From: Wietse Venema Date: Wed, 26 Aug 2009 05:00:00 +0000 (-0500) Subject: postfix-2.4.12 X-Git-Tag: v2.4.12^0 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=276ffe548b59b80f0485e78ad8bab7ca6fe7f113;p=thirdparty%2Fpostfix.git postfix-2.4.12 --- diff --git a/postfix/HISTORY b/postfix/HISTORY index c90407813..267a52880 100644 --- a/postfix/HISTORY +++ b/postfix/HISTORY @@ -13674,3 +13674,47 @@ Apologies for any names omitted. Robustness: don't re-enable SIGTERM if it is ignored in the parent. Files: postsuper/postsuper.c, postdrop/postdrop.c. + +20090710 + + Bugfix (introduced Postfix 2.3): Postfix got out of sync + with a Milter application after the application sent a + "quarantine" request at end-of-message time. The milter + application would still be in the end-of-message state, + while Postfix would already be working on the next SMTP + event (typically, QUIT or MAIL FROM). Problem diagnosed + with help from Alban Deniz. File: milter/milter8.c. + +20090805 + + Bugfix: don't panic when an unexpected smtpd access map is + specified. File: smtpd/smtpd_check.c. + +20090807 + + Workaround: NS record lookups for certain domains always + fail, while other queries for those domains always succeed + (and even return replies with NS records as additional + information). + + This inconsistency in DNS lookup results would allow spammers + to circumvent the Postfix check_{client,helo,sender,etc}_ns_access + restrictions, because those restrictions have effect only + for NS records that can be looked up in the DNS. + + To address this inconsistency, check_{client,etc}_ns_access + now require that a known-in-DNS domain name (or parent + thereof) always resolves to at least one name server IP + address. + + For consistency, check_{client,etc}_mx_access now require + that a known-in-DNS domain name always resolves to at least + one mail server IP address. + + These measures merely raise the difficulty level for spammers. + The IP address information thus obtained is not necessarily + "correct". There is little to stop an uncooperative DNS + server from lying, especially when the owner of the domain + has no desire to receive email. File: smtpd/smtpd_check.c. + + Problem reported by MXTools.com. diff --git a/postfix/RELEASE_NOTES b/postfix/RELEASE_NOTES index cf371e567..c3bf9f8b6 100644 --- a/postfix/RELEASE_NOTES +++ b/postfix/RELEASE_NOTES @@ -11,6 +11,28 @@ instead, a new snapshot is released. The mail_release_date configuration parameter (format: yyyymmdd) specifies the release date of a stable release or snapshot release. +Incompatibility with Postfix 2.4.12 +=================================== + +With some domain names, NS record lookups always fail while other +lookups always succeed (and may even return NS records as additional +information). This anomaly could be used by evil elements to skip +Postfix check_{client,helo,sender,recipient}_ns_access checks, +because these apply only to NS records that are found in the DNS. + +To address this specific problem, check_{client,etc}_ns_access now +requires that a known-in-DNS domain name (or parent thereof) always +resolves to at least one name server IP address. + +For consistency, check_{client,etc}_mx_access now requires that a +known-in-DNS domain name always resolves to at least one mail server +IP address. + +These measures provide no hard assurances that the IP address +information thus obtained is correct. There is little to stop an +uncooperative DNS server from lying, especially when the owner of +the domain has no desire to receive email. + Incompatibility with Postfix 2.4.4 ================================== diff --git a/postfix/src/global/mail_version.h b/postfix/src/global/mail_version.h index 4a79c60bd..354ba7aec 100644 --- a/postfix/src/global/mail_version.h +++ b/postfix/src/global/mail_version.h @@ -20,8 +20,8 @@ * Patches change both the patchlevel and the release date. Snapshots have no * patchlevel; they change the release date only. */ -#define MAIL_RELEASE_DATE "20090511" -#define MAIL_VERSION_NUMBER "2.4.11" +#define MAIL_RELEASE_DATE "20090826" +#define MAIL_VERSION_NUMBER "2.4.12" #ifdef SNAPSHOT # define MAIL_VERSION_DATE "-" MAIL_RELEASE_DATE diff --git a/postfix/src/milter/milter8.c b/postfix/src/milter/milter8.c index 27cba9738..952f2938f 100644 --- a/postfix/src/milter/milter8.c +++ b/postfix/src/milter/milter8.c @@ -1217,7 +1217,8 @@ static const char *milter8_event(MILTER8 *milter, int event, /* * Decision: quarantine. In Sendmail 8.13 this does not imply a * transition in the receiver state (reply, reject, tempfail, - * accept, discard). + * accept, discard). We should not transition, either, otherwise + * we get out of sync. */ #ifdef SMFIR_QUARANTINE case SMFIR_QUARANTINE: @@ -1226,7 +1227,8 @@ static const char *milter8_event(MILTER8 *milter, int event, MILTER8_DATA_BUFFER, milter->buf, MILTER8_DATA_END) != 0) MILTER8_EVENT_BREAK(milter->def_reply); - MILTER8_EVENT_BREAK("H"); + milter8_def_reply(milter, "H"); + continue; #endif /* diff --git a/postfix/src/smtpd/smtpd_check.c b/postfix/src/smtpd/smtpd_check.c index be7f6a346..e84fbfdc4 100644 --- a/postfix/src/smtpd/smtpd_check.c +++ b/postfix/src/smtpd/smtpd_check.c @@ -2269,8 +2269,13 @@ static int check_access(SMTPD_STATE *state, const char *table, const char *name, if (msg_verbose) msg_info("%s: %s", myname, name); - if ((dict = dict_handle(table)) == 0) - msg_panic("%s: dictionary not found: %s", myname, table); + if ((dict = dict_handle(table)) == 0) { + msg_warn("%s: unexpected dictionary: %s", myname, table); + value = "451 4.3.5 Server configuration error"; + CHK_ACCESS_RETURN(check_table_result(state, table, value, name, + reply_name, reply_class, + def_acl), FOUND); + } if (flags == 0 || (flags & dict->flags) != 0) { if ((value = dict_get(dict, name)) != 0) CHK_ACCESS_RETURN(check_table_result(state, table, value, name, @@ -2314,8 +2319,13 @@ static int check_domain_access(SMTPD_STATE *state, const char *table, */ #define CHK_DOMAIN_RETURN(x,y) { *found = y; return(x); } - if ((dict = dict_handle(table)) == 0) - msg_panic("%s: dictionary not found: %s", myname, table); + if ((dict = dict_handle(table)) == 0) { + msg_warn("%s: unexpected dictionary: %s", myname, table); + value = "451 4.3.5 Server configuration error"; + CHK_DOMAIN_RETURN(check_table_result(state, table, value, + domain, reply_name, reply_class, + def_acl), FOUND); + } for (name = domain; *name != 0; name = next) { if (flags == 0 || (flags & dict->flags) != 0) { if ((value = dict_get(dict, name)) != 0) @@ -2373,8 +2383,13 @@ static int check_addr_access(SMTPD_STATE *state, const char *table, #endif delim = '.'; - if ((dict = dict_handle(table)) == 0) - msg_panic("%s: dictionary not found: %s", myname, table); + if ((dict = dict_handle(table)) == 0) { + msg_warn("%s: unexpected dictionary: %s", myname, table); + value = "451 4.3.5 Server configuration error"; + CHK_ADDR_RETURN(check_table_result(state, table, value, address, + reply_name, reply_class, + def_acl), FOUND); + } do { if (flags == 0 || (flags & dict->flags) != 0) { if ((value = dict_get(dict, addr)) != 0) @@ -2454,6 +2469,10 @@ static int check_server_access(SMTPD_STATE *state, const char *table, struct addrinfo *res; int status; INET_PROTO_INFO *proto_info; + const char *saved_domain; + int non_err, soft_err; + int known_name_in_dns; + int ping_status; /* * Sanity check. @@ -2508,15 +2527,26 @@ static int check_server_access(SMTPD_STATE *state, const char *table, * * If the domain name exists but no NS record exists, look up parent domain * NS records. + * + * After the initial lookup fails, do one final DNS sanity check. Reject + * mail when the name exists, but MX lookup produces no valid response or + * NS lookup fails for any reason. Beware, this sanity check provides no + * hard assurance. An uncooperative DNS server may lie about everything, + * including non-existence. */ +#define SOME_DNS_RR_EXISTS(stat, herr) \ + ((stat) == DNS_OK || (stat) == DNS_INVAL || (herr) == NO_DATA) + + saved_domain = domain; dns_status = dns_lookup(domain, type, 0, &server_list, (VSTRING *) 0, (VSTRING *) 0); - if (dns_status == DNS_NOTFOUND && h_errno == NO_DATA) { + known_name_in_dns = SOME_DNS_RR_EXISTS(dns_status, h_errno); + if (dns_status == DNS_NOTFOUND /* Not: h_errno == NO_DATA */ ) { if (type == T_MX) { server_list = dns_rr_create(domain, domain, type, C_IN, 0, 0, domain, strlen(domain) + 1); dns_status = DNS_OK; - } else if (type == T_NS) { + } else if (type == T_NS && h_errno == NO_DATA) { while ((domain = strchr(domain, '.')) != 0 && domain[1]) { domain += 1; dns_status = dns_lookup(domain, type, 0, &server_list, @@ -2526,9 +2556,31 @@ static int check_server_access(SMTPD_STATE *state, const char *table, } } } + +#ifndef VAR_MAP_DEFER_CODE +#define var_map_reject_code var_reject_code +#define var_map_defer_code var_defer_code +#endif + if (dns_status != DNS_OK) { msg_warn("Unable to look up %s host for %s: %s", dns_strtype(type), domain && domain[1] ? domain : name, dns_strerror(h_errno)); + if (known_name_in_dns == 0) { + /* With hostile DNS, an address query is more likely to work. */ + ping_status = dns_lookup_l(saved_domain, 0, (DNS_RR **) 0, + (VSTRING *) 0, (VSTRING *) 0, + DNS_REQ_FLAG_STOP_OK, + RR_ADDR_TYPES, 0); + known_name_in_dns = SOME_DNS_RR_EXISTS(ping_status, h_errno); + } + if (known_name_in_dns) + return (smtpd_check_reject(state, MAIL_ERROR_POLICY, + dns_status == DNS_RETRY ? + var_map_defer_code : var_map_reject_code, + smtpd_dsn_fix("4.1.8", reply_class), + "<%s>: %s rejected: %s", + reply_name, reply_class, + "Domain not found")); return (SMTPD_CHECK_DUNNO); } @@ -2541,10 +2593,19 @@ static int check_server_access(SMTPD_STATE *state, const char *table, * Check the hostnames first, then the addresses. */ proto_info = inet_proto_info(); + non_err = soft_err = 0; for (server = server_list; server != 0; server = server->next) { if (msg_verbose) msg_info("%s: %s hostname check: %s", myname, dns_strtype(type), (char *) server->data); + if (valid_hostaddr((char *) server->data, DONT_GRIPE)) { + non_err = 1; + if ((status = check_addr_access(state, table, (char *) server->data, + FULL, &found, reply_name, reply_class, + def_acl)) != 0 || found) + CHECK_SERVER_RETURN(status); + continue; + } if ((status = check_domain_access(state, table, (char *) server->data, FULL, &found, reply_name, reply_class, def_acl)) != 0 || found) @@ -2554,8 +2615,11 @@ static int check_server_access(SMTPD_STATE *state, const char *table, msg_warn("Unable to look up %s host %s for %s %s: %s", dns_strtype(type), (char *) server->data, reply_class, reply_name, MAI_STRERROR(aierr)); + if (aierr == EAI_AGAIN || aierr == EAI_SYSTEM) + soft_err = 1; continue; } + non_err = 1; /* Now we must also free the addrinfo result. */ if (msg_verbose) msg_info("%s: %s host address check: %s", @@ -2579,7 +2643,15 @@ static int check_server_access(SMTPD_STATE *state, const char *table, } freeaddrinfo(res0); /* 200412 */ } - CHECK_SERVER_RETURN(SMTPD_CHECK_DUNNO); + status = non_err ? SMTPD_CHECK_DUNNO : + smtpd_check_reject(state, MAIL_ERROR_POLICY, + soft_err ? var_map_defer_code : + var_map_reject_code, + smtpd_dsn_fix("4.1.8", reply_class), + "<%s>: %s rejected: %s", + reply_name, reply_class, + "Domain not found"); + CHECK_SERVER_RETURN(status); } /* check_ccert_access - access for TLS clients by certificate fingerprint */