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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "chromeos/network/client_cert_util.h"
      6 
      7 #include <cert.h>
      8 #include <pk11pub.h>
      9 
     10 #include <list>
     11 #include <string>
     12 #include <vector>
     13 
     14 #include "base/values.h"
     15 #include "chromeos/network/certificate_pattern.h"
     16 #include "net/base/net_errors.h"
     17 #include "net/cert/cert_database.h"
     18 #include "net/cert/nss_cert_database.h"
     19 #include "net/cert/x509_cert_types.h"
     20 #include "net/cert/x509_certificate.h"
     21 #include "third_party/cros_system_api/dbus/service_constants.h"
     22 
     23 namespace chromeos {
     24 
     25 namespace client_cert {
     26 
     27 namespace {
     28 
     29 // Functor to filter out non-matching issuers.
     30 class IssuerFilter {
     31  public:
     32   explicit IssuerFilter(const IssuerSubjectPattern& issuer)
     33     : issuer_(issuer) {}
     34   bool operator()(const scoped_refptr<net::X509Certificate>& cert) const {
     35     return !CertPrincipalMatches(issuer_, cert.get()->issuer());
     36   }
     37  private:
     38   const IssuerSubjectPattern& issuer_;
     39 };
     40 
     41 // Functor to filter out non-matching subjects.
     42 class SubjectFilter {
     43  public:
     44   explicit SubjectFilter(const IssuerSubjectPattern& subject)
     45     : subject_(subject) {}
     46   bool operator()(const scoped_refptr<net::X509Certificate>& cert) const {
     47     return !CertPrincipalMatches(subject_, cert.get()->subject());
     48   }
     49  private:
     50   const IssuerSubjectPattern& subject_;
     51 };
     52 
     53 // Functor to filter out certs that don't have private keys, or are invalid.
     54 class PrivateKeyFilter {
     55  public:
     56   explicit PrivateKeyFilter(net::CertDatabase* cert_db) : cert_db_(cert_db) {}
     57   bool operator()(const scoped_refptr<net::X509Certificate>& cert) const {
     58     return cert_db_->CheckUserCert(cert.get()) != net::OK;
     59   }
     60  private:
     61   net::CertDatabase* cert_db_;
     62 };
     63 
     64 // Functor to filter out certs that don't have an issuer in the associated
     65 // IssuerCAPEMs list.
     66 class IssuerCaFilter {
     67  public:
     68   explicit IssuerCaFilter(const std::vector<std::string>& issuer_ca_pems)
     69     : issuer_ca_pems_(issuer_ca_pems) {}
     70   bool operator()(const scoped_refptr<net::X509Certificate>& cert) const {
     71     // Find the certificate issuer for each certificate.
     72     // TODO(gspencer): this functionality should be available from
     73     // X509Certificate or NSSCertDatabase.
     74     CERTCertificate* issuer_cert = CERT_FindCertIssuer(
     75         cert.get()->os_cert_handle(), PR_Now(), certUsageAnyCA);
     76 
     77     if (!issuer_cert)
     78       return true;
     79 
     80     std::string pem_encoded;
     81     if (!net::X509Certificate::GetPEMEncoded(issuer_cert, &pem_encoded)) {
     82       LOG(ERROR) << "Couldn't PEM-encode certificate.";
     83       return true;
     84     }
     85 
     86     return (std::find(issuer_ca_pems_.begin(), issuer_ca_pems_.end(),
     87                       pem_encoded) ==
     88             issuer_ca_pems_.end());
     89   }
     90  private:
     91   const std::vector<std::string>& issuer_ca_pems_;
     92 };
     93 
     94 }  // namespace
     95 
     96 // Returns true only if any fields set in this pattern match exactly with
     97 // similar fields in the principal.  If organization_ or organizational_unit_
     98 // are set, then at least one of the organizations or units in the principal
     99 // must match.
    100 bool CertPrincipalMatches(const IssuerSubjectPattern& pattern,
    101                           const net::CertPrincipal& principal) {
    102   if (!pattern.common_name().empty() &&
    103       pattern.common_name() != principal.common_name) {
    104     return false;
    105   }
    106 
    107   if (!pattern.locality().empty() &&
    108       pattern.locality() != principal.locality_name) {
    109     return false;
    110   }
    111 
    112   if (!pattern.organization().empty()) {
    113     if (std::find(principal.organization_names.begin(),
    114                   principal.organization_names.end(),
    115                   pattern.organization()) ==
    116         principal.organization_names.end()) {
    117       return false;
    118     }
    119   }
    120 
    121   if (!pattern.organizational_unit().empty()) {
    122     if (std::find(principal.organization_unit_names.begin(),
    123                   principal.organization_unit_names.end(),
    124                   pattern.organizational_unit()) ==
    125         principal.organization_unit_names.end()) {
    126       return false;
    127     }
    128   }
    129 
    130   return true;
    131 }
    132 
    133 scoped_refptr<net::X509Certificate> GetCertificateMatch(
    134     const CertificatePattern& pattern) {
    135   typedef std::list<scoped_refptr<net::X509Certificate> > CertificateStlList;
    136 
    137   // Start with all the certs, and narrow it down from there.
    138   net::CertificateList all_certs;
    139   CertificateStlList matching_certs;
    140   net::NSSCertDatabase::GetInstance()->ListCerts(&all_certs);
    141 
    142   if (all_certs.empty())
    143     return NULL;
    144 
    145   for (net::CertificateList::iterator iter = all_certs.begin();
    146        iter != all_certs.end(); ++iter) {
    147     matching_certs.push_back(*iter);
    148   }
    149 
    150   // Strip off any certs that don't have the right issuer and/or subject.
    151   if (!pattern.issuer().Empty()) {
    152     matching_certs.remove_if(IssuerFilter(pattern.issuer()));
    153     if (matching_certs.empty())
    154       return NULL;
    155   }
    156 
    157   if (!pattern.subject().Empty()) {
    158     matching_certs.remove_if(SubjectFilter(pattern.subject()));
    159     if (matching_certs.empty())
    160       return NULL;
    161   }
    162 
    163   if (!pattern.issuer_ca_pems().empty()) {
    164     matching_certs.remove_if(IssuerCaFilter(pattern.issuer_ca_pems()));
    165     if (matching_certs.empty())
    166       return NULL;
    167   }
    168 
    169   // Eliminate any certs that don't have private keys associated with
    170   // them.  The CheckUserCert call in the filter is a little slow (because of
    171   // underlying PKCS11 calls), so we do this last to reduce the number of times
    172   // we have to call it.
    173   PrivateKeyFilter private_filter(net::CertDatabase::GetInstance());
    174   matching_certs.remove_if(private_filter);
    175 
    176   if (matching_certs.empty())
    177     return NULL;
    178 
    179   // We now have a list of certificates that match the pattern we're
    180   // looking for.  Now we find the one with the latest start date.
    181   scoped_refptr<net::X509Certificate> latest(NULL);
    182 
    183   // Iterate over the rest looking for the one that was issued latest.
    184   for (CertificateStlList::iterator iter = matching_certs.begin();
    185        iter != matching_certs.end(); ++iter) {
    186     if (!latest.get() || (*iter)->valid_start() > latest->valid_start())
    187       latest = *iter;
    188   }
    189 
    190   return latest;
    191 }
    192 
    193 void SetShillProperties(const client_cert::ConfigType cert_config_type,
    194                         const std::string& tpm_slot,
    195                         const std::string& tpm_pin,
    196                         const std::string* pkcs11_id,
    197                         base::DictionaryValue* properties) {
    198   const char* tpm_pin_property = NULL;
    199   switch (cert_config_type) {
    200     case CONFIG_TYPE_NONE: {
    201       return;
    202     }
    203     case CONFIG_TYPE_OPENVPN: {
    204       tpm_pin_property = flimflam::kOpenVPNPinProperty;
    205       if (pkcs11_id) {
    206         properties->SetStringWithoutPathExpansion(
    207             flimflam::kOpenVPNClientCertIdProperty, *pkcs11_id);
    208       }
    209       break;
    210     }
    211     case CONFIG_TYPE_IPSEC: {
    212       tpm_pin_property = flimflam::kL2tpIpsecPinProperty;
    213       if (!tpm_slot.empty()) {
    214         properties->SetStringWithoutPathExpansion(
    215             flimflam::kL2tpIpsecClientCertSlotProperty, tpm_slot);
    216       }
    217       if (pkcs11_id) {
    218         properties->SetStringWithoutPathExpansion(
    219             flimflam::kL2tpIpsecClientCertIdProperty, *pkcs11_id);
    220       }
    221       break;
    222     }
    223     case CONFIG_TYPE_EAP: {
    224       tpm_pin_property = flimflam::kEapPinProperty;
    225       if (pkcs11_id) {
    226         // Shill requires both CertID and KeyID for TLS connections, despite the
    227         // fact that by convention they are the same ID.
    228         properties->SetStringWithoutPathExpansion(flimflam::kEapCertIdProperty,
    229                                                   *pkcs11_id);
    230         properties->SetStringWithoutPathExpansion(flimflam::kEapKeyIdProperty,
    231                                                   *pkcs11_id);
    232       }
    233       break;
    234     }
    235   }
    236   DCHECK(tpm_pin_property);
    237   if (!tpm_pin.empty())
    238     properties->SetStringWithoutPathExpansion(tpm_pin_property, tpm_pin);
    239 }
    240 
    241 }  // namespace client_cert
    242 
    243 }  // namespace chromeos
    244