src/acl/ServerName.cc

   1 /*
   2  * Copyright (C) 1996-2021 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 /* DEBUG: section 28    Access Control */
  10
  11 #include "squid.h"
  12 #include "acl/DomainData.h"
  13 #include "acl/FilledChecklist.h"
  14 #include "acl/RegexData.h"
  15 #include "acl/ServerName.h"
  16 #include "client_side.h"
  17 #include "fde.h"
  18 #include "http/Stream.h"
  19 #include "HttpRequest.h"
  20 #include "ipcache.h"
  21 #include "SquidString.h"
  22 #include "ssl/bio.h"
  23 #include "ssl/ServerBump.h"
  24 #include "ssl/support.h"
  25
  26 // Compare function for tree search algorithms
  27 static int
  28 aclHostDomainCompare( char *const &a, char * const &b)
  29 {
  30     const char *h = static_cast<const char *>(a);
  31     const char *d = static_cast<const char *>(b);
  32     debugs(28, 7, "Match:" << h << " <>  " << d);
  33     return matchDomainName(h, d, mdnHonorWildcards);
  34 }
  35
  36 bool
  37 ACLServerNameData::match(const char *host)
  38 {
  39     if (host == NULL)
  40         return 0;
  41
  42     debugs(28, 3, "checking '" << host << "'");
  43
  44     char *h = const_cast<char *>(host);
  45     char const * const * result = domains->find(h, aclHostDomainCompare);
  46
  47     debugs(28, 3, "'" << host << "' " << (result ? "found" : "NOT found"));
  48
  49     return (result != NULL);
  50
  51 }
  52
  53 ACLData<char const *> *
  54 ACLServerNameData::clone() const
  55 {
  56     /* Splay trees don't clone yet. */
  57     assert (!domains);
  58     return new ACLServerNameData;
  59 }
  60
  61 /// A helper function to be used with Ssl::matchX509CommonNames().
  62 /// \retval 0 when the name (cn or an alternate name) matches acl data
  63 /// \retval 1 when the name does not match
  64 template<class MatchType>
  65 int
  66 check_cert_domain( void *check_data, ASN1_STRING *cn_data)
  67 {
  68     char cn[1024];
  69     ACLData<MatchType> * data = (ACLData<MatchType> *)check_data;
  70
  71     if (cn_data->length > (int)sizeof(cn) - 1)
  72         return 1; // ignore data that does not fit our buffer
  73
  74     char *s = reinterpret_cast<char *>(cn_data->data);
  75     char *d = cn;
  76     for (int i = 0; i < cn_data->length; ++i, ++d, ++s) {
  77         if (*s == '\0')
  78             return 1; // always a domain mismatch. contains 0x00
  79         *d = *s;
  80     }
  81     cn[cn_data->length] = '\0';
  82     debugs(28, 4, "Verifying certificate name/subjectAltName " << cn);
  83     if (data->match(cn))
  84         return 0;
  85     return 1;
  86 }
  87
  88 int
  89 ACLServerNameStrategy::match (ACLData<MatchType> * &data, ACLFilledChecklist *checklist)
  90 {
  91     assert(checklist != NULL && checklist->request != NULL);
  92
  93     const char *serverName = nullptr;
  94     SBuf clientSniKeeper; // because c_str() is not constant
  95     if (ConnStateData *conn = checklist->conn()) {
  96         const char *clientRequestedServerName = nullptr;
  97         clientSniKeeper = conn->tlsClientSni();
  98         if (clientSniKeeper.isEmpty()) {
  99             const char *host = checklist->request->url.host();
 100             if (host && *host) // paranoid first condition: host() is never nil
 101                 clientRequestedServerName = host;
 102         } else
 103             clientRequestedServerName = clientSniKeeper.c_str();
 104
 105         if (useConsensus) {
 106             X509 *peer_cert = conn->serverBump() ? conn->serverBump()->serverCert.get() : nullptr;
 107             // use the client requested name if it matches the server
 108             // certificate or if the certificate is not available
 109             if (!peer_cert || Ssl::checkX509ServerValidity(peer_cert, clientRequestedServerName))
 110                 serverName = clientRequestedServerName;
 111         } else if (useClientRequested)
 112             serverName = clientRequestedServerName;
 113         else { // either no options or useServerProvided
 114             if (X509 *peer_cert = (conn->serverBump() ? conn->serverBump()->serverCert.get() : nullptr))
 115                 return Ssl::matchX509CommonNames(peer_cert, (void *)data, check_cert_domain<MatchType>);
 116             if (!useServerProvided)
 117                 serverName = clientRequestedServerName;
 118         }
 119     }
 120
 121     if (!serverName)
 122         serverName = "none";
 123
 124     return data->match(serverName);
 125 }
 126
 127 const Acl::Options &
 128 ACLServerNameStrategy::options()
 129 {
 130     static const Acl::BooleanOption ClientRequested;
 131     static const Acl::BooleanOption ServerProvided;
 132     static const Acl::BooleanOption Consensus;
 133     static const Acl::Options MyOptions = {
 134         {"--client-requested", &ClientRequested},
 135         {"--server-provided", &ServerProvided},
 136         {"--consensus", &Consensus}
 137     };
 138
 139     ClientRequested.linkWith(&useClientRequested);
 140     ServerProvided.linkWith(&useServerProvided);
 141     Consensus.linkWith(&useConsensus);
 142     return MyOptions;
 143 }
 144
 145 bool
 146 ACLServerNameStrategy::valid() const
 147 {
 148     int optionCount = 0;
 149
 150     if (useClientRequested)
 151         optionCount++;
 152     if (useServerProvided)
 153         optionCount++;
 154     if (useConsensus)
 155         optionCount++;
 156
 157     if (optionCount > 1) {
 158         debugs(28, DBG_CRITICAL, "ERROR: Multiple options given for the server_name ACL");
 159         return false;
 160     }
 161     return true;
 162 }
 163