1 files changed, 733 insertions, 0 deletions

diff --git a/main/openvpn/contrib/keychain-mcd/cert_data.c b/main/openvpn/contrib/keychain-mcd/cert_data.c
new file mode 100644
index 00000000..f2b33edc
--- /dev/null
+++ b/main/openvpn/contrib/keychain-mcd/cert_data.c
@@ -0,0 +1,733 @@
+/*
+ *  OpenVPN -- An application to securely tunnel IP networks
+ *             over a single UDP port, with support for SSL/TLS-based
+ *             session authentication and key exchange,
+ *             packet encryption, packet authentication, and
+ *             packet compression.
+ *
+ *  Copyright (C) 2010 Brian Raderman <brian@irregularexpression.org>
+ *  Copyright (C) 2013-2015 Vasily Kulikov <segoon@openwall.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program (see the file COPYING included with this
+ *  distribution); if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+
+#include "cert_data.h"
+#include <CommonCrypto/CommonDigest.h>
+#include <openssl/ssl.h>
+
+#include "common_osx.h"
+#include "crypto_osx.h"
+#include <err.h>
+
+CFStringRef kCertDataSubjectName = CFSTR("subject"),
+            kCertDataIssuerName = CFSTR("issuer"),
+            kCertDataSha1Name = CFSTR("SHA1"),
+            kCertDataMd5Name = CFSTR("MD5"),
+            kCertDataSerialName = CFSTR("serial"),
+            kCertNameFwdSlash = CFSTR("/"),
+            kCertNameEquals = CFSTR("=");
+CFStringRef kCertNameOrganization = CFSTR("o"),
+            kCertNameOrganizationalUnit = CFSTR("ou"),
+            kCertNameCountry = CFSTR("c"),
+            kCertNameLocality = CFSTR("l"),
+            kCertNameState = CFSTR("st"),
+            kCertNameCommonName = CFSTR("cn"),
+            kCertNameEmail = CFSTR("e");
+CFStringRef kStringSpace = CFSTR(" "),
+            kStringEmpty = CFSTR("");
+
+typedef struct _CertName
+{
+  CFArrayRef countryName, organization, organizationalUnit, commonName, description, emailAddress,
+             stateName, localityName;
+} CertName, *CertNameRef;
+
+typedef struct _DescData
+{
+  CFStringRef name, value;
+} DescData, *DescDataRef;
+
+void destroyDescData(DescDataRef pData);
+
+CertNameRef createCertName()
+{
+  CertNameRef pCertName = (CertNameRef)malloc(sizeof(CertName));
+  pCertName->countryName = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
+  pCertName->organization =  CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
+  pCertName->organizationalUnit = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
+  pCertName->commonName = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
+  pCertName->description = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
+  pCertName->emailAddress = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
+  pCertName->stateName = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
+  pCertName->localityName = CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks);
+  return pCertName;
+}
+
+void destroyCertName(CertNameRef pCertName)
+{
+  if (!pCertName)
+    return;
+
+  CFRelease(pCertName->countryName);
+  CFRelease(pCertName->organization);
+  CFRelease(pCertName->organizationalUnit);
+  CFRelease(pCertName->commonName);
+  CFRelease(pCertName->description);
+  CFRelease(pCertName->emailAddress);
+  CFRelease(pCertName->stateName);
+  CFRelease(pCertName->localityName);
+  free(pCertName);
+}
+
+bool CFStringRefCmpCString(CFStringRef cfstr, const char *str)
+{
+  CFStringRef tmp = CFStringCreateWithCStringNoCopy(NULL, str, kCFStringEncodingUTF8, kCFAllocatorNull);
+  CFComparisonResult cresult = CFStringCompare(cfstr, tmp, 0);
+  bool result = cresult == kCFCompareEqualTo;
+  CFRelease(tmp);
+  return result;
+}
+
+CFDateRef GetDateFieldFromCertificate(SecCertificateRef certificate, CFTypeRef oid)
+{
+  const void *keys[] = { oid };
+  CFDictionaryRef dict = NULL;
+  CFErrorRef error;
+  CFDateRef date = NULL;
+
+  CFArrayRef keySelection = CFArrayCreate(NULL, keys , sizeof(keys)/sizeof(keys[0]), &kCFTypeArrayCallBacks);
+  dict = SecCertificateCopyValues(certificate, keySelection, &error);
+  if (dict == NULL)
+    {
+      printErrorMsg("GetDateFieldFromCertificate: SecCertificateCopyValues", error);
+      goto release_ks;
+    }
+  CFDictionaryRef vals = dict ? CFDictionaryGetValue(dict, oid) : NULL;
+  CFNumberRef vals2 = vals ? CFDictionaryGetValue(vals, kSecPropertyKeyValue) : NULL;
+  if (vals2 == NULL)
+    goto release_dict;
+
+  CFAbsoluteTime validityNotBefore;
+  if (CFNumberGetValue(vals2, kCFNumberDoubleType, &validityNotBefore))
+    date = CFDateCreate(kCFAllocatorDefault,validityNotBefore);
+
+release_dict:
+  CFRelease(dict);
+release_ks:
+  CFRelease(keySelection);
+  return date;
+}
+
+CFArrayRef GetFieldsFromCertificate(SecCertificateRef certificate, CFTypeRef oid)
+{
+  CFMutableArrayRef fields = CFArrayCreateMutable(NULL, 0, NULL);
+  CertNameRef pCertName = createCertName();
+  const void* keys[] = { oid, };
+  CFDictionaryRef dict;
+  CFErrorRef error;
+
+  CFArrayRef keySelection = CFArrayCreate(NULL, keys , 1, NULL);
+
+  dict = SecCertificateCopyValues(certificate, keySelection, &error);
+  if (dict == NULL) {
+      printErrorMsg("GetFieldsFromCertificate: SecCertificateCopyValues", error);
+      CFRelease(keySelection);
+      CFRelease(fields);
+      return NULL;
+  }
+  CFDictionaryRef vals = CFDictionaryGetValue(dict, oid);
+  CFArrayRef vals2 = vals ? CFDictionaryGetValue(vals, kSecPropertyKeyValue) : NULL;
+  if (vals2)
+    {
+      for(int i = 0; i < CFArrayGetCount(vals2); i++) {
+        CFDictionaryRef subDict = CFArrayGetValueAtIndex(vals2, i);
+        CFStringRef label = CFDictionaryGetValue(subDict, kSecPropertyKeyLabel);
+        CFStringRef value = CFDictionaryGetValue(subDict, kSecPropertyKeyValue);
+
+        if (CFStringCompare(label, kSecOIDEmailAddress, 0) == kCFCompareEqualTo)
+          CFArrayAppendValue((CFMutableArrayRef)pCertName->emailAddress, value);
+        else if (CFStringCompare(label, kSecOIDCountryName, 0) == kCFCompareEqualTo)
+          CFArrayAppendValue((CFMutableArrayRef)pCertName->countryName, value);
+        else if (CFStringCompare(label, kSecOIDOrganizationName, 0) == kCFCompareEqualTo)
+          CFArrayAppendValue((CFMutableArrayRef)pCertName->organization, value);
+        else if (CFStringCompare(label, kSecOIDOrganizationalUnitName, 0) == kCFCompareEqualTo)
+          CFArrayAppendValue((CFMutableArrayRef)pCertName->organizationalUnit, value);
+        else if (CFStringCompare(label, kSecOIDCommonName, 0) == kCFCompareEqualTo)
+          CFArrayAppendValue((CFMutableArrayRef)pCertName->commonName, value);
+        else if (CFStringCompare(label, kSecOIDDescription, 0) == kCFCompareEqualTo)
+          CFArrayAppendValue((CFMutableArrayRef)pCertName->description, value);
+        else if (CFStringCompare(label, kSecOIDStateProvinceName, 0) == kCFCompareEqualTo)
+          CFArrayAppendValue((CFMutableArrayRef)pCertName->stateName, value);
+        else if (CFStringCompare(label, kSecOIDLocalityName, 0) == kCFCompareEqualTo)
+          CFArrayAppendValue((CFMutableArrayRef)pCertName->localityName, value);
+      }
+      CFArrayAppendValue(fields, pCertName);
+    }
+
+  CFRelease(dict);
+  CFRelease(keySelection);
+  return fields;
+}
+
+CertDataRef createCertDataFromCertificate(SecCertificateRef certificate)
+{
+  CertDataRef pCertData = (CertDataRef)malloc(sizeof(CertData));
+  pCertData->subject = GetFieldsFromCertificate(certificate, kSecOIDX509V1SubjectName);
+  pCertData->issuer = GetFieldsFromCertificate(certificate, kSecOIDX509V1IssuerName);
+
+  CFDataRef data = SecCertificateCopyData(certificate);
+  if (data == NULL)
+    {
+      warnx("SecCertificateCopyData() returned NULL");
+      destroyCertData(pCertData);
+      return NULL;
+    }
+
+  unsigned char sha1[CC_SHA1_DIGEST_LENGTH];
+  CC_SHA1(CFDataGetBytePtr(data), CFDataGetLength(data), sha1);
+  pCertData->sha1 = createHexString(sha1, CC_SHA1_DIGEST_LENGTH);
+
+  unsigned char md5[CC_MD5_DIGEST_LENGTH];
+  CC_MD5(CFDataGetBytePtr(data), CFDataGetLength(data), md5);
+  pCertData->md5 = createHexString((unsigned char*)md5, CC_MD5_DIGEST_LENGTH);
+
+  CFDataRef serial = SecCertificateCopySerialNumber(certificate, NULL);
+  pCertData->serial = createHexString((unsigned char *)CFDataGetBytePtr(serial), CFDataGetLength(serial));
+  CFRelease(serial);
+
+  return pCertData;
+}
+
+CFStringRef stringFromRange(const char *cstring, CFRange range)
+{
+  CFStringRef str = CFStringCreateWithBytes (NULL, (uint8*)&cstring[range.location], range.length, kCFStringEncodingUTF8, false);
+  CFMutableStringRef mutableStr = CFStringCreateMutableCopy(NULL, 0, str);
+  CFStringTrimWhitespace(mutableStr);
+  CFRelease(str);
+  return mutableStr;
+}
+
+DescDataRef createDescData(const char *description, CFRange nameRange, CFRange valueRange)
+{
+  DescDataRef pRetVal = (DescDataRef)malloc(sizeof(DescData));
+
+  memset(pRetVal, 0, sizeof(DescData));
+
+  if (nameRange.length > 0)
+    pRetVal->name = stringFromRange(description, nameRange);
+
+  if (valueRange.length > 0)
+    pRetVal->value = stringFromRange(description, valueRange);
+
+#if 0
+  fprintf(stderr, "name = '%s', value = '%s'\n",
+      CFStringGetCStringPtr(pRetVal->name, kCFStringEncodingUTF8),
+      CFStringGetCStringPtr(pRetVal->value, kCFStringEncodingUTF8));
+#endif
+  return pRetVal;
+}
+
+void destroyDescData(DescDataRef pData)
+{
+  if (pData->name)
+    CFRelease(pData->name);
+
+  if (pData->value)
+    CFRelease(pData->value);
+
+  free(pData);
+}
+
+CFArrayRef createDescDataPairs(const char *description)
+{
+  int numChars = strlen(description);
+  CFRange nameRange, valueRange;
+  DescDataRef pData;
+  CFMutableArrayRef retVal = CFArrayCreateMutable(NULL, 0, NULL);
+
+  int i = 0;
+
+  nameRange = CFRangeMake(0, 0);
+  valueRange = CFRangeMake(0, 0);
+  bool bInValue = false;
+
+  while(i < numChars)
+    {
+      if (!bInValue && (description[i] != ':'))
+        {
+          nameRange.length++;
+        }
+      else if (bInValue && (description[i] != ':'))
+        {
+          valueRange.length++;
+        }
+      else if(!bInValue)
+        {
+          bInValue = true;
+          valueRange.location = i + 1;
+          valueRange.length = 0;
+        }
+      else //(bInValue)
+        {
+          bInValue = false;
+          while(description[i] != ' ')
+            {
+              valueRange.length--;
+              i--;
+            }
+
+          pData = createDescData(description, nameRange, valueRange);
+          CFArrayAppendValue(retVal, pData);
+
+          nameRange.location = i + 1;
+          nameRange.length = 0;
+        }
+
+      i++;
+    }
+
+  pData = createDescData(description, nameRange, valueRange);
+  CFArrayAppendValue(retVal, pData);
+  return retVal;
+}
+
+void arrayDestroyDescData(const void *val, void *context)
+{
+  DescDataRef pData = (DescDataRef) val;
+  destroyDescData(pData);
+}
+
+
+int parseNameComponent(CFStringRef dn, CFStringRef *pName, CFStringRef *pValue)
+{
+  CFArrayRef nameStrings = CFStringCreateArrayBySeparatingStrings(NULL, dn, kCertNameEquals);
+
+  *pName = *pValue = NULL;
+
+  if (CFArrayGetCount(nameStrings) != 2)
+    return 0;
+
+  CFMutableStringRef str;
+
+  str = CFStringCreateMutableCopy(NULL, 0, CFArrayGetValueAtIndex(nameStrings, 0));
+  CFStringTrimWhitespace(str);
+  *pName = str;
+
+  str = CFStringCreateMutableCopy(NULL, 0, CFArrayGetValueAtIndex(nameStrings, 1));
+  CFStringTrimWhitespace(str);
+  *pValue = str;
+
+  CFRelease(nameStrings);
+  return 1;
+}
+
+int tryAppendSingleCertField(CertNameRef pCertName, CFArrayRef where, CFStringRef key,
+    CFStringRef name, CFStringRef value)
+{
+  if (CFStringCompareWithOptions(name, key, CFRangeMake(0, CFStringGetLength(name)), kCFCompareCaseInsensitive)
+      == kCFCompareEqualTo) {
+    CFArrayAppendValue((CFMutableArrayRef)where, value);
+    return 1;
+  }
+  return 0;
+}
+
+int appendCertField(CertNameRef pCert, CFStringRef name, CFStringRef value)
+{
+  struct {
+    CFArrayRef field;
+    CFStringRef key;
+  } fields[] = {
+    { pCert->organization, kCertNameOrganization},
+    { pCert->organizationalUnit, kCertNameOrganizationalUnit},
+    { pCert->countryName, kCertNameCountry},
+    { pCert->localityName, kCertNameLocality},
+    { pCert->stateName, kCertNameState},
+    { pCert->commonName, kCertNameCommonName},
+    { pCert->emailAddress, kCertNameEmail},
+  };
+  int i;
+  int ret = 0;
+
+  for (i=0; i<sizeof(fields)/sizeof(fields[0]); i++)
+    ret += tryAppendSingleCertField(pCert, fields[i].field, fields[i].key, name, value);
+  return ret;
+}
+
+int parseCertName(CFStringRef nameDesc, CFMutableArrayRef names)
+{
+  CFArrayRef nameStrings = CFStringCreateArrayBySeparatingStrings(NULL, nameDesc, kCertNameFwdSlash);
+  int count = CFArrayGetCount(nameStrings);
+  int i;
+  int ret = 1;
+
+  CertNameRef pCertName = createCertName();
+
+  for(i = 0;i < count;i++)
+    {
+      CFMutableStringRef dn = CFStringCreateMutableCopy(NULL, 0, CFArrayGetValueAtIndex(nameStrings, i));
+      CFStringTrimWhitespace(dn);
+
+      CFStringRef name, value;
+
+      if (!parseNameComponent(dn, &name, &value))
+        ret = 0;
+
+      if (!name || !value)
+        {
+          if (name)
+            CFRelease(name);
+
+          if (value)
+            CFRelease(value);
+          if (name && !value)
+            ret = 0;
+
+          CFRelease(dn);
+          continue;
+        }
+
+      if (!appendCertField(pCertName, name, value))
+        ret = 0;
+      CFRelease(name);
+      CFRelease(value);
+      CFRelease(dn);
+    }
+
+  CFArrayAppendValue(names, pCertName);
+  CFRelease(nameStrings);
+  return ret;
+}
+
+int arrayParseDescDataPair(const void *val, void *context)
+{
+  DescDataRef pDescData = (DescDataRef)val;
+  CertDataRef pCertData = (CertDataRef)context;
+  int ret = 1;
+
+  if (!pDescData->name || !pDescData->value)
+    return 0;
+
+  if (CFStringCompareWithOptions(pDescData->name, kCertDataSubjectName, CFRangeMake(0, CFStringGetLength(pDescData->name)), kCFCompareCaseInsensitive) == kCFCompareEqualTo)
+    ret = parseCertName(pDescData->value, (CFMutableArrayRef)pCertData->subject);
+  else if (CFStringCompareWithOptions(pDescData->name, kCertDataIssuerName, CFRangeMake(0, CFStringGetLength(pDescData->name)), kCFCompareCaseInsensitive) == kCFCompareEqualTo)
+    ret = parseCertName(pDescData->value, (CFMutableArrayRef)pCertData->issuer);
+  else if (CFStringCompareWithOptions(pDescData->name, kCertDataSha1Name, CFRangeMake(0, CFStringGetLength(pDescData->name)), kCFCompareCaseInsensitive) == kCFCompareEqualTo)
+    pCertData->sha1 = CFRetain(pDescData->value);
+  else if (CFStringCompareWithOptions(pDescData->name, kCertDataMd5Name, CFRangeMake(0, CFStringGetLength(pDescData->name)), kCFCompareCaseInsensitive) == kCFCompareEqualTo)
+    pCertData->md5 = CFRetain(pDescData->value);
+  else if (CFStringCompareWithOptions(pDescData->name, kCertDataSerialName, CFRangeMake(0, CFStringGetLength(pDescData->name)), kCFCompareCaseInsensitive) == kCFCompareEqualTo)
+    pCertData->serial = CFRetain(pDescData->value);
+  else
+    return 0;
+
+  return ret;
+}
+
+CertDataRef createCertDataFromString(const char *description)
+{
+  CertDataRef pCertData = (CertDataRef)malloc(sizeof(CertData));
+  pCertData->subject = CFArrayCreateMutable(NULL, 0, NULL);
+  pCertData->issuer = CFArrayCreateMutable(NULL, 0, NULL);
+  pCertData->sha1 = NULL;
+  pCertData->md5 = NULL;
+  pCertData->serial = NULL;
+
+  CFArrayRef pairs = createDescDataPairs(description);
+  for (int i=0; i<CFArrayGetCount(pairs); i++)
+    if (!arrayParseDescDataPair(CFArrayGetValueAtIndex(pairs, i), pCertData)) {
+      arrayDestroyDescData(pCertData, NULL);
+      CFArrayApplyFunction(pairs, CFRangeMake(0, CFArrayGetCount(pairs)), arrayDestroyDescData, NULL);
+      CFRelease(pairs);
+      return 0;
+    }
+
+  CFArrayApplyFunction(pairs, CFRangeMake(0, CFArrayGetCount(pairs)), arrayDestroyDescData, NULL);
+  CFRelease(pairs);
+  return pCertData;
+}
+
+void arrayDestroyCertName(const void *val, void *context)
+{
+  CertNameRef pCertName = (CertNameRef)val;
+  destroyCertName(pCertName);
+}
+
+void destroyCertData(CertDataRef pCertData)
+{
+  if (pCertData->subject)
+    {
+      CFArrayApplyFunction(pCertData->subject, CFRangeMake(0, CFArrayGetCount(pCertData->subject)), arrayDestroyCertName, NULL);
+      CFRelease(pCertData->subject);
+    }
+
+  if (pCertData->issuer)
+    {
+      CFArrayApplyFunction(pCertData->issuer, CFRangeMake(0, CFArrayGetCount(pCertData->issuer)), arrayDestroyCertName, NULL);
+      CFRelease(pCertData->issuer);
+    }
+
+  if (pCertData->sha1)
+    CFRelease(pCertData->sha1);
+
+  if (pCertData->md5)
+    CFRelease(pCertData->md5);
+
+  if (pCertData->serial)
+    CFRelease(pCertData->serial);
+
+  free(pCertData);
+}
+
+bool stringArrayMatchesTemplate(CFArrayRef strings, CFArrayRef templateArray)
+{
+  int templateCount, stringCount, i;
+
+  templateCount = CFArrayGetCount(templateArray);
+
+  if (templateCount > 0)
+    {
+      stringCount = CFArrayGetCount(strings);
+      if (stringCount != templateCount)
+        return false;
+
+      for(i = 0;i < stringCount;i++)
+        {
+          CFStringRef str, template;
+
+          template = (CFStringRef)CFArrayGetValueAtIndex(templateArray, i);
+          str = (CFStringRef)CFArrayGetValueAtIndex(strings, i);
+
+          if (CFStringCompareWithOptions(template, str, CFRangeMake(0, CFStringGetLength(template)), kCFCompareCaseInsensitive) != kCFCompareEqualTo)
+            return false;
+        }
+    }
+
+  return true;
+
+}
+
+bool certNameMatchesTemplate(CertNameRef pCertName, CertNameRef pTemplate)
+{
+  if (!stringArrayMatchesTemplate(pCertName->countryName, pTemplate->countryName))
+    return false;
+  else if (!stringArrayMatchesTemplate(pCertName->organization, pTemplate->organization))
+    return false;
+  else if (!stringArrayMatchesTemplate(pCertName->organizationalUnit, pTemplate->organizationalUnit))
+    return false;
+  else if (!stringArrayMatchesTemplate(pCertName->commonName, pTemplate->commonName))
+    return false;
+  else if (!stringArrayMatchesTemplate(pCertName->emailAddress, pTemplate->emailAddress))
+    return false;
+  else if (!stringArrayMatchesTemplate(pCertName->stateName, pTemplate->stateName))
+    return false;
+  else if (!stringArrayMatchesTemplate(pCertName->localityName, pTemplate->localityName))
+    return false;
+  else
+    return true;
+}
+
+bool certNameArrayMatchesTemplate(CFArrayRef certNameArray, CFArrayRef templateArray)
+{
+  int templateCount, certCount, i;
+
+  templateCount = CFArrayGetCount(templateArray);
+
+  if (templateCount > 0)
+    {
+      certCount = CFArrayGetCount(certNameArray);
+      if (certCount != templateCount)
+        return false;
+
+      for(i = 0;i < certCount;i++)
+        {
+          CertNameRef pName, pTemplateName;
+
+          pTemplateName = (CertNameRef)CFArrayGetValueAtIndex(templateArray, i);
+          pName = (CertNameRef)CFArrayGetValueAtIndex(certNameArray, i);
+
+          if (!certNameMatchesTemplate(pName, pTemplateName))
+            return false;
+        }
+    }
+
+  return true;
+}
+
+bool hexStringMatchesTemplate(CFStringRef str, CFStringRef template)
+{
+  if (template)
+    {
+      if (!str)
+        return false;
+
+      CFMutableStringRef strMutable, templateMutable;
+
+      strMutable = CFStringCreateMutableCopy(NULL, 0, str);
+      templateMutable = CFStringCreateMutableCopy(NULL, 0, template);
+
+      CFStringFindAndReplace(strMutable, kStringSpace, kStringEmpty, CFRangeMake(0, CFStringGetLength(strMutable)), 0);
+      CFStringFindAndReplace(templateMutable, kStringSpace, kStringEmpty, CFRangeMake(0, CFStringGetLength(templateMutable)), 0);
+
+      CFComparisonResult result = CFStringCompareWithOptions(templateMutable, strMutable, CFRangeMake(0, CFStringGetLength(templateMutable)), kCFCompareCaseInsensitive);
+
+      CFRelease(strMutable);
+      CFRelease(templateMutable);
+
+      if (result != kCFCompareEqualTo)
+        return false;
+    }
+
+  return true;
+}
+
+bool certDataMatchesTemplate(CertDataRef pCertData, CertDataRef pTemplate)
+{
+  if (!certNameArrayMatchesTemplate(pCertData->subject, pTemplate->subject))
+    return false;
+
+  if (!certNameArrayMatchesTemplate(pCertData->issuer, pTemplate->issuer))
+    return false;
+
+  if (!hexStringMatchesTemplate(pCertData->sha1, pTemplate->sha1))
+    return false;
+
+  if (!hexStringMatchesTemplate(pCertData->md5, pTemplate->md5))
+    return false;
+
+  if (!hexStringMatchesTemplate(pCertData->serial, pTemplate->serial))
+    return false;
+
+  return true;
+}
+
+bool certExpired(SecCertificateRef certificate)
+{
+  bool result;
+  CFDateRef notAfter = GetDateFieldFromCertificate(certificate, kSecOIDX509V1ValidityNotAfter);
+  CFDateRef notBefore = GetDateFieldFromCertificate(certificate, kSecOIDX509V1ValidityNotBefore);
+  CFDateRef now = CFDateCreate(kCFAllocatorDefault, CFAbsoluteTimeGetCurrent());
+
+  if (!notAfter || !notBefore || !now)
+    {
+      warnx("GetDateFieldFromCertificate() returned NULL");
+      result = true;
+    }
+  else
+    {
+      if (CFDateCompare(notBefore, now, NULL) != kCFCompareLessThan ||
+          CFDateCompare(now, notAfter, NULL) != kCFCompareLessThan)
+        result = true;
+      else
+        result = false;
+    }
+
+  CFRelease(notAfter);
+  CFRelease(notBefore);
+  CFRelease(now);
+  return result;
+}
+
+SecIdentityRef findIdentity(CertDataRef pCertDataTemplate)
+{
+  const void *keys[] = {
+    kSecClass,
+    kSecReturnRef,
+    kSecMatchLimit
+  };
+  const void *values[] = {
+    kSecClassIdentity,
+    kCFBooleanTrue,
+    kSecMatchLimitAll
+  };
+  CFArrayRef result = NULL;
+
+  CFDictionaryRef query = CFDictionaryCreate(NULL, keys, values,
+      sizeof(keys) / sizeof(*keys),
+      &kCFTypeDictionaryKeyCallBacks,
+      &kCFTypeDictionaryValueCallBacks);
+  OSStatus status = SecItemCopyMatching(query, (CFTypeRef*)&result);
+  CFRelease(query);
+  if (status != noErr)
+    {
+      warnx ("No identities in keychain found");
+      return NULL;
+    }
+
+  SecIdentityRef bestIdentity = NULL;
+  CFDateRef bestNotBeforeDate = NULL;
+
+  for (int i=0; i<CFArrayGetCount(result); i++)
+    {
+      SecIdentityRef identity = (SecIdentityRef)CFArrayGetValueAtIndex(result, i);
+      if (identity == NULL)
+        {
+          warnx ("identity == NULL");
+          continue;
+        }
+
+      SecCertificateRef certificate = NULL;
+      SecIdentityCopyCertificate (identity, &certificate);
+      if (certificate == NULL)
+        {
+          warnx ("SecIdentityCopyCertificate() returned NULL");
+          continue;
+        }
+
+      CertDataRef pCertData2 = createCertDataFromCertificate(certificate);
+      if (pCertData2 == NULL)
+        {
+          warnx ("createCertDataFromCertificate() returned NULL");
+          goto release_cert;
+        }
+      bool bMatches = certDataMatchesTemplate(pCertData2, pCertDataTemplate);
+      bool bExpired = certExpired(certificate);
+      destroyCertData(pCertData2);
+
+      if (bMatches && !bExpired)
+        {
+          CFDateRef notBeforeDate = GetDateFieldFromCertificate(certificate, kSecOIDX509V1ValidityNotBefore);
+          if (!notBeforeDate)
+            {
+              warnx ("GetDateFieldFromCertificate() returned NULL");
+              goto release_cert;
+            }
+          if (bestIdentity == NULL)
+            {
+              CFRetain(identity);
+              bestIdentity = identity;
+
+              bestNotBeforeDate = notBeforeDate;
+              CFRetain(notBeforeDate);
+            }
+          else if (CFDateCompare(bestNotBeforeDate, notBeforeDate, NULL) == kCFCompareLessThan)
+            {
+              CFRelease(bestIdentity);
+              CFRetain(identity);
+              bestIdentity = identity;
+
+              bestNotBeforeDate = notBeforeDate;
+              CFRetain(notBeforeDate);
+            }
+          CFRelease(notBeforeDate);
+        }
+    release_cert:
+      CFRelease(certificate);
+    }
+  CFRelease(result);
+
+  return bestIdentity;
+}