diff options
Diffstat (limited to 'dom/media/webrtc/transport/dtlsidentity.cpp')
| -rw-r--r-- | dom/media/webrtc/transport/dtlsidentity.cpp | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/dom/media/webrtc/transport/dtlsidentity.cpp b/dom/media/webrtc/transport/dtlsidentity.cpp new file mode 100644 index 0000000000..c466ce7d88 --- /dev/null +++ b/dom/media/webrtc/transport/dtlsidentity.cpp @@ -0,0 +1,331 @@ +/* -*- 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 "dtlsidentity.h" + +#include "cert.h" +#include "cryptohi.h" +#include "keyhi.h" +#include "nsError.h" +#include "pk11pub.h" +#include "sechash.h" +#include "mozpkix/nss_scoped_ptrs.h" +#include "secerr.h" +#include "sslerr.h" + +#include "mozilla/Sprintf.h" + +namespace mozilla { + +SECItem* WrapPrivateKeyInfoWithEmptyPassword( + SECKEYPrivateKey* pk) /* encrypt this private key */ +{ + if (!pk) { + PR_SetError(SEC_ERROR_INVALID_ARGS, 0); + return nullptr; + } + + UniquePK11SlotInfo slot(PK11_GetInternalSlot()); + if (!slot) { + return nullptr; + } + + // For private keys, NSS cannot export anything other than RSA, but we need EC + // also. So, we use the private key encryption function to serialize instead, + // using a hard-coded dummy password; this is not intended to provide any + // additional security, it just works around a limitation in NSS. + SECItem dummyPassword = {siBuffer, nullptr, 0}; + UniqueSECKEYEncryptedPrivateKeyInfo epki(PK11_ExportEncryptedPrivKeyInfo( + slot.get(), SEC_OID_AES_128_CBC, &dummyPassword, pk, 1, nullptr)); + + if (!epki) { + return nullptr; + } + + return SEC_ASN1EncodeItem( + nullptr, nullptr, epki.get(), + NSS_Get_SECKEY_EncryptedPrivateKeyInfoTemplate(nullptr, false)); +} + +SECStatus UnwrapPrivateKeyInfoWithEmptyPassword( + SECItem* derPKI, const UniqueCERTCertificate& aCert, + SECKEYPrivateKey** privk) { + if (!derPKI || !aCert || !privk) { + PR_SetError(SEC_ERROR_INVALID_ARGS, 0); + return SECFailure; + } + + UniqueSECKEYPublicKey publicKey(CERT_ExtractPublicKey(aCert.get())); + // This is a pointer to data inside publicKey + SECItem* publicValue = nullptr; + switch (publicKey->keyType) { + case dsaKey: + publicValue = &publicKey->u.dsa.publicValue; + break; + case dhKey: + publicValue = &publicKey->u.dh.publicValue; + break; + case rsaKey: + publicValue = &publicKey->u.rsa.modulus; + break; + case ecKey: + publicValue = &publicKey->u.ec.publicValue; + break; + default: + MOZ_ASSERT(false); + PR_SetError(SSL_ERROR_BAD_CERTIFICATE, 0); + return SECFailure; + } + + UniquePK11SlotInfo slot(PK11_GetInternalSlot()); + if (!slot) { + return SECFailure; + } + + UniquePLArenaPool temparena(PORT_NewArena(DER_DEFAULT_CHUNKSIZE)); + if (!temparena) { + return SECFailure; + } + + SECKEYEncryptedPrivateKeyInfo* epki = + PORT_ArenaZNew(temparena.get(), SECKEYEncryptedPrivateKeyInfo); + if (!epki) { + return SECFailure; + } + + SECStatus rv = SEC_ASN1DecodeItem( + temparena.get(), epki, + NSS_Get_SECKEY_EncryptedPrivateKeyInfoTemplate(nullptr, false), derPKI); + if (rv != SECSuccess) { + // If SEC_ASN1DecodeItem fails, we cannot assume anything about the + // validity of the data in epki. The best we can do is free the arena + // and return. + return rv; + } + + // See comment in WrapPrivateKeyInfoWithEmptyPassword about this + // dummy password stuff. + SECItem dummyPassword = {siBuffer, nullptr, 0}; + return PK11_ImportEncryptedPrivateKeyInfoAndReturnKey( + slot.get(), epki, &dummyPassword, nullptr, publicValue, false, false, + publicKey->keyType, KU_ALL, privk, nullptr); +} + +nsresult DtlsIdentity::Serialize(nsTArray<uint8_t>* aKeyDer, + nsTArray<uint8_t>* aCertDer) { + ScopedSECItem derPki(WrapPrivateKeyInfoWithEmptyPassword(private_key_.get())); + if (!derPki) { + return NS_ERROR_FAILURE; + } + + aKeyDer->AppendElements(derPki->data, derPki->len); + aCertDer->AppendElements(cert_->derCert.data, cert_->derCert.len); + return NS_OK; +} + +/* static */ +RefPtr<DtlsIdentity> DtlsIdentity::Deserialize( + const nsTArray<uint8_t>& aKeyDer, const nsTArray<uint8_t>& aCertDer, + SSLKEAType authType) { + SECItem certDer = {siBuffer, const_cast<uint8_t*>(aCertDer.Elements()), + static_cast<unsigned int>(aCertDer.Length())}; + UniqueCERTCertificate cert(CERT_NewTempCertificate( + CERT_GetDefaultCertDB(), &certDer, nullptr, true, true)); + + SECItem derPKI = {siBuffer, const_cast<uint8_t*>(aKeyDer.Elements()), + static_cast<unsigned int>(aKeyDer.Length())}; + + SECKEYPrivateKey* privateKey; + if (UnwrapPrivateKeyInfoWithEmptyPassword(&derPKI, cert, &privateKey) != + SECSuccess) { + MOZ_ASSERT(false); + return nullptr; + } + + return new DtlsIdentity(UniqueSECKEYPrivateKey(privateKey), std::move(cert), + authType); +} + +RefPtr<DtlsIdentity> DtlsIdentity::Generate() { + UniquePK11SlotInfo slot(PK11_GetInternalSlot()); + if (!slot) { + return nullptr; + } + + uint8_t random_name[16]; + + SECStatus rv = + PK11_GenerateRandomOnSlot(slot.get(), random_name, sizeof(random_name)); + if (rv != SECSuccess) return nullptr; + + std::string name; + char chunk[3]; + for (unsigned char r_name : random_name) { + SprintfLiteral(chunk, "%.2x", r_name); + name += chunk; + } + + std::string subject_name_string = "CN=" + name; + UniqueCERTName subject_name(CERT_AsciiToName(subject_name_string.c_str())); + if (!subject_name) { + return nullptr; + } + + unsigned char paramBuf[12]; // OIDs are small + SECItem ecdsaParams = {siBuffer, paramBuf, sizeof(paramBuf)}; + SECOidData* oidData = SECOID_FindOIDByTag(SEC_OID_SECG_EC_SECP256R1); + if (!oidData || (oidData->oid.len > (sizeof(paramBuf) - 2))) { + return nullptr; + } + ecdsaParams.data[0] = SEC_ASN1_OBJECT_ID; + ecdsaParams.data[1] = oidData->oid.len; + memcpy(ecdsaParams.data + 2, oidData->oid.data, oidData->oid.len); + ecdsaParams.len = oidData->oid.len + 2; + + SECKEYPublicKey* pubkey; + UniqueSECKEYPrivateKey private_key( + PK11_GenerateKeyPair(slot.get(), CKM_EC_KEY_PAIR_GEN, &ecdsaParams, + &pubkey, PR_FALSE, PR_TRUE, nullptr)); + if (private_key == nullptr) return nullptr; + UniqueSECKEYPublicKey public_key(pubkey); + pubkey = nullptr; + + UniqueCERTSubjectPublicKeyInfo spki( + SECKEY_CreateSubjectPublicKeyInfo(public_key.get())); + if (!spki) { + return nullptr; + } + + UniqueCERTCertificateRequest certreq( + CERT_CreateCertificateRequest(subject_name.get(), spki.get(), 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); + + UniqueCERTValidity 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.get(), reinterpret_cast<unsigned char*>(&serial), sizeof(serial)); + if (rv != SECSuccess) { + return nullptr; + } + + // NB: CERTCertificates created with CERT_CreateCertificate are not safe to + // use with other NSS functions like CERT_DupCertificate. + // The strategy here is to create a tbsCertificate ("to-be-signed + // certificate"), encode it, and sign it, resulting in a signed DER + // certificate that can be decoded into a CERTCertificate. + UniqueCERTCertificate tbsCertificate(CERT_CreateCertificate( + serial, subject_name.get(), validity.get(), certreq.get())); + if (!tbsCertificate) { + return nullptr; + } + + PLArenaPool* arena = tbsCertificate->arena; + + rv = SECOID_SetAlgorithmID(arena, &tbsCertificate->signature, + SEC_OID_ANSIX962_ECDSA_SHA256_SIGNATURE, nullptr); + if (rv != SECSuccess) return nullptr; + + // Set version to X509v3. + *(tbsCertificate->version.data) = SEC_CERTIFICATE_VERSION_3; + tbsCertificate->version.len = 1; + + SECItem innerDER; + innerDER.len = 0; + innerDER.data = nullptr; + + if (!SEC_ASN1EncodeItem(arena, &innerDER, tbsCertificate.get(), + SEC_ASN1_GET(CERT_CertificateTemplate))) { + return nullptr; + } + + SECItem* certDer = PORT_ArenaZNew(arena, SECItem); + if (!certDer) { + return nullptr; + } + + rv = SEC_DerSignData(arena, certDer, innerDER.data, innerDER.len, + private_key.get(), + SEC_OID_ANSIX962_ECDSA_SHA256_SIGNATURE); + if (rv != SECSuccess) { + return nullptr; + } + + UniqueCERTCertificate certificate(CERT_NewTempCertificate( + CERT_GetDefaultCertDB(), certDer, nullptr, false, true)); + + return new DtlsIdentity(std::move(private_key), std::move(certificate), + ssl_kea_ecdh); +} + +const std::string DtlsIdentity::DEFAULT_HASH_ALGORITHM = "sha-256"; + +nsresult DtlsIdentity::ComputeFingerprint(DtlsDigest* digest) const { + const UniqueCERTCertificate& c = cert(); + MOZ_ASSERT(c); + + return ComputeFingerprint(c, digest); +} + +nsresult DtlsIdentity::ComputeFingerprint(const UniqueCERTCertificate& cert, + DtlsDigest* digest) { + MOZ_ASSERT(cert); + + HASH_HashType ht; + + if (digest->algorithm_ == "sha-1") { + ht = HASH_AlgSHA1; + } else if (digest->algorithm_ == "sha-224") { + ht = HASH_AlgSHA224; + } else if (digest->algorithm_ == "sha-256") { + ht = HASH_AlgSHA256; + } else if (digest->algorithm_ == "sha-384") { + ht = HASH_AlgSHA384; + } else if (digest->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 + digest->value_.resize(ho->length); + + SECStatus rv = HASH_HashBuf(ho->type, digest->value_.data(), + cert->derCert.data, cert->derCert.len); + if (rv != SECSuccess) { + return NS_ERROR_FAILURE; + } + + return NS_OK; +} + +} // namespace mozilla |