X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/25ba25448b55c2fd5ea9b1aeed82e02d59816a07..a85c067ba6c6940512cf57ec213277a370d87e70:/src/src/tlscert-gnu.c

diff --git a/src/src/tlscert-gnu.c b/src/src/tlscert-gnu.c
index 9b9c83d8b..8840d5cfd 100644
--- a/src/src/tlscert-gnu.c
+++ b/src/src/tlscert-gnu.c
@@ -2,7 +2,9 @@
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 
-/* Copyright (c) Jeremy Harris 2014 */
+/* Copyright (c) The Exim Maintainers 2021 - 2022 */
+/* Copyright (c) Jeremy Harris 2014 - 2018 */
+/* SPDX-License-Identifier: GPL-2.0-only */
 
 /* This file provides TLS/SSL support for Exim using the GnuTLS library,
 one of the available supported implementations.  This file is #included into
@@ -20,18 +22,25 @@ tls.c when USE_GNUTLS has been set.
 
 /*****************************************************
 *  Export/import a certificate, binary/printable
-*****************************************************/
-int
+******************************************************
+Return: boolean success
+*/
+
+BOOL
 tls_export_cert(uschar * buf, size_t buflen, void * cert)
 {
 size_t sz = buflen;
-void * reset_point = store_get(0);
-int fail = 0;
-uschar * cp;
+rmark reset_point = store_mark();
+BOOL fail;
+const uschar * cp;
 
-if (gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
-    GNUTLS_X509_FMT_PEM, buf, &sz))
-  return 1;
+if ((fail = gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
+    GNUTLS_X509_FMT_PEM, buf, &sz)))
+  {
+  log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
+    gnutls_strerror(fail));
+  return FALSE;
+  }
 if ((cp = string_printing(buf)) != buf)
   {
   Ustrncpy(buf, cp, buflen);
@@ -39,41 +48,56 @@ if ((cp = string_printing(buf)) != buf)
     fail = 1;
   }
 store_reset(reset_point);
-return fail;
+return !fail;
 }
 
-int
+/* On error, NULL out the destination */
+BOOL
 tls_import_cert(const uschar * buf, void ** cert)
 {
-void * reset_point = store_get(0);
+rmark reset_point = store_mark();
 gnutls_datum_t datum;
-gnutls_x509_crt_t crt;
-int fail = 0;
+gnutls_x509_crt_t crt = *(gnutls_x509_crt_t *)cert;
+int rc;
+
+if (crt)
+  gnutls_x509_crt_deinit(crt);
+else
+  gnutls_global_init();
 
-gnutls_global_init();
 gnutls_x509_crt_init(&crt);
 
 datum.data = string_unprinting(US buf);
 datum.size = Ustrlen(datum.data);
-if (gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM))
-  fail = 1;
-else
-  *cert = (void *)crt;
-
+if ((rc = gnutls_x509_crt_import(crt, &datum, GNUTLS_X509_FMT_PEM)))
+  {
+  log_write(0, LOG_MAIN, "TLS error in certificate import: %s",
+    gnutls_strerror(rc));
+  crt = NULL;
+  }
+*cert = (void *)crt;
 store_reset(reset_point);
-return fail;
+return rc != 0;
 }
 
 void
-tls_free_cert(void * cert)
+tls_free_cert(void ** cert)
 {
-gnutls_x509_crt_deinit((gnutls_x509_crt_t) cert);
-gnutls_global_deinit();
+gnutls_x509_crt_t crt = *(gnutls_x509_crt_t *)cert;
+if (crt)
+  {
+  gnutls_x509_crt_deinit(crt);
+  gnutls_global_deinit();
+  *cert = NULL;
+  }
 }
 
 /*****************************************************
 *  Certificate field extraction routines
 *****************************************************/
+
+/* First, some internal service functions */
+
 static uschar *
 g_err(const char * tag, const char * from, int gnutls_err)
 {
@@ -87,19 +111,33 @@ static uschar *
 time_copy(time_t t, uschar * mod)
 {
 uschar * cp;
-struct tm * tp;
-size_t len;
+size_t len = 32;
 
 if (mod && Ustrcmp(mod, "int") == 0)
   return string_sprintf("%u", (unsigned)t);
 
-cp = store_get(32);
-tp = gmtime(&t);
-len = strftime(CS cp, 32, "%b %e %T %Y %Z", tp);
+cp = store_get(len, GET_UNTAINTED);
+if (f.timestamps_utc)
+  {
+  uschar * tz = to_tz(US"GMT0");
+  len = strftime(CS cp, len, "%b %e %T %Y %Z", gmtime(&t));
+  restore_tz(tz);
+  }
+else
+  len = strftime(CS cp, len, "%b %e %T %Y %Z", localtime(&t));
 return len > 0 ? cp : NULL;
 }
 
+
 /**/
+/* Now the extractors, called from expand.c
+Arguments:
+  cert		The certificate
+  mod		Optional modifiers for the operator
+
+Return:
+  Allocated string with extracted value
+*/
 
 uschar *
 tls_cert_issuer(void * cert, uschar * mod)
@@ -108,12 +146,12 @@ uschar * cp = NULL;
 int ret;
 size_t siz = 0;
 
-if ((ret = gnutls_x509_crt_get_issuer_dn(cert, cp, &siz))
+if ((ret = gnutls_x509_crt_get_issuer_dn(cert, CS cp, &siz))
     != GNUTLS_E_SHORT_MEMORY_BUFFER)
   return g_err("gi0", __FUNCTION__, ret);
 
-cp = store_get(siz);
-if ((ret = gnutls_x509_crt_get_issuer_dn(cert, cp, &siz)) < 0)
+cp = store_get(siz, GET_TAINTED);
+if ((ret = gnutls_x509_crt_get_issuer_dn(cert, CS cp, &siz)) < 0)
   return g_err("gi1", __FUNCTION__, ret);
 
 return mod ? tls_field_from_dn(cp, mod) : cp;
@@ -139,15 +177,16 @@ uschar *
 tls_cert_serial_number(void * cert, uschar * mod)
 {
 uschar bin[50], txt[150];
+uschar * sp = bin;
 size_t sz = sizeof(bin);
-uschar * sp;
-uschar * dp;
+int ret;
 
-if (gnutls_x509_crt_get_serial((gnutls_x509_crt_t)cert,
-    bin, &sz) || sz > sizeof(bin))
-  return NULL;
-for(dp = txt, sp = bin; sz; dp += 2, sp++, sz--)
-  sprintf(dp, "%.2x", *sp);
+if ((ret = gnutls_x509_crt_get_serial((gnutls_x509_crt_t)cert,
+    bin, &sz)))
+  return g_err("gs0", __FUNCTION__, ret);
+
+for(uschar * dp = txt; sz; sz--)
+  dp += sprintf(CS dp, "%.2x", *sp++);
 for(sp = txt; sp[0]=='0' && sp[1]; ) sp++;	/* leading zeroes */
 return string_copy(sp);
 }
@@ -155,22 +194,22 @@ return string_copy(sp);
 uschar *
 tls_cert_signature(void * cert, uschar * mod)
 {
-uschar * cp1;
+uschar * cp1 = NULL;
 uschar * cp2;
 uschar * cp3;
 size_t len = 0;
 int ret;
 
-if ((ret = gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, cp1, &len))
+if ((ret = gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, CS cp1, &len))
     != GNUTLS_E_SHORT_MEMORY_BUFFER)
   return g_err("gs0", __FUNCTION__, ret);
 
-cp1 = store_get(len*4+1);
-if (gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, cp1, &len) != 0)
+cp1 = store_get(len*4+1, GET_TAINTED);
+if (gnutls_x509_crt_get_signature((gnutls_x509_crt_t)cert, CS cp1, &len) != 0)
   return g_err("gs1", __FUNCTION__, ret);
 
-for(cp3 = cp2 = cp1+len; cp1 < cp2; cp3 += 3, cp1++)
-  sprintf(cp3, "%.2x ", *cp1);
+for(cp3 = cp2 = cp1+len; cp1 < cp2; cp1++)
+  cp3 += sprintf(CS cp3, "%.2x ", *cp1);
 cp3[-1]= '\0';
 
 return cp2;
@@ -181,7 +220,7 @@ tls_cert_signature_algorithm(void * cert, uschar * mod)
 {
 gnutls_sign_algorithm_t algo =
   gnutls_x509_crt_get_signature_algorithm((gnutls_x509_crt_t)cert);
-return algo < 0 ? NULL : string_copy(gnutls_sign_get_name(algo));
+return algo < 0 ? NULL : string_copy(US gnutls_sign_get_name(algo));
 }
 
 uschar *
@@ -191,12 +230,12 @@ uschar * cp = NULL;
 int ret;
 size_t siz = 0;
 
-if ((ret = gnutls_x509_crt_get_dn(cert, cp, &siz))
+if ((ret = gnutls_x509_crt_get_dn(cert, CS cp, &siz))
     != GNUTLS_E_SHORT_MEMORY_BUFFER)
   return g_err("gs0", __FUNCTION__, ret);
 
-cp = store_get(siz);
-if ((ret = gnutls_x509_crt_get_dn(cert, cp, &siz)) < 0)
+cp = store_get(siz, GET_TAINTED);
+if ((ret = gnutls_x509_crt_get_dn(cert, CS cp, &siz)) < 0)
   return g_err("gs1", __FUNCTION__, ret);
 
 return mod ? tls_field_from_dn(cp, mod) : cp;
@@ -219,22 +258,22 @@ unsigned int crit;
 int ret;
 
 ret = gnutls_x509_crt_get_extension_by_oid ((gnutls_x509_crt_t)cert,
-  oid, idx, cp1, &siz, &crit);
+  CS oid, idx, CS cp1, &siz, &crit);
 if (ret != GNUTLS_E_SHORT_MEMORY_BUFFER)
   return g_err("ge0", __FUNCTION__, ret);
 
-cp1 = store_get(siz*4 + 1);
+cp1 = store_get(siz*4 + 1, GET_TAINTED);
 
 ret = gnutls_x509_crt_get_extension_by_oid ((gnutls_x509_crt_t)cert,
-  oid, idx, cp1, &siz, &crit);
+  CS oid, idx, CS cp1, &siz, &crit);
 if (ret < 0)
   return g_err("ge1", __FUNCTION__, ret);
 
 /* binary data, DER encoded */
 
 /* just dump for now */
-for(cp3 = cp2 = cp1+siz; cp1 < cp2; cp3 += 3, cp1++)
-  sprintf(cp3, "%.2x ", *cp1);
+for(cp3 = cp2 = cp1+siz; cp1 < cp2; cp1++)
+  cp3 += sprintf(CS cp3, "%.2x ", *cp1);
 cp3[-1]= '\0';
 
 return cp2;
@@ -243,8 +282,7 @@ return cp2;
 uschar *
 tls_cert_subject_altname(void * cert, uschar * mod)
 {
-uschar * list = NULL;
-int index;
+gstring * list = NULL;
 size_t siz;
 int ret;
 uschar sep = '\n';
@@ -252,26 +290,26 @@ uschar * tag = US"";
 uschar * ele;
 int match = -1;
 
-while (mod)
+if (mod) while (*mod)
   {
   if (*mod == '>' && *++mod) sep = *mod++;
-  else if (Ustrcmp(mod, "dns")==0) { match = GNUTLS_SAN_DNSNAME; mod += 3; }
-  else if (Ustrcmp(mod, "uri")==0) { match = GNUTLS_SAN_URI; mod += 3; }
-  else if (Ustrcmp(mod, "mail")==0) { match = GNUTLS_SAN_RFC822NAME; mod += 4; }
-  else continue;
+  else if (Ustrncmp(mod, "dns", 3)==0) { match = GNUTLS_SAN_DNSNAME; mod += 3; }
+  else if (Ustrncmp(mod, "uri", 3)==0) { match = GNUTLS_SAN_URI; mod += 3; }
+  else if (Ustrncmp(mod, "mail", 4)==0) { match = GNUTLS_SAN_RFC822NAME; mod += 4; }
+  else break;
 
   if (*mod++ != ',')
     break;
   }
 
-for(index = 0;; index++)
+for (int index = 0;; index++)
   {
   siz = 0;
   switch(ret = gnutls_x509_crt_get_subject_alt_name(
-    (gnutls_x509_crt_t)cert, index, NULL, &siz, NULL))
+      (gnutls_x509_crt_t)cert, index, NULL, &siz, NULL))
     {
     case GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE:
-      return list;	/* no more elements; normal exit */
+      return string_from_gstring(list);	/* no more elements; normal exit */
 
     case GNUTLS_E_SHORT_MEMORY_BUFFER:
       break;
@@ -280,22 +318,23 @@ for(index = 0;; index++)
       return g_err("gs0", __FUNCTION__, ret);
     }
 
-  ele = store_get(siz+1);
+  ele = store_get(siz+1, GET_TAINTED);
   if ((ret = gnutls_x509_crt_get_subject_alt_name(
     (gnutls_x509_crt_t)cert, index, ele, &siz, NULL)) < 0)
     return g_err("gs1", __FUNCTION__, ret);
   ele[siz] = '\0';
 
-  if (match != -1 && match != ret)
+  if (  match != -1 && match != ret	/* wrong type of SAN */
+     || Ustrlen(ele) != siz)		/* contains a NUL */
     continue;
   switch (ret)
     {
     case GNUTLS_SAN_DNSNAME:    tag = US"DNS";  break;
-    case GNUTLS_SAN_URI:        tag = US"URI";  break; 
+    case GNUTLS_SAN_URI:        tag = US"URI";  break;
     case GNUTLS_SAN_RFC822NAME: tag = US"MAIL"; break;
     default: continue;        /* ignore unrecognised types */
     }
-  list = string_append_listele(list, sep, 
+  list = string_append_listele(list, sep,
           match == -1 ? string_sprintf("%s=%s", tag, ele) : ele);
   }
 /*NOTREACHED*/
@@ -308,30 +347,28 @@ tls_cert_ocsp_uri(void * cert, uschar * mod)
 gnutls_datum_t uri;
 int ret;
 uschar sep = '\n';
-int index;
-uschar * list = NULL;
+gstring * list = NULL;
 
 if (mod)
   if (*mod == '>' && *++mod) sep = *mod++;
 
-for(index = 0;; index++)
+for (int index = 0;; index++)
   {
   ret = gnutls_x509_crt_get_authority_info_access((gnutls_x509_crt_t)cert,
 	  index, GNUTLS_IA_OCSP_URI, &uri, NULL);
 
   if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
-    return list;
+    return string_from_gstring(list);
   if (ret < 0)
     return g_err("gai", __FUNCTION__, ret);
 
-  list = string_append_listele(list, sep,
-	    string_copyn(uri.data, uri.size));
+  list = string_append_listele_n(list, sep, uri.data, uri.size);
   }
 /*NOTREACHED*/
 
 #else
 
-expand_string_message = 
+expand_string_message =
   string_sprintf("%s: OCSP support with GnuTLS requires version 3.0.0\n",
     __FUNCTION__);
 return NULL;
@@ -343,36 +380,33 @@ uschar *
 tls_cert_crl_uri(void * cert, uschar * mod)
 {
 int ret;
-size_t siz;
 uschar sep = '\n';
-int index;
-uschar * list = NULL;
+gstring * list = NULL;
 uschar * ele;
 
 if (mod)
   if (*mod == '>' && *++mod) sep = *mod++;
 
-for(index = 0;; index++)
+for (int index = 0;; index++)
   {
-  siz = 0;
+  size_t siz = 0;
   switch(ret = gnutls_x509_crt_get_crl_dist_points(
     (gnutls_x509_crt_t)cert, index, NULL, &siz, NULL, NULL))
     {
     case GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE:
-      return list;
+      return string_from_gstring(list);
     case GNUTLS_E_SHORT_MEMORY_BUFFER:
       break;
     default:
       return g_err("gc0", __FUNCTION__, ret);
     }
 
-  ele = store_get(siz+1);
+  ele = store_get(siz, GET_TAINTED);
   if ((ret = gnutls_x509_crt_get_crl_dist_points(
       (gnutls_x509_crt_t)cert, index, ele, &siz, NULL, NULL)) < 0)
     return g_err("gc1", __FUNCTION__, ret);
 
-  ele[siz] = '\0';
-  list = string_append_listele(list, sep, ele);
+  list = string_append_listele_n(list, sep, ele, siz);
   }
 /*NOTREACHED*/
 }
@@ -381,6 +415,28 @@ for(index = 0;; index++)
 /*****************************************************
 *  Certificate operator routines
 *****************************************************/
+uschar *
+tls_cert_der_b64(void * cert)
+{
+size_t len = 0;
+uschar * cp = NULL;
+int fail;
+
+if (  (fail = gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
+	GNUTLS_X509_FMT_DER, cp, &len)) != GNUTLS_E_SHORT_MEMORY_BUFFER
+   || !(cp = store_get((int)len, GET_TAINTED), TRUE)	/* tainted */
+   || (fail = gnutls_x509_crt_export((gnutls_x509_crt_t)cert,
+        GNUTLS_X509_FMT_DER, cp, &len))
+   )
+  {
+  log_write(0, LOG_MAIN, "TLS error in certificate export: %s",
+    gnutls_strerror(fail));
+  return NULL;
+  }
+return b64encode(CUS cp, (int)len);
+}
+
+
 static uschar *
 fingerprint(gnutls_x509_crt_t cert, gnutls_digest_algorithm_t algo)
 {
@@ -388,18 +444,17 @@ int ret;
 size_t siz = 0;
 uschar * cp;
 uschar * cp2;
-uschar * cp3;
 
 if ((ret = gnutls_x509_crt_get_fingerprint(cert, algo, NULL, &siz))
     != GNUTLS_E_SHORT_MEMORY_BUFFER)
   return g_err("gf0", __FUNCTION__, ret);
 
-cp = store_get(siz*3+1);
+cp = store_get(siz*3+1, GET_TAINTED);
 if ((ret = gnutls_x509_crt_get_fingerprint(cert, algo, cp, &siz)) < 0)
   return g_err("gf1", __FUNCTION__, ret);
 
-for (cp3 = cp2 = cp+siz; cp < cp2; cp++, cp3+=2)
-  sprintf(cp3, "%02X",*cp);
+for (uschar * cp3 = cp2 = cp+siz; cp < cp2; cp++)
+  cp3 += sprintf(CS cp3, "%02X", *cp);
 return cp2;
 }