The Tor Browser: media/mtransport/dtlsidentity.cpp@6474c204b198 (annotated)

media/mtransport/dtlsidentity.cpp@6474c204b198 (annotated)

media/mtransport/dtlsidentity.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include <iomanip>
 #include "logging.h"
 #include "nspr.h"
 #include "cryptohi.h"
 #include "ssl.h"
 #include "keyhi.h"
 #include "pk11pub.h"
 #include "sechash.h"
 #include "nsError.h"
 #include "dtlsidentity.h"
 namespace mozilla {
 MOZ_MTLOG_MODULE("mtransport")
 DtlsIdentity::~DtlsIdentity() {
   // XXX: make cert_ a smart pointer to avoid this, after we figure
   // out the linking problem.
   if (cert_)
     CERT_DestroyCertificate(cert_);
 }
 const std::string DtlsIdentity::DEFAULT_HASH_ALGORITHM = "sha-256";
 const size_t DtlsIdentity::HASH_ALGORITHM_MAX_LENGTH = 64;
 TemporaryRef<DtlsIdentity> DtlsIdentity::Generate() {
   ScopedPK11SlotInfo slot(PK11_GetInternalSlot());
   if (!slot) {
     return nullptr;
   }
   uint8_t random_name[16];
   SECStatus rv = PK11_GenerateRandomOnSlot(slot, random_name,
                                            sizeof(random_name));
   if (rv != SECSuccess)
     return nullptr;
   std::string name;
   char chunk[3];
   for (size_t i = 0; i < sizeof(random_name); ++i) {
     PR_snprintf(chunk, sizeof(chunk), "%.2x", random_name[i]);
     name += chunk;
   }
   std::string subject_name_string = "CN=" + name;
   ScopedCERTName subject_name(CERT_AsciiToName(subject_name_string.c_str()));
   if (!subject_name) {
     return nullptr;
   }
   PK11RSAGenParams rsaparams;
   rsaparams.keySizeInBits = 1024; // TODO: make this stronger when we
                                   // pre-generate.
   rsaparams.pe = 65537; // We are too paranoid to use 3 as the exponent.
   ScopedSECKEYPrivateKey private_key;
   ScopedSECKEYPublicKey public_key;
   SECKEYPublicKey *pubkey;
   private_key =
       PK11_GenerateKeyPair(slot,
                            CKM_RSA_PKCS_KEY_PAIR_GEN, &rsaparams, &pubkey,
                            PR_FALSE, PR_TRUE, nullptr);
   if (private_key == nullptr)
     return nullptr;
   public_key = pubkey;
   ScopedCERTSubjectPublicKeyInfo spki(
       SECKEY_CreateSubjectPublicKeyInfo(pubkey));
   if (!spki) {
     return nullptr;
   }
   ScopedCERTCertificateRequest certreq(
       CERT_CreateCertificateRequest(subject_name, spki, nullptr));
   if (!certreq) {
     return nullptr;
   }
   // From 1 day before todayto 30 days after.
   // This is a sort of arbitrary range designed to be valid
   // now with some slack in case the other side expects
   // some before expiry.
   //
   // Note: explicit casts necessary to avoid
   //       warning C4307: '*' : integral constant overflow
   static const PRTime oneDay = PRTime(PR_USEC_PER_SEC)
                              * PRTime(60)  // sec
                              * PRTime(60)  // min
                              * PRTime(24); // hours
   PRTime now = PR_Now();
   PRTime notBefore = now - oneDay;
   PRTime notAfter = now + (PRTime(30) * oneDay);
   ScopedCERTValidity validity(CERT_CreateValidity(notBefore, notAfter));
   if (!validity) {
     return nullptr;
   }
   unsigned long serial;
   // Note: This serial in principle could collide, but it's unlikely
   rv = PK11_GenerateRandomOnSlot(slot,
                                  reinterpret_cast<unsigned char *>(&serial),
                                  sizeof(serial));
   if (rv != SECSuccess) {
     return nullptr;
   }
   ScopedCERTCertificate certificate(
       CERT_CreateCertificate(serial, subject_name, validity, certreq));
   if (!certificate) {
     return nullptr;
   }
   PLArenaPool *arena = certificate->arena;
   rv = SECOID_SetAlgorithmID(arena, &certificate->signature,
                              SEC_OID_PKCS1_SHA1_WITH_RSA_ENCRYPTION, 0);
   if (rv != SECSuccess)
     return nullptr;
   // Set version to X509v3.
   *(certificate->version.data) = SEC_CERTIFICATE_VERSION_3;
   certificate->version.len = 1;
   SECItem innerDER;
   innerDER.len = 0;
   innerDER.data = nullptr;
   if (!SEC_ASN1EncodeItem(arena, &innerDER, certificate,
                           SEC_ASN1_GET(CERT_CertificateTemplate))) {
     return nullptr;
   }
   SECItem *signedCert = PORT_ArenaZNew(arena, SECItem);
   if (!signedCert) {
     return nullptr;
   }
   rv = SEC_DerSignData(arena, signedCert, innerDER.data, innerDER.len,
                        private_key,
                        SEC_OID_PKCS1_SHA1_WITH_RSA_ENCRYPTION);
   if (rv != SECSuccess) {
     return nullptr;
   }
   certificate->derCert = *signedCert;
   return new DtlsIdentity(private_key.forget(), certificate.forget());
 }
 nsresult DtlsIdentity::ComputeFingerprint(const std::string algorithm,
                                           unsigned char *digest,
                                           std::size_t size,
                                           std::size_t *digest_length) {
   MOZ_ASSERT(cert_);
   return ComputeFingerprint(cert_, algorithm, digest, size, digest_length);
 }
 nsresult DtlsIdentity::ComputeFingerprint(const CERTCertificate *cert,
                                           const std::string algorithm,
                                           unsigned char *digest,
                                           std::size_t size,
                                           std::size_t *digest_length) {
   MOZ_ASSERT(cert);
   HASH_HashType ht;
   if (algorithm == "sha-1") {
     ht = HASH_AlgSHA1;
   } else if (algorithm == "sha-224") {
     ht = HASH_AlgSHA224;
   } else if (algorithm == "sha-256") {
     ht = HASH_AlgSHA256;
   } else if (algorithm == "sha-384") {
     ht = HASH_AlgSHA384;
   }  else if (algorithm == "sha-512") {
     ht = HASH_AlgSHA512;
   } else {
     return NS_ERROR_INVALID_ARG;
   }
   const SECHashObject *ho = HASH_GetHashObject(ht);
   MOZ_ASSERT(ho);
   if (!ho)
     return NS_ERROR_INVALID_ARG;
   MOZ_ASSERT(ho->length >= 20);  // Double check
   if (size < ho->length)
     return NS_ERROR_INVALID_ARG;
   SECStatus rv = HASH_HashBuf(ho->type, digest,
                               cert->derCert.data,
                               cert->derCert.len);
   if (rv != SECSuccess)
     return NS_ERROR_FAILURE;
   *digest_length = ho->length;
   return NS_OK;
 }
 // Format the fingerprint in RFC 4572 Section 5 attribute format, including both
 // the hash name and the fingerprint, colons and all.
 // returns an empty string if there is a problem
 std::string DtlsIdentity::GetFormattedFingerprint(const std::string &algorithm) {
   unsigned char digest[HASH_ALGORITHM_MAX_LENGTH];
   size_t digest_length;
   nsresult res = this->ComputeFingerprint(algorithm,
                                           digest,
                                           sizeof(digest),
                                           &digest_length);
   if (NS_FAILED(res)) {
     MOZ_MTLOG(ML_ERROR, "Unable to compute " << algorithm
               << " hash for identity: nsresult = 0x"
               << std::hex << std::uppercase
               << static_cast<uint32_t>(res)
               << std::nouppercase << std::dec);
     return "";
   }
   return algorithm + " " + this->FormatFingerprint(digest, digest_length);
 }
 std::string DtlsIdentity::FormatFingerprint(const unsigned char *digest,
                                             std::size_t size) {
   std::string str("");
   char group[3];
   for (std::size_t i=0; i < size; i++) {
     PR_snprintf(group, sizeof(group), "%.2X", digest[i]);
     if (i != 0) {
       str += ":";
     }
     str += group;
   }
   MOZ_ASSERT(str.size() == (size * 3 - 1));  // Check result length
   return str;
 }
 // Parse a fingerprint in RFC 4572 format.
 // Note that this tolerates some badly formatted data, in particular:
 // (a) arbitrary runs of colons
 // (b) colons at the beginning or end.
 nsresult DtlsIdentity::ParseFingerprint(const std::string fp,
                                         unsigned char *digest,
                                         size_t size,
                                         size_t *length) {
   size_t offset = 0;
   bool top_half = true;
   uint8_t val = 0;
   for (size_t i=0; i<fp.length(); i++) {
     if (offset >= size) {
       // Note: no known way for offset to get > size
       MOZ_MTLOG(ML_ERROR, "Fingerprint too long for buffer");
       return NS_ERROR_INVALID_ARG;
     }
     if (top_half && (fp[i] == ':')) {
       continue;
     } else if ((fp[i] >= '0') && (fp[i] <= '9')) {
       val |= fp[i] - '0';
     } else if ((fp[i] >= 'A') && (fp[i] <= 'F')) {
       val |= fp[i] - 'A' + 10;
     } else {
       MOZ_MTLOG(ML_ERROR, "Invalid fingerprint value " << fp[i]);
       return NS_ERROR_ILLEGAL_VALUE;
     }
     if (top_half) {
       val <<= 4;
       top_half = false;
     } else {
       digest[offset++] = val;
       top_half = true;
       val = 0;
     }
   }
   *length = offset;
   return NS_OK;
 }
 }  // close namespace

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media/mtransport/dtlsidentity.cpp@6474c204b198 (annotated)

media/mtransport/dtlsidentity.cpp