/* * socket.c -- socket library functions * * Copyright 1998 - 2004 by Eric S. Raymond. * Copyright 2004 - 2019 by Matthias Andree. * Contributions by Alexander Bluhm, Earl Chew, John Beck. * For license terms, see the file COPYING in this directory. */ #include "config.h" #include "fetchmail.h" #include #include #include #include /* isspace() */ #ifdef HAVE_MEMORY_H #include #endif /* HAVE_MEMORY_H */ #include #include #include #include #include #ifdef HAVE_ARPA_INET_H #include #endif #include #if defined(STDC_HEADERS) #include #endif #if defined(HAVE_UNISTD_H) #include #endif #if defined(HAVE_STDARG_H) #include #else #include #endif #if TIME_WITH_SYS_TIME # include # include #else # if HAVE_SYS_TIME_H # include # else # include # endif #endif #include "socket.h" #include "getaddrinfo.h" #include "i18n.h" #include "sdump.h" #include "uid_db.h" /* Defines to allow BeOS and Cygwin to play nice... */ #ifdef __BEOS__ static char peeked; #define fm_close(a) closesocket(a) #define fm_write(a,b,c) send(a,b,c,0) #define fm_peek(a,b,c) recv(a,b,c,0) #define fm_read(a,b,c) recv(a,b,c,0) #else #define fm_close(a) close(a) #define fm_write(a,b,c) write(a,b,c) #define fm_peek(a,b,c) recv(a,b,c, MSG_PEEK) #ifdef __CYGWIN__ #define fm_read(a,b,c) cygwin_read(a,b,c) static ssize_t cygwin_read(int sock, void *buf, size_t count); #else /* ! __CYGWIN__ */ #define fm_read(a,b,c) read(a,b,c) #endif /* __CYGWIN__ */ #endif /* We need to define h_errno only if it is not already */ #ifndef h_errno # if !HAVE_DECL_H_ERRNO extern int h_errno; # endif #endif /* ndef h_errno */ #ifdef HAVE_SOCKETPAIR static char *const *parse_plugin(const char *plugin, const char *host, const char *service) { char **argvec; const char *c, *p; char *cp, *plugin_copy; unsigned int plugin_copy_len; unsigned int plugin_offset = 0, plugin_copy_offset = 0; unsigned int i, vecsiz = 2 * sizeof(char*), host_count = 0, service_count = 0; unsigned int plugin_len = strlen(plugin); unsigned int host_len = strlen(host); unsigned int service_len = strlen(service); for (c = p = plugin; *c; c++) { if (isspace((unsigned char)*c) && !isspace((unsigned char)*p)) vecsiz += sizeof(char*); if (*p == '%' && *c == 'h') host_count++; if (*p == '%' && *c == 'p') service_count++; p = c; } /* we need to discount 2 bytes for each placeholder */ plugin_copy_len = plugin_len + (host_len - 2) * host_count + (service_len - 2) * service_count; plugin_copy = (char *)malloc(plugin_copy_len + 1); if (!plugin_copy) { report(stderr, GT_("fetchmail: malloc failed\n")); return NULL; } while (plugin_offset < plugin_len && plugin_copy_offset < plugin_copy_len) { if ((plugin[plugin_offset] == '%') && (plugin[plugin_offset + 1] == 'h')) { strcpy(plugin_copy + plugin_copy_offset, host); plugin_offset += 2; plugin_copy_offset += host_len; } else if ((plugin[plugin_offset] == '%') && (plugin[plugin_offset + 1] == 'p')) { strcpy(plugin_copy + plugin_copy_offset, service); plugin_offset += 2; plugin_copy_offset += service_len; } else { plugin_copy[plugin_copy_offset] = plugin[plugin_offset]; plugin_offset++; plugin_copy_offset++; } } plugin_copy[plugin_copy_offset] = 0; /* XXX FIXME - is this perhaps a bit too simplistic to chop down the argument strings without any respect to quoting? * better write a generic function that tracks arguments instead... */ argvec = (char **)malloc(vecsiz); if (!argvec) { free(plugin_copy); report(stderr, GT_("fetchmail: malloc failed\n")); return NULL; } memset(argvec, 0, vecsiz); for (p = cp = plugin_copy, i = 0; *cp; cp++) { if ((!isspace((unsigned char)*cp)) && (cp == p ? 1 : isspace((unsigned char)*p))) { argvec[i] = cp; i++; } p = cp; } for (cp = plugin_copy; *cp; cp++) { if (isspace((unsigned char)*cp)) *cp = 0; } return argvec; } static int handle_plugin(const char *host, const char *service, const char *plugin) /* get a socket mediated through a given external command */ { int fds[2]; char *const *argvec; /* * The author of this code, Felix von Leitner , says: * he chose socketpair() instead of pipe() because socketpair creates * bidirectional sockets while allegedly some pipe() implementations don't. */ if (socketpair(AF_UNIX,SOCK_STREAM,0,fds)) { report(stderr, GT_("fetchmail: socketpair failed\n")); return -1; } switch (fork()) { case -1: /* error */ report(stderr, GT_("fetchmail: fork failed\n")); return -1; case 0: /* child */ /* fds[1] is the parent's end; close it for proper EOF ** detection */ (void) close(fds[1]); if ( (dup2(fds[0],0) == -1) || (dup2(fds[0],1) == -1) ) { report(stderr, GT_("dup2 failed\n")); _exit(EXIT_FAILURE); } /* fds[0] is now connected to 0 and 1; close it */ (void) close(fds[0]); if (outlevel >= O_VERBOSE) report(stderr, GT_("running %s (host %s service %s)\n"), plugin, host, service); argvec = parse_plugin(plugin,host,service); if (argvec == NULL) _exit(EXIT_FAILURE); execvp(*argvec, argvec); report(stderr, GT_("execvp(%s) failed\n"), *argvec); _exit(EXIT_FAILURE); break; default: /* parent */ /* NOP */ break; } /* fds[0] is the child's end; close it for proper EOF detection */ (void) close(fds[0]); return fds[1]; } #endif /* HAVE_SOCKETPAIR */ /** Set socket to SO_KEEPALIVE. \return 0 for success. */ static int SockKeepalive(int sock) { int keepalive = 1; return setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, &keepalive, sizeof keepalive); } int UnixOpen(const char *path) { int sock = -1; struct sockaddr_un ad; memset(&ad, 0, sizeof(ad)); ad.sun_family = AF_UNIX; strlcpy(ad.sun_path, path, sizeof(ad.sun_path)); sock = socket( AF_UNIX, SOCK_STREAM, 0 ); if (sock < 0) { h_errno = 0; return -1; } /* Socket opened saved. Useful if connect timeout * because it can be closed. */ mailserver_socket_temp = sock; if (connect(sock, (struct sockaddr *) &ad, sizeof(ad)) < 0) { int olderr = errno; fm_close(sock); /* don't use SockClose, no traffic yet */ h_errno = 0; errno = olderr; sock = -1; } /* No connect timeout, then no need to set mailserver_socket_temp */ mailserver_socket_temp = -1; return sock; } int SockOpen(const char *host, const char *service, const char *plugin, struct addrinfo **ai_in) { struct addrinfo *ai, req; int i, acterr = 0; int ord; char errbuf[8192] = ""; #ifdef HAVE_SOCKETPAIR if (plugin) return handle_plugin(host,service,plugin); #endif /* HAVE_SOCKETPAIR */ memset(&req, 0, sizeof(struct addrinfo)); req.ai_socktype = SOCK_STREAM; #ifdef AI_ADDRCONFIG req.ai_flags = AI_ADDRCONFIG; #endif i = fm_getaddrinfo(host, service, &req, ai_in); if (i) { report(stderr, GT_("getaddrinfo(\"%s\",\"%s\") error: %s\n"), host, service, gai_strerror(i)); if (i == EAI_SERVICE) report(stderr, GT_("Try adding the --service option (see also FAQ item R12).\n")); return -1; } /* NOTE a Linux bug here - getaddrinfo will happily return 127.0.0.1 * twice if no IPv6 is configured */ i = -1; for (ord = 0, ai = *ai_in; ai; ord++, ai = ai->ai_next) { char buf[256]; /* hostname */ char pb[256]; /* service name */ int gnie; /* getnameinfo result code */ gnie = getnameinfo(ai->ai_addr, ai->ai_addrlen, buf, sizeof(buf), NULL, 0, NI_NUMERICHOST); if (gnie) snprintf(buf, sizeof(buf), GT_("unknown (%s)"), gai_strerror(gnie)); gnie = getnameinfo(ai->ai_addr, ai->ai_addrlen, NULL, 0, pb, sizeof(pb), NI_NUMERICSERV); if (gnie) snprintf(pb, sizeof(pb), GT_("unknown (%s)"), gai_strerror(gnie)); if (outlevel >= O_VERBOSE) report_build(stdout, GT_("Trying to connect to %s/%s..."), buf, pb); i = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); if (i < 0) { int e = errno; /* mask EAFNOSUPPORT errors, they confuse users for * multihomed hosts */ if (errno != EAFNOSUPPORT) acterr = errno; if (outlevel >= O_VERBOSE) report_complete(stdout, GT_("cannot create socket: %s\n"), strerror(e)); snprintf(errbuf+strlen(errbuf), sizeof(errbuf)-strlen(errbuf),\ GT_("name %d: cannot create socket family %d type %d: %s\n"), ord, ai->ai_family, ai->ai_socktype, strerror(e)); continue; } SockKeepalive(i); /* Save socket descriptor. * Used to close the socket after connect timeout. */ mailserver_socket_temp = i; if (connect(i, (struct sockaddr *) ai->ai_addr, ai->ai_addrlen) < 0) { int e = errno; /* additionally, suppress IPv4 network unreach errors */ if (e != EAFNOSUPPORT) acterr = errno; if (outlevel >= O_VERBOSE) report_complete(stdout, GT_("connection failed.\n")); if (outlevel >= O_VERBOSE) report(stderr, GT_("connection to %s:%s [%s/%s] failed: %s.\n"), host, service, buf, pb, strerror(e)); snprintf(errbuf+strlen(errbuf), sizeof(errbuf)-strlen(errbuf), GT_("name %d: connection to %s:%s [%s/%s] failed: %s.\n"), ord, host, service, buf, pb, strerror(e)); fm_close(i); i = -1; continue; } else { if (outlevel >= O_VERBOSE) report_complete(stdout, GT_("connected.\n")); } /* No connect timeout, then no need to set mailserver_socket_temp */ mailserver_socket_temp = -1; break; } fm_freeaddrinfo(*ai_in); *ai_in = NULL; if (i == -1) { report(stderr, GT_("Connection errors for this poll:\n%s"), errbuf); errno = acterr; } return i; } #if defined(HAVE_STDARG_H) int SockPrintf(int sock, const char* format, ...) { #else int SockPrintf(sock,format,va_alist) int sock; char *format; va_dcl { #endif va_list ap; char buf[8192]; #if defined(HAVE_STDARG_H) va_start(ap, format) ; #else va_start(ap); #endif vsnprintf(buf, sizeof(buf), format, ap); va_end(ap); return SockWrite(sock, buf, strlen(buf)); } #ifdef SSL_ENABLE /* OPENSSL_NO_SSL_INTERN: transitional feature for OpenSSL 1.0.1 up to and excluding 1.1.0 to make sure we do not access internal structures! */ #define OPENSSL_NO_SSL_INTERN 1 #define OPENSSL_NO_DEPRECATED 23 #include #include #include #include #include #define fm_MIN_OPENSSL_VER 0x1000200fL #ifdef LIBRESSL_VERSION_NUMBER #pragma message "WARNING - LibreSSL is unsupported. Use at your own risk." #endif #if OPENSSL_VERSION_NUMBER < fm_MIN_OPENSSL_VER #error Your OpenSSL version must be at least 1.0.2 release. Older OpenSSL versions are unsupported. #else /* #define __fm_ossl_ver(x) #x #define _fm_ossl_ver(x) __fm_ossl_ver(x) #pragma message "Building with OpenSSL headers version " _fm_ossl_ver(OPENSSL_VERSION_NUMBER) ", " OPENSSL_VERSION_TEXT */ #endif static void report_SSL_errors(FILE *stream) { unsigned long err; while (0ul != (err = ERR_get_error())) { char *errstr = ERR_error_string(err, NULL); report(stream, GT_("OpenSSL reported: %s\n"), errstr); } } /* override ERR_print_errors_fp to our own implementation */ #undef ERR_print_errors_fp #define ERR_print_errors_fp(stream) report_SSL_errors((stream)) static SSL_CTX *_ctx[FD_SETSIZE]; static SSL *_ssl_context[FD_SETSIZE]; static SSL *SSLGetContext( int ); #endif /* SSL_ENABLE */ int SockWrite(int sock, const char *buf, int len) { int n, wrlen = 0; #ifdef SSL_ENABLE SSL *ssl; #endif while (len) { #ifdef SSL_ENABLE if( NULL != ( ssl = SSLGetContext( sock ) ) ) n = SSL_write(ssl, buf, len); else #endif /* SSL_ENABLE */ n = fm_write(sock, buf, len); if (n <= 0) return -1; len -= n; wrlen += n; buf += n; } return wrlen; } int SockRead(int sock, char *buf, int len) { char *newline, *bp = buf; int n; #ifdef SSL_ENABLE SSL *ssl; #endif if (--len < 1) return(-1); #ifdef __BEOS__ if (peeked != 0){ (*bp) = peeked; bp++; len--; peeked = 0; } #endif do { /* * The reason for these gymnastics is that we want two things: * (1) to read \n-terminated lines, * (2) to return the true length of data read, even if the * data coming in has embedded NULS. */ #ifdef SSL_ENABLE if( NULL != ( ssl = SSLGetContext( sock ) ) ) { /* Hack alert! */ /* OK... SSL_peek works a little different from MSG_PEEK Problem is that SSL_peek can return 0 if there is no data currently available. If, on the other hand, we lose the socket, we also get a zero, but the SSL_read then SEGFAULTS! To deal with this, we'll check the error code any time we get a return of zero from SSL_peek. If we have an error, we bail. If we don't, we read one character in SSL_read and loop. This should continue to work even if they later change the behavior of SSL_peek to "fix" this problem... :-( */ if ((n = SSL_peek(ssl, bp, len)) < 0) { (void)SSL_get_error(ssl, n); return(-1); } if( 0 == n ) { /* SSL_peek says no data... Does he mean no data or did the connection blow up? If we got an error then bail! */ if (0 != SSL_get_error(ssl, n)) { return -1; } /* We didn't get an error so read at least one character at this point and loop */ n = 1; /* Make sure newline start out NULL! * We don't have a string to pass through * the strchr at this point yet */ newline = NULL; } else if ((newline = (char *)memchr(bp, '\n', n)) != NULL) n = newline - bp + 1; /* Matthias Andree: SSL_read can return 0, in that case * we must call SSL_get_error to figure if there was * an error or just a "no data" condition */ if ((n = SSL_read(ssl, bp, n)) <= 0) { if ((n = SSL_get_error(ssl, n))) { return(-1); } } /* Check for case where our single character turned out to * be a newline... (It wasn't going to get caught by * the strchr above if it came from the hack... ). */ if( NULL == newline && 1 == n && '\n' == *bp ) { /* Got our newline - this will break out of the loop now */ newline = bp; } } else #endif /* SSL_ENABLE */ { #ifdef __BEOS__ if ((n = fm_read(sock, bp, 1)) <= 0) #else if ((n = fm_peek(sock, bp, len)) <= 0) #endif return (-1); if ((newline = (char *)memchr(bp, '\n', n)) != NULL) n = newline - bp + 1; #ifndef __BEOS__ if ((n = fm_read(sock, bp, n)) == -1) return(-1); #endif /* __BEOS__ */ } bp += n; len -= n; } while (!newline && len); *bp = '\0'; return bp - buf; } int SockPeek(int sock) /* peek at the next socket character without actually reading it */ { int n; char ch; #ifdef SSL_ENABLE SSL *ssl; #endif #ifdef SSL_ENABLE if( NULL != ( ssl = SSLGetContext( sock ) ) ) { n = SSL_peek(ssl, &ch, 1); if (n < 0) { (void)SSL_get_error(ssl, n); return -1; } if( 0 == n ) { /* This code really needs to implement a "hold back" * to simulate a functioning SSL_peek()... sigh... * Has to be coordinated with the read code above. * Next on the list todo... */ /* SSL_peek says 0... Does that mean no data or did the connection blow up? If we got an error then bail! */ if(0 != SSL_get_error(ssl, n)) { return -1; } /* Haven't seen this case actually occur, but... if the problem in SockRead can occur, this should be possible... Just not sure what to do here. This should be a safe "punt" the "peek" but don't "punt" the "session"... */ return 0; /* Give him a '\0' character */ } } else #endif /* SSL_ENABLE */ n = fm_peek(sock, &ch, 1); if (n == -1) return -1; #ifdef __BEOS__ peeked = ch; #endif return(ch); } #ifdef SSL_ENABLE static char *_ssl_server_cname = NULL; static int _check_fp; static char *_check_digest; static char *_server_label; static int _depth0ck; static int _firstrun; static int _prev_err; static int _verify_ok; SSL *SSLGetContext( int sock ) { if( sock < 0 || (unsigned)sock > FD_SETSIZE ) return NULL; if( _ctx[sock] == NULL ) return NULL; return _ssl_context[sock]; } /* ok_return (preverify_ok) is 1 if this stage of certificate verification passed, or 0 if it failed. This callback lets us display informative errors, and perform additional validation (e.g. CN matches) */ static int SSL_verify_callback(int ok_return, X509_STORE_CTX *ctx, int strict) { #define SSLverbose (((outlevel) >= O_DEBUG) || ((outlevel) >= O_VERBOSE && (depth) == 0)) char buf[257]; X509 *x509_cert; int err, depth, i; unsigned char digest[EVP_MAX_MD_SIZE]; char text[EVP_MAX_MD_SIZE * 3 + 1], *tp, *te; const EVP_MD *digest_tp; unsigned int dsz, esz; X509_NAME *subj, *issuer; char *tt; x509_cert = X509_STORE_CTX_get_current_cert(ctx); err = X509_STORE_CTX_get_error(ctx); depth = X509_STORE_CTX_get_error_depth(ctx); subj = X509_get_subject_name(x509_cert); issuer = X509_get_issuer_name(x509_cert); if (outlevel >= O_DEBUG) { if (SSLverbose) report(stdout, GT_("SSL verify callback depth %d: preverify_ok == %d, err = %d, %s\n"), depth, ok_return, err, X509_verify_cert_error_string(err)); } if (outlevel >= O_VERBOSE) { if (depth == 0 && SSLverbose) report(stdout, GT_("Server certificate:\n")); else { if (_firstrun) { _firstrun = 0; if (SSLverbose) report(stdout, GT_("Certificate chain, from root to peer, starting at depth %d:\n"), depth); } else { if (SSLverbose) report(stdout, GT_("Certificate at depth %d:\n"), depth); } } if (SSLverbose) { if ((i = X509_NAME_get_text_by_NID(issuer, NID_organizationName, buf, sizeof(buf))) != -1) { report(stdout, GT_("Issuer Organization: %s\n"), (tt = sdump(buf, i))); xfree(tt); if ((size_t)i >= sizeof(buf) - 1) report(stdout, GT_("Warning: Issuer Organization Name too long (possibly truncated).\n")); } else report(stdout, GT_("Unknown Organization\n")); if ((i = X509_NAME_get_text_by_NID(issuer, NID_commonName, buf, sizeof(buf))) != -1) { report(stdout, GT_("Issuer CommonName: %s\n"), (tt = sdump(buf, i))); xfree(tt); if ((size_t)i >= sizeof(buf) - 1) report(stdout, GT_("Warning: Issuer CommonName too long (possibly truncated).\n")); } else report(stdout, GT_("Unknown Issuer CommonName\n")); } } if ((i = X509_NAME_get_text_by_NID(subj, NID_commonName, buf, sizeof(buf))) != -1) { if (SSLverbose) { report(stdout, GT_("Subject CommonName: %s\n"), (tt = sdump(buf, i))); xfree(tt); } if ((size_t)i >= sizeof(buf) - 1) { /* Possible truncation. In this case, this is a DNS name, so this * is really bad. We do not tolerate this even in the non-strict case. */ report(stderr, GT_("Bad certificate: Subject CommonName too long!\n")); return (0); } if ((size_t)i > strlen(buf)) { /* Name contains embedded NUL characters, so we complain. This is likely * a certificate spoofing attack. */ report(stderr, GT_("Bad certificate: Subject CommonName contains NUL, aborting!\n")); return 0; } } if (depth == 0) { /* peer certificate */ if (!_depth0ck) { _depth0ck = 1; } if ((i = X509_NAME_get_text_by_NID(subj, NID_commonName, buf, sizeof(buf))) != -1) { if (_ssl_server_cname != NULL) { char *p1 = buf; char *p2 = _ssl_server_cname; int matched = 0; STACK_OF(GENERAL_NAME) *gens; /* RFC 2595 section 2.4: find a matching name * first find a match among alternative names */ gens = (STACK_OF(GENERAL_NAME) *)X509_get_ext_d2i(x509_cert, NID_subject_alt_name, NULL, NULL); if (gens) { int j, r; for (j = 0, r = sk_GENERAL_NAME_num(gens); j < r; ++j) { const GENERAL_NAME *gn = sk_GENERAL_NAME_value(gens, j); if (gn->type == GEN_DNS) { char *pp1 = (char *)gn->d.ia5->data; char *pp2 = _ssl_server_cname; if (outlevel >= O_VERBOSE) { report(stdout, GT_("Subject Alternative Name: %s\n"), (tt = sdump(pp1, (size_t)gn->d.ia5->length))); xfree(tt); } /* Name contains embedded NUL characters, so we complain. This * is likely a certificate spoofing attack. */ if ((size_t)gn->d.ia5->length != strlen(pp1)) { report(stderr, GT_("Bad certificate: Subject Alternative Name contains NUL, aborting!\n")); sk_GENERAL_NAME_free(gens); return 0; } if (name_match(pp1, pp2)) { matched = 1; } } } GENERAL_NAMES_free(gens); } if (name_match(p1, p2)) { matched = 1; } if (!matched) { if (strict || SSLverbose) { report(stderr, GT_("Server CommonName mismatch: %s != %s\n"), (tt = sdump(buf, i)), _ssl_server_cname ); xfree(tt); } ok_return = 0; } } else if (ok_return) { report(stderr, GT_("Server name not set, could not verify certificate!\n")); if (strict) return (0); } } else { if (outlevel >= O_VERBOSE) report(stdout, GT_("Unknown Server CommonName\n")); if (ok_return && strict) { report(stderr, GT_("Server name not specified in certificate!\n")); return (0); } } /* Print the finger print. Note that on errors, we might print it more than once * normally; we kluge around that by using a global variable. */ if (_check_fp == 1) { unsigned dp; _check_fp = -1; digest_tp = EVP_md5(); if (digest_tp == NULL) { report(stderr, GT_("EVP_md5() failed!\n")); return (0); } if (!X509_digest(x509_cert, digest_tp, digest, &dsz)) { report(stderr, GT_("Out of memory!\n")); return (0); } tp = text; te = text + sizeof(text); for (dp = 0; dp < dsz; dp++) { esz = snprintf(tp, te - tp, dp > 0 ? ":%02X" : "%02X", digest[dp]); if (esz >= (size_t)(te - tp)) { report(stderr, GT_("Digest text buffer too small!\n")); return (0); } tp += esz; } if (outlevel > O_NORMAL) report(stdout, GT_("%s key fingerprint: %s\n"), _server_label, text); if (_check_digest != NULL) { if (strcasecmp(text, _check_digest) == 0) { if (outlevel > O_NORMAL) report(stdout, GT_("%s fingerprints match.\n"), _server_label); } else { report(stderr, GT_("%s fingerprints do not match!\n"), _server_label); return (0); } } /* if (_check_digest != NULL) */ } /* if (_check_fp) */ } /* if (depth == 0 && !_depth0ck) */ if (err != X509_V_OK && err != _prev_err && !(_check_fp != 0 && _check_digest && !strict)) { char *tmp; int did_rep_err = 0; _prev_err = err; report(stderr, GT_("Server certificate verification error: %s\n"), X509_verify_cert_error_string(err)); /* We gave the error code, but maybe we can add some more details for debugging */ switch (err) { /* actually we do not want to lump these together, but * since OpenSSL flipped the meaning of these error * codes in the past, and they do hardly make a * practical difference because servers need not provide * the root signing certificate, we don't bother telling * users the difference: */ case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY: case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT: X509_NAME_oneline(issuer, buf, sizeof(buf)); buf[sizeof(buf) - 1] = '\0'; report(stderr, GT_("Broken certification chain at: %s\n"), (tmp = sdump(buf, strlen(buf)))); xfree(tmp); report(stderr, GT_( "This could mean that the server did not provide the intermediate CA's certificate(s), " "which is nothing fetchmail could do anything about. For details, " "please see the README.SSL-SERVER document that ships with fetchmail.\n")); did_rep_err = 1; /* FALLTHROUGH */ case X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT: case X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN: if (!did_rep_err) { X509_NAME_oneline(issuer, buf, sizeof(buf)); buf[sizeof(buf) - 1] = '\0'; report(stderr, GT_("Missing trust anchor certificate: %s\n"), (tmp = sdump(buf, strlen(buf)))); xfree(tmp); } report(stderr, GT_( "This could mean that the root CA's signing certificate is not in the " "trusted CA certificate location, or that c_rehash needs to be run " "on the certificate directory. For details, please " "see the documentation of --sslcertpath and --sslcertfile in the manual page. " "See README.SSL for details.\n")); break; default: break; } } /* * If not in strict checking mode (--sslcertck), override this * and pretend that verification had succeeded. */ _verify_ok &= ok_return; if (!strict) ok_return = 1; return ok_return; } static int SSL_nock_verify_callback( int ok_return, X509_STORE_CTX *ctx ) { return SSL_verify_callback(ok_return, ctx, 0); } static int SSL_ck_verify_callback( int ok_return, X509_STORE_CTX *ctx ) { return SSL_verify_callback(ok_return, ctx, 1); } /* get commonName from certificate set in file. * commonName is stored in buffer namebuffer, limited with namebufferlen */ static const char *SSLCertGetCN(const char *mycert, char *namebuffer, size_t namebufferlen) { const char *ret = NULL; BIO *certBio = NULL; X509 *x509_cert = NULL; X509_NAME *certname = NULL; if (namebuffer && namebufferlen > 0) { namebuffer[0] = 0x00; certBio = BIO_new_file(mycert,"r"); if (certBio) { x509_cert = PEM_read_bio_X509(certBio,NULL,NULL,NULL); BIO_free(certBio); } if (x509_cert) { certname = X509_get_subject_name(x509_cert); if (certname && X509_NAME_get_text_by_NID(certname, NID_commonName, namebuffer, namebufferlen) > 0) ret = namebuffer; X509_free(x509_cert); } } return ret; } #if defined(LIBRESSL_VERSION_NUMBER) || OPENSSL_VERSION_NUMBER < 0x1010000fL /* OSSL_proto_version_logic for OpenSSL 1.0.x and LibreSSL */ static int OSSL10X_proto_version_logic(int sock, const char **myproto, int *avoid_ssl_versions) { if (!*myproto) { *myproto = "auto"; } if (!strcasecmp("ssl3", *myproto)) { #if (HAVE_DECL_SSLV3_CLIENT_METHOD > 0) && (0 == OPENSSL_NO_SSL3 + 0) _ctx[sock] = SSL_CTX_new(SSLv3_client_method()); *avoid_ssl_versions &= ~SSL_OP_NO_SSLv3; #else report(stderr, GT_("Your OpenSSL version does not support SSLv3.\n")); return -1; #endif } else if (!strcasecmp("ssl3+", *myproto)) { *avoid_ssl_versions &= ~SSL_OP_NO_SSLv3; *myproto = NULL; } else if (!strcasecmp("tls1", *myproto)) { _ctx[sock] = SSL_CTX_new(TLSv1_client_method()); } else if (!strcasecmp("tls1+", *myproto)) { *myproto = NULL; #if defined(TLS1_1_VERSION) } else if (!strcasecmp("tls1.1", *myproto)) { _ctx[sock] = SSL_CTX_new(TLSv1_1_client_method()); } else if (!strcasecmp("tls1.1+", *myproto)) { *myproto = NULL; *avoid_ssl_versions |= SSL_OP_NO_TLSv1; #else } else if(!strcasecmp("tls1.1",*myproto) || !strcasecmp("tls1.1+", *myproto)) { report(stderr, GT_("Your OpenSSL version does not support TLS v1.1.\n")); return -1; #endif #if defined(TLS1_2_VERSION) } else if (!strcasecmp("tls1.2", *myproto)) { _ctx[sock] = SSL_CTX_new(TLSv1_2_client_method()); } else if (!strcasecmp("tls1.2+", *myproto)) { *myproto = NULL; *avoid_ssl_versions |= SSL_OP_NO_TLSv1 | SSL_OP_NO_TLSv1_1; #else } else if(!strcasecmp("tls1.2",*myproto) || !strcasecmp("tls1.2+", *myproto)) { report(stderr, GT_("Your OpenSSL version does not support TLS v1.2.\n")); return -1; #endif #if defined(TLS1_3_VERSION) } else if (!strcasecmp("tls1.3", *myproto)) { _ctx[sock] = SSL_CTX_new(TLSv1_3_client_method()); } else if (!strcasecmp("tls1.3+", *myproto)) { *myproto = NULL; *avoid_ssl_versions |= SSL_OP_NO_TLSv1 | SSL_OP_NO_TLSv1_1 | SSL_OP_NO_TLSv1_2; #else } else if(!strcasecmp("tls1.3",*myproto) || !strcasecmp("tls1.3+", *myproto)) { report(stderr, GT_("Your OpenSSL version does not support TLS v1.3.\n")); return -1; #endif } else if (!strcasecmp("ssl23", *myproto) || 0 == strcasecmp("auto", *myproto)) { *myproto = NULL; } else { report(stderr, GT_("Invalid SSL protocol '%s' specified, using default autoselect (auto).\n"), *myproto); *myproto = NULL; } return 0; } #define OSSL_proto_version_logic(a,b,c) OSSL10X_proto_version_logic((a),(b),(c)) #undef OSSL110_API #else /* implementation for OpenSSL 1.1.0 */ #define OSSL110_API 1 static int OSSL110_proto_version_logic(int sock, const char **myproto, int *avoid_ssl_versions) { /* NOTE - this code MUST NOT set myproto to NULL, else the * SSL_...set_..._proto_version() call becomes ineffective. */ _ctx[sock] = SSL_CTX_new(TLS_client_method()); SSL_CTX_set_min_proto_version(_ctx[sock], TLS1_VERSION); if (!*myproto) { *myproto = "auto"; } if (!strcasecmp("ssl3", *myproto)) { #if (0 == OPENSSL_NO_SSL3 + 0) SSL_CTX_set_min_proto_version(_ctx[sock], SSL3_VERSION); SSL_CTX_set_max_proto_version(_ctx[sock], SSL3_VERSION); *avoid_ssl_versions &= ~SSL_OP_NO_SSLv3; #else report(stderr, GT_("Your OpenSSL version does not support SSLv3.\n")); return -1; #endif } else if (!strcasecmp("ssl3+", *myproto)) { SSL_CTX_set_min_proto_version(_ctx[sock], SSL3_VERSION); *avoid_ssl_versions &= ~SSL_OP_NO_SSLv3; } else if (!strcasecmp("tls1", *myproto)) { SSL_CTX_set_max_proto_version(_ctx[sock], TLS1_VERSION); } else if (!strcasecmp("tls1+", *myproto)) { /* do nothing, min_proto_version is already at TLS1_VERSION */ #if defined(TLS1_1_VERSION) } else if (!strcasecmp("tls1.1", *myproto)) { SSL_CTX_set_min_proto_version(_ctx[sock], TLS1_1_VERSION); SSL_CTX_set_max_proto_version(_ctx[sock], TLS1_1_VERSION); } else if (!strcasecmp("tls1.1+", *myproto)) { SSL_CTX_set_min_proto_version(_ctx[sock], TLS1_1_VERSION); #else } else if(!strcasecmp("tls1.1",*myproto) || !strcasecmp("tls1.1+", *myproto)) { report(stderr, GT_("Your OpenSSL version does not support TLS v1.1.\n")); return -1; #endif #if defined(TLS1_2_VERSION) } else if (!strcasecmp("tls1.2", *myproto)) { SSL_CTX_set_min_proto_version(_ctx[sock], TLS1_2_VERSION); SSL_CTX_set_max_proto_version(_ctx[sock], TLS1_2_VERSION); } else if (!strcasecmp("tls1.2+", *myproto)) { SSL_CTX_set_min_proto_version(_ctx[sock], TLS1_2_VERSION); #else } else if(!strcasecmp("tls1.2",*myproto) || !strcasecmp("tls1.2+", *myproto)) { report(stderr, GT_("Your OpenSSL version does not support TLS v1.2.\n")); return -1; #endif #if defined(TLS1_3_VERSION) } else if (!strcasecmp("tls1.3", *myproto)) { SSL_CTX_set_min_proto_version(_ctx[sock], TLS1_3_VERSION); SSL_CTX_set_max_proto_version(_ctx[sock], TLS1_3_VERSION); } else if (!strcasecmp("tls1.3+", *myproto)) { SSL_CTX_set_min_proto_version(_ctx[sock], TLS1_3_VERSION); #else } else if(!strcasecmp("tls1.3",*myproto) || !strcasecmp("tls1.3+", *myproto)) { report(stderr, GT_("Your OpenSSL version does not support TLS v1.3.\n")); return -1; #endif } else if (!strcasecmp("ssl23", *myproto) || 0 == strcasecmp("auto", *myproto)) { /* do nothing */ } else { /* This should not happen. */ report(stderr, GT_("Invalid SSL protocol '%s' specified, using default autoselect (auto).\n"), *myproto); report(stderr, "fetchmail internal error in OSSL110_proto_version_logic\n"); abort(); } return 0; } #define OSSL_proto_version_logic(a,b,c) OSSL110_proto_version_logic((a),(b),(c)) #endif /* performs initial SSL handshake over the connected socket * uses SSL *ssl global variable, which is currently defined * in this file */ int SSLOpen(int sock, char *mycert, char *mykey, const char *myproto, int certck, char *cacertfile, char *certpath, char *fingerprint, char *servercname, char *label, char **remotename) { struct stat randstat; int i; int avoid_ssl_versions = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3; long sslopts = SSL_OP_ALL | SSL_OP_SINGLE_DH_USE; int ssle_connect = 0; long ver; #ifndef OSSL110_API SSL_load_error_strings(); SSL_library_init(); OpenSSL_add_all_algorithms(); /* see Debian Bug#576430 and manpage */ ver = SSLeay(); #else ver = OpenSSL_version_num(); #endif if (ver < OPENSSL_VERSION_NUMBER) { report(stderr, GT_("Loaded OpenSSL library %#lx older than headers %#lx, refusing to work.\n"), (long)ver, (long)(OPENSSL_VERSION_NUMBER)); return -1; } if (ver > OPENSSL_VERSION_NUMBER && outlevel >= O_VERBOSE) { report(stdout, GT_("Loaded OpenSSL library %#lx newer than headers %#lx, trying to continue.\n"), (long)ver, (long)(OPENSSL_VERSION_NUMBER)); } if (stat("/dev/random", &randstat) && stat("/dev/urandom", &randstat)) { /* Neither /dev/random nor /dev/urandom are present, so add entropy to the SSL PRNG a hard way. */ for (i = 0; i < 10000 && ! RAND_status (); ++i) { char buf[4]; struct timeval tv; gettimeofday (&tv, 0); buf[0] = tv.tv_usec & 0xF; buf[2] = (tv.tv_usec & 0xF0) >> 4; buf[3] = (tv.tv_usec & 0xF00) >> 8; buf[1] = (tv.tv_usec & 0xF000) >> 12; RAND_add (buf, sizeof buf, 0.1); } } if( sock < 0 || (unsigned)sock > FD_SETSIZE ) { report(stderr, GT_("File descriptor out of range for SSL") ); return( -1 ); } /* Make sure a connection referring to an older context is not left */ _ssl_context[sock] = NULL; { int rc = OSSL_proto_version_logic(sock, &myproto, &avoid_ssl_versions); if (rc) return rc; } /* do not combine into an else { } as myproto may be nulled above! */ if (!myproto) { /* SSLv23 is a misnomer and will in fact use the best available protocol, subject to SSL_OP_NO* constraints. */ _ctx[sock] = SSL_CTX_new(SSLv23_client_method()); } if(_ctx[sock] == NULL) { unsigned long ec = ERR_peek_last_error(); ERR_print_errors_fp(stderr); if (ERR_GET_REASON(ec) == SSL_R_NULL_SSL_METHOD_PASSED) { report(stderr, GT_("Note that some distributions disable older protocol versions in weird non-standard ways. Try a newer protocol version.\n")); } return(-1); } { char *tmp = getenv("FETCHMAIL_DISABLE_CBC_IV_COUNTERMEASURE"); if (tmp == NULL || *tmp == '\0' || strspn(tmp, " \t") == strlen(tmp)) sslopts &= ~ SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS; } SSL_CTX_set_options(_ctx[sock], sslopts | avoid_ssl_versions); if (certck) { SSL_CTX_set_verify(_ctx[sock], SSL_VERIFY_PEER, SSL_ck_verify_callback); } else { /* In this case, we do not fail if verification fails. However, * we provide the callback for output and possible fingerprint * checks. */ SSL_CTX_set_verify(_ctx[sock], SSL_VERIFY_PEER, SSL_nock_verify_callback); } /* Check which trusted X.509 CA certificate store(s) to load */ { char *tmp; int want_default_cacerts = 0; /* Load user locations if any is given */ if (certpath || cacertfile) SSL_CTX_load_verify_locations(_ctx[sock], cacertfile, certpath); else want_default_cacerts = 1; tmp = getenv("FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS"); if (want_default_cacerts || (tmp && tmp[0])) { SSL_CTX_set_default_verify_paths(_ctx[sock]); } } _ssl_context[sock] = SSL_new(_ctx[sock]); if(_ssl_context[sock] == NULL) { ERR_print_errors_fp(stderr); SSL_CTX_free(_ctx[sock]); _ctx[sock] = NULL; return(-1); } /* This static is for the verify callback */ _ssl_server_cname = servercname; _server_label = label; _check_fp = 1; _check_digest = fingerprint; _depth0ck = 0; _firstrun = 1; _verify_ok = 1; _prev_err = -1; /* * Support SNI, some servers (googlemail) appear to require it. */ { long r; r = SSL_set_tlsext_host_name(_ssl_context[sock], servercname); if (0 == r) { /* handle error */ report(stderr, GT_("Warning: SSL_set_tlsext_host_name(%p, \"%s\") failed (code %#lx), trying to continue.\n"), (void *)_ssl_context[sock], servercname, r); ERR_print_errors_fp(stderr); } } /* OpenSSL >= 1.0.2: set host name for verification */ /* XXX FIXME: do we need to change the function's signature and pass the akalist to * permit the other hostnames through SSL? */ /* https://wiki.openssl.org/index.php/Hostname_validation */ { int r; X509_VERIFY_PARAM *param = SSL_get0_param(_ssl_context[sock]); X509_VERIFY_PARAM_set_hostflags(param, X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS); if (0 == (r = X509_VERIFY_PARAM_set1_host(param, servercname, strlen(servercname)))) { report(stderr, GT_("Warning: X509_VERIFY_PARAM_set1_host(%p, \"%s\") failed (code %#x), trying to continue.\n"), (void *)_ssl_context[sock], servercname, r); ERR_print_errors_fp(stderr); } } if( mycert || mykey ) { /* Ok... He has a certificate file defined, so lets declare it. If * he does NOT have a separate certificate and private key file then * assume that it's a combined key and certificate file. */ char buffer[256]; if( !mykey ) mykey = mycert; if( !mycert ) mycert = mykey; if ((!*remotename || !**remotename) && SSLCertGetCN(mycert, buffer, sizeof(buffer))) { free(*remotename); *remotename = xstrdup(buffer); } SSL_use_certificate_file(_ssl_context[sock], mycert, SSL_FILETYPE_PEM); SSL_use_RSAPrivateKey_file(_ssl_context[sock], mykey, SSL_FILETYPE_PEM); } if (SSL_set_fd(_ssl_context[sock], sock) == 0 || (ssle_connect = SSL_connect(_ssl_context[sock])) < 1) { int e = errno; unsigned long ssle_err_from_get_error = SSL_get_error(_ssl_context[sock], ssle_connect); unsigned long ssle_err_from_queue = ERR_peek_error(); ERR_print_errors_fp(stderr); if (SSL_ERROR_SYSCALL == ssle_err_from_get_error && 0 == ssle_err_from_queue) { if (0 == ssle_connect) { /* FIXME: the next line was hacked in 6.4.0-rc1 so the translation strings don't change. * The %s could be merged to the inside of GT_(). */ report(stderr, "%s: %s", servercname, GT_("Server shut down connection prematurely during SSL_connect().\n")); } else if (ssle_connect < 0) { report(stderr, "%s: ", servercname); report(stderr, GT_("System error during SSL_connect(): %s\n"), e ? strerror(e) : GT_("handshake failed at protocol or connection level.")); } } SSL_free( _ssl_context[sock] ); _ssl_context[sock] = NULL; SSL_CTX_free(_ctx[sock]); _ctx[sock] = NULL; return(-1); } if (outlevel >= O_VERBOSE) { SSL_CIPHER const *sc; int bitsmax, bitsused; const char *vers; vers = SSL_get_version(_ssl_context[sock]); sc = SSL_get_current_cipher(_ssl_context[sock]); if (!sc) { report (stderr, GT_("Cannot obtain current SSL/TLS cipher - no session established?\n")); } else { bitsused = SSL_CIPHER_get_bits(sc, &bitsmax); report(stdout, GT_("SSL/TLS: using protocol %s, cipher %s, %d/%d secret/processed bits\n"), vers, SSL_CIPHER_get_name(sc), bitsused, bitsmax); } } /* Paranoia: was the callback not called as we expected? */ if (!_depth0ck) { report(stderr, GT_("Certificate/fingerprint verification was somehow skipped!\n")); if (fingerprint != NULL || certck) { if( NULL != SSLGetContext( sock ) ) { /* Clean up the SSL stack */ SSL_shutdown( _ssl_context[sock] ); SSL_free( _ssl_context[sock] ); _ssl_context[sock] = NULL; SSL_CTX_free(_ctx[sock]); _ctx[sock] = NULL; } return(-1); } } if (!certck && !fingerprint && (SSL_get_verify_result(_ssl_context[sock]) != X509_V_OK || !_verify_ok)) { report(stderr, GT_("Warning: the connection is insecure, continuing anyways. (Better use --sslcertck!)\n")); } return(0); } #endif int SockClose(int sock) /* close a socket gracefully */ { #ifdef SSL_ENABLE if( NULL != SSLGetContext( sock ) ) { /* Clean up the SSL stack */ SSL_shutdown( _ssl_context[sock] ); SSL_free( _ssl_context[sock] ); _ssl_context[sock] = NULL; SSL_CTX_free(_ctx[sock]); _ctx[sock] = NULL; } #endif /* if there's an error closing at this point, not much we can do */ return(fm_close(sock)); /* this is guarded */ } #ifdef __CYGWIN__ /* * Workaround Microsoft Winsock recv/WSARecv(..., MSG_PEEK) bug. * See http://sources.redhat.com/ml/cygwin/2001-08/msg00628.html * for more details. */ static ssize_t cygwin_read(int sock, void *buf, size_t count) { char *bp = (char *)buf; size_t n = 0; if ((n = read(sock, bp, count)) == (size_t)-1) return(-1); if (n != count) { size_t n2 = 0; if (outlevel >= O_VERBOSE) report(stdout, GT_("Cygwin socket read retry\n")); n2 = read(sock, bp + n, count - n); if (n2 == (size_t)-1 || n + n2 != count) { report(stderr, GT_("Cygwin socket read retry failed!\n")); return(-1); } } return count; } #endif /* __CYGWIN__ */