasl_auth_cache_text(auth_cache)
+/* SMTP_SASL_AUTH_CACHE *auth_cache;
+/* DESCRIPTION
+/* This module maintains a cache of SASL authentication server replies.
+/* This can be used to avoid repeated login failure errors.
+/*
+/* smtp_sasl_auth_cache_init() opens or creates the named cache.
+/*
+/* smtp_sasl_auth_cache_store() stores information about a
+/* SASL login attempt together with the server status and
+/* complete response.
+/*
+/* smtp_sasl_auth_cache_find() returns non-zero when a cache
+/* entry exists for the given host, username and password.
+/*
+/* smtp_sasl_auth_cache_dsn() and smtp_sasl_auth_cache_text()
+/* return the status and complete server response as found
+/* with smtp_sasl_auth_cache_find().
+/*
+/* Arguments:
+/* .IP map
+/* Lookup table name. The name must be singular and must start
+/* with "proxy:".
+/* .IP ttl
+/* The time after which a cache entry is considered expired.
+/* .IP session
+/* Session context.
+/* .IP resp
+/* Remote SMTP server response, to be stored into the cache.
+/* DIAGNOSTICS
+/* All errors are fatal.
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Original author:
+/* Keean Schupke
+/* Fry-IT Ltd.
+/*
+/* Updated by:
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*--*/
+
+ /*
+ * System library.
+ */
+#include <sys_defs.h>
+
+ /*
+ * Utility library
+ */
+#include <msg.h>
+#include <mymalloc.h>
+#include <stringops.h>
+#include <base64_code.h>
+#include <dict.h>
+
+ /*
+ * Global library
+ */
+#include <dsn_util.h>
+#include <dict_proxy.h>
+
+ /*
+ * Application-specific
+ */
+#include "smtp.h"
+#include "smtp_sasl_auth_cache.h"
+
+ /*
+ * XXX This feature stores passwords, so we must mask them with a strong
+ * cryptographic hash. This requires OpenSSL support.
+ *
+ * XXX It would be even better if the stored hash were salted.
+ */
+#ifdef HAVE_SASL_AUTH_CACHE
+
+/* smtp_sasl_auth_cache_init - per-process initialization (pre jail) */
+
+SMTP_SASL_AUTH_CACHE *smtp_sasl_auth_cache_init(const char *map, int ttl)
+{
+ const char *myname = "smtp_sasl_auth_cache_init";
+ SMTP_SASL_AUTH_CACHE *auth_cache;
+
+ /*
+ * Sanity checks.
+ */
+#define HAS_MULTIPLE_VALUES(s) ((s)[strcspn((s), CHARS_COMMA_SP)] != 0)
+
+ if (*map == 0)
+ msg_panic("%s: empty SASL authentication cache name", myname);
+ if (ttl < 0)
+ msg_panic("%s: bad SASL authentication cache ttl: %d", myname, ttl);
+ if (HAS_MULTIPLE_VALUES(map))
+ msg_fatal("SASL authentication cache name \"%s\" "
+ "contains multiple values", map);
+
+ /*
+ * XXX To avoid multiple writers the map needs to be maintained by the
+ * proxywrite service. We would like to have a DICT_FLAG_REQ_PROXY flag
+ * so that the library can enforce this, but that requires moving the
+ * dict_proxy module one level down in the build dependency hierarchy.
+ */
+#define CACHE_DICT_OPEN_FLAGS \
+ (DICT_FLAG_DUP_REPLACE | DICT_FLAG_SYNC_UPDATE | DICT_FLAG_UTF8_REQUEST)
+#define PROXY_COLON DICT_TYPE_PROXY ":"
+#define PROXY_COLON_LEN (sizeof(PROXY_COLON) - 1)
+
+ if (strncmp(map, PROXY_COLON, PROXY_COLON_LEN) != 0)
+ msg_fatal("SASL authentication cache name \"%s\" must start with \""
+ PROXY_COLON, map);
+
+ auth_cache = (SMTP_SASL_AUTH_CACHE *) mymalloc(sizeof(*auth_cache));
+ auth_cache->dict = dict_open(map, O_CREAT | O_RDWR, CACHE_DICT_OPEN_FLAGS);
+ auth_cache->ttl = ttl;
+ auth_cache->dsn = mystrdup("");
+ auth_cache->text = mystrdup("");
+ return (auth_cache);
+}
+
+ /*
+ * Each cache lookup key contains a server host name and user name. Each
+ * cache value contains a time stamp, a hashed password, and the server
+ * response. With this organization, we don't have to worry about cache
+ * pollution, because we can detect if a cache entry has expired, or if the
+ * password has changed.
+ */
+
+/* smtp_sasl_auth_cache_make_key - format auth failure cache lookup key */
+
+static char *smtp_sasl_auth_cache_make_key(const char *host, const char *user)
+{
+ VSTRING *buf = vstring_alloc(100);
+
+ vstring_sprintf(buf, "%s;%s", host, user);
+ return (vstring_export(buf));
+}
+
+/* smtp_sasl_auth_cache_make_pass - hash the auth failure cache password */
+
+static char *smtp_sasl_auth_cache_make_pass(const char *password)
+{
+ VSTRING *buf = vstring_alloc(2 * SHA_DIGEST_LENGTH);
+
+ base64_encode(buf, (const char *) SHA1((const unsigned char *) password,
+ strlen(password), 0),
+ SHA_DIGEST_LENGTH);
+ return (vstring_export(buf));
+}
+
+/* smtp_sasl_auth_cache_make_value - format auth failure cache value */
+
+static char *smtp_sasl_auth_cache_make_value(const char *password,
+ const char *dsn,
+ const char *rep_str)
+{
+ VSTRING *val_buf = vstring_alloc(100);
+ char *pwd_hash;
+ unsigned long now = (unsigned long) time((time_t *) 0);
+
+ pwd_hash = smtp_sasl_auth_cache_make_pass(password);
+ vstring_sprintf(val_buf, "%lu;%s;%s;%s", now, pwd_hash, dsn, rep_str);
+ myfree(pwd_hash);
+ return (vstring_export(val_buf));
+}
+
+/* smtp_sasl_auth_cache_valid_value - validate auth failure cache value */
+
+static int smtp_sasl_auth_cache_valid_value(SMTP_SASL_AUTH_CACHE *auth_cache,
+ const char *entry,
+ const char *password)
+{
+ ssize_t len = strlen(entry);
+ char *cache_hash = mymalloc(len);
+ char *curr_hash;
+ unsigned long now = (unsigned long) time((time_t *) 0);
+ unsigned long time_stamp;
+ int valid;
+
+ auth_cache->dsn = myrealloc(auth_cache->dsn, len);
+ auth_cache->text = myrealloc(auth_cache->text, len);
+
+ if (sscanf(entry, "%lu;%[^;];%[^;];%[^\n]", &time_stamp, cache_hash,
+ auth_cache->dsn, auth_cache->text) != 4
+ || !dsn_valid(auth_cache->dsn)) {
+ msg_warn("bad smtp_sasl_auth_cache entry: %.100s", entry);
+ valid = 0;
+ } else if (time_stamp + auth_cache->ttl < now) {
+ valid = 0;
+ } else {
+ curr_hash = smtp_sasl_auth_cache_make_pass(password);
+ valid = (strcmp(cache_hash, curr_hash) == 0);
+ myfree(curr_hash);
+ }
+ myfree(cache_hash);
+ return (valid);
+}
+
+/* smtp_sasl_auth_cache_find - search auth failure cache */
+
+int smtp_sasl_auth_cache_find(SMTP_SASL_AUTH_CACHE *auth_cache,
+ const SMTP_SESSION *session)
+{
+ SMTP_ITERATOR *iter = session->iterator;
+ char *key;
+ const char *entry;
+ int valid = 0;
+
+ key = smtp_sasl_auth_cache_make_key(STR(iter->host), session->sasl_username);
+ if ((entry = dict_get(auth_cache->dict, key)) != 0)
+ if ((valid = smtp_sasl_auth_cache_valid_value(auth_cache, entry,
+ session->sasl_passwd)) == 0)
+ /* Remove expired, password changed, or malformed cache entry. */
+ if (dict_del(auth_cache->dict, key) != 0)
+ msg_warn("SASL auth failure map %s: entry not deleted: %s",
+ auth_cache->dict->name, key);
+ if (auth_cache->dict->error)
+ msg_warn("SASL auth failure map %s: lookup failed for %s",
+ auth_cache->dict->name, key);
+ myfree(key);
+ return (valid);
+}
+
+/* smtp_sasl_auth_cache_store - update auth failure cache */
+
+void smtp_sasl_auth_cache_store(SMTP_SASL_AUTH_CACHE *auth_cache,
+ const SMTP_SESSION *session,
+ const SMTP_RESP *resp)
+{
+ SMTP_ITERATOR *iter = session->iterator;
+ char *key;
+ char *value;
+
+ key = smtp_sasl_auth_cache_make_key(STR(iter->host), session->sasl_username);
+ value = smtp_sasl_auth_cache_make_value(session->sasl_passwd,
+ resp->dsn, resp->str);
+ dict_put(auth_cache->dict, key, value);
+
+ myfree(value);
+ myfree(key);
+}
+
+#endif
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