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-rw-r--r--src/qmail-smtpam.c631
1 files changed, 631 insertions, 0 deletions
diff --git a/src/qmail-smtpam.c b/src/qmail-smtpam.c
new file mode 100644
index 0000000..c0c6550
--- /dev/null
+++ b/src/qmail-smtpam.c
@@ -0,0 +1,631 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include "sig.h"
+#include "genalloc.h"
+#include "stralloc.h"
+#include "buffer.h"
+#include "scan.h"
+#include "case.h"
+#include "byte.h"
+#include "error.h"
+#include "auto_qmail.h"
+#include "control.h"
+#include "dns.h"
+#include "alloc.h"
+#include "quote.h"
+#include "ip.h"
+#include "ipalloc.h"
+#include "ipme.h"
+#include "str.h"
+#include "now.h"
+#include "exit.h"
+#include "constmap.h"
+#include "tcpto.h"
+#include "socket_if.h"
+#include "ucspissl.h"
+#include "timeout.h"
+#include "timeoutconn.h"
+#include "tls_remote.h"
+#include "tls_errors.h"
+#include "tls_timeoutio.h"
+#include "uint_t.h"
+
+#define MAX_SIZE 200000000
+#define HUGESMTPTEXT 5000
+#define PORT_SMTP 25 /* silly rabbit, /etc/services is for users */
+#define PORT_SMTPS 465
+#define VERIFYDEPTH 1
+#define FDPAM 3
+
+#define WHO "qmail-smtpam"
+
+/** @file qmail-smtpam.c -- TLS enabled SMTP PAM to check mailbox at remote MX
+ */
+
+int flagauth = 0; /* 1 = login; 2 = plain; 3 =crammd5 */
+int flagsmtps = 0; /* RFC 8314 - 'implicit TLS' */
+int flagtls = 0; /* -2 = rejected; -1 = not; 0 = no, default;
+ > 0 see tls_remote.c
+ +10 = SMTPS; +20 = QMTPS; 100 = active TLS connection */
+int flagverify = 0; /* 1 = verify Cert against CA ; -1 = Cert pinning */
+int flagutf8mail = 0;
+
+unsigned long port = PORT_SMTP;
+
+GEN_ALLOC_typedef(saa,stralloc,sa,len,a)
+GEN_ALLOC_readyplus(saa,stralloc,sa,len,a,i,n,x,10,saa_readyplus)
+
+stralloc helohost = {0};
+stralloc host = {0};
+stralloc ports = {0};
+stralloc remotehost = {0};
+stralloc sender = {0};
+stralloc canonhost = {0};
+stralloc canonbox = {0};
+stralloc sendip = {0};
+stralloc recipient = {0};
+
+stralloc domainips = {0};
+struct constmap mapdomainips;
+char ip4[4];
+char ip6[16];
+uint32 ifidx = 0;
+
+stralloc routes = {0};
+struct constmap maproutes;
+
+struct ip_mx partner;
+
+SSL *ssl;
+SSL_CTX *ctx;
+
+void out(char *s) { if (buffer_puts(buffer_1small,s) == -1) _exit(111); }
+void zero() { if (buffer_put(buffer_1small,"\0",1) == -1) _exit(111); }
+void zerodie() { zero(); buffer_flush(buffer_1small); _exit(111); }
+void outsafe(stralloc *sa)
+{
+ int i;
+ char ch;
+ for (i = 0; i < sa->len; ++i) {
+ ch = sa->s[i];
+ if (ch < 33) ch = '?';
+ if (ch > 126) ch = '?';
+ if (buffer_put(buffer_1small,&ch,1) == -1) _exit(111);
+ }
+}
+
+void temp_noip()
+{
+ out("Zinvalid ipaddr in control/domainips (#4.3.0)\n");
+ zerodie();
+}
+void temp_nomem()
+{
+ out("ZOut of memory. (#4.3.0)\n");
+ zerodie();
+}
+void temp_oserr()
+{
+ out("ZSystem resources temporarily unavailable. (#4.3.0)\n");
+ zerodie();
+}
+void temp_osip()
+{
+ out("ZCan't bind to local ip address: ");
+ outsafe(&sendip);
+ out(". (#4.3.0)\n");
+ zerodie();
+}
+void temp_noconn()
+{
+ out("ZSorry, I wasn't able to establish an SMTP connection. (#4.4.1)\n");
+ zerodie();
+}
+void temp_dnscanon()
+{
+ out("ZCNAME lookup failed temporarily for: ");
+ outsafe(&canonhost);
+ out(". (#4.4.3)\n");
+ zerodie();
+}
+void temp_dns()
+{
+ out("ZSorry, I couldn't find any host named: ");
+ outsafe(&host);
+ out(". (#4.1.2)\n");
+ zerodie();
+}
+void temp_chdir()
+{
+ out("ZUnable to switch to home directory. (#4.3.0)\n");
+ zerodie();
+}
+void temp_control()
+{
+ out("ZUnable to read control files. (#4.3.0)\n");
+ zerodie();
+}
+void perm_usage()
+{
+ out("Dqmail-smtpam was invoked improperly. (#5.3.5)\n");
+ zerodie();
+}
+void perm_dns()
+{
+ out("DSorry, I couldn't find any host named: ");
+ outsafe(&host);
+ out(". (#5.1.2)\n");
+ zerodie();
+}
+void outhost()
+{
+ char ipaddr[IPFMT];
+ int len;
+
+ switch (partner.af) {
+ case AF_INET:
+ len = ip4_fmt(ipaddr,(char *)&partner.addr.ip4.d); break;
+ case AF_INET6:
+ len = ip6_fmt(ipaddr,(char *)&partner.addr.ip6.d); break;
+ }
+ if (buffer_put(buffer_1small,ipaddr,len) == -1) _exit(0);
+}
+
+int flagcritical = 0;
+
+void dropped()
+{
+ out("ZConnected to ");
+ outhost();
+ out(" but connection died. ");
+ if (flagcritical) out("Possible duplicate! ");
+ out("(#4.4.2)\n");
+ zerodie();
+}
+
+int timeoutconnect = 60;
+int smtpfd;
+int timeout = 1200;
+
+ssize_t saferead(int fd,char *buf,int len)
+{
+ int r;
+ r = timeoutread(timeout,smtpfd,buf,len);
+ if (r <= 0) dropped();
+ return r;
+}
+
+ssize_t safewrite(int fd,char *buf,int len)
+{
+ int r;
+ r = timeoutwrite(timeout,smtpfd,buf,len);
+ if (r <= 0) dropped();
+ return r;
+}
+
+char outbuf[1450];
+buffer bo = BUFFER_INIT(safewrite,-1,outbuf,sizeof(outbuf));
+char frombuf[128];
+buffer bi = BUFFER_INIT(saferead,-1,frombuf,sizeof(frombuf));
+
+stralloc smtptext = {0};
+
+void get(char *ch)
+{
+ buffer_get(&bi,ch,1);
+ if (*ch != '\r')
+ if (smtptext.len < HUGESMTPTEXT)
+ if (!stralloc_append(&smtptext,ch)) temp_nomem();
+}
+
+unsigned long smtpcode()
+{
+ unsigned char ch;
+ unsigned long code;
+
+ if (!stralloc_copys(&smtptext,"")) temp_nomem();
+
+ get(&ch); code = ch - '0';
+ get(&ch); code = code * 10 + (ch - '0');
+ get(&ch); code = code * 10 + (ch - '0');
+ for (;;) {
+ get(&ch);
+ if (ch != '-') break;
+ while (ch != '\n') get(&ch);
+ get(&ch);
+ get(&ch);
+ get(&ch);
+ }
+ while (ch != '\n') get(&ch);
+
+ return code;
+}
+
+void outsmtptext()
+{
+ int i;
+ if (smtptext.s) if (smtptext.len) {
+ out("Remote host said: ");
+ for (i = 0; i < smtptext.len; ++i)
+ if (!smtptext.s[i]) smtptext.s[i] = '?';
+ if (buffer_put(buffer_1small,smtptext.s,smtptext.len) == -1) _exit(111);
+ smtptext.len = 0;
+ }
+}
+
+void quit(char *prepend,char *append)
+{
+ buffer_putsflush(&bo,"QUIT\r\n");
+ /* waiting for remote side is just too ridiculous */
+ out(prepend);
+ outhost();
+ out(append);
+ out(".\n");
+ outsmtptext();
+ zerodie();
+}
+
+stralloc recip = {0};
+
+/* this file is too long -------------------------------------- client TLS */
+
+stralloc cafile = {0};
+stralloc cadir = {0};
+stralloc certfile = {0};
+stralloc keyfile = {0};
+stralloc keypwd = {0};
+stralloc ciphers = {0};
+stralloc tlsdest = {0};
+
+char *tlsdestinfo = 0;
+char *tlsdomaininfo = 0;
+
+stralloc domaincerts = {0};
+struct constmap mapdomaincerts;
+stralloc tlsdestinations = {0};
+struct constmap maptlsdestinations;
+unsigned long verifydepth = VERIFYDEPTH;
+
+void tls_init()
+{
+/* Client CTX */
+
+ ctx = ssl_client();
+ ssl_errstr();
+ if (!ctx) temp_tlsctx();
+
+/* Fetch CA infos for dest */
+
+ if (flagverify > 0)
+ if (cafile.len || cadir.len)
+ if (!ssl_ca(ctx,cafile.s,cadir.s,(int) verifydepth)) temp_tlsca();
+
+ if (ciphers.len)
+ if (!ssl_ciphers(ctx,ciphers.s)) temp_tlscipher();
+
+/* Set SSL Context */
+
+ ssl = ssl_new(ctx,smtpfd);
+ if (!ssl) temp_tlsctx();
+
+/* Setup SSL FDs */
+
+ if (!tls_conn(ssl,smtpfd)) temp_tlscon();
+
+/* Go on in none-blocking mode */
+
+ if (tls_timeoutconn(timeout,smtpfd,smtpfd,ssl) <= 0)
+ temp_tlserr();
+}
+
+int starttls_peer()
+{
+ int i = 0;
+
+ while ( (i += str_chr(smtptext.s + i,'\n') + 1) &&
+ (i < smtptext.len - 8) ) {
+ if (!str_diffn(smtptext.s + i + 4,"STARTTLS",8)) return 1; }
+
+ return 0;
+}
+
+void tls_peercheck()
+{
+ X509 *cert;
+
+ cert = SSL_get_peer_certificate(ssl);
+ if (!cert) { flagtls = 100; return; }
+
+ if (flagverify < 0) {
+ if (cafile.len) case_lowerb(cafile.s,cafile.len);
+ switch (tls_fingerprint(cert,cafile.s + 1,cafile.len - 1)) {
+ case -1: temp_tlspeercert();
+ case -2: temp_tlsdigest();
+ case -3: temp_invaliddigest();
+ case 1: temp_tlscertfp();
+ }
+ } else {
+ switch (tls_checkpeer(ssl,cert,remotehost,flagtls,flagverify)) {
+ case -1: temp_tlspeercert();
+ case -2: temp_tlspeerverify();
+ case -3: temp_tlspeervalid();
+ case 1: flagtls = 101; break;
+ case 2: flagtls = 102; break;
+ case 3: flagtls = 103; break;
+ }
+ }
+
+ if (flagtls < 100) flagtls = 100;
+
+ X509_free(cert);
+
+ return;
+}
+
+int utf8flag(unsigned char *ch,int len)
+{
+ int i = 0;
+ while (i < len)
+ if (ch[i++] > 127) return 1;
+ return 0;
+}
+
+/* this file is too long -------------------------------------- SMTP connection */
+
+unsigned long code;
+
+void smtp_greeting()
+{
+ buffer_puts(&bo,"EHLO ");
+ buffer_put(&bo,helohost.s,helohost.len);
+ buffer_puts(&bo,"\r\n");
+ buffer_flush(&bo);
+
+ if (smtpcode() != 250) {
+ buffer_puts(&bo,"HELO ");
+ buffer_put(&bo,helohost.s,helohost.len);
+ buffer_puts(&bo,"\r\n");
+ buffer_flush(&bo);
+ code = smtpcode();
+ if (code >= 500) quit("DConnected to"," but my name was rejected");
+ if (code != 250) quit("ZConnected to"," but my name was rejected");
+ }
+}
+
+void smtp_starttls()
+{
+ buffer_puts(&bo,"STARTTLS\r\n");
+ buffer_flush(&bo);
+ if (smtpcode() == 220) {
+ tls_init();
+ tls_peercheck();
+ smtp_greeting();
+ } else {
+ flagtls = -2;
+ quit("ZConnected to"," but STARTTLS was rejected");
+ }
+}
+
+void smtp()
+{
+
+ if (flagtls > 10 && flagtls < 20) { /* SMTPS */
+ tls_init();
+ tls_peercheck();
+ }
+
+ code = smtpcode();
+ if (code >= 500) quit("DConnected to "," but sender was rejected");
+ if (code >= 400) quit("ZConnected to "," but sender was probably greylisted");
+
+ smtp_greeting();
+
+ if (flagutf8mail) buffer_puts(&bo," SMTPUTF8");
+
+ if (flagtls > 0 && flagtls < 10) /* STARTTLS */
+ if (starttls_peer()) {
+ smtp_starttls();
+ } else if (flagtls > 2) {
+ temp_tlshost();
+ }
+
+ buffer_puts(&bo,"MAIL FROM:<>");
+ if (flagutf8mail)
+ buffer_puts(&bo," SMTPUTF8");
+ buffer_puts(&bo,"\r\n");
+ buffer_flush(&bo);
+ code = smtpcode();
+ if (code >= 500) quit("DConnected to "," but sender was rejected");
+ if (code >= 400) quit("ZConnected to "," but sender was rejected");
+
+ buffer_puts(&bo,"RCPT TO:<");
+ buffer_put(&bo,recipient.s,recipient.len);
+ buffer_puts(&bo,">\r\n");
+ buffer_flush(&bo);
+ code = smtpcode();
+ close(smtpfd);
+ if (code == 250) _exit(0);
+ _exit(1);
+}
+
+void getcontrols()
+{
+ if (control_init() == -1) temp_control();
+ if (control_readint(&timeout,"control/timeoutremote") == -1) temp_control();
+ if (control_readint(&timeoutconnect,"control/timeoutconnect") == -1)
+ temp_control();
+ if (control_rldef(&helohost,"control/helohost",1,(char *) 0) != 1)
+ temp_control();
+ switch (control_readfile(&domainips,"control/domainips",0)) {
+ case -1: temp_control();
+ case 0: if (!constmap_init(&mapdomainips,"",0,1)) temp_nomem(); break;
+ case 1: if (!constmap_init(&mapdomainips,domainips.s,domainips.len,1)) temp_nomem(); break;
+ }
+ switch (control_readfile(&tlsdestinations,"control/tlsdestinations",0)) {
+ case -1: temp_control();
+ case 0: if (!constmap_init(&maptlsdestinations,"",0,1)) temp_nomem(); break;
+ case 1: if (!constmap_init(&maptlsdestinations,tlsdestinations.s,tlsdestinations.len,1)) temp_nomem(); break;
+ }
+
+}
+
+char up[513];
+int uplen;
+
+int main(int argc,char **argv)
+{
+ static ipalloc ip = {0};
+ stralloc netif = {0};
+ int i, j, k;
+ int r; /* reserved for return code */
+ int p; /* reserved for port */
+ char *localip = 0;
+ char *tlsdestinfo = 0;
+
+ sig_pipeignore();
+ if (argc < 2) perm_usage();
+ if (chdir(auto_qmail) == -1) temp_chdir();
+ getcontrols();
+
+ if (!stralloc_copys(&host,argv[1])) temp_nomem();
+
+ if (argv[2]) {
+ if (!stralloc_copys(&ports,argv[2])) temp_nomem();
+ if (*ports.s == 's') { ports.s++; flagsmtps = 1; }
+ scan_ulong(ports.s,&port);
+ }
+
+ if (ipme_init() != 1) temp_oserr();
+
+/* this file is too long -------------------------------------- set domain ip + helohost */
+
+ if (!localip)
+ localip = constmap(&mapdomainips,"*",1); /* one for all */
+
+ if (localip) {
+ j = str_chr(localip,'%');
+ if (localip[j] != '%') j = 0;
+ k = str_chr(localip,'|');
+ if (localip[k] != '|') k = 0;
+ if (k) { /* helohost */
+ if (!stralloc_copys(&helohost,localip + k + 1)) temp_nomem();
+ localip[k] = 0;
+ }
+ if (j) { /* if index */
+ localip[j] = 0;
+ if (!stralloc_copys(&netif,localip + j + 1)) temp_nomem();
+ if (!stralloc_0(&netif)) temp_nomem();
+ }
+ }
+
+
+/* this file is too long -------------------------------------- TLS destinations */
+
+ flagtls = tls_destination((const stralloc) host); // un-terminated
+
+ if (flagtls > 0) {
+ if (tlsdestinfo) {
+ i = str_chr(tlsdestinfo,'|'); /* ca file or cert fingerprint */
+ if (tlsdestinfo[i] == '|') {
+ tlsdestinfo[i] = 0;
+ j = str_chr(tlsdestinfo+i+1,'|'); /* cipher */
+ if (tlsdestinfo[i + j + 1] == '|') {
+ tlsdestinfo[i + j + 1] = 0;
+ k = str_chr(tlsdestinfo + i + j + 2,'|'); /* cone domain */
+ if (tlsdestinfo[i + j + k + 2] == '|') {
+ tlsdestinfo[i + j + k + 2] = 0;
+ if (str_diffn(tlsdestinfo + j + k + 3,canonhost.s,canonhost.len)) flagtls = 0;
+ }
+ p = str_chr(tlsdestinfo + i + j + 2,';'); /* verifydepth;port */
+ if (tlsdestinfo[i + j + p + 2] == ';') {
+ if (tlsdestinfo[i + j + p + 3] == 's') { flagsmtps = 1; p++; }
+ tlsdestinfo[i + j + p + 2] = 0;
+ if (p > 0) scan_ulong(tlsdestinfo+i+j + 2,&verifydepth);
+ scan_ulong(tlsdestinfo+i+j + p + 3,&port);
+ }
+ }
+ if (!stralloc_copys(&ciphers,tlsdestinfo + i + 1)) temp_nomem();
+ }
+ if (!stralloc_copys(&cafile,tlsdestinfo)) temp_nomem();
+ }
+
+/* cafile starts with '=' => it is a fingerprint
+ cafile ends with '/' => consider it as cadir */
+
+ if (cafile.len) {
+ flagverify = 1;
+ if (cafile.s[cafile.len] == '/') {
+ cafile.len = 0;
+ flagverify = 2;
+ if (!stralloc_copys(&cadir,tlsdestinfo)) temp_nomem();
+ if (!stralloc_0(&cadir)) temp_nomem();
+ } else {
+ if (cafile.s[0] == '%') flagverify = -1;
+ if (!stralloc_0(&cafile)) temp_nomem();
+ }
+ } else {
+ cafile.len = cadir.len = ciphers.len = p = 0;
+ }
+
+ if (port == PORT_SMTPS || flagsmtps) flagtls = flagtls + 10;
+ }
+
+/* this file is too long -------------------------------------- Setup connection */
+
+ uplen = 0;
+ for (;;) {
+ do
+ r = read(FDPAM,up + uplen,sizeof(up) - uplen);
+ while ((r == -1) && (errno == EINTR));
+ if (r == -1) _exit(111);
+ if (r == 0) break;
+ uplen += r;
+ if (uplen >= sizeof(up)) _exit(111);
+ }
+ close(FDPAM);
+
+ if (!stralloc_copyb(&recipient,up,uplen)) temp_nomem();
+ if (!stralloc_0(&recipient)) temp_nomem();
+ if (!stralloc_0(&host)) temp_nomem();
+ if (!stralloc_copys(&remotehost,host.s)) temp_nomem();
+
+ flagutf8mail = utf8flag(recipient.s,recipient.len);
+
+ switch (dns_ip(&ip,&remotehost)) {
+ case DNS_MEM: temp_nomem();
+ case DNS_ERR: temp_dns();
+ case DNS_COM: temp_dnscanon();
+ default: if (ip.len <= 0) perm_dns();
+ }
+
+ smtpfd = socket(ip.ix[i].af,SOCK_STREAM,0);
+ if (smtpfd == -1) temp_oserr();
+
+ if (localip) { /* set domain ip */
+ if (!stralloc_copyb(&sendip,localip,str_len(localip))) temp_nomem();
+ j = str_chr(localip,':');
+ if (j && localip[j] == ':') { /* IPv6 */
+ if (!ip6_scan(localip,ip6)) temp_noip();
+ ifidx = socket_getifidx(netif.s);
+ if (socket_bind6(smtpfd,ip6,0,ifidx) < 0) temp_osip();
+ } else { /* IPv4 */
+ if (!ip4_scan(localip,ip4)) temp_noip();
+ if (socket_bind4(smtpfd,ip4,0) < 0) temp_osip();
+ }
+ }
+
+ r = timeoutconn(smtpfd,&ip.ix[i].addr,(unsigned int) port,timeoutconnect,ifidx);
+ if (r == 0) {
+ tcpto_err(&ip.ix[i],0);
+ partner = ip.ix[i];
+ smtp(); /* does not return */
+ }
+ tcpto_err(&ip.ix[i],errno == ETIMEDOUT);
+ close(smtpfd);
+
+ temp_noconn();
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-22 08:39:39 +0000