michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "PublicKeyPinningService.h"
michael@0: #include "pkix/nullptr.h"
michael@0: #include "StaticHPKPins.h" // autogenerated by genHPKPStaticpins.js
michael@0: 
michael@0: #include "cert.h"
michael@0: #include "mozilla/Base64.h"
michael@0: #include "mozilla/Telemetry.h"
michael@0: #include "nsString.h"
michael@0: #include "nssb64.h"
michael@0: #include "pkix/pkixtypes.h"
michael@0: #include "prlog.h"
michael@0: #include "ScopedNSSTypes.h"
michael@0: #include "seccomon.h"
michael@0: #include "sechash.h"
michael@0: 
michael@0: using namespace mozilla;
michael@0: using namespace mozilla::pkix;
michael@0: using namespace mozilla::psm;
michael@0: 
michael@0: #if defined(PR_LOGGING)
michael@0: PRLogModuleInfo* gPublicKeyPinningLog =
michael@0:   PR_NewLogModule("PublicKeyPinningService");
michael@0: #endif
michael@0: 
michael@0: /**
michael@0:  Computes in the location specified by base64Out the SHA256 digest
michael@0:  of the DER Encoded subject Public Key Info for the given cert
michael@0: */
michael@0: static SECStatus
michael@0: GetBase64HashSPKI(const CERTCertificate* cert, SECOidTag hashType,
michael@0:                   nsACString& hashSPKIDigest)
michael@0: {
michael@0:   hashSPKIDigest.Truncate();
michael@0:   Digest digest;
michael@0:   nsresult rv = digest.DigestBuf(hashType, cert->derPublicKey.data,
michael@0:                                  cert->derPublicKey.len);
michael@0:   if (NS_WARN_IF(NS_FAILED(rv))) {
michael@0:     return SECFailure;
michael@0:   }
michael@0:   rv = Base64Encode(nsDependentCSubstring(
michael@0:                       reinterpret_cast<const char*>(digest.get().data),
michael@0:                       digest.get().len),
michael@0:                       hashSPKIDigest);
michael@0:   if (NS_WARN_IF(NS_FAILED(rv))) {
michael@0:     return SECFailure;
michael@0:   }
michael@0:   return SECSuccess;
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * Returns true if a given cert matches any hashType fingerprints from the
michael@0:  * given pinset, false otherwise.
michael@0:  */
michael@0: static bool
michael@0: EvalCertWithHashType(const CERTCertificate* cert, SECOidTag hashType,
michael@0:                      const StaticFingerprints* fingerprints)
michael@0: {
michael@0:   if (!fingerprints) {
michael@0:     PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG,
michael@0:            ("pkpin: No hashes found for hash type: %d\n", hashType));
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   nsAutoCString base64Out;
michael@0:   SECStatus srv = GetBase64HashSPKI(cert, hashType, base64Out);
michael@0:   if (srv != SECSuccess) {
michael@0:     PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG,
michael@0:            ("pkpin: GetBase64HashSPKI failed!\n"));
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   for (size_t i = 0; i < fingerprints->size; i++) {
michael@0:     if (base64Out.Equals(fingerprints->data[i])) {
michael@0:       PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG,
michael@0:              ("pkpin: found pin base_64 ='%s'\n", base64Out.get()));
michael@0:       return true;
michael@0:     }
michael@0:   }
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * Returns true if a given chain matches any hashType fingerprints from the
michael@0:  * given pinset, false otherwise.
michael@0:  */
michael@0: static bool
michael@0: EvalChainWithHashType(const CERTCertList* certList, SECOidTag hashType,
michael@0:                       const StaticPinset* pinset)
michael@0: {
michael@0:   CERTCertificate* currentCert;
michael@0: 
michael@0:   const StaticFingerprints* fingerprints = nullptr;
michael@0:   if (hashType == SEC_OID_SHA256) {
michael@0:     fingerprints = pinset->sha256;
michael@0:   } else if (hashType == SEC_OID_SHA1) {
michael@0:     fingerprints = pinset->sha1;
michael@0:   }
michael@0:   if (!fingerprints) {
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   CERTCertListNode* node;
michael@0:   for (node = CERT_LIST_HEAD(certList); !CERT_LIST_END(node, certList);
michael@0:        node = CERT_LIST_NEXT(node)) {
michael@0:     currentCert = node->cert;
michael@0:     PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG,
michael@0:            ("pkpin: certArray subject: '%s'\n",
michael@0:             currentCert->subjectName));
michael@0:     PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG,
michael@0:            ("pkpin: certArray common_name: '%s'\n",
michael@0:             CERT_GetCommonName(&(currentCert->issuer))));
michael@0:     if (EvalCertWithHashType(currentCert, hashType, fingerprints)) {
michael@0:       return true;
michael@0:     }
michael@0:   }
michael@0:   PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG, ("pkpin: no matches found\n"));
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Given a pinset and certlist, return true if one of the certificates on
michael@0:  * the list matches a fingerprint in the pinset, false otherwise.
michael@0:  */
michael@0: static bool
michael@0: EvalChainWithPinset(const CERTCertList* certList,
michael@0:                     const StaticPinset* pinset) {
michael@0:   // SHA256 is more trustworthy, try that first.
michael@0:   if (EvalChainWithHashType(certList, SEC_OID_SHA256, pinset)) {
michael@0:     return true;
michael@0:   }
michael@0:   return EvalChainWithHashType(certList, SEC_OID_SHA1, pinset);
michael@0: }
michael@0: 
michael@0: /**
michael@0:   Comparator for the is public key pinned host.
michael@0: */
michael@0: static int
michael@0: TransportSecurityPreloadCompare(const void *key, const void *entry) {
michael@0:   const char *keyStr = reinterpret_cast<const char *>(key);
michael@0:   const TransportSecurityPreload *preloadEntry =
michael@0:     reinterpret_cast<const TransportSecurityPreload *>(entry);
michael@0: 
michael@0:   return strcmp(keyStr, preloadEntry->mHost);
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Check PKPins on the given certlist against the specified hostname
michael@0:  */
michael@0: static bool
michael@0: CheckPinsForHostname(const CERTCertList *certList, const char *hostname,
michael@0:                      bool enforceTestMode)
michael@0: {
michael@0:   if (!certList) {
michael@0:     return false;
michael@0:   }
michael@0:   if (!hostname || hostname[0] == 0) {
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   TransportSecurityPreload *foundEntry = nullptr;
michael@0:   char *evalHost = const_cast<char*>(hostname);
michael@0:   char *evalPart;
michael@0:   // Notice how the (xx = strchr) prevents pins for unqualified domain names.
michael@0:   while (!foundEntry && (evalPart = strchr(evalHost, '.'))) {
michael@0:     PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG,
michael@0:            ("pkpin: Querying pinsets for host: '%s'\n", evalHost));
michael@0:     foundEntry = (TransportSecurityPreload *)bsearch(evalHost,
michael@0:       kPublicKeyPinningPreloadList,
michael@0:       sizeof(kPublicKeyPinningPreloadList) / sizeof(TransportSecurityPreload),
michael@0:       sizeof(TransportSecurityPreload),
michael@0:       TransportSecurityPreloadCompare);
michael@0:     if (foundEntry) {
michael@0:       PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG,
michael@0:              ("pkpin: Found pinset for host: '%s'\n", evalHost));
michael@0:       if (evalHost != hostname) {
michael@0:         if (!foundEntry->mIncludeSubdomains) {
michael@0:           // Does not apply to this host, continue iterating
michael@0:           foundEntry = nullptr;
michael@0:         }
michael@0:       }
michael@0:     } else {
michael@0:       PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG,
michael@0:              ("pkpin: Didn't find pinset for host: '%s'\n", evalHost));
michael@0:     }
michael@0:     // Add one for '.'
michael@0:     evalHost = evalPart + 1;
michael@0:   }
michael@0: 
michael@0:   if (foundEntry && foundEntry->pinset) {
michael@0:     bool result = EvalChainWithPinset(certList, foundEntry->pinset);
michael@0:     bool retval = result;
michael@0:     Telemetry::ID histogram = foundEntry->mIsMoz
michael@0:       ? Telemetry::CERT_PINNING_MOZ_RESULTS
michael@0:       : Telemetry::CERT_PINNING_RESULTS;
michael@0:     if (foundEntry->mTestMode) {
michael@0:       histogram = foundEntry->mIsMoz
michael@0:         ? Telemetry::CERT_PINNING_MOZ_TEST_RESULTS
michael@0:         : Telemetry::CERT_PINNING_TEST_RESULTS;
michael@0:       if (!enforceTestMode) {
michael@0:         retval = true;
michael@0:       }
michael@0:     }
michael@0:     // We can collect per-host pinning violations for this host because it is
michael@0:     // operationally critical to Firefox.
michael@0:     if (foundEntry->mId != kUnknownId) {
michael@0:       int32_t bucket = foundEntry->mId * 2 + (result ? 1 : 0);
michael@0:       histogram = foundEntry->mTestMode
michael@0:         ? Telemetry::CERT_PINNING_MOZ_TEST_RESULTS_BY_HOST
michael@0:         : Telemetry::CERT_PINNING_MOZ_RESULTS_BY_HOST;
michael@0:       Telemetry::Accumulate(histogram, bucket);
michael@0:     } else {
michael@0:       Telemetry::Accumulate(histogram, result ? 1 : 0);
michael@0:     }
michael@0:     PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG,
michael@0:            ("pkpin: Pin check %s for %s host '%s' (mode=%s)\n",
michael@0:             result ? "passed" : "failed",
michael@0:             foundEntry->mIsMoz ? "mozilla" : "non-mozilla",
michael@0:             hostname, foundEntry->mTestMode ? "test" : "production"));
michael@0:     return retval;
michael@0:   }
michael@0:   return true; // No pinning information for this hostname
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Extract all the DNS names for a host (including CN) and evaluate the
michael@0:  * certifiate pins against all of them (Currently is an OR so we stop
michael@0:  * evaluating at the first OK pin).
michael@0:  */
michael@0: static bool
michael@0: CheckChainAgainstAllNames(const CERTCertList* certList, bool enforceTestMode)
michael@0: {
michael@0:   PR_LOG(gPublicKeyPinningLog, PR_LOG_DEBUG,
michael@0:          ("pkpin: top of checkChainAgainstAllNames"));
michael@0:   CERTCertListNode* node = CERT_LIST_HEAD(certList);
michael@0:   if (!node) {
michael@0:     return false;
michael@0:   }
michael@0:   CERTCertificate* cert = node->cert;
michael@0:   if (!cert) {
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   ScopedPLArenaPool arena(PORT_NewArena(DER_DEFAULT_CHUNKSIZE));
michael@0:   if (!arena) {
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   bool hasValidPins = false;
michael@0:   CERTGeneralName* nameList;
michael@0:   CERTGeneralName* currentName;
michael@0:   nameList = CERT_GetConstrainedCertificateNames(cert, arena.get(), PR_TRUE);
michael@0:   if (!nameList) {
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   currentName = nameList;
michael@0:   do {
michael@0:     if (currentName->type == certDNSName
michael@0:         && currentName->name.other.data[0] != 0) {
michael@0:       // no need to cleaup, as the arena cleanup will do
michael@0:       char *hostName = (char *)PORT_ArenaAlloc(arena.get(),
michael@0:                                                currentName->name.other.len + 1);
michael@0:       if (!hostName) {
michael@0:         break;
michael@0:       }
michael@0:       // We use a temporary buffer as the hostname as returned might not be
michael@0:       // null terminated.
michael@0:       hostName[currentName->name.other.len] = 0;
michael@0:       memcpy(hostName, currentName->name.other.data,
michael@0:              currentName->name.other.len);
michael@0:       if (!hostName[0]) {
michael@0:         // cannot call CheckPinsForHostname on empty or null hostname
michael@0:         break;
michael@0:       }
michael@0:       if (CheckPinsForHostname(certList, hostName, enforceTestMode)) {
michael@0:         hasValidPins = true;
michael@0:         break;
michael@0:       }
michael@0:     }
michael@0:     currentName = CERT_GetNextGeneralName(currentName);
michael@0:   } while (currentName != nameList);
michael@0: 
michael@0:   return hasValidPins;
michael@0: }
michael@0: 
michael@0: bool
michael@0: PublicKeyPinningService::ChainHasValidPins(const CERTCertList* certList,
michael@0:                                            const char* hostname,
michael@0:                                            const PRTime time,
michael@0:                                            bool enforceTestMode)
michael@0: {
michael@0:   if (!certList) {
michael@0:     return false;
michael@0:   }
michael@0:   if (time > kPreloadPKPinsExpirationTime) {
michael@0:     return true;
michael@0:   }
michael@0:   if (!hostname || hostname[0] == 0) {
michael@0:     return CheckChainAgainstAllNames(certList, enforceTestMode);
michael@0:   }
michael@0:   return CheckPinsForHostname(certList, hostname, enforceTestMode);
michael@0: }