From: Wietse Venema Date: Sun, 17 Jan 2021 05:00:00 +0000 (-0500) Subject: postfix-3.2.21 X-Git-Tag: v3.2.21^0 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ab0bc67bca60f3e347d0f83160cb4e145cebff26;p=thirdparty%2Fpostfix.git postfix-3.2.21 --- diff --git a/postfix/HISTORY b/postfix/HISTORY index 1372f176e..62a68c260 100644 --- a/postfix/HISTORY +++ b/postfix/HISTORY @@ -23406,3 +23406,27 @@ Apologies for any names omitted. Bugfix (introduced: Postfix 2.3): static maps did not free their casefolding buffer. File: util/dict_static.c. + +20210116 + + Feature: when a Postfix program makes a DNS query that + requests DNSSEC validation (usually for Postfix DANE support) + but the DNS response is not DNSSEC validated, Postfix will + send a DNS query configured with the "dnssec_probe" parameter + to determine if DNSSEC support is available, and logs a + warning if it is not. By default, the probe has type "ns" + and domain name ".". The probe is sent once per process + lifetime. Files: dns/dns.h, dns/dns_lookup.c, dns/dns_sec.c, + test_dns_lookup.c, global/mail_params.[hc], mantools/postlink. + + The makedefs script no longer disables DNSSEC when Postfix + is built with libc-musl. Instead Postfix will rely on the + new dnssec_probe feature, and will log a warning when Postfix + requests DNSSEC validation, but the infrastructure does not + validate DNSSEC signatures. File: makedefs. + + The default "smtp_tls_dane_insecure_mx_policy = dane" was + causing unnecessary dnssec_probe activity. The default is now + "dane" when smtp_tls_security_level is "dane", otherwise it is + "may". File: global/mail_params.h. + diff --git a/postfix/RELEASE_NOTES b/postfix/RELEASE_NOTES index a0e2b29de..1eabf8c15 100644 --- a/postfix/RELEASE_NOTES +++ b/postfix/RELEASE_NOTES @@ -16,6 +16,47 @@ specifies the release date of a stable release or snapshot release. If you upgrade from Postfix 3.0 or earlier, read RELEASE_NOTES-3.1 before proceeding. +Runtime detection of DNSSEC support +----------------------------------- + +The Postfix build system will no longer automatically disable DNSSEC +support when it determines that Postfix will use libc-musl. This removes +the earlier libc-musl workaround for Postfix 3.2.15, 3.3.10, 3.4.12, +and 3.5.2. + +Now, when a Postfix process requests DNSSEC support (typically, for +Postfix DANE support), the process may do a runtime test to determine if +DNSSEC validation is available. DNSSEC support may be broken because of +local configuration, libc incompatibility, or other infrastructure issues. + +Background: DNSSEC validation is needed for Postfix DANE support; +this ensures that Postfix receives TLSA records with secure TLS +server certificate info. When DNSSEC validation is unavailable, +mail deliveries using opportunistic DANE will not be protected by +server certificate info in TLSA records, and mail deliveries using +mandatory DANE will not be made at all. + +The dnssec_probe parameter specifies the DNS query type (default: +"ns") and DNS query name (default: ".") that Postfix may use to +determine whether DNSSEC validation is available. Specify an empty +value to disable this feature. + +By default, a Postfix process will send a DNSSEC probe after 1) the +process made a DNS query that requested DNSSEC validation, 2) the +process did not receive a DNSSEC validated response to this query +or to an earlier query, and 3) the process did not already send a +DNSSEC probe. + +When the DNSSEC probe has no response, or when the response is not +DNSSEC validated, Postfix logs a warning that DNSSEC validation may +be unavailable. Examples: + +warning: DNSSEC validation may be unavailable +warning: reason: dnssec_probe 'ns:.' received a response that is not DNSSEC validated +warning: reason: dnssec_probe 'ns:.' received no response: Server failure + +This feature was backported from Postfix 3.6. + libc-musl workaround for Postfix 3.2.15, 3.3.10, 3.4.12, and 3.5.2 ------------------------------------------------------------------ diff --git a/postfix/html/lmtp.8.html b/postfix/html/lmtp.8.html index 1be182f1f..7a4423e42 100644 --- a/postfix/html/lmtp.8.html +++ b/postfix/html/lmtp.8.html @@ -303,6 +303,13 @@ SMTP(8) SMTP(8) smtp_dns_reply_filter (empty) Optional filter for Postfix SMTP client DNS lookup results. + Available in Postfix 3.2.21 and later: + + dnssec_probe (ns:.) + The DNS query type (default: "ns") and DNS query name (default: + ".") that Postfix may use to determine whether DNSSEC validation + is available. + MIME PROCESSING CONTROLS Available in Postfix version 2.0 and later: diff --git a/postfix/html/postconf.5.html b/postfix/html/postconf.5.html index 922e88603..cb999e3ee 100644 --- a/postfix/html/postconf.5.html +++ b/postfix/html/postconf.5.html @@ -3016,6 +3016,66 @@ service performs DNS white/blacklist lookups.

This feature is available in Postfix 2.8 and later.

+ + +
dnssec_probe +(default: ns:.)
+ +

The DNS query type (default: "ns") and DNS query name (default: +".") that Postfix may use to determine whether DNSSEC validation +is available. +

+ +

Background: DNSSEC validation is needed for Postfix DANE support; +this ensures that Postfix receives TLSA records with secure TLS +server certificate info. When DNSSEC validation is unavailable, +mail deliveries using opportunistic DANE will not be protected +by server certificate info in TLSA records, and mail deliveries +using mandatory DANE will not be made at all.

+ +

By default, a Postfix process will send a DNSSEC probe after +1) the process made a DNS query that requested DNSSEC validation, +2) the process did not receive a DNSSEC validated response to this +query or to an earlier query, and 3) the process did not already +send a DNSSEC probe.

+ +

When the DNSSEC probe has no response, or when the response is +not DNSSEC validated, Postfix logs a warning that DNSSEC validation +may be unavailable.

+ +

Example:

+ +
+warning: DNSSEC validation may be unavailable
+warning: reason: dnssec_probe 'ns:.' received a response that is not DNSSEC validated
+warning: reason: dnssec_probe 'ns:.' received no response: Server failure
+
+ +

Possible reasons why DNSSEC validation may be unavailable:

+ + + +

By default, the DNSSEC probe asks for the DNS root zone NS +records, because resolvers should always have that information +cached. If Postfix runs on a network where the DNS root zone is not +reachable, specify a different probe, or specify an empty dnssec_probe +value to disable the feature.

+ +

This feature was backported from Postfix 3.6 to Postfix versions +3.5.9, 3.4.19, 3.3.16. 3.2.21.

+ +
dont_remove @@ -11877,7 +11937,7 @@ and opportunistic TLS always uses "export" or better (i.e. all) ciphers.

smtp_tls_dane_insecure_mx_policy -(default: dane)
+(default: see "postconf -d" output)

The TLS policy for MX hosts with "secure" TLSA records when the nexthop destination security level is dane, but the MX @@ -11901,6 +11961,12 @@ authentication succeeds, it will be logged only as "Trusted", not "Verified", because the MX host name could have been forged.

+

The default setting for Postfix ≥ 3.6 is "dane" with +"smtp_tls_security_level = dane", otherwise "may". This behavior +was backported to Postfix versions 3.5.9, 3.4.19, 3.3.16. 3.2.21. +With earlier +Postfix versions the default setting was always "dane".

+

Though with "insecure" MX records an active attacker can compromise SMTP transport security by returning forged MX records, such attacks are "tamper-evident" since any forged MX hostnames diff --git a/postfix/html/smtp.8.html b/postfix/html/smtp.8.html index 1be182f1f..7a4423e42 100644 --- a/postfix/html/smtp.8.html +++ b/postfix/html/smtp.8.html @@ -303,6 +303,13 @@ SMTP(8) SMTP(8) smtp_dns_reply_filter (empty) Optional filter for Postfix SMTP client DNS lookup results. + Available in Postfix 3.2.21 and later: + + dnssec_probe (ns:.) + The DNS query type (default: "ns") and DNS query name (default: + ".") that Postfix may use to determine whether DNSSEC validation + is available. + MIME PROCESSING CONTROLS Available in Postfix version 2.0 and later: diff --git a/postfix/makedefs b/postfix/makedefs index 40c21b739..3b3e86286 100644 --- a/postfix/makedefs +++ b/postfix/makedefs @@ -223,19 +223,6 @@ case $# in *) echo usage: $0 [system release] 1>&2; exit 1;; esac -case "$SYSTEM" in - Linux) - case "`PATH=/bin:/usr/bin ldd /bin/sh`" in - *-musl-*) - case "$CCARGS" in - *-DNO_DNSSEC*) ;; - *) echo Warning: libc-musl breaks DANE/TLSA security. 1>&2 - echo This build will not support DANE/TLSA. 1>&2 - CCARGS="$CCARGS -DNO_DNSSEC";; - esac;; - esac;; -esac - case "$SYSTEM.$RELEASE" in SCO_SV.3.2) SYSTYPE=SCO5 # Use the native compiler by default diff --git a/postfix/man/man5/postconf.5 b/postfix/man/man5/postconf.5 index 57ed46f95..bd45409d5 100644 --- a/postfix/man/man5/postconf.5 +++ b/postfix/man/man5/postconf.5 @@ -1887,6 +1887,60 @@ The name of the \fBdnsblog\fR(8) service entry in master.cf. This service performs DNS white/blacklist lookups. .PP This feature is available in Postfix 2.8 and later. +.SH dnssec_probe (default: ns:.) +The DNS query type (default: "ns") and DNS query name (default: +".") that Postfix may use to determine whether DNSSEC validation +is available. +.PP +Background: DNSSEC validation is needed for Postfix DANE support; +this ensures that Postfix receives TLSA records with secure TLS +server certificate info. When DNSSEC validation is unavailable, +mail deliveries using \fIopportunistic\fR DANE will not be protected +by server certificate info in TLSA records, and mail deliveries +using \fImandatory\fR DANE will not be made at all. +.PP +By default, a Postfix process will send a DNSSEC probe after +1) the process made a DNS query that requested DNSSEC validation, +2) the process did not receive a DNSSEC validated response to this +query or to an earlier query, and 3) the process did not already +send a DNSSEC probe. +.PP +When the DNSSEC probe has no response, or when the response is +not DNSSEC validated, Postfix logs a warning that DNSSEC validation +may be unavailable. +.PP +Example: +.PP +.nf +.na +.ft C +warning: DNSSEC validation may be unavailable +warning: reason: dnssec_probe 'ns:.' received a response that is not DNSSEC validated +warning: reason: dnssec_probe 'ns:.' received no response: Server failure +.fi +.ad +.ft R +.PP +Possible reasons why DNSSEC validation may be unavailable: +.IP \(bu +The local /etc/resolv.conf file specifies a DNS resolver that +does not validate DNSSEC signatures (that's +$queue_directory/etc/resolv.conf when a Postfix daemon runs in a +chroot jail). +.IP \(bu +The local system library does not pass on the "DNSSEC validated" +bit to Postfix, or Postfix does not know how to ask the library to +do that. +.br +.PP +By default, the DNSSEC probe asks for the DNS root zone NS +records, because resolvers should always have that information +cached. If Postfix runs on a network where the DNS root zone is not +reachable, specify a different probe, or specify an empty dnssec_probe +value to disable the feature. +.PP +This feature was backported from Postfix 3.6 to Postfix versions +3.5.9, 3.4.19, 3.3.16. 3.2.21. .SH dont_remove (default: 0) Don't remove queue files and save them to the "saved" mail queue. This is a debugging aid. To inspect the envelope information and @@ -7491,7 +7545,7 @@ ciphers on a per\-destination basis. This feature is available in Postfix 2.6 and later. With earlier Postfix releases only the smtp_tls_mandatory_ciphers parameter is implemented, and opportunistic TLS always uses "export" or better (i.e. all) ciphers. -.SH smtp_tls_dane_insecure_mx_policy (default: dane) +.SH smtp_tls_dane_insecure_mx_policy (default: see "postconf \-d" output) The TLS policy for MX hosts with "secure" TLSA records when the nexthop destination security level is \fBdane\fR, but the MX record was found via an "insecure" MX lookup. The choices are: @@ -7512,6 +7566,12 @@ authentication succeeds, it will be logged only as "Trusted", not "Verified", because the MX host name could have been forged. .br .br +The default setting for Postfix >= 3.6 is "dane" with +"smtp_tls_security_level = dane", otherwise "may". This behavior +was backported to Postfix versions 3.5.9, 3.4.19, 3.3.16. 3.2.21. +With earlier +Postfix versions the default setting was always "dane". +.PP Though with "insecure" MX records an active attacker can compromise SMTP transport security by returning forged MX records, such attacks are "tamper\-evident" since any forged MX hostnames diff --git a/postfix/man/man8/smtp.8 b/postfix/man/man8/smtp.8 index b1f88888c..09802afdc 100644 --- a/postfix/man/man8/smtp.8 +++ b/postfix/man/man8/smtp.8 @@ -285,6 +285,12 @@ delivery status code or explanatory text of successful or unsuccessful deliveries. .IP "\fBsmtp_dns_reply_filter (empty)\fR" Optional filter for Postfix SMTP client DNS lookup results. +.PP +Available in Postfix 3.2.21 and later: +.IP "\fBdnssec_probe (ns:.)\fR" +The DNS query type (default: "ns") and DNS query name (default: +".") that Postfix may use to determine whether DNSSEC validation +is available. .SH "MIME PROCESSING CONTROLS" .na .nf diff --git a/postfix/mantools/postlink b/postfix/mantools/postlink index ab17d9241..ed42607b3 100755 --- a/postfix/mantools/postlink +++ b/postfix/mantools/postlink @@ -687,6 +687,7 @@ while (<>) { s;\bsmtp_address_preference\b;$&;g; s;\bsmtp_per_record_deadline\b;$&;g; s;\bsmtp_send_dummy_mail_auth\b;$&;g; + s;\bdnssec_probe\b;$&;g; s;\bsmtpd_enforce_tls\b;$&;g; s;\bsmtpd_sasl_tls_security_options\b;$&;g; s;\bsmtpd_sasl_type\b;$&;g; diff --git a/postfix/proto/postconf.proto b/postfix/proto/postconf.proto index 2e72dd7a9..c3bfc93e0 100644 --- a/postfix/proto/postconf.proto +++ b/postfix/proto/postconf.proto @@ -16624,7 +16624,7 @@ clients).

This feature is available in Postfix 3.1 and later.

-%PARAM smtp_tls_dane_insecure_mx_policy dane +%PARAM smtp_tls_dane_insecure_mx_policy see "postconf -d" output

The TLS policy for MX hosts with "secure" TLSA records when the nexthop destination security level is dane, but the MX @@ -16648,6 +16648,12 @@ authentication succeeds, it will be logged only as "Trusted", not "Verified", because the MX host name could have been forged. +

The default setting for Postfix ≥ 3.6 is "dane" with +"smtp_tls_security_level = dane", otherwise "may". This behavior +was backported to Postfix versions 3.5.9, 3.4.19, 3.3.16. 3.2.21. +With earlier +Postfix versions the default setting was always "dane".

+

Though with "insecure" MX records an active attacker can compromise SMTP transport security by returning forged MX records, such attacks are "tamper-evident" since any forged MX hostnames @@ -16739,3 +16745,59 @@ See http://unicode.org/cldr/utility/idna.jsp for more examples.

This feature is available in Postfix 3.2 and later.

+ +%PARAM dnssec_probe ns:. + +

The DNS query type (default: "ns") and DNS query name (default: +".") that Postfix may use to determine whether DNSSEC validation +is available. +

+ +

Background: DNSSEC validation is needed for Postfix DANE support; +this ensures that Postfix receives TLSA records with secure TLS +server certificate info. When DNSSEC validation is unavailable, +mail deliveries using opportunistic DANE will not be protected +by server certificate info in TLSA records, and mail deliveries +using mandatory DANE will not be made at all.

+ +

By default, a Postfix process will send a DNSSEC probe after +1) the process made a DNS query that requested DNSSEC validation, +2) the process did not receive a DNSSEC validated response to this +query or to an earlier query, and 3) the process did not already +send a DNSSEC probe.

+ +

When the DNSSEC probe has no response, or when the response is +not DNSSEC validated, Postfix logs a warning that DNSSEC validation +may be unavailable.

+ +

Example:

+ +
+warning: DNSSEC validation may be unavailable
+warning: reason: dnssec_probe 'ns:.' received a response that is not DNSSEC validated
+warning: reason: dnssec_probe 'ns:.' received no response: Server failure
+
+ +

Possible reasons why DNSSEC validation may be unavailable:

+ + + +

By default, the DNSSEC probe asks for the DNS root zone NS +records, because resolvers should always have that information +cached. If Postfix runs on a network where the DNS root zone is not +reachable, specify a different probe, or specify an empty dnssec_probe +value to disable the feature.

+ +

This feature was backported from Postfix 3.6 to Postfix versions +3.5.9, 3.4.19, 3.3.16. 3.2.21.

diff --git a/postfix/src/dns/Makefile.in b/postfix/src/dns/Makefile.in index 1913bc3f0..0af33f4ab 100644 --- a/postfix/src/dns/Makefile.in +++ b/postfix/src/dns/Makefile.in @@ -1,10 +1,10 @@ SHELL = /bin/sh SRCS = dns_lookup.c dns_rr.c dns_strerror.c dns_strtype.c dns_rr_to_pa.c \ dns_sa_to_rr.c dns_rr_eq_sa.c dns_rr_to_sa.c dns_strrecord.c \ - dns_rr_filter.c dns_str_resflags.c + dns_rr_filter.c dns_str_resflags.c dns_sec.c OBJS = dns_lookup.o dns_rr.o dns_strerror.o dns_strtype.o dns_rr_to_pa.o \ dns_sa_to_rr.o dns_rr_eq_sa.o dns_rr_to_sa.o dns_strrecord.o \ - dns_rr_filter.o dns_str_resflags.o + dns_rr_filter.o dns_str_resflags.o dns_sec.o HDRS = dns.h TESTSRC = test_dns_lookup.c test_alias_token.c DEFS = -I. -I$(INC_DIR) -D$(SYSTYPE) @@ -76,7 +76,7 @@ update: $(LIB_DIR)/$(LIB) $(HDRS) done cd $(INC_DIR); chmod 644 $(HDRS) -test_dns_lookup: test_dns_lookup.c $(LIB) $(LIBS) +test_dns_lookup: test_dns_lookup.c all $(LIB) $(LIBS) $(CC) $(CFLAGS) -o $@ $@.c $(LIB) $(LIBS) $(SYSLIBS) dns_rr_to_pa: $(LIB) $(LIBS) @@ -354,6 +354,18 @@ dns_sa_to_rr.o: ../../include/vbuf.h dns_sa_to_rr.o: ../../include/vstring.h dns_sa_to_rr.o: dns.h dns_sa_to_rr.o: dns_sa_to_rr.c +dns_sec.o: ../../include/check_arg.h +dns_sec.o: ../../include/mail_params.h +dns_sec.o: ../../include/msg.h +dns_sec.o: ../../include/myaddrinfo.h +dns_sec.o: ../../include/mymalloc.h +dns_sec.o: ../../include/sock_addr.h +dns_sec.o: ../../include/split_at.h +dns_sec.o: ../../include/sys_defs.h +dns_sec.o: ../../include/vbuf.h +dns_sec.o: ../../include/vstring.h +dns_sec.o: dns.h +dns_sec.o: dns_sec.c dns_str_resflags.o: ../../include/check_arg.h dns_str_resflags.o: ../../include/myaddrinfo.h dns_str_resflags.o: ../../include/name_mask.h diff --git a/postfix/src/dns/dns.h b/postfix/src/dns/dns.h index c2462b982..9cb4dd255 100644 --- a/postfix/src/dns/dns.h +++ b/postfix/src/dns/dns.h @@ -244,7 +244,12 @@ extern int dns_lookup_rv(const char *, unsigned, DNS_RR **, VSTRING *, (lflags), (ltype)) /* - * Request flags. + * The dns_lookup() rflag that requests DNSSEC validation. + */ +#define DNS_WANT_DNSSEC_VALIDATION(rflags) ((rflags) & RES_USE_DNSSEC) + + /* + * lflags. */ #define DNS_REQ_FLAG_STOP_OK (1<<0) #define DNS_REQ_FLAG_STOP_INVAL (1<<1) @@ -309,6 +314,18 @@ extern int dns_rr_filter_execute(DNS_RR **); */ const char *dns_str_resflags(unsigned long); + /* + * dns_sec.c. + */ +#define DNS_SEC_FLAG_AVAILABLE (1<<0) /* got some DNSSEC validated reply */ +#define DNS_SEC_FLAG_DONT_PROBE (1<<1) /* probe already sent, or disabled */ + +#define DNS_SEC_STATS_SET(flags) (dns_sec_stats |= (flags)) +#define DNS_SEC_STATS_TEST(flags) (dns_sec_stats & (flags)) + +extern int dns_sec_stats; /* See DNS_SEC_FLAG_XXX above */ +extern void dns_sec_probe(int); + /* LICENSE /* .ad /* .fi diff --git a/postfix/src/dns/dns_lookup.c b/postfix/src/dns/dns_lookup.c index 2ae64836a..68e243ba0 100644 --- a/postfix/src/dns/dns_lookup.c +++ b/postfix/src/dns/dns_lookup.c @@ -169,6 +169,12 @@ /* Pointer to storage for the reply RCODE value. This gives /* more detailed information than DNS_FAIL, DNS_RETRY, etc. /* DIAGNOSTICS +/* If DNSSEC validation is requested but the response is not +/* DNSSEC validated, dns_lookup() will send a one-time probe +/* query as configured with the \fBdnssec_probe\fR configuration +/* parameter, and will log a warning when the probe response +/* was not DNSSEC validated. +/* .PP /* dns_lookup() returns one of the following codes and sets the /* \fIwhy\fR argument accordingly: /* .IP DNS_OK @@ -458,7 +464,7 @@ static int dns_query(const char *name, int type, unsigned flags, */ #define XTRA_FLAGS (RES_USE_EDNS0 | RES_TRUSTAD) - if (flags & RES_USE_DNSSEC) + if (DNS_WANT_DNSSEC_VALIDATION(flags)) flags |= (RES_USE_EDNS0 | RES_TRUSTAD); /* @@ -487,6 +493,8 @@ static int dns_query(const char *name, int type, unsigned flags, _res.options |= saved_options; reply_header = (HEADER *) reply->buf; reply->rcode = reply_header->rcode; + if ((reply->dnssec_ad = !!reply_header->ad) != 0) + DNS_SEC_STATS_SET(DNS_SEC_FLAG_AVAILABLE); if (h_errno != 0) { if (why) vstring_sprintf(why, "Host or domain name not found. " @@ -538,13 +546,8 @@ static int dns_query(const char *name, int type, unsigned flags, /* * Initialize the reply structure. Some structure members are filled on - * the fly while the reply is being parsed. Coerce AD bit to boolean. + * the fly while the reply is being parsed. */ -#if RES_USE_DNSSEC != 0 - reply->dnssec_ad = (flags & RES_USE_DNSSEC) ? !!reply_header->ad : 0; -#else - reply->dnssec_ad = 0; -#endif SET_HAVE_DNS_REPLY_PACKET(reply, len); reply->query_start = reply->buf + sizeof(HEADER); reply->answer_start = 0; @@ -862,7 +865,9 @@ static int dns_get_answer(const char *orig_name, DNS_REPLY *reply, int type, CORRUPT(DNS_RETRY); if ((status = dns_get_fixed(pos, &fixed)) != DNS_OK) CORRUPT(status); - if (!valid_rr_name(rr_name, "resource name", fixed.type, reply)) + if (strcmp(orig_name, ".") == 0 && *rr_name == 0) + /* Allow empty response name for root queries. */ ; + else if (!valid_rr_name(rr_name, "resource name", fixed.type, reply)) CORRUPT(DNS_INVAL); if (fqdn) vstring_strcpy(fqdn, rr_name); @@ -950,7 +955,7 @@ int dns_lookup_x(const char *name, unsigned type, unsigned flags, /* * The Linux resolver misbehaves when given an invalid domain name. */ - if (!valid_hostname(name, DONT_GRIPE)) { + if (strcmp(name, ".") && !valid_hostname(name, DONT_GRIPE)) { if (why) vstring_sprintf(why, "Name service error for %s: invalid host or domain name", @@ -987,6 +992,10 @@ int dns_lookup_x(const char *name, unsigned type, unsigned flags, (void) dns_get_answer(orig_name, &reply, T_SOA, rrlist, fqdn, cname, c_len, &maybe_secure); } + if (DNS_WANT_DNSSEC_VALIDATION(flags) + && !DNS_SEC_STATS_TEST(DNS_SEC_FLAG_AVAILABLE | \ + DNS_SEC_FLAG_DONT_PROBE)) + dns_sec_probe(flags); /* XXX Clobbers 'reply' */ return (status); } @@ -996,6 +1005,10 @@ int dns_lookup_x(const char *name, unsigned type, unsigned flags, */ status = dns_get_answer(orig_name, &reply, type, rrlist, fqdn, cname, c_len, &maybe_secure); + if (DNS_WANT_DNSSEC_VALIDATION(flags) + && !DNS_SEC_STATS_TEST(DNS_SEC_FLAG_AVAILABLE | \ + DNS_SEC_FLAG_DONT_PROBE)) + dns_sec_probe(flags); /* XXX Clobbers 'reply' */ switch (status) { default: if (why) diff --git a/postfix/src/dns/dns_sec.c b/postfix/src/dns/dns_sec.c new file mode 100644 index 000000000..849627e4b --- /dev/null +++ b/postfix/src/dns/dns_sec.c @@ -0,0 +1,144 @@ +/*++ +/* NAME +/* dns_sec 3 +/* SUMMARY +/* DNSSEC validation availability +/* SYNOPSIS +/* #include +/* +/* DNS_SEC_STATS_SET( +/* int flags) +/* +/* DNS_SEC_STATS_TEST( +/* int flags) +/* +/* void dns_sec_probe( +/* int rflags) +/* DESCRIPTION +/* This module maintains information about the availability of +/* DNSSEC validation, in global flags that summarize +/* process-lifetime history. +/* .IP DNS_SEC_FLAG_AVAILABLE +/* The process has received at least one DNSSEC validated +/* response to a query that requested DNSSEC validation. +/* .IP DNS_SEC_FLAG_DONT_PROBE +/* The process has sent a DNSSEC probe (see below), or DNSSEC +/* probing is disabled by configuration. +/* .PP +/* DNS_SEC_STATS_SET() sets one or more DNS_SEC_FLAG_* flags, +/* and DNS_SEC_STATS_TEST() returns non-zero if any of the +/* specified flags is set. +/* +/* dns_sec_probe() generates a query to the target specified +/* with the \fBdnssec_probe\fR configuration parameter. It +/* sets the DNS_SEC_FLAG_DONT_PROBE flag, and it calls +/* dns_lookup() which sets DNS_SEC_FLAG_AVAILABLE if it receives +/* a DNSSEC validated response. Preconditions: +/* .IP \(bu +/* The rflags argument must request DNSSEC validation (in the +/* same manner as dns_lookup() rflags argument). +/* .IP \(bu +/* The DNS_SEC_FLAG_AVAILABLE and DNS_SEC_FLAG_DONT_PROBE +/* flags must be false. +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* Google, Inc. +/* 111 8th Avenue +/* New York, NY 10011, USA +/*--*/ + +#include + + /* + * Utility library. + */ +#include +#include +#include +#include + + /* + * Global library. + */ +#include + + /* + * DNS library. + */ +#include + +int dns_sec_stats; + +/* dns_sec_probe - send a probe to establish DNSSEC viability */ + +void dns_sec_probe(int rflags) +{ + const char myname[] = "dns_sec_probe"; + char *saved_dnssec_probe; + char *qname; + int qtype; + DNS_RR *rrlist = 0; + int dns_status; + VSTRING *why; + + /* + * Sanity checks. + */ + if (!DNS_WANT_DNSSEC_VALIDATION(rflags)) + msg_panic("%s: DNSSEC is not requested", myname); + if (DNS_SEC_STATS_TEST(DNS_SEC_FLAG_DONT_PROBE)) + msg_panic("%s: DNSSEC probe was already sent, or probing is disabled", + myname); + if (DNS_SEC_STATS_TEST(DNS_SEC_FLAG_AVAILABLE)) + msg_panic("%s: already have validated DNS response", myname); + + /* + * Don't recurse. + */ + DNS_SEC_STATS_SET(DNS_SEC_FLAG_DONT_PROBE); + + /* + * Don't probe. + */ + if (*var_dnssec_probe == 0) + return; + + /* + * Parse the probe spec. Format is type:resource. + */ + saved_dnssec_probe = mystrdup(var_dnssec_probe); + if ((qname = split_at(saved_dnssec_probe, ':')) == 0 || *qname == 0 + || (qtype = dns_type(saved_dnssec_probe)) == 0) + msg_fatal("malformed %s value: %s format is qtype:qname", + VAR_DNSSEC_PROBE, var_dnssec_probe); + + why = vstring_alloc(100); + dns_status = dns_lookup(qname, qtype, rflags, &rrlist, (VSTRING *) 0, why); + if (!DNS_SEC_STATS_TEST(DNS_SEC_FLAG_AVAILABLE)) + msg_warn("DNSSEC validation may be unavailable"); + else if (msg_verbose) + msg_info(VAR_DNSSEC_PROBE + " '%s' received a response that is DNSSEC validated", + var_dnssec_probe); + switch (dns_status) { + default: + if (!DNS_SEC_STATS_TEST(DNS_SEC_FLAG_AVAILABLE)) + msg_warn("reason: " VAR_DNSSEC_PROBE + " '%s' received a response that is not DNSSEC validated", + var_dnssec_probe); + if (rrlist) + dns_rr_free(rrlist); + break; + case DNS_RETRY: + case DNS_FAIL: + msg_warn("reason: " VAR_DNSSEC_PROBE " '%s' received no response: %s", + var_dnssec_probe, vstring_str(why)); + break; + } + myfree(saved_dnssec_probe); + vstring_free(why); +} diff --git a/postfix/src/dns/test_dns_lookup.c b/postfix/src/dns/test_dns_lookup.c index 003fc3992..8366cf7c0 100644 --- a/postfix/src/dns/test_dns_lookup.c +++ b/postfix/src/dns/test_dns_lookup.c @@ -77,6 +77,9 @@ int main(int argc, char **argv) int ch; int lflags = DNS_REQ_FLAG_NONE; + if (var_dnssec_probe == 0) + var_dnssec_probe = mystrdup(DEF_DNSSEC_PROBE); + msg_vstream_init(argv[0], VSTREAM_ERR); while ((ch = GETOPT(argc, argv, "f:npv")) > 0) { switch (ch) { diff --git a/postfix/src/global/mail_params.c b/postfix/src/global/mail_params.c index 2a9e1bc4a..8fcfbab17 100644 --- a/postfix/src/global/mail_params.c +++ b/postfix/src/global/mail_params.c @@ -142,6 +142,8 @@ /* int warn_compat_break_relay_domains; /* int warn_compat_break_flush_domains; /* int warn_compat_break_mynetworks_style; +/* +/* char *var_dnssec_probe; /* DESCRIPTION /* This module (actually the associated include file) defines /* the names and defaults of all mail configuration parameters. @@ -343,6 +345,8 @@ int var_idna2003_compat; int var_compat_level; char *var_drop_hdrs; +char *var_dnssec_probe; + const char null_format_string[1] = ""; /* @@ -649,6 +653,7 @@ void mail_params_init() /* multi_instance_wrapper may have dependencies but not dependents. */ VAR_MULTI_GROUP, DEF_MULTI_GROUP, &var_multi_group, 0, 0, VAR_MULTI_NAME, DEF_MULTI_NAME, &var_multi_name, 0, 0, + VAR_DNSSEC_PROBE, DEF_DNSSEC_PROBE, &var_dnssec_probe, 0, 0, 0, }; static const CONFIG_BOOL_TABLE first_bool_defaults[] = { diff --git a/postfix/src/global/mail_params.h b/postfix/src/global/mail_params.h index 3b4121d93..650dd05ae 100644 --- a/postfix/src/global/mail_params.h +++ b/postfix/src/global/mail_params.h @@ -1591,7 +1591,7 @@ extern bool var_smtp_tls_force_tlsa; /* SMTP only */ #define VAR_SMTP_TLS_INSECURE_MX_POLICY "smtp_tls_dane_insecure_mx_policy" -#define DEF_SMTP_TLS_INSECURE_MX_POLICY "dane" +#define DEF_SMTP_TLS_INSECURE_MX_POLICY "${{$smtp_tls_security_level} == {dane} ? {dane} : {may}}" extern char *var_smtp_tls_insecure_mx_policy; /* @@ -4042,6 +4042,13 @@ extern int var_idna2003_compat; #define DEF_DNS_NCACHE_TTL_FIX 0 extern bool var_dns_ncache_ttl_fix; + /* + * DNSSEC probing, to find out if DNSSEC validation is available. + */ +#define VAR_DNSSEC_PROBE "dnssec_probe" +#define DEF_DNSSEC_PROBE "ns:." +extern char *var_dnssec_probe; + /* LICENSE /* .ad /* .fi diff --git a/postfix/src/global/mail_version.h b/postfix/src/global/mail_version.h index dd1915323..8932334e5 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 "20201107" -#define MAIL_VERSION_NUMBER "3.2.20" +#define MAIL_RELEASE_DATE "20210117" +#define MAIL_VERSION_NUMBER "3.2.21" #ifdef SNAPSHOT #define MAIL_VERSION_DATE "-" MAIL_RELEASE_DATE diff --git a/postfix/src/smtp/smtp.c b/postfix/src/smtp/smtp.c index 3d0aabb3c..ba8062141 100644 --- a/postfix/src/smtp/smtp.c +++ b/postfix/src/smtp/smtp.c @@ -263,6 +263,12 @@ /* deliveries. /* .IP "\fBsmtp_dns_reply_filter (empty)\fR" /* Optional filter for Postfix SMTP client DNS lookup results. +/* .PP +/* Available in Postfix 3.2.21 and later: +/* .IP "\fBdnssec_probe (ns:.)\fR" +/* The DNS query type (default: "ns") and DNS query name (default: +/* ".") that Postfix may use to determine whether DNSSEC validation +/* is available. /* MIME PROCESSING CONTROLS /* .ad /* .fi