diff options
| -rw-r--r-- | Makefile | 43 | ||||
| -rw-r--r-- | TARGETS | 4 | ||||
| -rw-r--r-- | conf-cc | 2 | ||||
| -rw-r--r-- | dns.c | 15 | ||||
| -rw-r--r-- | hier.c | 3 | ||||
| -rw-r--r-- | ipalloc.h | 8 | ||||
| -rw-r--r-- | qmail-control.9 | 9 | ||||
| -rw-r--r-- | qmail-remote.8 | 43 | ||||
| -rw-r--r-- | qmail-remote.c | 349 | ||||
| -rw-r--r-- | qmail-smtpd.8 | 65 | ||||
| -rw-r--r-- | qmail-smtpd.c | 292 |
11 files changed, 824 insertions, 9 deletions
@@ -812,7 +812,7 @@ dnsptr dnsip dnsmxip dnsfq hostname ipmeprint qreceipt qsmhook qbiff \ forward preline condredirect bouncesaying except maildirmake \ maildir2mbox maildirwatch qail elq pinq idedit install-big install \ instcheck home home+df proc proc+df binm1 binm1+df binm2 binm2+df \ -binm3 binm3+df +binm3 binm3+df update_tmprsadh load: \ make-load warn-auto.sh systype @@ -1448,6 +1448,7 @@ ndelay.a case.a sig.a open.a lock.a seek.a getln.a stralloc.a alloc.a \ substdio.a error.a str.a fs.a auto_qmail.o dns.lib socket.lib ./load qmail-remote control.o constmap.o timeoutread.o \ timeoutwrite.o timeoutconn.o tcpto.o now.o dns.o ip.o \ + tls.o ssl_timeoutio.o -L/usr/local/ssl/lib -lssl -lcrypto \ ipalloc.o ipme.o quote.o ndelay.a case.a sig.a open.a \ lock.a seek.a getln.a stralloc.a alloc.a substdio.a error.a \ str.a fs.a auto_qmail.o `cat dns.lib` `cat socket.lib` @@ -1543,6 +1544,7 @@ open.a sig.a case.a env.a stralloc.a alloc.a substdio.a error.a str.a \ fs.a auto_qmail.o base64.o socket.lib ./load qmail-smtpd rcpthosts.o commands.o timeoutread.o \ timeoutwrite.o ip.o ipme.o ipalloc.o control.o constmap.o \ + tls.o ssl_timeoutio.o ndelay.a -L/usr/local/ssl/lib -lssl -lcrypto \ received.o date822fmt.o now.o qmail.o cdb.a fd.a wait.a \ datetime.a getln.a open.a sig.a case.a env.a stralloc.a \ alloc.a substdio.a error.a str.a fs.a auto_qmail.o base64.o `cat \ @@ -1832,7 +1834,8 @@ date822fmt.h date822fmt.c dns.h dns.c trylsock.c tryrsolv.c ip.h ip.c \ ipalloc.h ipalloc.c select.h1 select.h2 trysysel.c ndelay.h ndelay.c \ ndelay_off.c direntry.3 direntry.h1 direntry.h2 trydrent.c prot.h \ prot.c chkshsgr.c warn-shsgr tryshsgr.c ipme.h ipme.c trysalen.c \ -maildir.5 maildir.h maildir.c tcp-environ.5 constmap.h constmap.c +maildir.5 maildir.h maildir.c tcp-environ.5 constmap.h constmap.c \ +update_tmprsadh shar -m `cat FILES` > shar chmod 400 shar @@ -2113,6 +2116,19 @@ timeoutwrite.o: \ compile timeoutwrite.c timeoutwrite.h select.h error.h readwrite.h ./compile timeoutwrite.c +qmail-smtpd: tls.o ssl_timeoutio.o ndelay.a +qmail-remote: tls.o ssl_timeoutio.o +qmail-smtpd.o: tls.h ssl_timeoutio.h +qmail-remote.o: tls.h ssl_timeoutio.h + +tls.o: \ +compile tls.c exit.h error.h + ./compile tls.c + +ssl_timeoutio.o: \ +compile ssl_timeoutio.c ssl_timeoutio.h select.h error.h ndelay.h + ./compile ssl_timeoutio.c + token822.o: \ compile token822.c stralloc.h gen_alloc.h alloc.h str.h token822.h \ gen_alloc.h gen_allocdefs.h @@ -2144,3 +2160,26 @@ compile wait_nohang.c haswaitp.h wait_pid.o: \ compile wait_pid.c error.h haswaitp.h ./compile wait_pid.c + +cert cert-req: \ +Makefile-cert + @$(MAKE) -sf $< $@ + +Makefile-cert: \ +conf-qmail conf-users conf-groups Makefile-cert.mk + @cat Makefile-cert.mk \ + | sed s}QMAIL}"`head -1 conf-qmail`"}g \ + > $@ + +update_tmprsadh: \ +conf-qmail conf-users conf-groups update_tmprsadh.sh + @cat update_tmprsadh.sh\ + | sed s}UGQMAILD}"`head -2 conf-users|tail -1`:`head -1 conf-groups`"}g \ + | sed s}QMAIL}"`head -1 conf-qmail`"}g \ + > $@ + chmod 755 update_tmprsadh + +tmprsadh: \ +update_tmprsadh + echo "Creating new temporary RSA and DH parameters" + ./update_tmprsadh @@ -168,6 +168,8 @@ control.o constmap.o timeoutread.o timeoutwrite.o +tls.o +ssl_timeoutio.o timeoutconn.o tcpto.o dns.o @@ -321,6 +323,7 @@ binm2 binm2+df binm3 binm3+df +Makefile-cert it qmail-local.0 qmail-lspawn.0 @@ -386,3 +389,4 @@ forgeries.0 man setup check +update_tmprsadh @@ -1,3 +1,3 @@ -cc -O2 +cc -O2 -DTLS=20151215 -I/usr/local/ssl/include This will be used to compile .c files. @@ -284,12 +284,11 @@ stralloc *sa; int pref; { int r; - struct ip_mx ix; + struct ip_mx ix = {0}; if (!stralloc_copy(&glue,sa)) return DNS_MEM; if (!stralloc_0(&glue)) return DNS_MEM; if (glue.s[0]) { - ix.pref = 0; if (!glue.s[ip_scan(glue.s,&ix.ip)] || !glue.s[ip_scanbracket(glue.s,&ix.ip)]) { if (!ipalloc_append(ia,&ix)) return DNS_MEM; @@ -308,9 +307,16 @@ int pref; ix.ip = ip; ix.pref = pref; if (r == DNS_SOFT) return DNS_SOFT; - if (r == 1) + if (r == 1) { +#ifdef IX_FQDN + ix.fqdn = glue.s; +#endif if (!ipalloc_append(ia,&ix)) return DNS_MEM; } + } +#ifdef IX_FQDN + glue.s = 0; +#endif return 0; } @@ -330,7 +336,7 @@ unsigned long random; { int r; struct mx { stralloc sa; unsigned short p; } *mx; - struct ip_mx ix; + struct ip_mx ix = {0}; int nummx; int i; int j; @@ -342,7 +348,6 @@ unsigned long random; if (!stralloc_copy(&glue,sa)) return DNS_MEM; if (!stralloc_0(&glue)) return DNS_MEM; if (glue.s[0]) { - ix.pref = 0; if (!glue.s[ip_scan(glue.s,&ix.ip)] || !glue.s[ip_scanbracket(glue.s,&ix.ip)]) { if (!ipalloc_append(ia,&ix)) return DNS_MEM; @@ -143,6 +143,9 @@ void hier() c(auto_qmail,"bin","qail",auto_uido,auto_gidq,0755); c(auto_qmail,"bin","elq",auto_uido,auto_gidq,0755); c(auto_qmail,"bin","pinq",auto_uido,auto_gidq,0755); +#ifdef TLS + c(auto_qmail,"bin","update_tmprsadh",auto_uido,auto_gidq,0755); +#endif c(auto_qmail,"man/man5","addresses.5",auto_uido,auto_gidq,0644); c(auto_qmail,"man/cat5","addresses.0",auto_uido,auto_gidq,0644); @@ -3,7 +3,15 @@ #include "ip.h" +#ifdef TLS +# define IX_FQDN 1 +#endif + +#ifdef IX_FQDN +struct ip_mx { struct ip_address ip; int pref; char *fqdn; } ; +#else struct ip_mx { struct ip_address ip; int pref; } ; +#endif #include "gen_alloc.h" diff --git a/qmail-control.9 b/qmail-control.9 index 503ce93..945f15f 100644 --- a/qmail-control.9 +++ b/qmail-control.9 @@ -43,11 +43,14 @@ control default used by .I badmailfrom \fR(none) \fRqmail-smtpd .I bouncefrom \fRMAILER-DAEMON \fRqmail-send .I bouncehost \fIme \fRqmail-send +.I clientca.pem \fR(none) \fRqmail-smtpd +.I clientcert.pem \fR(none) \fRqmail-remote .I concurrencylocal \fR10 \fRqmail-send .I concurrencyremote \fR20 \fRqmail-send .I defaultdomain \fIme \fRqmail-inject .I defaulthost \fIme \fRqmail-inject .I databytes \fR0 \fRqmail-smtpd +.I dh2048.pem \fR(none) \fRqmail-smtpd .I doublebouncehost \fIme \fRqmail-send .I doublebounceto \fRpostmaster \fRqmail-send .I envnoathost \fIme \fRqmail-send @@ -61,11 +64,17 @@ control default used by .I qmqpservers \fR(none) \fRqmail-qmqpc .I queuelifetime \fR604800 \fRqmail-send .I rcpthosts \fR(none) \fRqmail-smtpd +.I rsa2048.pem \fR(none) \fRqmail-smtpd +.I servercert.pem \fR(none) \fRqmail-smtpd .I smtpgreeting \fIme \fRqmail-smtpd .I smtproutes \fR(none) \fRqmail-remote .I timeoutconnect \fR60 \fRqmail-remote .I timeoutremote \fR1200 \fRqmail-remote .I timeoutsmtpd \fR1200 \fRqmail-smtpd +.I tlsclients \fR(none) \fRqmail-smtpd +.I tlsclientciphers \fR(none) \fRqmail-remote +.I tlshosts/FQDN.pem \fR(none) \fRqmail-remote +.I tlsserverciphers \fR(none) \fRqmail-smtpd .I virtualdomains \fR(none) \fRqmail-send .fi .RE diff --git a/qmail-remote.8 b/qmail-remote.8 index 08bae85..5fac0f2 100644 --- a/qmail-remote.8 +++ b/qmail-remote.8 @@ -114,6 +114,10 @@ arguments. always exits zero. .SH "CONTROL FILES" .TP 5 +.I clientcert.pem +SSL certificate that is used to authenticate with the remote server +during a TLS session. +.TP 5 .I helohost Current host name, for use solely in saying hello to the remote SMTP server. @@ -123,6 +127,16 @@ if that is supplied; otherwise .B qmail-remote refuses to run. + +.TP 5 +.I notlshosts/<FQDN> +.B qmail-remote +will not try TLS on servers for which this file exists +.RB ( <FQDN> +is the fully-qualified domain name of the server). +.IR (tlshosts/<FQDN>.pem +takes precedence over this file however). + .TP 5 .I smtproutes Artificial SMTP routes. @@ -156,6 +170,8 @@ may be empty; this tells .B qmail-remote to look up MX records as usual. +.I port +value of 465 (deprecated smtps port) causes TLS session to be started. .I smtproutes may include wildcards: @@ -195,6 +211,33 @@ Number of seconds .B qmail-remote will wait for each response from the remote SMTP server. Default: 1200. + +.TP 5 +.I tlsclientciphers +A set of OpenSSL client cipher strings. Multiple ciphers +contained in a string should be separated by a colon. + +.TP 5 +.I tlshosts/<FQDN>.pem +.B qmail-remote +requires TLS authentication from servers for which this file exists +.RB ( <FQDN> +is the fully-qualified domain name of the server). One of the +.I dNSName +or the +.I CommonName +attributes have to match. The file contains the trusted CA certificates. + +.B WARNING: +this option may cause mail to be delayed, bounced, doublebounced, or lost. + +.TP 5 +.I tlshosts/exhaustivelist +if this file exists +no TLS will be tried on hosts other than those for which a file +.B tlshosts/<FQDN>.pem +exists. + .SH "SEE ALSO" addresses(5), envelopes(5), diff --git a/qmail-remote.c b/qmail-remote.c index 7d65473..24ee375 100644 --- a/qmail-remote.c +++ b/qmail-remote.c @@ -48,6 +48,17 @@ saa reciplist = {0}; struct ip_address partner; +#ifdef TLS +# include <sys/stat.h> +# include "tls.h" +# include "ssl_timeoutio.h" +# include <openssl/x509v3.h> +# define EHLO 1 + +int tls_init(); +const char *ssl_err_str = 0; +#endif + void out(s) char *s; { if (substdio_puts(subfdoutsmall,s) == -1) _exit(0); } void zero() { if (substdio_put(subfdoutsmall,"\0",1) == -1) _exit(0); } void zerodie() { zero(); substdio_flush(subfdoutsmall); _exit(0); } @@ -99,6 +110,9 @@ void dropped() { outhost(); out(" but connection died. "); if (flagcritical) out("Possible duplicate! "); +#ifdef TLS + if (ssl_err_str) { out(ssl_err_str); out(" "); } +#endif out("(#4.4.2)\n"); zerodie(); } @@ -110,6 +124,12 @@ int timeout = 1200; int saferead(fd,buf,len) int fd; char *buf; int len; { int r; +#ifdef TLS + if (ssl) { + r = ssl_timeoutread(timeout, smtpfd, smtpfd, ssl, buf, len); + if (r < 0) ssl_err_str = ssl_error_str(); + } else +#endif r = timeoutread(timeout,smtpfd,buf,len); if (r <= 0) dropped(); return r; @@ -117,6 +137,12 @@ int saferead(fd,buf,len) int fd; char *buf; int len; int safewrite(fd,buf,len) int fd; char *buf; int len; { int r; +#ifdef TLS + if (ssl) { + r = ssl_timeoutwrite(timeout, smtpfd, smtpfd, ssl, buf, len); + if (r < 0) ssl_err_str = ssl_error_str(); + } else +#endif r = timeoutwrite(timeout,smtpfd,buf,len); if (r <= 0) dropped(); return r; @@ -163,6 +189,65 @@ unsigned long smtpcode() return code; } +#ifdef EHLO +saa ehlokw = {0}; /* list of EHLO keywords and parameters */ +int maxehlokwlen = 0; + +unsigned long ehlo() +{ + stralloc *sa; + char *s, *e, *p; + unsigned long code; + + if (ehlokw.len > maxehlokwlen) maxehlokwlen = ehlokw.len; + ehlokw.len = 0; + +# ifdef MXPS + if (type == 's') return 0; +# endif + + substdio_puts(&smtpto, "EHLO "); + substdio_put(&smtpto, helohost.s, helohost.len); + substdio_puts(&smtpto, "\r\n"); + substdio_flush(&smtpto); + + code = smtpcode(); + if (code != 250) return code; + + s = smtptext.s; + while (*s++ != '\n') ; /* skip the first line: contains the domain */ + + e = smtptext.s + smtptext.len - 6; /* 250-?\n */ + while (s <= e) + { + int wasspace = 0; + + if (!saa_readyplus(&ehlokw, 1)) temp_nomem(); + sa = ehlokw.sa + ehlokw.len++; + if (ehlokw.len > maxehlokwlen) *sa = sauninit; else sa->len = 0; + + /* smtptext is known to end in a '\n' */ + for (p = (s += 4); ; ++p) + if (*p == '\n' || *p == ' ' || *p == '\t') { + if (!wasspace) + if (!stralloc_catb(sa, s, p - s) || !stralloc_0(sa)) temp_nomem(); + if (*p == '\n') break; + wasspace = 1; + } else if (wasspace == 1) { + wasspace = 0; + s = p; + } + s = ++p; + + /* keyword should consist of alpha-num and '-' + * broken AUTH might use '=' instead of space */ + for (p = sa->s; *p; ++p) if (*p == '=') { *p = 0; break; } + } + + return 250; +} +#endif + void outsmtptext() { int i; @@ -179,6 +264,11 @@ void quit(prepend,append) char *prepend; char *append; { +#ifdef TLS + /* shouldn't talk to the client unless in an appropriate state */ + int state = ssl ? ssl->state : SSL_ST_BEFORE; + if (state & SSL_ST_OK || (!smtps && state & SSL_ST_BEFORE)) +#endif substdio_putsflush(&smtpto,"QUIT\r\n"); /* waiting for remote side is just too ridiculous */ out(prepend); @@ -186,6 +276,30 @@ char *append; out(append); out(".\n"); outsmtptext(); + +#if defined(TLS) && defined(DEBUG) + if (ssl) { + X509 *peercert; + + out("STARTTLS proto="); out(SSL_get_version(ssl)); + out("; cipher="); out(SSL_get_cipher(ssl)); + + /* we want certificate details */ + if (peercert = SSL_get_peer_certificate(ssl)) { + char *str; + + str = X509_NAME_oneline(X509_get_subject_name(peercert), NULL, 0); + out("; subject="); out(str); OPENSSL_free(str); + + str = X509_NAME_oneline(X509_get_issuer_name(peercert), NULL, 0); + out("; issuer="); out(str); OPENSSL_free(str); + + X509_free(peercert); + } + out(";\n"); + } +#endif + zerodie(); } @@ -214,6 +328,199 @@ void blast() substdio_flush(&smtpto); } +#ifdef TLS +char *partner_fqdn = 0; + +# define TLS_QUIT quit(ssl ? "; connected to " : "; connecting to ", "") +void tls_quit(const char *s1, const char *s2) +{ + out(s1); if (s2) { out(": "); out(s2); } TLS_QUIT; +} +# define tls_quit_error(s) tls_quit(s, ssl_error()) + +int match_partner(const char *s, int len) +{ + if (!case_diffb(partner_fqdn, len, s) && !partner_fqdn[len]) return 1; + /* we also match if the name is *.domainname */ + if (*s == '*') { + const char *domain = partner_fqdn + str_chr(partner_fqdn, '.'); + if (!case_diffb(domain, --len, ++s) && !domain[len]) return 1; + } + return 0; +} + +/* don't want to fail handshake if certificate can't be verified */ +int verify_cb(int preverify_ok, X509_STORE_CTX *ctx) { return 1; } + +int tls_init() +{ + int i; + SSL *myssl; + SSL_CTX *ctx; + stralloc saciphers = {0}; + const char *ciphers, *servercert = 0; + + if (partner_fqdn) { + struct stat st; + stralloc tmp = {0}; + if (!stralloc_copys(&tmp, "control/tlshosts/") + || !stralloc_catb(&tmp, partner_fqdn, str_len(partner_fqdn)) + || !stralloc_catb(&tmp, ".pem", 5)) temp_nomem(); + if (stat(tmp.s, &st) == 0) + servercert = tmp.s; + else { + if (!stralloc_copys(&tmp, "control/notlshosts/") + || !stralloc_catb(&tmp, partner_fqdn, str_len(partner_fqdn)+1)) + temp_nomem(); + if ((stat("control/tlshosts/exhaustivelist", &st) == 0) || + (stat(tmp.s, &st) == 0)) { + alloc_free(tmp.s); + return 0; + } + alloc_free(tmp.s); + } + } + + if (!smtps) { + stralloc *sa = ehlokw.sa; + unsigned int len = ehlokw.len; + /* look for STARTTLS among EHLO keywords */ + for ( ; len && case_diffs(sa->s, "STARTTLS"); ++sa, --len) ; + if (!len) { + if (!servercert) return 0; + out("ZNo TLS achieved while "); out(servercert); + out(" exists"); smtptext.len = 0; TLS_QUIT; + } + } + + SSL_library_init(); + ctx = SSL_CTX_new(SSLv23_client_method()); + if (!ctx) { + if (!smtps && !servercert) return 0; + smtptext.len = 0; + tls_quit_error("ZTLS error initializing ctx"); + } + + /* POODLE vulnerability */ + SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3); + + if (servercert) { + if (!SSL_CTX_load_verify_locations(ctx, servercert, NULL)) { + SSL_CTX_free(ctx); + smtptext.len = 0; + out("ZTLS unable to load "); tls_quit_error(servercert); + } + /* set the callback here; SSL_set_verify didn't work before 0.9.6c */ + SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, verify_cb); + } + + /* let the other side complain if it needs a cert and we don't have one */ +# define CLIENTCERT "control/clientcert.pem" + if (SSL_CTX_use_certificate_chain_file(ctx, CLIENTCERT)) + SSL_CTX_use_RSAPrivateKey_file(ctx, CLIENTCERT, SSL_FILETYPE_PEM); +# undef CLIENTCERT + + myssl = SSL_new(ctx); + SSL_CTX_free(ctx); + if (!myssl) { + if (!smtps && !servercert) return 0; + smtptext.len = 0; + tls_quit_error("ZTLS error initializing ssl"); + } + + if (!smtps) substdio_putsflush(&smtpto, "STARTTLS\r\n"); + + /* while the server is preparing a response, do something else */ + if (control_readfile(&saciphers, "control/tlsclientciphers", 0) == -1) + { SSL_free(myssl); temp_control(); } + if (saciphers.len) { + for (i = 0; i < saciphers.len - 1; ++i) + if (!saciphers.s[i]) saciphers.s[i] = ':'; + ciphers = saciphers.s; + } + else ciphers = "DEFAULT"; + SSL_set_cipher_list(myssl, ciphers); + alloc_free(saciphers.s); + + SSL_set_fd(myssl, smtpfd); + + /* read the response to STARTTLS */ + if (!smtps) { + if (smtpcode() != 220) { + SSL_free(myssl); + if (!servercert) return 0; + out("ZSTARTTLS rejected while "); + out(servercert); out(" exists"); TLS_QUIT; + } + smtptext.len = 0; + } + + ssl = myssl; + if (ssl_timeoutconn(timeout, smtpfd, smtpfd, ssl) <= 0) + tls_quit("ZTLS connect failed", ssl_error_str()); + + if (servercert) { + X509 *peercert; + STACK_OF(GENERAL_NAME) *gens; + int found_gen_dns = 0; + + int r = SSL_get_verify_result(ssl); + if (r != X509_V_OK) { + out("ZTLS unable to verify server with "); + tls_quit(servercert, X509_verify_cert_error_string(r)); + } + alloc_free(servercert); + + peercert = SSL_get_peer_certificate(ssl); + if (!peercert) { + out("ZTLS unable to verify server "); + tls_quit(partner_fqdn, "no certificate provided"); + } + + /* RFC 2595 section 2.4: find a matching name + * first find a match among alternative names */ + gens = X509_get_ext_d2i(peercert, NID_subject_alt_name, 0, 0); + if (gens) { + for (i = 0, r = sk_GENERAL_NAME_num(gens); i < r; ++i) + { + const GENERAL_NAME *gn = sk_GENERAL_NAME_value(gens, i); + if (gn->type == GEN_DNS){ + found_gen_dns = 1; + if (match_partner(gn->d.ia5->data, gn->d.ia5->length)) break; + } + } + sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free); + } + + /* no SubjectAltName of type DNS found, look up commonName */ + if (!found_gen_dns) { + stralloc peer = {0}; + X509_NAME *subj = X509_get_subject_name(peercert); + i = X509_NAME_get_index_by_NID(subj, NID_commonName, -1); + if (i >= 0) { + const ASN1_STRING *s = X509_NAME_get_entry(subj, i)->value; + if (s) { peer.len = s->length; peer.s = s->data; } + } + if (peer.len <= 0) { + out("ZTLS unable to verify server "); + tls_quit(partner_fqdn, "certificate contains no valid commonName"); + } + if (!match_partner(peer.s, peer.len)) { + out("ZTLS unable to verify server "); out(partner_fqdn); + out(": received certificate for "); outsafe(&peer); TLS_QUIT; + } + } + + X509_free(peercert); + } + + if (smtps) if (smtpcode() != 220) + quit("ZTLS Connected to "," but greeting failed"); + + return 1; +} +#endif + stralloc recip = {0}; void smtp() @@ -221,15 +528,54 @@ void smtp() unsigned long code; int flagbother; int i; + +#ifndef PORT_SMTP + /* the qmtpc patch uses smtp_port and undefines PORT_SMTP */ +# define port smtp_port +#endif + +#ifdef TLS +# ifdef MXPS + if (type == 'S') smtps = 1; + else if (type != 's') +# endif + if (port == 465) smtps = 1; + if (!smtps) +#endif if (smtpcode() != 220) quit("ZConnected to "," but greeting failed"); +#ifdef EHLO +# ifdef TLS + if (!smtps) +# endif + code = ehlo(); + +# ifdef TLS + if (tls_init()) + /* RFC2487 says we should issue EHLO (even if we might not need + * extensions); at the same time, it does not prohibit a server + * to reject the EHLO and make us fallback to HELO */ + code = ehlo(); +# endif + + if (code == 250) { + /* add EHLO response checks here */ + + /* and if EHLO failed, use HELO */ + } else { +#endif + substdio_puts(&smtpto,"HELO "); substdio_put(&smtpto,helohost.s,helohost.len); substdio_puts(&smtpto,"\r\n"); substdio_flush(&smtpto); if (smtpcode() != 250) quit("ZConnected to "," but my name was rejected"); +#ifdef EHLO + } +#endif + substdio_puts(&smtpto,"MAIL FROM:<"); substdio_put(&smtpto,sender.s,sender.len); substdio_puts(&smtpto,">\r\n"); @@ -417,6 +763,9 @@ char **argv; if (timeoutconn(smtpfd,&ip.ix[i].ip,(unsigned int) port,timeoutconnect) == 0) { tcpto_err(&ip.ix[i].ip,0); partner = ip.ix[i].ip; +#ifdef TLS + partner_fqdn = ip.ix[i].fqdn; +#endif smtp(); /* does not return */ } tcpto_err(&ip.ix[i].ip,errno == error_timeout); diff --git a/qmail-smtpd.8 b/qmail-smtpd.8 index 3e6cce2..4e83fe1 100644 --- a/qmail-smtpd.8 +++ b/qmail-smtpd.8 @@ -19,6 +19,15 @@ must be supplied several environment variables; see .BR tcp-environ(5) . +If the environment variable +.B SMTPS +is non-empty, +.B qmail-smtpd +starts a TLS session (to support the deprecated SMTPS protocol, +normally on port 465). Otherwise, +.B qmail-smtpd +offers the STARTTLS extension to ESMTP. + .B qmail-smtpd is responsible for counting hops. It rejects any message with 100 or more @@ -76,6 +85,19 @@ may be of the form .BR @\fIhost , meaning every address at .IR host . + +.TP 5 +.I clientca.pem +A list of Certifying Authority (CA) certificates that are used to verify +the client-presented certificates during a TLS-encrypted session. + +.TP 5 +.I clientcrl.pem +A list of Certificate Revocation Lists (CRLs). If present it +should contain the CRLs of the CAs in +.I clientca.pem +and client certs will be checked for revocation. + .TP 5 .I databytes Maximum number of bytes allowed in a message, @@ -103,6 +125,18 @@ If the environment variable .B DATABYTES is set, it overrides .IR databytes . + +.TP 5 +.I dh2048.pem +If these 2048 bit DH parameters are provided, +.B qmail-smtpd +will use them for TLS sessions instead of generating one on-the-fly +(which is very timeconsuming). +.TP 5 +.I dh2048.pem +2048 bit counterpart for +.B dh2048.pem. + .TP 5 .I localiphost Replacement host name for local IP addresses. @@ -178,6 +212,19 @@ may include wildcards: Envelope recipient addresses without @ signs are always allowed through. + +.TP 5 +.I rsa512.pem +If this 512 bit RSA key is provided, +.B qmail-smtpd +will use it for TLS sessions instead of generating one on-the-fly. + +.TP 5 +.I servercert.pem +SSL certificate to be presented to clients in TLS-encrypted sessions. +Should contain both the certificate and the private key. Certifying Authority +(CA) and intermediate certificates can be added at the end of the file. + .TP 5 .I smtpgreeting SMTP greeting message. @@ -196,6 +243,24 @@ Number of seconds .B qmail-smtpd will wait for each new buffer of data from the remote SMTP client. Default: 1200. + +.TP 5 +.I tlsclients +A list of email addresses. When relay rules would reject an incoming message, +.B qmail-smtpd +can allow it if the client presents a certificate that can be verified against +the CA list in +.I clientca.pem +and the certificate email address is in +.IR tlsclients . + +.TP 5 +.I tlsserverciphers +A set of OpenSSL cipher strings. Multiple ciphers contained in a +string should be separated by a colon. If the environment variable +.B TLSCIPHERS +is set to such a string, it takes precedence. + .SH "SEE ALSO" tcp-env(1), tcp-environ(5), diff --git a/qmail-smtpd.c b/qmail-smtpd.c index 582a695..b545760 100644 --- a/qmail-smtpd.c +++ b/qmail-smtpd.c @@ -37,9 +37,27 @@ unsigned int databytes = 0; int timeout = 1200; +const char *protocol = "SMTP"; + +#ifdef TLS +#include <sys/stat.h> +#include "tls.h" +#include "ssl_timeoutio.h" + +void tls_init(); +int tls_verify(); +void tls_nogateway(); +int ssl_rfd = -1, ssl_wfd = -1; /* SSL_get_Xfd() are broken */ +#endif + int safewrite(fd,buf,len) int fd; char *buf; int len; { int r; +#ifdef TLS + if (ssl && fd == ssl_wfd) + r = ssl_timeoutwrite(timeout, ssl_rfd, ssl_wfd, ssl, buf, len); + else +#endif r = timeoutwrite(timeout,fd,buf,len); if (r <= 0) _exit(1); return r; @@ -60,7 +78,16 @@ void straynewline() { out("451 See http://pobox.com/~djb/docs/smtplf.html.\r\n") void err_badbounce() { out("550 sorry, bounce messages should have a single envelope recipient (#5.7.1)\r\n"); } void err_bmf() { out("553 sorry, your envelope sender is in my badmailfrom list (#5.7.1)\r\n"); } +#ifndef TLS void err_nogateway() { out("553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)\r\n"); } +#else +void err_nogateway() +{ + out("553 sorry, that domain isn't in my list of allowed rcpthosts"); + tls_nogateway(); + out(" (#5.7.1)\r\n"); +} +#endif void err_unimpl(arg) char *arg; { out("502 unimplemented (#5.5.1)\r\n"); } void err_syntax() { out("555 syntax error (#5.5.4)\r\n"); } void err_relay() { out("553 we don't relay (#5.7.1)\r\n"); } @@ -151,6 +178,11 @@ void setup() if (!remotehost) remotehost = "unknown"; remoteinfo = env_get("TCPREMOTEINFO"); relayclient = env_get("RELAYCLIENT"); + +#ifdef TLS + if (env_get("SMTPS")) { smtps = 1; tls_init(); } + else +#endif dohelo(remotehost); } @@ -236,6 +268,9 @@ int addrallowed() int r; r = rcpthosts(addr.s,str_len(addr.s)); if (r == -1) die_control(); +#ifdef TLS + if (r == 0) if (tls_verify()) r = -2; +#endif return r; } @@ -268,9 +303,17 @@ void smtp_helo(arg) char *arg; smtp_greet("250 "); out("\r\n"); seenmail = 0; dohelo(arg); } +/* ESMTP extensions are published here */ void smtp_ehlo(arg) char *arg; { +#ifdef TLS + struct stat st; +#endif smtp_greet("250-"); +#ifdef TLS + if (!ssl && (stat("control/servercert.pem",&st) == 0)) + out("\r\n250-STARTTLS"); +#endif out("\r\n250-PIPELINING\r\n250 8BITMIME\r\n"); seenmail = 0; dohelo(arg); } @@ -313,6 +356,11 @@ int saferead(fd,buf,len) int fd; char *buf; int len; { int r; flush(); +#ifdef TLS + if (ssl && fd == ssl_rfd) + r = ssl_timeoutread(timeout, ssl_rfd, ssl_wfd, ssl, buf, len); + else +#endif r = timeoutread(timeout,fd,buf,len); if (r == -1) if (errno == error_timeout) die_alarm(); if (r <= 0) die_read(); @@ -321,6 +369,9 @@ int saferead(fd,buf,len) int fd; char *buf; int len; char ssinbuf[1024]; substdio ssin = SUBSTDIO_FDBUF(saferead,0,ssinbuf,sizeof ssinbuf); +#ifdef TLS +void flush_io() { ssin.p = 0; flush(); } +#endif struct qmail qqt; unsigned int bytestooverflow = 0; @@ -423,7 +474,7 @@ void smtp_data(arg) char *arg; { qp = qmail_qp(&qqt); out("354 go ahead\r\n"); - received(&qqt,"SMTP",local,remoteip,remotehost,remoteinfo,fakehelo); + received(&qqt,protocol,local,remoteip,remotehost,remoteinfo,fakehelo); blast(&hops); hops = (hops >= MAXHOPS); if (hops) qmail_fail(&qqt); @@ -659,6 +710,242 @@ char *arg; } } +#ifdef TLS +stralloc proto = {0}; +int ssl_verified = 0; +const char *ssl_verify_err = 0; + +void smtp_tls(char *arg) +{ + if (ssl) err_unimpl(); + else if (*arg) out("501 Syntax error (no parameters allowed) (#5.5.4)\r\n"); + else tls_init(); +} + +RSA *tmp_rsa_cb(SSL *ssl, int export, int keylen) +{ + if (!export) keylen = 2048; + if (keylen == 2048) { + FILE *in = fopen("control/rsa2048.pem", "r"); + if (in) { + RSA *rsa = PEM_read_RSAPrivateKey(in, NULL, NULL, NULL); + fclose(in); + if (rsa) return rsa; + } + } + return RSA_generate_key(keylen, RSA_F4, NULL, NULL); +} + +DH *tmp_dh_cb(SSL *ssl, int export, int keylen) +{ + if (!export) keylen = 2048; + if (keylen == 2048) { + FILE *in = fopen("control/dh2048.pem", "r"); + if (in) { + DH *dh = PEM_read_DHparams(in, NULL, NULL, NULL); + fclose(in); + if (dh) return dh; + } + } + return DH_generate_parameters(keylen, DH_GENERATOR_2, NULL, NULL); +} + +/* don't want to fail handshake if cert isn't verifiable */ +int verify_cb(int preverify_ok, X509_STORE_CTX *ctx) { return 1; } + +void tls_nogateway() +{ + /* there may be cases when relayclient is set */ + if (!ssl || relayclient) return; + out("; no valid cert for gatewaying"); + if (ssl_verify_err) { out(": "); out(ssl_verify_err); } +} +void tls_out(const char *s1, const char *s2) +{ + out("454 TLS "); out(s1); + if (s2) { out(": "); out(s2); } + out(" (#4.3.0)\r\n"); flush(); +} +void tls_err(const char *s) { tls_out(s, ssl_error()); if (smtps) die_read(); } + +# define CLIENTCA "control/clientca.pem" +# define CLIENTCRL "control/clientcrl.pem" +# define SERVERCERT "control/servercert.pem" + +int tls_verify() +{ + stralloc clients = {0}; + struct constmap mapclients; + + if (!ssl || relayclient || ssl_verified) return 0; + ssl_verified = 1; /* don't do this twice */ + + /* request client cert to see if it can be verified by one of our CAs + * and the associated email address matches an entry in tlsclients */ + switch (control_readfile(&clients, "control/tlsclients", 0)) + { + case 1: + if (constmap_init(&mapclients, clients.s, clients.len, 0)) { + /* if CLIENTCA contains all the standard root certificates, a + * 0.9.6b client might fail with SSL_R_EXCESSIVE_MESSAGE_SIZE; + * it is probably due to 0.9.6b supporting only 8k key exchange + * data while the 0.9.6c release increases that limit to 100k */ + STACK_OF(X509_NAME) *sk = SSL_load_client_CA_file(CLIENTCA); + if (sk) { + SSL_set_client_CA_list(ssl, sk); + SSL_set_verify(ssl, SSL_VERIFY_PEER | SSL_VERIFY_CLIENT_ONCE, NULL); + break; + } + constmap_free(&mapclients); + } + case 0: alloc_free(clients.s); return 0; + case -1: die_control(); + } + + if (ssl_timeoutrehandshake(timeout, ssl_rfd, ssl_wfd, ssl) <= 0) { + const char *err = ssl_error_str(); + tls_out("rehandshake failed", err); die_read(); + } + + do { /* one iteration */ + X509 *peercert; + X509_NAME *subj; + stralloc email = {0}; + + int n = SSL_get_verify_result(ssl); + if (n != X509_V_OK) + { ssl_verify_err = X509_verify_cert_error_string(n); break; } + peercert = SSL_get_peer_certificate(ssl); + if (!peercert) break; + + subj = X509_get_subject_name(peercert); + n = X509_NAME_get_index_by_NID(subj, NID_pkcs9_emailAddress, -1); + if (n >= 0) { + const ASN1_STRING *s = X509_NAME_get_entry(subj, n)->value; + if (s) { email.len = s->length; email.s = s->data; } + } + + if (email.len <= 0) + ssl_verify_err = "contains no email address"; + else if (!constmap(&mapclients, email.s, email.len)) + ssl_verify_err = "email address not in my list of tlsclients"; + else { + /* add the cert email to the proto if it helped allow relaying */ + --proto.len; + if (!stralloc_cats(&proto, "\n (cert ") /* continuation line */ + || !stralloc_catb(&proto, email.s, email.len) + || !stralloc_cats(&proto, ")") + || !stralloc_0(&proto)) die_nomem(); + protocol = proto.s; + relayclient = ""; + /* also inform qmail-queue */ + if (!env_put("RELAYCLIENT=")) die_nomem(); + } + + X509_free(peercert); + } while (0); + constmap_free(&mapclients); alloc_free(clients.s); + + /* we are not going to need this anymore: free the memory */ + SSL_set_client_CA_list(ssl, NULL); + SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL); + + return relayclient ? 1 : 0; +} + +void tls_init() +{ + SSL *myssl; + SSL_CTX *ctx; + const char *ciphers; + stralloc saciphers = {0}; + X509_STORE *store; + X509_LOOKUP *lookup; + + SSL_library_init(); + + /* a new SSL context with the bare minimum of options */ + ctx = SSL_CTX_new(SSLv23_server_method()); + if (!ctx) { tls_err("unable to initialize ctx"); return; } + + /* POODLE vulnerability */ + SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3); + + if (!SSL_CTX_use_certificate_chain_file(ctx, SERVERCERT)) + { SSL_CTX_free(ctx); tls_err("missing certificate"); return; } + SSL_CTX_load_verify_locations(ctx, CLIENTCA, NULL); + +#if OPENSSL_VERSION_NUMBER >= 0x00907000L + /* crl checking */ + store = SSL_CTX_get_cert_store(ctx); + if ((lookup = X509_STORE_add_lookup(store, X509_LOOKUP_file())) && + (X509_load_crl_file(lookup, CLIENTCRL, X509_FILETYPE_PEM) == 1)) + X509_STORE_set_flags(store, X509_V_FLAG_CRL_CHECK | + X509_V_FLAG_CRL_CHECK_ALL); +#endif + +#if OPENSSL_VERSION_NUMBER >= 0x10002000L + /* support ECDH */ + SSL_CTX_set_ecdh_auto(ctx,1); +#endif + + /* set the callback here; SSL_set_verify didn't work before 0.9.6c */ + SSL_CTX_set_verify(ctx, SSL_VERIFY_NONE, verify_cb); + + /* a new SSL object, with the rest added to it directly to avoid copying */ + myssl = SSL_new(ctx); + SSL_CTX_free(ctx); + if (!myssl) { tls_err("unable to initialize ssl"); return; } + + /* this will also check whether public and private keys match */ + if (!SSL_use_RSAPrivateKey_file(myssl, SERVERCERT, SSL_FILETYPE_PEM)) + { SSL_free(myssl); tls_err("no valid RSA private key"); return; } + + ciphers = env_get("TLSCIPHERS"); + if (!ciphers) { + if (control_readfile(&saciphers, "control/tlsserverciphers", 0) == -1) + { SSL_free(myssl); die_control(); } + if (saciphers.len) { /* convert all '\0's except the last one to ':' */ + int i; + for (i = 0; i < saciphers.len - 1; ++i) + if (!saciphers.s[i]) saciphers.s[i] = ':'; + ciphers = saciphers.s; + } + } + if (!ciphers || !*ciphers) ciphers = "DEFAULT"; + SSL_set_cipher_list(myssl, ciphers); + alloc_free(saciphers.s); + + SSL_set_tmp_rsa_callback(myssl, tmp_rsa_cb); + SSL_set_tmp_dh_callback(myssl, tmp_dh_cb); + SSL_set_rfd(myssl, ssl_rfd = substdio_fileno(&ssin)); + SSL_set_wfd(myssl, ssl_wfd = substdio_fileno(&ssout)); + + if (!smtps) { out("220 ready for tls\r\n"); flush(); } + + if (ssl_timeoutaccept(timeout, ssl_rfd, ssl_wfd, myssl) <= 0) { + /* neither cleartext nor any other response here is part of a standard */ + const char *err = ssl_error_str(); + ssl_free(myssl); tls_out("connection failed", err); die_read(); + } + ssl = myssl; + + /* populate the protocol string, used in Received */ + if (!stralloc_copys(&proto, "ESMTPS (") + || !stralloc_cats(&proto, SSL_get_cipher(ssl)) + || !stralloc_cats(&proto, " encrypted)")) die_nomem(); + if (!stralloc_0(&proto)) die_nomem(); + protocol = proto.s; + + /* have to discard the pre-STARTTLS HELO/EHLO argument, if any */ + dohelo(remotehost); +} + +# undef SERVERCERT +# undef CLIENTCA + +#endif + struct commands smtpcommands[] = { { "rcpt", smtp_rcpt, 0 } , { "mail", smtp_mail, 0 } @@ -669,6 +956,9 @@ struct commands smtpcommands[] = { , { "ehlo", smtp_ehlo, flush } , { "rset", smtp_rset, 0 } , { "help", smtp_help, flush } +#ifdef TLS +, { "starttls", smtp_tls, flush_io } +#endif , { "noop", err_noop, flush } , { "vrfy", err_vrfy, flush } , { 0, err_unimpl, flush } |