X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/059ec3d9952740285fb1ebf47961b8aca2eb1b4a..0a49a7a4f1090b6f1ce1d0f9d969804c9226b53e:/src/src/tls-openssl.c

diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c
index 18165e306..a9251c7f4 100644
--- a/src/src/tls-openssl.c
+++ b/src/src/tls-openssl.c
@@ -1,10 +1,10 @@
-/* $Cambridge: exim/src/src/tls-openssl.c,v 1.1 2004/10/07 10:39:01 ph10 Exp $ */
+/* $Cambridge: exim/src/src/tls-openssl.c,v 1.22 2009/11/16 19:50:37 nm4 Exp $ */
 
 /*************************************************
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 
-/* Copyright (c) University of Cambridge 1995 - 2004 */
+/* Copyright (c) University of Cambridge 1995 - 2009 */
 /* See the file NOTICE for conditions of use and distribution. */
 
 /* This module provides the TLS (aka SSL) support for Exim using the OpenSSL
@@ -26,8 +26,8 @@ functions from the OpenSSL library. */
 /* Structure for collecting random data for seeding. */
 
 typedef struct randstuff {
-  time_t t;
-  pid_t  p;
+  struct timeval tv;
+  pid_t          p;
 } randstuff;
 
 /* Local static variables */
@@ -62,25 +62,33 @@ Argument:
   prefix    text to include in the logged error
   host      NULL if setting up a server;
             the connected host if setting up a client
+  msg       error message or NULL if we should ask OpenSSL
 
 Returns:    OK/DEFER/FAIL
 */
 
 static int
-tls_error(uschar *prefix, host_item *host)
+tls_error(uschar *prefix, host_item *host, uschar *msg)
 {
-ERR_error_string(ERR_get_error(), ssl_errstring);
+if (msg == NULL)
+  {
+  ERR_error_string(ERR_get_error(), ssl_errstring);
+  msg = (uschar *)ssl_errstring;
+  }
+
 if (host == NULL)
   {
-  log_write(0, LOG_MAIN, "TLS error on connection from %s (%s): %s",
-    (sender_fullhost != NULL)? sender_fullhost : US"local process",
-    prefix, ssl_errstring);
+  uschar *conn_info = smtp_get_connection_info();
+  if (Ustrncmp(conn_info, US"SMTP ", 5) == 0)
+    conn_info += 5;
+  log_write(0, LOG_MAIN, "TLS error on %s (%s): %s",
+    conn_info, prefix, msg);
   return DEFER;
   }
 else
   {
   log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s): %s",
-    host->name, host->address, prefix, ssl_errstring);
+    host->name, host->address, prefix, msg);
   return FAIL;
   }
 }
@@ -182,9 +190,6 @@ else
   tls_peerdn = txt;
   }
 
-
-debug_printf("+++verify_callback_called=%d\n", verify_callback_called);
-
 if (!verify_callback_called) tls_certificate_verified = TRUE;
 verify_callback_called = TRUE;
 
@@ -227,12 +232,13 @@ DEBUG(D_tls) debug_printf("SSL info: %s\n", SSL_state_string_long(s));
 
 Arguments:
   dhparam   DH parameter file
+  host      connected host, if client; NULL if server
 
 Returns:    TRUE if OK (nothing to set up, or setup worked)
 */
 
 static BOOL
-init_dh(uschar *dhparam)
+init_dh(uschar *dhparam, host_item *host)
 {
 BOOL yield = TRUE;
 BIO *bio;
@@ -246,16 +252,16 @@ if (dhexpanded == NULL) return TRUE;
 
 if ((bio = BIO_new_file(CS dhexpanded, "r")) == NULL)
   {
-  log_write(0, LOG_MAIN, "DH: could not read %s: %s", dhexpanded,
-    strerror(errno));
+  tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
+    host, (uschar *)strerror(errno));
   yield = FALSE;
   }
 else
   {
   if ((dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL)) == NULL)
     {
-    log_write(0, LOG_MAIN, "DH: could not load params from %s",
-      dhexpanded);
+    tls_error(string_sprintf("could not read dhparams file %s", dhexpanded),
+      host, NULL);
     yield = FALSE;
     }
   else
@@ -293,18 +299,24 @@ Returns:          OK/DEFER/FAIL
 */
 
 static int
-tls_init(host_item *host, uschar *dhparam, uschar *certificate, uschar *privatekey,
-  address_item *addr)
+tls_init(host_item *host, uschar *dhparam, uschar *certificate,
+  uschar *privatekey, address_item *addr)
 {
 SSL_load_error_strings();          /* basic set up */
 OpenSSL_add_ssl_algorithms();
 
+#if (OPENSSL_VERSION_NUMBER >= 0x0090800fL) && !defined(OPENSSL_NO_SHA256)
+/* SHA256 is becoming ever moar popular. This makes sure it gets added to the
+list of available digests. */
+EVP_add_digest(EVP_sha256());
+#endif
+
 /* Create a context */
 
 ctx = SSL_CTX_new((host == NULL)?
   SSLv23_server_method() : SSLv23_client_method());
 
-if (ctx == NULL) return tls_error(US"SSL_CTX_new", host);
+if (ctx == NULL) return tls_error(US"SSL_CTX_new", host, NULL);
 
 /* It turns out that we need to seed the random number generator this early in
 order to get the full complement of ciphers to work. It took me roughly a day
@@ -317,7 +329,7 @@ afterwards. */
 if (!RAND_status())
   {
   randstuff r;
-  r.t = time(NULL);
+  gettimeofday(&r.tv, NULL);
   r.p = getpid();
 
   RAND_seed((uschar *)(&r), sizeof(r));
@@ -325,29 +337,14 @@ if (!RAND_status())
   if (addr != NULL) RAND_seed((uschar *)addr, sizeof(addr));
 
   if (!RAND_status())
-    {
-    if (host == NULL)
-      {
-      log_write(0, LOG_MAIN, "TLS error on connection from %s: "
-        "unable to seed random number generator",
-        (sender_fullhost != NULL)? sender_fullhost : US"local process");
-      return DEFER;
-      }
-    else
-      {
-      log_write(0, LOG_MAIN, "TLS error on connection to %s [%s]: "
-        "unable to seed random number generator",
-        host->name, host->address);
-      return FAIL;
-      }
-    }
+    return tls_error(US"RAND_status", host,
+      US"unable to seed random number generator");
   }
 
 /* Set up the information callback, which outputs if debugging is at a suitable
 level. */
 
-if (!(SSL_CTX_set_info_callback(ctx, (void (*)())info_callback)))
-  return tls_error(US"SSL_CTX_set_info_callback", host);
+SSL_CTX_set_info_callback(ctx, (void (*)())info_callback);
 
 /* The following patch was supplied by Robert Roselius */
 
@@ -362,12 +359,12 @@ if (!(SSL_CTX_set_info_callback(ctx, (void (*)())info_callback)))
 /* XXX (Silently?) ignore failure here? XXX*/
 
 if (!(SSL_CTX_set_options(ctx, SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS)))
-  return tls_error(US"SSL_CTX_set_option", host);
+  return tls_error(US"SSL_CTX_set_option", host, NULL);
 #endif
 
 /* Initialize with DH parameters if supplied */
 
-if (!init_dh(dhparam)) return DEFER;
+if (!init_dh(dhparam, host)) return DEFER;
 
 /* Set up certificate and key */
 
@@ -381,18 +378,24 @@ if (certificate != NULL)
     {
     DEBUG(D_tls) debug_printf("tls_certificate file %s\n", expanded);
     if (!SSL_CTX_use_certificate_chain_file(ctx, CS expanded))
-      return tls_error(US"SSL_CTX_use_certificate_chain_file", host);
+      return tls_error(string_sprintf(
+        "SSL_CTX_use_certificate_chain_file file=%s", expanded), host, NULL);
     }
 
   if (privatekey != NULL &&
       !expand_check(privatekey, US"tls_privatekey", &expanded))
     return DEFER;
 
-  if (expanded != NULL)
+  /* If expansion was forced to fail, key_expanded will be NULL. If the result
+  of the expansion is an empty string, ignore it also, and assume the private
+  key is in the same file as the certificate. */
+
+  if (expanded != NULL && *expanded != 0)
     {
     DEBUG(D_tls) debug_printf("tls_privatekey file %s\n", expanded);
     if (!SSL_CTX_use_PrivateKey_file(ctx, CS expanded, SSL_FILETYPE_PEM))
-      return tls_error(US"SSL_CTX_use_PrivateKey_file", host);
+      return tls_error(string_sprintf(
+        "SSL_CTX_use_PrivateKey_file file=%s", expanded), host, NULL);
     }
   }
 
@@ -489,7 +492,7 @@ if (expcerts != NULL)
   {
   struct stat statbuf;
   if (!SSL_CTX_set_default_verify_paths(ctx))
-    return tls_error(US"SSL_CTX_set_default_verify_paths", host);
+    return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL);
 
   if (Ustat(expcerts, &statbuf) < 0)
     {
@@ -512,7 +515,7 @@ if (expcerts != NULL)
 
     if ((file == NULL || statbuf.st_size > 0) &&
           !SSL_CTX_load_verify_locations(ctx, CS file, CS dir))
-      return tls_error(US"SSL_CTX_load_verify_locations", host);
+      return tls_error(US"SSL_CTX_load_verify_locations", host, NULL);
 
     if (file != NULL)
       {
@@ -524,34 +527,51 @@ if (expcerts != NULL)
 
   #if OPENSSL_VERSION_NUMBER > 0x00907000L
 
+  /* This bit of code is now the version supplied by Lars Mainka. (I have
+   * merely reformatted it into the Exim code style.)
+
+   * "From here I changed the code to add support for multiple crl's
+   * in pem format in one file or to support hashed directory entries in
+   * pem format instead of a file. This method now uses the library function
+   * X509_STORE_load_locations to add the CRL location to the SSL context.
+   * OpenSSL will then handle the verify against CA certs and CRLs by
+   * itself in the verify callback." */
+
   if (!expand_check(crl, US"tls_crl", &expcrl)) return DEFER;
   if (expcrl != NULL && *expcrl != 0)
     {
-    BIO *crl_bio;
-    X509_CRL *crl_x509;
-    X509_STORE *cvstore;
-
-    cvstore = SSL_CTX_get_cert_store(ctx);  /* cert validation store */
-
-    crl_bio = BIO_new(BIO_s_file_internal());
-    if (crl_bio != NULL)
+    struct stat statbufcrl;
+    if (Ustat(expcrl, &statbufcrl) < 0)
+      {
+      log_write(0, LOG_MAIN|LOG_PANIC,
+        "failed to stat %s for certificates revocation lists", expcrl);
+      return DEFER;
+      }
+    else
       {
-      if (BIO_read_filename(crl_bio, expcrl))
+      /* is it a file or directory? */
+      uschar *file, *dir;
+      X509_STORE *cvstore = SSL_CTX_get_cert_store(ctx);
+      if ((statbufcrl.st_mode & S_IFMT) == S_IFDIR)
         {
-        crl_x509 = PEM_read_bio_X509_CRL(crl_bio, NULL, NULL, NULL);
-        BIO_free(crl_bio);
-        X509_STORE_add_crl(cvstore, crl_x509);
-        X509_CRL_free(crl_x509);
-        X509_STORE_set_flags(cvstore,
-          X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
+        file = NULL;
+        dir = expcrl;
+        DEBUG(D_tls) debug_printf("SSL CRL value is a directory %s\n", dir);
         }
       else
         {
-        BIO_free(crl_bio);
-        return tls_error(US"BIO_read_filename", host);
+        file = expcrl;
+        dir = NULL;
+        DEBUG(D_tls) debug_printf("SSL CRL value is a file %s\n", file);
         }
+      if (X509_STORE_load_locations(cvstore, CS file, CS dir) == 0)
+        return tls_error(US"X509_STORE_load_locations", host, NULL);
+
+      /* setting the flags to check against the complete crl chain */
+
+      X509_STORE_set_flags(cvstore,
+        X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
       }
-    else return tls_error(US"BIO_new", host);
     }
 
   #endif  /* OPENSSL_VERSION_NUMBER > 0x00907000L */
@@ -578,6 +598,11 @@ a TLS session.
 
 Arguments:
   require_ciphers   allowed ciphers
+  ------------------------------------------------------
+  require_mac      list of allowed MACs                 ) Not used
+  require_kx       list of allowed key_exchange methods )   for
+  require_proto    list of allowed protocols            ) OpenSSL
+  ------------------------------------------------------
 
 Returns:            OK on success
                     DEFER for errors before the start of the negotiation
@@ -586,7 +611,8 @@ Returns:            OK on success
 */
 
 int
-tls_server_start(uschar *require_ciphers)
+tls_server_start(uschar *require_ciphers, uschar *require_mac,
+  uschar *require_kx, uschar *require_proto)
 {
 int rc;
 uschar *expciphers;
@@ -595,9 +621,7 @@ uschar *expciphers;
 
 if (tls_active >= 0)
   {
-  log_write(0, LOG_MAIN, "STARTTLS received in already encrypted "
-    "connection from %s",
-    (sender_fullhost != NULL)? sender_fullhost : US"local process");
+  tls_error(US"STARTTLS received after TLS started", NULL, US"");
   smtp_printf("554 Already in TLS\r\n");
   return FAIL;
   }
@@ -621,7 +645,7 @@ if (expciphers != NULL)
   while (*s != 0) { if (*s == '_') *s = '-'; s++; }
   DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
   if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
-    return tls_error(US"SSL_CTX_set_cipher_list", NULL);
+    return tls_error(US"SSL_CTX_set_cipher_list", NULL, NULL);
   }
 
 /* If this is a host for which certificate verification is mandatory or
@@ -645,7 +669,7 @@ else if (verify_check_host(&tls_try_verify_hosts) == OK)
 
 /* Prepare for new connection */
 
-if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", NULL);
+if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", NULL, NULL);
 SSL_clear(ssl);
 
 /* Set context and tell client to go ahead, except in the case of TLS startup
@@ -664,7 +688,8 @@ if (!tls_on_connect)
 /* Now negotiate the TLS session. We put our own timer on it, since it seems
 that the OpenSSL library doesn't. */
 
-SSL_set_fd(ssl, fileno(smtp_out));
+SSL_set_wfd(ssl, fileno(smtp_out));
+SSL_set_rfd(ssl, fileno(smtp_in));
 SSL_set_accept_state(ssl);
 
 DEBUG(D_tls) debug_printf("Calling SSL_accept\n");
@@ -676,11 +701,7 @@ alarm(0);
 
 if (rc <= 0)
   {
-  if (sigalrm_seen) Ustrcpy(ssl_errstring, "timed out");
-    else ERR_error_string(ERR_get_error(), ssl_errstring);
-  log_write(0, LOG_MAIN, "TLS error on connection from %s (SSL_accept): %s",
-    (sender_fullhost != NULL)? sender_fullhost : US"local process",
-    ssl_errstring);
+  tls_error(US"SSL_accept", NULL, sigalrm_seen ? US"timed out" : NULL);
   return FAIL;
   }
 
@@ -707,6 +728,7 @@ receive_getc = tls_getc;
 receive_ungetc = tls_ungetc;
 receive_feof = tls_feof;
 receive_ferror = tls_ferror;
+receive_smtp_buffered = tls_smtp_buffered;
 
 tls_active = fileno(smtp_out);
 return OK;
@@ -725,12 +747,19 @@ return OK;
 Argument:
   fd               the fd of the connection
   host             connected host (for messages)
+  addr             the first address
   dhparam          DH parameter file
   certificate      certificate file
   privatekey       private key file
   verify_certs     file for certificate verify
   crl              file containing CRL
   require_ciphers  list of allowed ciphers
+  ------------------------------------------------------
+  require_mac      list of allowed MACs                 ) Not used
+  require_kx       list of allowed key_exchange methods )   for
+  require_proto    list of allowed protocols            ) OpenSSL
+  ------------------------------------------------------
+  timeout          startup timeout
 
 Returns:           OK on success
                    FAIL otherwise - note that tls_error() will not give DEFER
@@ -740,7 +769,8 @@ Returns:           OK on success
 int
 tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam,
   uschar *certificate, uschar *privatekey, uschar *verify_certs, uschar *crl,
-  uschar *require_ciphers, int timeout)
+  uschar *require_ciphers, uschar *require_mac, uschar *require_kx,
+  uschar *require_proto, int timeout)
 {
 static uschar txt[256];
 uschar *expciphers;
@@ -766,13 +796,13 @@ if (expciphers != NULL)
   while (*s != 0) { if (*s == '_') *s = '-'; s++; }
   DEBUG(D_tls) debug_printf("required ciphers: %s\n", expciphers);
   if (!SSL_CTX_set_cipher_list(ctx, CS expciphers))
-    return tls_error(US"SSL_CTX_set_cipher_list", host);
+    return tls_error(US"SSL_CTX_set_cipher_list", host, NULL);
   }
 
 rc = setup_certs(verify_certs, crl, host, FALSE);
 if (rc != OK) return rc;
 
-if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", host);
+if ((ssl = SSL_new(ctx)) == NULL) return tls_error(US"SSL_new", host, NULL);
 SSL_set_session_id_context(ssl, sid_ctx, Ustrlen(sid_ctx));
 SSL_set_fd(ssl, fd);
 SSL_set_connect_state(ssl);
@@ -786,15 +816,7 @@ rc = SSL_connect(ssl);
 alarm(0);
 
 if (rc <= 0)
-  {
-  if (sigalrm_seen)
-    {
-    log_write(0, LOG_MAIN, "TLS error on connection to %s [%s]: "
-      "SSL_connect timed out", host->name, host->address);
-    return FAIL;
-    }
-  else return tls_error(US"SSL_connect", host);
-  }
+  return tls_error(US"SSL_connect", host, sigalrm_seen ? US"timed out" : NULL);
 
 DEBUG(D_tls) debug_printf("SSL_connect succeeded\n");
 
@@ -852,6 +874,7 @@ if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm)
     receive_ungetc = smtp_ungetc;
     receive_feof = smtp_feof;
     receive_ferror = smtp_ferror;
+    receive_smtp_buffered = smtp_buffered;
 
     SSL_free(ssl);
     ssl = NULL;
@@ -870,7 +893,9 @@ if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm)
     ssl_xfer_error = 1;
     return EOF;
     }
-
+#ifndef DISABLE_DKIM
+  dkim_exim_verify_feed(ssl_xfer_buffer, inbytes);
+#endif
   ssl_xfer_buffer_hwm = inbytes;
   ssl_xfer_buffer_lwm = 0;
   }
@@ -1006,4 +1031,96 @@ ssl = NULL;
 tls_active = -1;
 }
 
+
+
+
+/*************************************************
+*         Report the library versions.           *
+*************************************************/
+
+/* There have historically been some issues with binary compatibility in
+OpenSSL libraries; if Exim (like many other applications) is built against
+one version of OpenSSL but the run-time linker picks up another version,
+it can result in serious failures, including crashing with a SIGSEGV.  So
+report the version found by the compiler and the run-time version.
+
+Arguments:   a FILE* to print the results to
+Returns:     nothing
+*/
+
+void
+tls_version_report(FILE *f)
+{
+fprintf(f, "OpenSSL compile-time version: %s\n", OPENSSL_VERSION_TEXT);
+fprintf(f, "OpenSSL runtime version: %s\n", SSLeay_version(SSLEAY_VERSION));
+}
+
+
+
+
+/*************************************************
+*        Pseudo-random number generation         *
+*************************************************/
+
+/* Pseudo-random number generation.  The result is not expected to be
+cryptographically strong but not so weak that someone will shoot themselves
+in the foot using it as a nonce in input in some email header scheme or
+whatever weirdness they'll twist this into.  The result should handle fork()
+and avoid repeating sequences.  OpenSSL handles that for us.
+
+Arguments:
+  max       range maximum
+Returns     a random number in range [0, max-1]
+*/
+
+int
+pseudo_random_number(int max)
+{
+unsigned int r;
+int i, needed_len;
+uschar *p;
+uschar smallbuf[sizeof(r)];
+
+if (max <= 1)
+  return 0;
+
+/* OpenSSL auto-seeds from /dev/random, etc, but this a double-check. */
+if (!RAND_status())
+  {
+  randstuff r;
+  gettimeofday(&r.tv, NULL);
+  r.p = getpid();
+
+  RAND_seed((uschar *)(&r), sizeof(r));
+  }
+/* We're after pseudo-random, not random; if we still don't have enough data
+in the internal PRNG then our options are limited.  We could sleep and hope
+for entropy to come along (prayer technique) but if the system is so depleted
+in the first place then something is likely to just keep taking it.  Instead,
+we'll just take whatever little bit of pseudo-random we can still manage to
+get. */
+
+needed_len = sizeof(r);
+/* Don't take 8 times more entropy than needed if int is 8 octets and we were
+asked for a number less than 10. */
+for (r = max, i = 0; r; ++i)
+  r >>= 1;
+i = (i + 7) / 8;
+if (i < needed_len)
+  needed_len = i;
+
+/* We do not care if crypto-strong */
+(void) RAND_pseudo_bytes(smallbuf, needed_len);
+r = 0;
+for (p = smallbuf; needed_len; --needed_len, ++p)
+  {
+  r *= 256;
+  r += *p;
+  }
+
+/* We don't particularly care about weighted results; if someone wants
+smooth distribution and cares enough then they should submit a patch then. */
+return r % max;
+}
+
 /* End of tls-openssl.c */