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chromium / chromiumos / platform / cryptohome / 20aa4e2fc0e991b6d4d552c49af6a8270e05ab55 / . / attestation.cc
blob: 45ab14023a6e46705b171599d5abda05e66e2e71 [file] [log] [blame]
// Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "attestation.h"
#include <algorithm>
#include <string>
#include <arpa/inet.h>
#include <base/stl_util.h>
#include <base/strings/string_number_conversions.h>
#include <base/strings/stringprintf.h>
#include <base/time/time.h>
#include <chromeos/secure_blob.h>
#include <google/protobuf/repeated_field.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/rsa.h>
#include <openssl/sha.h>
#include <openssl/x509.h>
#include "attestation.pb.h"
#include "cryptolib.h"
#include "keystore.h"
#include "pkcs11_keystore.h"
#include "platform.h"
#include "tpm.h"
#include "tpm_init.h"
using chromeos::SecureBlob;
using std::string;
namespace {
// Resets a boolean when it falls out of scope.
class ScopedBool {
public:
ScopedBool(bool* target, bool reset_value) : target_(target),
reset_value_(reset_value) {}
~ScopedBool() { *target_ = reset_value_; }
private:
bool* target_;
bool reset_value_;
};
}
namespace cryptohome {
const size_t Attestation::kQuoteExternalDataSize = 20;
const size_t Attestation::kCipherKeySize = 32;
const size_t Attestation::kNonceSize = 20; // As per TPM_NONCE definition.
const size_t Attestation::kDigestSize = 20; // As per TPM_DIGEST definition.
const char Attestation::kDefaultDatabasePath[] =
"/mnt/stateful_partition/unencrypted/preserve/attestation.epb";
#ifndef USE_TEST_PCA
// This has been extracted from the Chrome OS PCA's encryption certificate.
const char Attestation::kDefaultPCAPublicKey[] =
"A2976637E113CC457013F4334312A416395B08D4B2A9724FC9BAD65D0290F39C"
"866D1163C2CD6474A24A55403C968CF78FA153C338179407FE568C6E550949B1"
"B3A80731BA9311EC16F8F66060A2C550914D252DB90B44D19BC6C15E923FFCFB"
"E8A366038772803EE57C7D7E5B3D5E8090BF0960D4F6A6644CB9A456708508F0"
"6C19245486C3A49F807AB07C65D5E9954F4F8832BC9F882E9EE1AAA2621B1F43"
"4083FD98758745CBFFD6F55DA699B2EE983307C14C9990DDFB48897F26DF8FB2"
"CFFF03E631E62FAE59CBF89525EDACD1F7BBE0BA478B5418E756FF3E14AC9970"
"D334DB04A1DF267D2343C75E5D282A287060D345981ABDA0B2506AD882579FEF";
// This value is opaque; it is proprietary to the system managing the private
// key. In this case the value has been supplied by the PCA maintainers.
const char Attestation::kDefaultPCAPublicKeyID[] = "\x00\xc7\x0e\x50\xb1";
#else
// The test instance uses different keys.
const char Attestation::kDefaultPCAPublicKey[] =
"A1D50D088994000492B5F3ED8A9C5FC8772706219F4C063B2F6A8C6B74D3AD6B"
"212A53D01DABB34A6261288540D420D3BA59ED279D859DE6227A7AB6BD88FADD"
"FC3078D465F4DF97E03A52A587BD0165AE3B180FE7B255B7BEDC1BE81CB1383F"
"E9E46F9312B1EF28F4025E7D332E33F4416525FEB8F0FC7B815E8FBB79CDABE6"
"327B5A155FEF13F559A7086CB8A543D72AD6ECAEE2E704FF28824149D7F4E393"
"D3C74E721ACA97F7ADBE2CCF7B4BCC165F7380F48065F2C8370F25F066091259"
"D14EA362BAF236E3CD8771A94BDEDA3900577143A238AB92B6C55F11DEFAFB31"
"7D1DC5B6AE210C52B008D87F2A7BFF6EB5C4FB32D6ECEC6505796173951A3167";
const char Attestation::kDefaultPCAPublicKeyID[] = "\x00\xc2\xb0\x56\x2d";
#endif
const char Attestation::kEnterpriseSigningPublicKey[] =
"bf7fefa3a661437b26aed0801db64d7ba8b58875c351d3bdc9f653847d4a67b3"
"b67479327724d56aa0f71a3f57c2290fdc1ff05df80589715e381dfbbda2c4ac"
"114c30d0a73c5b7b2e22178d26d8b65860aa8dd65e1b3d61a07c81de87c1e7e4"
"590145624936a011ece10434c1d5d41f917c3dc4b41dd8392479130c4fd6eafc"
"3bb4e0dedcc8f6a9c28428bf8fbba8bd6438a325a9d3eabee1e89e838138ad99"
"69c292c6d9f6f52522333b84ddf9471ffe00f01bf2de5faa1621f967f49e158b"
"f2b305360f886826cc6fdbef11a12b2d6002d70d8d1e8f40e0901ff94c203cb2"
"01a36a0bd6e83955f14b494f4f2f17c0c826657b85c25ffb8a73599721fa17ab";
const char Attestation::kEnterpriseEncryptionPublicKey[] =
"edba5e723da811e41636f792c7a77aef633fbf39b542aa537c93c93eaba7a3b1"
"0bc3e484388c13d625ef5573358ec9e7fbeb6baaaa87ca87d93fb61bf5760e29"
"6813c435763ed2c81f631e26e3ff1a670261cdc3c39a4640b6bbf4ead3d6587b"
"e43ef7f1f08e7596b628ec0b44c9b7ad71c9ee3a1258852c7a986c7614f0c4ec"
"f0ce147650a53b6aa9ae107374a2d6d4e7922065f2f6eb537a994372e1936c87"
"eb08318611d44daf6044f8527687dc7ce5319b51eae6ab12bee6bd16e59c499e"
"fa53d80232ae886c7ee9ad8bc1cbd6e4ac55cb8fa515671f7e7ad66e98769f52"
"c3c309f98bf08a3b8fbb0166e97906151b46402217e65c5d01ddac8514340e8b";
// This value is opaque; it is proprietary to the system managing the private
// key. In this case the value has been supplied by the enterprise server
// maintainers.
const char Attestation::kEnterpriseEncryptionPublicKeyID[] =
"\x00\x4a\xe2\xdc\xae";
const Attestation::CertificateAuthority Attestation::kKnownEndorsementCA[] = {
{"IFX TPM EK Intermediate CA 06",
"de9e58a353313d21d683c687d6aaaab240248717557c077161c5e515f41d8efa"
"48329f45658fb550f43f91d1ba0c2519429fb6ef964f89657098c90a9783ad6d"
"3baea625db044734c478768db53b6022c556d8174ed744bd6e4455665715cd5c"
"beb7c3fcb822ab3dfab1ecee1a628c3d53f6085983431598fb646f04347d5ae0"
"021d5757cc6e3027c1e13f10633ae48bbf98732c079c17684b0db58bd0291add"
"e277b037dd13fa3db910e81a4969622a79c85ac768d870f079b54c2b98c856e7"
"15ef0ba9c01ee1da1241838a1307fe94b1ddfa65cdf7eeaa7e5b4b8a94c3dcd0"
"29bb5ebcfc935e56641f4c8cb5e726c68f9dd6b41f8602ef6dc78d870a773571"},
{"IFX TPM EK Intermediate CA 07",
"f04c9b5b9f3cbc2509179f5e0f31dceb302900f528458e002c3e914d6b29e5e0"
"924b0bcab2dd053f65d9d4a8eea8269c85c419dba640a88e14dc5f8c8c1a4269"
"7a5ac4594b36f923110f91d1803d385540c01a433140b06054c77a144ee3a6a6"
"5950c20f9215be3473b1002eb6b1756a22fbc18d21efacbbc8c270c66cf74982"
"e24f057825cab51c0dd840a4f2d059032239c33e3f52c6ca06fe49bf4f60cc28"
"a0fb1173d2ee05a141d30e8ffa32dbb86c1aeb5b309f76c2e462965612ec929a"
"0d3b04acfa4525912c76f765e948be71f505d619cc673a889f0ed9e1d75f237b"
"7af6a68550253cb4c3a8ff16c8091dbcbdea0ff8eee3d5bd92f49c53c5a15c93"},
{"IFX TPM EK Intermediate CA 14",
"D5B2EB8F8F23DD0B5CA0C15D4376E27A0380FD8EB1E52C2C270D961E8C0F66FD"
"62E6ED6B3660FFBD8B0735179476F5E9C2EA4C762F5FEEDD3B5EB91785A724BC"
"4C0617B83966336DD9DC407640871BF99DF4E1701EB5A1F5647FC57879CBB973"
"B2A72BABA8536B2646A37AA5B73E32A4C8F03E35C8834B391AD363F1F7D1DF2B"
"EE39233F47384F3E2D2E8EF83C9539B4DFC360C8AEB88B6111E757AF646DC01A"
"68DAA908C7F8068894E9E991C59005068DD9B0F87113E6A80AB045DB4C1B23FF"
"38A106098C2E184E1CF42A43EA68753F2649999048E8A3C3406032BEB1457070"
"BCBE3A93E122638F6F18FF505C35FB827CE5D0C12F27F45C0F59C8A4A8697849"},
{"IFX TPM EK Intermediate CA 16",
"B98D42D5284620036A6613ED05A1BE11431AE7DE435EC55F72814652B9265EC2"
"9035D401B538A9C84BB5B875450FAE8FBEDEF3430C4108D8516404F3DE4D4615"
"2F471013673A7C7F236304C7363B91C0E0FD9FC7A9EC751521A60A6042839CF7"
"7AEDE3243D0F51F47ACC39676D236BD5298E18B9A4783C60B2A1CD1B32124909"
"D5844649EE4539D6AA05A5902C147B4F062D5145708EAE224EC65A8B51D7A418"
"6327DA8F3B9E7C796F8B2DB3D2BDB39B829BDEBA8D2BF882CBADDB75D76FA8FA"
"313682688BCD2835533A3A68A4AFDF7E597D8B965402FF22A5A4A418FDB4B549"
"F218C3908E66BDCEAB3E2FE5EE0A4A1D9EB41A286ED07B6C112581FDAEA088D9"},
{"IFX TPM EK Intermediate CA 17",
"B0F3CC6F02E8C0486501102731069644A815F631ED41676C05CE3F7E5E5E40DF"
"B3BF6D99787F2A9BE8F8B8035C03D5C2226072985230D4CE8407ACD6403F72E1"
"A4DBF069504E56FA8C0807A704526EAC1E379AE559EB4BBAD9DB4E652B3B14E5"
"38497A5E7768BCE0BFFAF800C61F1F2262775C526E1790A2BECF9A072A58F6A0"
"F3042B5279FE9957BCADC3C9725428B66B15D5263F00C528AC47716DE6938199"
"0FF23BC28F2C33B72D89B5F8EEEF9053B60D230431081D656EA8EC16C7CEFD9E"
"F5A9061A3C921394D453D9AC77397D59B4C3BAF258266F65559469C3007987D5"
"A8338E10FC54CD930303C37007D6E1E6C63F36BCFBA1E494AFB3ECD9A2407FF9"},
{"IFX TPM EK Intermediate CA 21",
"8149397109974D6C0850C8A60304ED7D209B1B88F435B695394DAD9FB4E64180"
"02A3940966D2F04103C88659600EEA8E2A5C697C5F989F62D33A06DA10B50075"
"F37F3CE6AD070413A0E109E16FE652B393C4DAFC5579CCB9915E9A70F5C05BCE"
"0D341D6B887F43C4334BD8EC6A293FFAB737F77A45069CD0345D3D534E84D029"
"029C37A267C0CC2D8DCE3E2C76F21A40F5D8D463882A8CBB92D8235685266753"
"E8F051E78B681E87810A5B21EF719662A8208DFD94C55A126A112E39E0D732D7"
"3C599095FAFF52BBC0E8C5B3DCD904D05DE00D5C5112F3DF7B76602ABE5DC0F8"
"F89B55889A24C54EDBA1234AE498BE9B02CB5C8048D1DC90210705BAFC0E2837"},
{"NTC TPM EK Root CA 01",
"e836ac61b43e3252d5e1a8a4061997a6a0a272ba3d519d6be6360cc8b4b79e8c"
"d53c07a7ce9e9310ca84b82bbdad32184544ada357d458cf224c4a3130c97d00"
"4933b5db232d8b6509412eb4777e9e1b093c58b82b1679c84e57a6b218b4d61f"
"6dd4c3a66b2dd33b52cb1ffdff543289fa36dd71b7c83b66c1aae37caf7fe88d"
"851a3523e3ea92b59a6b0ca095c5e1d191484c1bff8a33048c3976e826d4c12a"
"e198f7199d183e0e70c8b46e8106edec3914397e051ae2b9a7f0b4bb9cd7f2ed"
"f71064eb0eb473df27b7ccef9a018d715c5fe6ab012a8315f933c7f4fc35d34c"
"efc27de224b2e3de3b3ba316d5df8b90b2eb879e219d270141b78dbb671a3a05"},
{"STM TPM EK Intermediate CA 03",
"a5152b4fbd2c70c0c9a0dd919f48ddcde2b5c0c9988cff3b04ecd844f6cc0035"
"6c4e01b52463deb5179f36acf0c06d4574327c37572292fcd0f272c2d45ea7f2"
"2e8d8d18aa62354c279e03be9220f0c3822d16de1ea1c130b59afc56e08f22f1"
"902a07f881ebea3703badaa594ecbdf8fd1709211ba16769f73e76f348e2755d"
"bba2f94c1869ef71e726f56f8ece987f345c622e8b5c2a5466d41093c0dc2982"
"e6203d96f539b542347a08e87fc6e248a346d61a505f52add7f768a5203d70b8"
"68b6ec92ef7a83a4e6d1e1d259018705755d812175489fae83c4ab2957f69a99"
"9394ac7a243a5c1cd85f92b8648a8e0d23165fdd86fad06990bfd16fb3293379"}
};
const Attestation::PCRValue Attestation::kKnownPCRValues[] = {
{ false, false, kVerified },
{ false, false, kDeveloper },
{ false, true, kVerified },
{ false, true, kDeveloper },
{ true, false, kVerified },
{ true, false, kDeveloper },
{ true, true, kVerified },
{ true, true, kDeveloper }
};
const unsigned char Attestation::kSha256DigestInfo[] = {
0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03,
0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20
};
const int Attestation::kNumTemporalValues = 5;
const char Attestation::kAlternatePCAKeyAttributeName[] =
"enterprise.alternate_pca_key";
const char Attestation::kAlternatePCAKeyIDAttributeName[] =
"enterprise.alternate_pca_key_id";
Attestation::Attestation()
: database_path_(kDefaultDatabasePath),
pkcs11_key_store_(new Pkcs11KeyStore()),
user_key_store_(pkcs11_key_store_.get()),
enterprise_test_key_(NULL),
install_attributes_observer_(this),
is_tpm_ready_(false),
is_prepare_in_progress_(false) {
metrics_.Init();
}
Attestation::~Attestation() {
if (!thread_.is_null())
base::PlatformThread::Join(thread_);
ClearDatabase();
}
void Attestation::Initialize(Tpm* tpm,
TpmInit* tpm_init,
Platform* platform,
Crypto* crypto,
InstallAttributes* install_attributes) {
base::AutoLock lock(lock_);
// Inject dependencies.
tpm_ = tpm;
tpm_init_ = tpm_init;
platform_ = platform;
crypto_ = crypto;
if (install_attributes_ != install_attributes) {
install_attributes_ = install_attributes;
install_attributes_observer_.Add(install_attributes_);
}
if (tpm_) {
string serial_encrypted_db;
if (!LoadDatabase(&serial_encrypted_db)) {
LOG(INFO) << "Attestation: Attestation data not found.";
return;
}
if (!DecryptDatabase(serial_encrypted_db, &database_pb_)) {
LOG(WARNING) << "Attestation: Attestation data invalid. "
"This is normal if the TPM has been cleared.";
return;
}
FinalizeEndorsementData();
LOG(INFO) << "Attestation: Valid attestation data exists.";
// Make sure the owner password is not being held on our account.
tpm_init_->RemoveTpmOwnerDependency(TpmInit::kAttestation);
}
}
bool Attestation::IsPreparedForEnrollment() {
base::AutoLock lock(lock_);
return database_pb_.has_credentials();
}
bool Attestation::IsEnrolled() {
bool enable_alternate_pca =
install_attributes_->Get(kAlternatePCAKeyAttributeName, NULL);
base::AutoLock lock(lock_);
bool default_enrolled = database_pb_.has_identity_key() &&
database_pb_.identity_key().has_identity_credential();
bool alternate_enrolled =
database_pb_.has_alternate_identity_key() &&
database_pb_.alternate_identity_key().has_identity_credential();
return default_enrolled && (alternate_enrolled || !enable_alternate_pca);
}
void Attestation::PrepareForEnrollment() {
// There are a few ways to trigger PrepareForEnrollment, make sure it only
// does the work once.
{
base::AutoLock lock(lock_);
if (is_prepare_in_progress_)
return;
is_prepare_in_progress_ = true;
}
// In the event of an error it is important to reset |is_prepare_in_progress_|
// so subsequent attempts are possible.
ScopedBool reset(&is_prepare_in_progress_, false);
// If there is no TPM, we have no work to do.
if (!IsTPMReady())
return;
if (IsPreparedForEnrollment())
return;
if (install_attributes_->is_first_install()) {
LOG(INFO) << "Attestation: Waiting for install attributes to be finalized.";
return;
}
bool enable_alternate_pca =
install_attributes_->Get(kAlternatePCAKeyAttributeName, NULL);
base::TimeTicks start = base::TimeTicks::Now();
LOG(INFO) << "Attestation: Preparing for enrollment...";
SecureBlob ek_public_key;
if (!tpm_->GetEndorsementPublicKey(&ek_public_key)) {
LOG(ERROR) << "Attestation: Failed to get EK public key.";
return;
}
// Create an AIK.
SecureBlob identity_public_key_der;
SecureBlob identity_public_key;
SecureBlob identity_key_blob;
SecureBlob identity_binding;
SecureBlob identity_label;
SecureBlob pca_public_key;
SecureBlob endorsement_credential;
SecureBlob platform_credential;
SecureBlob conformance_credential;
if (!tpm_->MakeIdentity(&identity_public_key_der,
&identity_public_key,
&identity_key_blob,
&identity_binding,
&identity_label,
&pca_public_key,
&endorsement_credential,
&platform_credential,
&conformance_credential)) {
LOG(ERROR) << "Attestation: Failed to make AIK.";
return;
}
// Quote PCR0.
SecureBlob external_data;
if (!tpm_->GetRandomData(kQuoteExternalDataSize, &external_data)) {
LOG(ERROR) << "Attestation: GetRandomData failed.";
return;
}
SecureBlob quoted_pcr_value;
SecureBlob quoted_data;
SecureBlob quote;
if (!tpm_->QuotePCR0(identity_key_blob,
external_data,
&quoted_pcr_value,
&quoted_data,
&quote)) {
LOG(ERROR) << "Attestation: Failed to generate quote.";
return;
}
// Create an AIK and quote for the alternate PCA.
SecureBlob alternate_identity_public_key_der;
SecureBlob alternate_identity_public_key;
SecureBlob alternate_identity_key_blob;
SecureBlob alternate_identity_binding;
SecureBlob alternate_identity_label;
SecureBlob alternate_pca_public_key;
SecureBlob alternate_quoted_pcr_value;
SecureBlob alternate_quoted_data;
SecureBlob alternate_quote;
if (enable_alternate_pca) {
if (!tpm_->MakeIdentity(&alternate_identity_public_key_der,
&alternate_identity_public_key,
&alternate_identity_key_blob,
&alternate_identity_binding,
&alternate_identity_label,
&alternate_pca_public_key,
&endorsement_credential,
&platform_credential,
&conformance_credential)) {
LOG(ERROR) << "Attestation: Failed to make AIK.";
return;
}
if (!tpm_->QuotePCR0(alternate_identity_key_blob,
external_data,
&alternate_quoted_pcr_value,
&alternate_quoted_data,
&alternate_quote)) {
LOG(ERROR) << "Attestation: Failed to generate quote.";
return;
}
}
// Create a delegate so we can activate the AIK later.
SecureBlob delegate_blob;
SecureBlob delegate_secret;
if (!tpm_->CreateDelegate(identity_key_blob, &delegate_blob,
&delegate_secret)) {
LOG(ERROR) << "Attestation: Failed to create delegate.";
return;
}
// Assemble a protobuf to store locally.
base::AutoLock lock(lock_);
TPMCredentials* credentials_pb = database_pb_.mutable_credentials();
credentials_pb->set_endorsement_public_key(ek_public_key.data(),
ek_public_key.size());
credentials_pb->set_endorsement_credential(endorsement_credential.data(),
endorsement_credential.size());
credentials_pb->set_platform_credential(platform_credential.data(),
platform_credential.size());
credentials_pb->set_conformance_credential(conformance_credential.data(),
conformance_credential.size());
if (!EncryptEndorsementCredential(
kDefaultPCA,
endorsement_credential,
credentials_pb->mutable_default_encrypted_endorsement_credential())) {
LOG(ERROR) << "Attestation: Failed to encrypt EK cert.";
return;
}
if (enable_alternate_pca) {
if (!EncryptEndorsementCredential(
kAlternatePCA,
endorsement_credential,
credentials_pb->mutable_alternate_encrypted_endorsement_credential())) {
LOG(ERROR) << "Attestation: Failed to encrypt EK cert.";
return;
}
}
IdentityKey* key_pb = database_pb_.mutable_identity_key();
key_pb->set_identity_public_key(identity_public_key_der.data(),
identity_public_key_der.size());
key_pb->set_identity_key_blob(identity_key_blob.data(),
identity_key_blob.size());
IdentityBinding* binding_pb = database_pb_.mutable_identity_binding();
binding_pb->set_identity_binding(identity_binding.data(),
identity_binding.size());
binding_pb->set_identity_public_key_der(identity_public_key_der.data(),
identity_public_key_der.size());
binding_pb->set_identity_public_key(identity_public_key.data(),
identity_public_key.size());
binding_pb->set_identity_label(identity_label.data(), identity_label.size());
binding_pb->set_pca_public_key(pca_public_key.data(), pca_public_key.size());
Quote* quote_pb = database_pb_.mutable_pcr0_quote();
quote_pb->set_quote(quote.data(), quote.size());
quote_pb->set_quoted_data(quoted_data.data(), quoted_data.size());
quote_pb->set_quoted_pcr_value(quoted_pcr_value.data(),
quoted_pcr_value.size());
if (enable_alternate_pca) {
IdentityKey* alternate_key_pb =
database_pb_.mutable_alternate_identity_key();
alternate_key_pb->set_identity_public_key(
alternate_identity_public_key_der.data(),
alternate_identity_public_key_der.size());
alternate_key_pb->set_identity_key_blob(alternate_identity_key_blob.data(),
alternate_identity_key_blob.size());
IdentityBinding* alternate_binding_pb =
database_pb_.mutable_alternate_identity_binding();
alternate_binding_pb->set_identity_binding(
alternate_identity_binding.data(),
alternate_identity_binding.size());
alternate_binding_pb->set_identity_public_key_der(
alternate_identity_public_key_der.data(),
alternate_identity_public_key_der.size());
alternate_binding_pb->set_identity_public_key(
alternate_identity_public_key.data(),
alternate_identity_public_key.size());
alternate_binding_pb->set_identity_label(alternate_identity_label.data(),
alternate_identity_label.size());
alternate_binding_pb->set_pca_public_key(alternate_pca_public_key.data(),
alternate_pca_public_key.size());
Quote* alternate_quote_pb = database_pb_.mutable_alternate_pcr0_quote();
alternate_quote_pb->set_quote(alternate_quote.data(),
alternate_quote.size());
alternate_quote_pb->set_quoted_data(alternate_quoted_data.data(),
alternate_quoted_data.size());
alternate_quote_pb->set_quoted_pcr_value(alternate_quoted_pcr_value.data(),
alternate_quoted_pcr_value.size());
}
Delegation* delegate_pb = database_pb_.mutable_delegate();
delegate_pb->set_blob(delegate_blob.data(), delegate_blob.size());
delegate_pb->set_secret(delegate_secret.data(), delegate_secret.size());
string serial_encrypted_db;
if (!EncryptDatabase(database_pb_, &serial_encrypted_db)) {
LOG(ERROR) << "Attestation: Failed to encrypt db.";
return;
}
if (!StoreDatabase(serial_encrypted_db)) {
LOG(ERROR) << "Attestation: Failed to store db.";
return;
}
tpm_init_->RemoveTpmOwnerDependency(TpmInit::kAttestation);
base::TimeDelta delta = (base::TimeTicks::Now() - start);
LOG(INFO) << "Attestation: Prepared successfully (" << delta.InMilliseconds()
<< "ms).";
}
void Attestation::PrepareForEnrollmentAsync() {
base::AutoLock lock(lock_);
if (!thread_.is_null()) {
LOG(WARNING) << "PrepareForEnrollmentAsync called multiple times.";
return;
}
base::PlatformThread::Create(0, this, &thread_);
}
bool Attestation::Verify() {
if (!IsTPMReady())
return false;
LOG(INFO) << "Attestation: Verifying data.";
base::AutoLock lock(lock_);
const TPMCredentials& credentials = database_pb_.credentials();
if (!credentials.has_endorsement_credential() ||
!credentials.has_endorsement_public_key()) {
LOG(INFO) << "Attestation: Endorsement data is not available.";
return false;
}
SecureBlob ek_public_key = ConvertStringToBlob(
credentials.endorsement_public_key());
if (!VerifyEndorsementCredential(
ConvertStringToBlob(credentials.endorsement_credential()),
ek_public_key)) {
LOG(ERROR) << "Attestation: Bad endorsement credential.";
return false;
}
if (!VerifyIdentityBinding(database_pb_.identity_binding())) {
LOG(ERROR) << "Attestation: Bad identity binding.";
return false;
}
SecureBlob aik_public_key = ConvertStringToBlob(
database_pb_.identity_binding().identity_public_key_der());
if (!VerifyQuote(aik_public_key, database_pb_.pcr0_quote())) {
LOG(ERROR) << "Attestation: Bad PCR0 quote.";
return false;
}
SecureBlob nonce;
if (!tpm_->GetRandomData(kNonceSize, &nonce)) {
LOG(ERROR) << "Attestation: GetRandomData failed.";
return false;
}
SecureBlob identity_key_blob = ConvertStringToBlob(
database_pb_.identity_key().identity_key_blob());
SecureBlob public_key;
SecureBlob public_key_der;
SecureBlob key_blob;
SecureBlob key_info;
SecureBlob proof;
if (!tpm_->CreateCertifiedKey(identity_key_blob, nonce,
&public_key, &public_key_der,
&key_blob, &key_info, &proof)) {
LOG(ERROR) << "Attestation: Failed to create certified key.";
return false;
}
if (!VerifyCertifiedKey(aik_public_key, public_key_der, key_info, proof)) {
LOG(ERROR) << "Attestation: Bad certified key.";
return false;
}
SecureBlob delegate_blob =
ConvertStringToBlob(database_pb_.delegate().blob());
SecureBlob delegate_secret =
ConvertStringToBlob(database_pb_.delegate().secret());
SecureBlob aik_public_key_tpm = ConvertStringToBlob(
database_pb_.identity_binding().identity_public_key());
if (!VerifyActivateIdentity(delegate_blob, delegate_secret,
identity_key_blob, aik_public_key_tpm,
ek_public_key)) {
LOG(ERROR) << "Attestation: Failed to verify owner delegation.";
return false;
}
LOG(INFO) << "Attestation: Verified OK.";
return true;
}
bool Attestation::VerifyEK() {
if (!IsTPMReady())
return false;
base::AutoLock lock(lock_);
SecureBlob ek_cert;
SecureBlob ek_public_key;
if (database_pb_.has_credentials()) {
const TPMCredentials& credentials = database_pb_.credentials();
if (credentials.has_endorsement_credential()) {
ek_public_key = ConvertStringToBlob(credentials.endorsement_public_key());
ek_cert = ConvertStringToBlob(credentials.endorsement_credential());
}
}
if (ek_cert.size() == 0 && !tpm_->GetEndorsementCredential(&ek_cert)) {
LOG(ERROR) << __func__ << ": Failed to get EK certificate.";
return false;
}
if (ek_public_key.size() == 0 &&
!tpm_->GetEndorsementPublicKey(&ek_public_key)) {
LOG(ERROR) << __func__ << ": Failed to get EK public key.";
return false;
}
return VerifyEndorsementCredential(ek_cert, ek_public_key);
}
bool Attestation::CreateEnrollRequest(PCAType pca_type,
SecureBlob* pca_request) {
if (!IsTPMReady())
return false;
if (!IsPreparedForEnrollment()) {
LOG(ERROR) << __func__ << ": Enrollment is not possible, attestation data "
<< "does not exist.";
return false;
}
base::AutoLock lock(lock_);
AttestationEnrollmentRequest request_pb;
bool use_alternate_pca = (pca_type == kAlternatePCA);
*request_pb.mutable_encrypted_endorsement_credential() = use_alternate_pca ?
database_pb_.credentials().alternate_encrypted_endorsement_credential() :
database_pb_.credentials().default_encrypted_endorsement_credential();
request_pb.set_identity_public_key(use_alternate_pca ?
database_pb_.alternate_identity_binding().identity_public_key() :
database_pb_.identity_binding().identity_public_key());
*request_pb.mutable_pcr0_quote() = use_alternate_pca ?
database_pb_.alternate_pcr0_quote() :
database_pb_.pcr0_quote();
string tmp;
if (!request_pb.SerializeToString(&tmp)) {
LOG(ERROR) << __func__ << ": Failed to serialize protobuf.";
return false;
}
*pca_request = ConvertStringToBlob(tmp);
return true;
}
bool Attestation::Enroll(PCAType pca_type,
const SecureBlob& pca_response) {
if (!IsTPMReady())
return false;
AttestationEnrollmentResponse response_pb;
if (!response_pb.ParseFromArray(pca_response.const_data(),
pca_response.size())) {
LOG(ERROR) << __func__ << ": Failed to parse response from Privacy CA.";
return false;
}
if (response_pb.status() != OK) {
LOG(ERROR) << __func__ << ": Error received from Privacy CA: "
<< response_pb.detail();
return false;
}
base::AutoLock lock(lock_);
SecureBlob delegate_blob = ConvertStringToBlob(
database_pb_.delegate().blob());
SecureBlob delegate_secret = ConvertStringToBlob(
database_pb_.delegate().secret());
bool use_alternate_pca = (pca_type == kAlternatePCA);
SecureBlob aik_blob = ConvertStringToBlob(use_alternate_pca ?
database_pb_.alternate_identity_key().identity_key_blob() :
database_pb_.identity_key().identity_key_blob());
SecureBlob encrypted_asym = ConvertStringToBlob(
response_pb.encrypted_identity_credential().asym_ca_contents());
SecureBlob encrypted_sym = ConvertStringToBlob(
response_pb.encrypted_identity_credential().sym_ca_attestation());
SecureBlob aik_credential;
if (!tpm_->ActivateIdentity(delegate_blob, delegate_secret,
aik_blob, encrypted_asym, encrypted_sym,
&aik_credential)) {
LOG(ERROR) << __func__ << ": Failed to activate identity.";
return false;
}
IdentityKey* key_pb = use_alternate_pca ?
database_pb_.mutable_alternate_identity_key() :
database_pb_.mutable_identity_key();
key_pb->set_identity_credential(ConvertBlobToString(aik_credential));
if (!PersistDatabaseChanges()) {
LOG(ERROR) << __func__ << ": Failed to persist database changes.";
return false;
}
LOG(INFO) << "Attestation: Enrollment complete.";
return true;
}
bool Attestation::CreateCertRequest(PCAType pca_type,
CertificateProfile profile,
const string& username,
const string& origin,
SecureBlob* pca_request) {
if (!IsTPMReady())
return false;
if (!IsEnrolled()) {
LOG(ERROR) << __func__ << ": Device is not enrolled for attestation.";
return false;
}
bool use_alternate_pca = (pca_type == kAlternatePCA);
base::AutoLock lock(lock_);
AttestationCertificateRequest request_pb;
string message_id(kNonceSize, 0);
CryptoLib::GetSecureRandom(
reinterpret_cast<unsigned char*>(string_as_array(&message_id)),
kNonceSize);
request_pb.set_message_id(message_id);
request_pb.set_identity_credential(use_alternate_pca ?
database_pb_.alternate_identity_key().identity_credential() :
database_pb_.identity_key().identity_credential());
request_pb.set_profile(profile);
if (!origin.empty() &&
(profile == CONTENT_PROTECTION_CERTIFICATE_WITH_STABLE_ID)) {
request_pb.set_origin(origin);
request_pb.set_temporal_index(ChooseTemporalIndex(username, origin));
}
SecureBlob nonce;
if (!tpm_->GetRandomData(kNonceSize, &nonce)) {
LOG(ERROR) << __func__ << ": GetRandomData failed.";
return false;
}
SecureBlob identity_key_blob = ConvertStringToBlob(use_alternate_pca ?
database_pb_.alternate_identity_key().identity_key_blob() :
database_pb_.identity_key().identity_key_blob());
SecureBlob public_key;
SecureBlob public_key_der;
SecureBlob key_blob;
SecureBlob key_info;
SecureBlob proof;
if (!tpm_->CreateCertifiedKey(identity_key_blob, nonce,
&public_key, &public_key_der,
&key_blob, &key_info, &proof)) {
LOG(ERROR) << __func__ << ": Failed to create certified key.";
return false;
}
request_pb.set_certified_public_key(ConvertBlobToString(public_key));
request_pb.set_certified_key_info(ConvertBlobToString(key_info));
request_pb.set_certified_key_proof(ConvertBlobToString(proof));
string tmp;
if (!request_pb.SerializeToString(&tmp)) {
LOG(ERROR) << __func__ << ": Failed to serialize protobuf.";
return false;
}
*pca_request = ConvertStringToBlob(tmp);
ClearString(&tmp);
// Save certified key blob so we can finish the operation later.
CertifiedKey certified_key_pb;
certified_key_pb.set_key_blob(ConvertBlobToString(key_blob));
certified_key_pb.set_public_key(ConvertBlobToString(public_key_der));
if (!certified_key_pb.SerializeToString(&tmp)) {
LOG(ERROR) << __func__ << ": Failed to serialize protobuf.";
return false;
}
pending_cert_requests_[message_id] = ConvertStringToBlob(tmp);
ClearString(&tmp);
return true;
}
bool Attestation::FinishCertRequest(const SecureBlob& pca_response,
bool is_user_specific,
const string& username,
const string& key_name,
SecureBlob* certificate_chain) {
if (!IsTPMReady())
return false;
AttestationCertificateResponse response_pb;
if (!response_pb.ParseFromArray(pca_response.const_data(),
pca_response.size())) {
LOG(ERROR) << __func__ << ": Failed to parse response from Privacy CA.";
return false;
}
base::AutoLock lock(lock_);
CertRequestMap::iterator iter = pending_cert_requests_.find(
response_pb.message_id());
if (iter == pending_cert_requests_.end()) {
LOG(ERROR) << __func__ << ": Pending request not found.";
return false;
}
if (response_pb.status() != OK) {
LOG(ERROR) << __func__ << ": Error received from Privacy CA: "
<< response_pb.detail();
pending_cert_requests_.erase(iter);
return false;
}
CertifiedKey certified_key_pb;
if (!certified_key_pb.ParseFromArray(iter->second.const_data(),
iter->second.size())) {
LOG(ERROR) << __func__ << ": Failed to parse pending request.";
pending_cert_requests_.erase(iter);
return false;
}
pending_cert_requests_.erase(iter);
// The PCA issued a certificate and the response matched a pending request.
// Now we want to finish populating the CertifiedKey and store it for later.
certified_key_pb.set_certified_key_credential(
response_pb.certified_key_credential());
certified_key_pb.set_intermediate_ca_cert(response_pb.intermediate_ca_cert());
certified_key_pb.set_key_name(key_name);
if (!SaveKey(is_user_specific, username, key_name, certified_key_pb))
return false;
LOG(INFO) << "Attestation: Certified key credential received and stored.";
return CreatePEMCertificateChain(response_pb.certified_key_credential(),
response_pb.intermediate_ca_cert(),
certificate_chain);
}
bool Attestation::GetCertificateChain(bool is_user_specific,
const string& username,
const string& key_name,
SecureBlob* certificate_chain) {
base::AutoLock lock(lock_);
CertifiedKey key;
if (!FindKeyByName(is_user_specific, username, key_name, &key)) {
LOG(ERROR) << __func__ << ": Could not find certified key: " << key_name;
return false;
}
return CreatePEMCertificateChain(key.certified_key_credential(),
key.intermediate_ca_cert(),
certificate_chain);
}
bool Attestation::GetPublicKey(bool is_user_specific,
const string& username,
const string& key_name,
SecureBlob* public_key) {
base::AutoLock lock(lock_);
CertifiedKey key;
if (!FindKeyByName(is_user_specific, username, key_name, &key)) {
LOG(ERROR) << __func__ << ": Could not find certified key: " << key_name;
return false;
}
SecureBlob public_key_der = ConvertStringToBlob(key.public_key());
// Convert from PKCS #1 RSAPublicKey to X.509 SubjectPublicKeyInfo.
const unsigned char* asn1_ptr = &public_key_der.front();
scoped_ptr<RSA, RSADeleter> rsa(
d2i_RSAPublicKey(NULL, &asn1_ptr, public_key_der.size()));
if (!rsa.get()) {
LOG(ERROR) << __func__ << ": Failed to decode public key.";
return false;
}
unsigned char* buffer = NULL;
int length = i2d_RSA_PUBKEY(rsa.get(), &buffer);
if (length <= 0) {
LOG(ERROR) << __func__ << ": Failed to encode public key.";
return false;
}
SecureBlob tmp(buffer, length);
chromeos::SecureMemset(buffer, 0, length);
OPENSSL_free(buffer);
public_key->swap(tmp);
return true;
}
bool Attestation::DoesKeyExist(bool is_user_specific,
const string& username,
const string& key_name) {
base::AutoLock lock(lock_);
CertifiedKey key;
return FindKeyByName(is_user_specific, username, key_name, &key);
}
bool Attestation::SignEnterpriseChallenge(
bool is_user_specific,
const string& username,
const string& key_name,
const string& domain,
const SecureBlob& device_id,
bool include_signed_public_key,
const SecureBlob& challenge,
SecureBlob* response) {
if (!IsTPMReady())
return false;
base::AutoLock lock(lock_);
CertifiedKey key;
if (!FindKeyByName(is_user_specific, username, key_name, &key)) {
LOG(ERROR) << __func__ << ": Key not found.";
return false;
}
// Validate that the challenge is coming from the expected source.
SignedData signed_challenge;
if (!signed_challenge.ParseFromArray(challenge.const_data(),
challenge.size())) {
LOG(ERROR) << __func__ << ": Failed to parse signed challenge.";
return false;
}
if (!ValidateEnterpriseChallenge(signed_challenge)) {
LOG(ERROR) << __func__ << ": Invalid challenge.";
return false;
}
// Assemble a response protobuf.
ChallengeResponse response_pb;
*response_pb.mutable_challenge() = signed_challenge;
SecureBlob nonce;
if (!tpm_->GetRandomData(kNonceSize, &nonce)) {
LOG(ERROR) << __func__ << ": Failed to generate nonce.";
return false;
}
response_pb.set_nonce(ConvertBlobToString(nonce));
KeyInfo key_info;
// EUK -> Enterprise User Key
// EMK -> Enterprise Machine Key
key_info.set_key_type(is_user_specific ? EUK : EMK);
key_info.set_domain(domain);
key_info.set_device_id(ConvertBlobToString(device_id));
// Only include the certificate if this is a user key.
if (is_user_specific) {
SecureBlob certificate_chain;
if (!CreatePEMCertificateChain(key.certified_key_credential(),
key.intermediate_ca_cert(),
&certificate_chain)) {
LOG(ERROR) << __func__ << ": Failed to construct certificate chain.";
return false;
}
key_info.set_certificate(ConvertBlobToString(certificate_chain));
}
if (is_user_specific && include_signed_public_key) {
SecureBlob spkac;
if (!CreateSignedPublicKey(key, &spkac)) {
LOG(ERROR) << __func__ << ": Failed to create signed public key.";
return false;
}
key_info.set_signed_public_key_and_challenge(ConvertBlobToString(spkac));
}
if (!EncryptEnterpriseKeyInfo(key_info,
response_pb.mutable_encrypted_key_info())) {
LOG(ERROR) << __func__ << ": Failed to encrypt KeyInfo.";
return false;
}
// Serialize and sign the response protobuf.
string serialized;
if (!response_pb.SerializeToString(&serialized)) {
LOG(ERROR) << __func__ << ": Failed to serialize response protobuf.";
return false;
}
SecureBlob input_data = ConvertStringToBlob(serialized);
ClearString(&serialized);
if (!SignChallengeData(key, input_data, response)) {
LOG(ERROR) << __func__ << ": Failed to sign data.";
return false;
}
return true;
}
bool Attestation::SignSimpleChallenge(bool is_user_specific,
const string& username,
const string& key_name,
const SecureBlob& challenge,
SecureBlob* response) {
if (!IsTPMReady())
return false;
base::AutoLock lock(lock_);
CertifiedKey key;
if (!FindKeyByName(is_user_specific, username, key_name, &key)) {
LOG(ERROR) << __func__ << ": Key not found.";
return false;
}
// Add a nonce to ensure this service cannot be used to sign arbitrary data.
SecureBlob nonce;
if (!tpm_->GetRandomData(kNonceSize, &nonce)) {
LOG(ERROR) << __func__ << ": Failed to generate nonce.";
return false;
}
SecureBlob input_data = SecureCat(challenge, nonce);
if (!SignChallengeData(key, input_data, response)) {
LOG(ERROR) << __func__ << ": Failed to sign data.";
return false;
}
return true;
}
bool Attestation::RegisterKey(bool is_user_specific,
const string& username,
const string& key_name) {
if (!is_user_specific) {
// Currently there are no use cases which require a non-user key to be
// registered. This prevents any accidental or malicious registration.
LOG(WARNING) << "Attestation: Rejecting attempt to register machine key.";
return false;
}
base::AutoLock lock(lock_);
CertifiedKey key;
if (!FindKeyByName(true, username, key_name, &key)) {
LOG(ERROR) << __func__ << ": Key not found.";
return false;
}
if (!user_key_store_->Register(username,
ConvertStringToBlob(key.key_blob()),
ConvertStringToBlob(key.public_key()))) {
LOG(ERROR) << __func__ << ": Failed to register key.";
return false;
}
if (!user_key_store_->Delete(username, key_name)) {
LOG(WARNING) << __func__ << ": Failed to delete registered key.";
}
return true;
}
bool Attestation::GetKeyPayload(bool is_user_specific,
const string& username,
const string& key_name,
SecureBlob* payload) {
base::AutoLock lock(lock_);
CertifiedKey key;
if (!FindKeyByName(is_user_specific, username, key_name, &key)) {
LOG(ERROR) << __func__ << ": Key not found.";
return false;
}
SecureBlob tmp = ConvertStringToBlob(key.payload());
payload->swap(tmp);
return true;
}
bool Attestation::SetKeyPayload(bool is_user_specific,
const string& username,
const string& key_name,
const SecureBlob& payload) {
base::AutoLock lock(lock_);
CertifiedKey key;
if (!FindKeyByName(is_user_specific, username, key_name, &key)) {
LOG(ERROR) << __func__ << ": Key not found.";
return false;
}
key.set_payload(ConvertBlobToString(payload));
return SaveKey(is_user_specific, username, key_name, key);
}
bool Attestation::DeleteKeysByPrefix(bool is_user_specific,
const string& username,
const string& key_prefix) {
base::AutoLock lock(lock_);
if (is_user_specific) {
return user_key_store_->DeleteByPrefix(username, key_prefix);
}
// Manipulate the device keys protobuf field. Linear time strategy is to swap
// all elements we want to keep to the front and then truncate.
google::protobuf::RepeatedPtrField<CertifiedKey>* device_keys =
database_pb_.mutable_device_keys();
int next_keep_index = 0;
for (int i = 0; i < device_keys->size(); ++i) {
if (device_keys->Get(i).key_name().find(key_prefix) != 0) {
// Prefix doesn't match -> keep.
if (i != next_keep_index)
device_keys->SwapElements(next_keep_index, i);
++next_keep_index;
}
}
while (next_keep_index < device_keys->size()) {
device_keys->RemoveLast();
}
return PersistDatabaseChanges();
}
bool Attestation::GetEKInfo(std::string* ek_info) {
if (!IsTPMReady())
return false;
SecureBlob ek_cert;
if (!tpm_->GetEndorsementCredential(&ek_cert)) {
LOG(ERROR) << "Cannot get EK certificate from TPM. EK info not available.";
return false;
}
SecureBlob hash = CryptoLib::Sha256(ek_cert);
*ek_info = base::StringPrintf(
"EK Certificate:\n%s\nHash:\n%s\n",
CreatePEMCertificate(ConvertBlobToString(ek_cert)).c_str(),
base::HexEncode(hash.data(), hash.size()).c_str());
return true;
}
bool Attestation::GetIdentityResetRequest(const string& reset_token,
SecureBlob* reset_request) {
base::AutoLock lock(lock_);
AttestationResetRequest proto;
proto.set_token(reset_token);
*proto.mutable_encrypted_endorsement_credential() =
database_pb_.credentials().default_encrypted_endorsement_credential();
std::string serial;
if (!proto.SerializeToString(&serial)) {
LOG(ERROR) << __func__ << "Failed to serialize protobuf.";
return false;
}
SecureBlob tmp(serial);
ClearString(&serial);
reset_request->swap(tmp);
return true;
}
SecureBlob Attestation::ConvertStringToBlob(const string& s) {
return SecureBlob(s.data(), s.length());
}
string Attestation::ConvertBlobToString(const chromeos::Blob& blob) {
return string(reinterpret_cast<const char*>(vector_as_array(&blob)),
blob.size());
}
SecureBlob Attestation::SecureCat(const SecureBlob& blob1,
const SecureBlob& blob2) {
SecureBlob result(blob1.size() + blob2.size());
unsigned char* buffer = vector_as_array(&result);
memcpy(buffer, blob1.const_data(), blob1.size());
memcpy(buffer + blob1.size(), blob2.const_data(), blob2.size());
return SecureBlob(result.begin(), result.end());
}
bool Attestation::EncryptDatabase(const AttestationDatabase& db,
string* serial_encrypted_db) {
CHECK(crypto_);
string serial_string;
if (!db.SerializeToString(&serial_string)) {
LOG(ERROR) << "Failed to serialize db.";
return false;
}
SecureBlob serial_data(serial_string.data(), serial_string.size());
if (database_key_.empty() || sealed_database_key_.empty()) {
if (!crypto_->CreateSealedKey(&database_key_, &sealed_database_key_)) {
LOG(ERROR) << "Failed to generate database key.";
return false;
}
}
if (!crypto_->EncryptData(serial_data, database_key_, sealed_database_key_,
serial_encrypted_db)) {
LOG(ERROR) << "Attestation: Failed to encrypt database.";
return false;
}
return true;
}
bool Attestation::DecryptDatabase(const string& serial_encrypted_db,
AttestationDatabase* db) {
CHECK(crypto_);
if (!crypto_->UnsealKey(serial_encrypted_db, &database_key_,
&sealed_database_key_)){
LOG(ERROR) << "Attestation: Could not unseal decryption key.";
return false;
}
SecureBlob serial_blob;
if (!crypto_->DecryptData(serial_encrypted_db, database_key_, &serial_blob))
{
LOG(ERROR) << "Attestation: Failed to decrypt database with Tpm.";
return false;
}
string serial_string = ConvertBlobToString(serial_blob);
if (!db->ParseFromString(serial_string)) {
// Previously the DB was encrypted with CryptoLib::AesEncrypt which appends
// a SHA-1. This can be safely ignored.
const size_t kLegacyJunkSize = 20;
if (serial_string.size() < kLegacyJunkSize ||
!db->ParseFromArray(serial_string.data(),
serial_string.length() - kLegacyJunkSize)) {
LOG(ERROR) << "Failed to parse database.";
return false;
}
}
return true;
}
bool Attestation::StoreDatabase(const string& serial_encrypted_db) {
if (!platform_->WriteStringToFile(database_path_.value(),
serial_encrypted_db) ||
!platform_->SyncFile(database_path_.value())) {
LOG(ERROR) << "Failed to write db.";
return false;
}
CheckDatabasePermissions();
return true;
}
bool Attestation::LoadDatabase(string* serial_encrypted_db) {
CheckDatabasePermissions();
if (!platform_->ReadFileToString(database_path_.value(),
serial_encrypted_db)) {
return false;
}
return true;
}
bool Attestation::PersistDatabaseChanges() {
string serial_encrypted_db;
if (!EncryptDatabase(database_pb_, &serial_encrypted_db))
return false;
return StoreDatabase(serial_encrypted_db);
}
void Attestation::CheckDatabasePermissions() {
const mode_t kMask = 0007; // No permissions for 'others'.
CHECK(platform_);
mode_t permissions = 0;
if (!platform_->GetPermissions(database_path_.value(), &permissions))
return;
if ((permissions & kMask) == 0)
return;
platform_->SetPermissions(database_path_.value(), permissions & ~kMask);
}
bool Attestation::VerifyEndorsementCredential(const SecureBlob& credential,
const SecureBlob& public_key) {
const unsigned char* asn1_ptr = &credential.front();
scoped_ptr<X509, X509Deleter> x509(
d2i_X509(NULL, &asn1_ptr, credential.size()));
if (!x509.get()) {
LOG(ERROR) << "Failed to parse endorsement credential.";
return false;
}
// Manually verify the certificate signature.
char issuer[100]; // A longer CN will truncate.
X509_NAME_get_text_by_NID(x509.get()->cert_info->issuer,
NID_commonName,
issuer,
arraysize(issuer));
scoped_ptr<EVP_PKEY, EVP_PKEYDeleter> issuer_key =
GetAuthorityPublicKey(issuer);
if (!issuer_key.get()) {
LOG(ERROR) << "Unknown endorsement credential issuer.";
return false;
}
if (X509_verify(x509.get(), issuer_key.get()) != 1) {
LOG(ERROR) << "Bad endorsement credential signature.";
return false;
}
// Verify that the given public key matches the public key in the credential.
// Note: Do not use any openssl functions that attempt to decode the public
// key. These will fail because openssl does not recognize the OAEP key type.
SecureBlob credential_public_key(
x509.get()->cert_info->key->public_key->data,
x509.get()->cert_info->key->public_key->length);
if (credential_public_key.size() != public_key.size() ||
memcmp(&credential_public_key.front(),
&public_key.front(),
public_key.size()) != 0) {
LOG(ERROR) << "Bad endorsement credential public key.";
return false;
}
return true;
}
bool Attestation::VerifyIdentityBinding(const IdentityBinding& binding) {
// Reconstruct and hash a serialized TPM_IDENTITY_CONTENTS structure.
const unsigned char header[] = {1, 1, 0, 0, 0, 0, 0, 0x79};
string label_ca = binding.identity_label() + binding.pca_public_key();
SecureBlob label_ca_digest = CryptoLib::Sha1(ConvertStringToBlob(label_ca));
ClearString(&label_ca);
// The signed data is header + digest + pubkey.
SecureBlob contents = SecureCat(SecureCat(
SecureBlob(header, arraysize(header)),
label_ca_digest),
ConvertStringToBlob(binding.identity_public_key()));
// Now verify the signature.
if (!VerifySignature(ConvertStringToBlob(binding.identity_public_key_der()),
contents,
ConvertStringToBlob(binding.identity_binding()))) {
LOG(ERROR) << "Failed to verify identity binding signature.";
return false;
}
return true;
}
bool Attestation::VerifyQuote(const SecureBlob& aik_public_key,
const Quote& quote) {
if (!VerifySignature(aik_public_key,
ConvertStringToBlob(quote.quoted_data()),
ConvertStringToBlob(quote.quote()))) {
LOG(ERROR) << "Failed to verify quote signature.";
return false;
}
// Check that the quoted value matches the given PCR value. We can verify this
// by reconstructing the TPM_PCR_COMPOSITE structure the TPM would create.
const uint8_t header[] = {
static_cast<uint8_t>(0), static_cast<uint8_t>(2),
static_cast<uint8_t>(1), static_cast<uint8_t>(0),
static_cast<uint8_t>(0), static_cast<uint8_t>(0),
static_cast<uint8_t>(0),
static_cast<uint8_t>(quote.quoted_pcr_value().size())};
SecureBlob pcr_composite = SecureCat(
SecureBlob(header, arraysize(header)),
ConvertStringToBlob(quote.quoted_pcr_value()));
SecureBlob pcr_digest = CryptoLib::Sha1(pcr_composite);
SecureBlob quoted_data = ConvertStringToBlob(quote.quoted_data());
if (search(quoted_data.begin(), quoted_data.end(),
pcr_digest.begin(), pcr_digest.end()) == quoted_data.end()) {
LOG(ERROR) << "PCR0 value mismatch.";
return false;
}
// Check if the PCR0 value represents a known mode.
for (size_t i = 0; i < arraysize(kKnownPCRValues); ++i) {
SecureBlob settings_blob(3);
settings_blob[0] = kKnownPCRValues[i].developer_mode_enabled;
settings_blob[1] = kKnownPCRValues[i].recovery_mode_enabled;
settings_blob[2] = kKnownPCRValues[i].firmware_type;
SecureBlob settings_digest = CryptoLib::Sha1(settings_blob);
chromeos::Blob extend_pcr_value(kDigestSize, 0);
extend_pcr_value.insert(extend_pcr_value.end(), settings_digest.begin(),
settings_digest.end());
SecureBlob final_pcr_value = CryptoLib::Sha1(extend_pcr_value);
if (quote.quoted_pcr_value().size() == final_pcr_value.size() &&
0 == memcmp(quote.quoted_pcr_value().data(), final_pcr_value.data(),
final_pcr_value.size())) {
string description = "Developer Mode: ";
description += kKnownPCRValues[i].developer_mode_enabled ? "On" : "Off";
description += ", Recovery Mode: ";
description += kKnownPCRValues[i].recovery_mode_enabled ? "On" : "Off";
description += ", Firmware Type: ";
description += (kKnownPCRValues[i].firmware_type == 1) ? "Verified" :
"Developer";
LOG(INFO) << "PCR0: " << description;
return true;
}
}
LOG(WARNING) << "PCR0 value not recognized.";
return true;
}
bool Attestation::VerifyCertifiedKey(
const SecureBlob& aik_public_key,
const SecureBlob& certified_public_key,
const SecureBlob& certified_key_info,
const SecureBlob& proof) {
string key_info = ConvertBlobToString(certified_key_info);
if (!VerifySignature(aik_public_key, certified_key_info, proof)) {
LOG(ERROR) << "Failed to verify certified key proof signature.";
return false;
}
const unsigned char* asn1_ptr = &certified_public_key.front();
scoped_ptr<RSA, RSADeleter> rsa(
d2i_RSAPublicKey(NULL, &asn1_ptr, certified_public_key.size()));
if (!rsa.get()) {
LOG(ERROR) << "Failed to decode certified public key.";
return false;
}
SecureBlob modulus(BN_num_bytes(rsa.get()->n));
BN_bn2bin(rsa.get()->n, vector_as_array(&modulus));
SecureBlob key_digest = CryptoLib::Sha1(modulus);
if (std::search(certified_key_info.begin(),
certified_key_info.end(),
key_digest.begin(),
key_digest.end()) == certified_key_info.end()) {
LOG(ERROR) << "Certified public key mismatch.";
return false;
}
return true;
}
scoped_ptr<EVP_PKEY, Attestation::EVP_PKEYDeleter>
Attestation::GetAuthorityPublicKey(const char* issuer_name) {
const int kNumIssuers = arraysize(kKnownEndorsementCA);
for (int i = 0; i < kNumIssuers; ++i) {
if (0 == strcmp(issuer_name, kKnownEndorsementCA[i].issuer)) {
scoped_ptr<RSA, RSADeleter> rsa = CreateRSAFromHexModulus(
kKnownEndorsementCA[i].modulus);
scoped_ptr<EVP_PKEY, EVP_PKEYDeleter> pkey(EVP_PKEY_new());
if (!pkey.get()) {
return scoped_ptr<EVP_PKEY, EVP_PKEYDeleter>();
}
EVP_PKEY_assign_RSA(pkey.get(), rsa.release());
return pkey.Pass();
}
}
return scoped_ptr<EVP_PKEY, EVP_PKEYDeleter>();
}
bool Attestation::VerifySignature(const SecureBlob& public_key,
const SecureBlob& signed_data,
const SecureBlob& signature) {
const unsigned char* asn1_ptr = &public_key.front();
scoped_ptr<RSA, RSADeleter> rsa(
d2i_RSAPublicKey(NULL, &asn1_ptr, public_key.size()));
if (!rsa.get()) {
LOG(ERROR) << "Failed to decode public key.";
return false;
}
SecureBlob digest = CryptoLib::Sha1(signed_data);
if (!RSA_verify(NID_sha1, &digest.front(), digest.size(),
const_cast<unsigned char*>(&signature.front()),
signature.size(), rsa.get())) {
LOG(ERROR) << "Failed to verify signature.";
return false;
}
return true;
}
void Attestation::ClearDatabase() {
if (database_pb_.has_credentials()) {
TPMCredentials* credentials = database_pb_.mutable_credentials();
ClearString(credentials->mutable_endorsement_public_key());
ClearString(credentials->mutable_endorsement_credential());
ClearString(credentials->mutable_platform_credential());
ClearString(credentials->mutable_conformance_credential());
}
if (database_pb_.has_identity_binding()) {
IdentityBinding* binding = database_pb_.mutable_identity_binding();
ClearString(binding->mutable_identity_binding());
ClearString(binding->mutable_identity_public_key_der());
ClearString(binding->mutable_identity_public_key());
ClearString(binding->mutable_identity_label());
ClearString(binding->mutable_pca_public_key());
}
if (database_pb_.has_identity_key()) {
IdentityKey* key = database_pb_.mutable_identity_key();
ClearString(key->mutable_identity_public_key());
ClearString(key->mutable_identity_key_blob());
ClearString(key->mutable_identity_credential());
}
if (database_pb_.has_pcr0_quote()) {
Quote* quote = database_pb_.mutable_pcr0_quote();
ClearString(quote->mutable_quote());
ClearString(quote->mutable_quoted_data());
ClearString(quote->mutable_quoted_pcr_value());
}
if (database_pb_.has_delegate()) {
Delegation* delegate = database_pb_.mutable_delegate();
ClearString(delegate->mutable_blob());
ClearString(delegate->mutable_secret());
}
}
void Attestation::ClearString(string* s) {
chromeos::SecureMemset(string_as_array(s), 0, s->length());
s->clear();
}
bool Attestation::VerifyActivateIdentity(const SecureBlob& delegate_blob,
const SecureBlob& delegate_secret,
const SecureBlob& identity_key_blob,
const SecureBlob& identity_public_key,
const SecureBlob& ek_public_key) {
const char* kTestCredential = "test";
const uint8_t kAlgAES256 = 9; // This comes from TPM_ALG_AES256.
const uint8_t kEncModeCBC = 2; // This comes from TPM_SYM_MODE_CBC.
const uint8_t kAsymContentHeader[] =
{0, 0, 0, kAlgAES256, 0, kEncModeCBC, 0, kCipherKeySize};
const uint8_t kSymContentHeader[12] = {0};
// Generate an AES key and encrypt the credential.
SecureBlob aes_key(kCipherKeySize);
CryptoLib::GetSecureRandom(vector_as_array(&aes_key), aes_key.size());
SecureBlob credential(kTestCredential, strlen(kTestCredential));
SecureBlob encrypted_credential;
if (!tpm_->TssCompatibleEncrypt(aes_key, credential, &encrypted_credential)) {
LOG(ERROR) << "Failed to encrypt credential.";
return false;
}
// Construct a TPM_ASYM_CA_CONTENTS structure.
SecureBlob public_key_digest = CryptoLib::Sha1(identity_public_key);
SecureBlob asym_content = SecureCat(SecureCat(
SecureBlob(kAsymContentHeader, arraysize(kAsymContentHeader)),
aes_key),
public_key_digest);
// Encrypt the TPM_ASYM_CA_CONTENTS with the EK public key.
const unsigned char* asn1_ptr = &ek_public_key[0];
scoped_ptr<RSA, RSADeleter> rsa(
d2i_RSAPublicKey(NULL, &asn1_ptr, ek_public_key.size()));
if (!rsa.get()) {
LOG(ERROR) << "Failed to decode EK public key.";
return false;
}
SecureBlob encrypted_asym_content;
if (!tpm_->TpmCompatibleOAEPEncrypt(rsa.get(), asym_content,
&encrypted_asym_content)) {
LOG(ERROR) << "Failed to encrypt with EK public key.";
return false;
}
// Construct a TPM_SYM_CA_ATTESTATION structure.
uint32_t length = htonl(encrypted_credential.size());
SecureBlob length_blob(sizeof(uint32_t));
memcpy(length_blob.data(), &length, sizeof(uint32_t));
SecureBlob sym_content = SecureCat(SecureCat(
length_blob,
SecureBlob(kSymContentHeader, arraysize(kSymContentHeader))),
encrypted_credential);
// Attempt to activate the identity.
SecureBlob credential_out;
if (!tpm_->ActivateIdentity(delegate_blob, delegate_secret, identity_key_blob,
encrypted_asym_content, sym_content,
&credential_out)) {
LOG(ERROR) << "Failed to activate identity.";
return false;
}
if (credential.size() != credential_out.size() ||
chromeos::SafeMemcmp(credential.data(), credential_out.data(),
credential.size()) != 0) {
LOG(ERROR) << "Invalid identity credential.";
return false;
}
return true;
}
bool Attestation::EncryptEndorsementCredential(
PCAType pca_type,
const SecureBlob& credential,
EncryptedData* encrypted_credential) {
scoped_ptr<RSA, RSADeleter> rsa;
string key_id;
switch(pca_type) {
case kDefaultPCA:
rsa = CreateRSAFromHexModulus(kDefaultPCAPublicKey);
key_id = std::string(kDefaultPCAPublicKeyID,
arraysize(kDefaultPCAPublicKeyID) - 1);
break;
case kAlternatePCA:
{
chromeos::Blob pca_key;
if (!install_attributes_->Get(kAlternatePCAKeyAttributeName,
&pca_key)) {
LOG(ERROR) << __func__ << "Alternate PCA key does not exist.";
return false;
}
const unsigned char* asn1_ptr = &pca_key.front();
rsa.reset(d2i_RSA_PUBKEY(NULL, &asn1_ptr, pca_key.size()));
chromeos::Blob key_id_blob;
// Ignore result, an empty ID is ok.
install_attributes_->Get(kAlternatePCAKeyIDAttributeName, &key_id_blob);
key_id = ConvertBlobToString(key_id_blob);
}
break;
default:
NOTREACHED();
}
if (!rsa.get()) {
LOG(ERROR) << __func__ << ": Failed to decode public key.";
return false;
}
return EncryptData(credential, rsa.get(), key_id, encrypted_credential);
}
bool Attestation::AddDeviceKey(const string& key_name,
const CertifiedKey& key) {
// If a key by this name already exists, reuse the field.
bool found = false;
for (int i = 0; i < database_pb_.device_keys_size(); ++i) {
if (database_pb_.device_keys(i).key_name() == key_name) {
found = true;
*database_pb_.mutable_device_keys(i) = key;
break;
}
}
if (!found)
*database_pb_.add_device_keys() = key;
return PersistDatabaseChanges();
}
bool Attestation::FindKeyByName(bool is_user_specific,
const string& username,
const string& key_name,
CertifiedKey* key) {
if (is_user_specific) {
SecureBlob key_data;
if (!user_key_store_->Read(username, key_name, &key_data)) {
LOG(INFO) << "Key not found: " << key_name;
return false;
}
if (!key->ParseFromArray(key_data.const_data(), key_data.size())) {
LOG(ERROR) << "Failed to parse key: " << key_name;
return false;
}
return true;
}
for (int i = 0; i < database_pb_.device_keys_size(); ++i) {
if (database_pb_.device_keys(i).key_name() == key_name) {
*key = database_pb_.device_keys(i);
return true;
}
}
LOG(INFO) << "Key not found: " << key_name;
return false;
}
bool Attestation::SaveKey(bool is_user_specific,
const string& username,
const string& key_name,
const CertifiedKey& key) {
if (is_user_specific) {
string tmp;
if (!key.SerializeToString(&tmp)) {
LOG(ERROR) << __func__ << ": Failed to serialize protobuf.";
return false;
}
SecureBlob blob = ConvertStringToBlob(tmp);
ClearString(&tmp);
if (!user_key_store_->Write(username, key_name, blob)) {
LOG(ERROR) << __func__ << ": Failed to store certified key for user.";
return false;
}
} else {
if (!AddDeviceKey(key_name, key)) {
LOG(ERROR) << __func__ << ": Failed to store certified key for device.";
return false;
}
}
return true;
}
bool Attestation::CreatePEMCertificateChain(const string& leaf_certificate,
const string& intermediate_ca_cert,
SecureBlob* certificate_chain) {
if (leaf_certificate.empty()) {
LOG(ERROR) << "Certificate is empty.";
return false;
}
string pem = CreatePEMCertificate(leaf_certificate);
if (!intermediate_ca_cert.empty()) {
pem += "\n";
pem += CreatePEMCertificate(intermediate_ca_cert);
}
*certificate_chain = ConvertStringToBlob(pem);
ClearString(&pem);
return true;
}
string Attestation::CreatePEMCertificate(const string& certificate) {
const char kBeginCertificate[] = "-----BEGIN CERTIFICATE-----\n";
const char kEndCertificate[] = "-----END CERTIFICATE-----";
string pem = kBeginCertificate;
pem += CryptoLib::Base64Encode(certificate, true);
pem += kEndCertificate;
return pem;
}
bool Attestation::SignChallengeData(const CertifiedKey& key,
const SecureBlob& data_to_sign,
SecureBlob* response) {
SecureBlob der_header(kSha256DigestInfo, arraysize(kSha256DigestInfo));
SecureBlob der_encoded_input = SecureCat(der_header,
CryptoLib::Sha256(data_to_sign));
SecureBlob signature;
if (!tpm_->Sign(ConvertStringToBlob(key.key_blob()),
der_encoded_input,
&signature)) {
LOG(ERROR) << "Failed to generate signature.";
return false;
}
SignedData signed_data;
signed_data.set_data(ConvertBlobToString(data_to_sign));
signed_data.set_signature(ConvertBlobToString(signature));
string serialized;
if (!signed_data.SerializeToString(&serialized)) {
LOG(ERROR) << "Failed to serialize signed data.";
return false;
}
SecureBlob tmp = ConvertStringToBlob(serialized);
ClearString(&serialized);
response->swap(tmp);
return true;
}
bool Attestation::ValidateEnterpriseChallenge(
const SignedData& signed_challenge) {
const char kExpectedChallengePrefix[] = "EnterpriseKeyChallenge";
scoped_ptr<RSA, RSADeleter> rsa =
CreateRSAFromHexModulus(kEnterpriseSigningPublicKey);
if (!rsa.get()) {
LOG(ERROR) << "Failed to decode public key.";
return false;
}
SecureBlob digest = CryptoLib::Sha256(
ConvertStringToBlob(signed_challenge.data()));
SecureBlob signature = ConvertStringToBlob(signed_challenge.signature());
RSA* enterprise_key = enterprise_test_key_ ? enterprise_test_key_ : rsa.get();
if (!RSA_verify(NID_sha256, &digest.front(), digest.size(),
const_cast<unsigned char*>(&signature.front()),
signature.size(), enterprise_key)) {
LOG(ERROR) << "Failed to verify challenge signature.";
return false;
}
Challenge challenge;
if (!challenge.ParseFromString(signed_challenge.data())) {
LOG(ERROR) << "Failed to parse challenge protobuf.";
return false;
}
if (challenge.prefix() != kExpectedChallengePrefix) {
LOG(ERROR) << "Unexpected challenge prefix.";
return false;
}
return true;
}
bool Attestation::EncryptEnterpriseKeyInfo(const KeyInfo& key_info,
EncryptedData* encrypted_data) {
scoped_ptr<RSA, RSADeleter> rsa =
CreateRSAFromHexModulus(kEnterpriseEncryptionPublicKey);
if (!rsa.get()) {
LOG(ERROR) << "Failed to decode public key.";
return false;
}
string serialized;
if (!key_info.SerializeToString(&serialized)) {
LOG(ERROR) << "Failed to serialize key info.";
return false;
}
RSA* enterprise_key = enterprise_test_key_ ? enterprise_test_key_ : rsa.get();
string enterprise_key_id(kEnterpriseEncryptionPublicKeyID,
arraysize(kEnterpriseEncryptionPublicKeyID) - 1);
bool result = EncryptData(ConvertStringToBlob(serialized),
enterprise_key,
enterprise_key_id,
encrypted_data);
ClearString(&serialized);
return result;
}
bool Attestation::EncryptData(const SecureBlob& input,
RSA* wrapping_key,
const string& wrapping_key_id,
EncryptedData* output) {
// Encrypt with a randomly generated AES key.
SecureBlob aes_key;
if (!tpm_->GetRandomData(kCipherKeySize, &aes_key)) {
LOG(ERROR) << "GetRandomData failed.";
return false;
}
SecureBlob aes_iv;
if (!tpm_->GetRandomData(kAesBlockSize, &aes_iv)) {
LOG(ERROR) << "GetRandomData failed.";
return false;
}
SecureBlob encrypted;
if (!AesEncrypt(input, aes_key, aes_iv, &encrypted)) {
LOG(ERROR) << "AesEncrypt failed.";
return false;
}
output->set_encrypted_data(encrypted.data(), encrypted.size());
output->set_iv(aes_iv.data(), aes_iv.size());
output->set_wrapping_key_id(wrapping_key_id);
output->set_mac(CryptoLib::ComputeEncryptedDataHMAC(*output, aes_key));
// Wrap the AES key with the given public key.
string encrypted_key;
encrypted_key.resize(RSA_size(wrapping_key));
unsigned char* buffer = reinterpret_cast<unsigned char*>(
string_as_array(&encrypted_key));
int length = RSA_public_encrypt(aes_key.size(),
vector_as_array(&aes_key),
buffer, wrapping_key, RSA_PKCS1_OAEP_PADDING);
if (length == -1) {
LOG(ERROR) << "RSA_public_encrypt failed.";
return false;
}
encrypted_key.resize(length);
output->set_wrapped_key(encrypted_key);
return true;
}
scoped_ptr<RSA, Attestation::RSADeleter> Attestation::CreateRSAFromHexModulus(
const string& hex_modulus) {
scoped_ptr<RSA, RSADeleter> rsa(RSA_new());
if (!rsa.get())
return scoped_ptr<RSA, RSADeleter>();
rsa->e = BN_new();
if (!rsa->e)
return scoped_ptr<RSA, RSADeleter>();
BN_set_word(rsa->e, kWellKnownExponent);
rsa->n = BN_new();
if (!rsa->n)
return scoped_ptr<RSA, RSADeleter>();
if (0 == BN_hex2bn(&rsa->n, hex_modulus.c_str()))
return scoped_ptr<RSA, RSADeleter>();
return rsa.Pass();
}
bool Attestation::CreateSignedPublicKey(
const CertifiedKey& key,
chromeos::SecureBlob* signed_public_key) {
// Get the certified public key as an EVP_PKEY.
const unsigned char* asn1_ptr =
reinterpret_cast<const unsigned char*>(key.public_key().data());
scoped_ptr<RSA, RSADeleter> rsa(
d2i_RSAPublicKey(NULL, &asn1_ptr, key.public_key().size()));
if (!rsa.get())
return false;
scoped_ptr<EVP_PKEY, EVP_PKEYDeleter> public_key(EVP_PKEY_new());
if (!public_key.get())
return false;
EVP_PKEY_assign_RSA(public_key.get(), rsa.release());
// Fill in the public key.
scoped_ptr<NETSCAPE_SPKI, NETSCAPE_SPKIDeleter> spki(NETSCAPE_SPKI_new());
if (!spki.get())
return false;
if (!NETSCAPE_SPKI_set_pubkey(spki.get(), public_key.get()))
return false;
// Fill in a random challenge.
SecureBlob challenge;
if (!tpm_->GetRandomData(kNonceSize, &challenge))
return false;
string challenge_hex = base::HexEncode(challenge.data(), challenge.size());
if (!ASN1_STRING_set(spki.get()->spkac->challenge,
challenge_hex.data(),
challenge_hex.size()))
return false;
// Generate the signature.
unsigned char* buffer = NULL;
int length = i2d_NETSCAPE_SPKAC(spki.get()->spkac, &buffer);
if (length <= 0)
return false;
SecureBlob data_to_sign(buffer, length);
OPENSSL_free(buffer);
SecureBlob der_header(kSha256DigestInfo, arraysize(kSha256DigestInfo));
SecureBlob der_encoded_input = SecureCat(der_header,
CryptoLib::Sha256(data_to_sign));
SecureBlob signature;
if (!tpm_->Sign(ConvertStringToBlob(key.key_blob()),
der_encoded_input,
&signature))
return false;
// Fill in the signature and algorithm.
buffer = reinterpret_cast<unsigned char*>(OPENSSL_malloc(signature.size()));
if (!buffer)
return false;
memcpy(buffer, signature.data(), signature.size());
spki.get()->signature->data = buffer;
spki.get()->signature->length = signature.size();
X509_ALGOR_set0(spki.get()->sig_algor,
OBJ_nid2obj(NID_sha256WithRSAEncryption),
V_ASN1_NULL,
NULL);
// DER encode.
buffer = NULL;
length = i2d_NETSCAPE_SPKI(spki.get(), &buffer);
if (length <= 0)
return false;
SecureBlob tmp(buffer, length);
OPENSSL_free(buffer);
signed_public_key->swap(tmp);
return true;
}
bool Attestation::AesEncrypt(const chromeos::SecureBlob& plaintext,
const chromeos::SecureBlob& key,
const chromeos::SecureBlob& iv,
chromeos::SecureBlob* ciphertext) {
return CryptoLib::AesEncryptSpecifyBlockMode(plaintext, 0, plaintext.size(),
key, iv,
CryptoLib::kPaddingStandard,
CryptoLib::kCbc,
ciphertext);
}
bool Attestation::AesDecrypt(const chromeos::SecureBlob& ciphertext,
const chromeos::SecureBlob& key,
const chromeos::SecureBlob& iv,
chromeos::SecureBlob* plaintext) {
return CryptoLib::AesDecryptSpecifyBlockMode(ciphertext, 0, ciphertext.size(),
key, iv,
CryptoLib::kPaddingStandard,
CryptoLib::kCbc,
plaintext);
}
int Attestation::ChooseTemporalIndex(const std::string& user,
const std::string& origin) {
string user_hash = ConvertBlobToString(CryptoLib::Sha256(
ConvertStringToBlob(user)));
string origin_hash = ConvertBlobToString(CryptoLib::Sha256(
ConvertStringToBlob(origin)));
int histogram[kNumTemporalValues] = {0};
for (int i = 0; i < database_pb_.temporal_index_record_size(); ++i) {
const AttestationDatabase::TemporalIndexRecord& record =
database_pb_.temporal_index_record(i);
// Ignore out-of-range index values.
if (record.temporal_index() < 0 ||
record.temporal_index() >= kNumTemporalValues)
continue;
if (record.origin_hash() == origin_hash) {
if (record.user_hash() == user_hash) {
// We've previously chosen this index for this user, reuse it.
return record.temporal_index();
} else {
// We've previously chosen this index for another user.
++histogram[record.temporal_index()];
}
}
}
int least_used_index = 0;
for (int i = 1; i < kNumTemporalValues; ++i) {
if (histogram[i] < histogram[least_used_index])
least_used_index = i;
}
if (histogram[least_used_index] > 0) {
LOG(WARNING) << "Unique origin-specific identifiers have been exhausted.";
metrics_.SendCrosEventToUMA("Attestation.OriginSpecificExhausted");
}
// Record our choice for later reference.
AttestationDatabase::TemporalIndexRecord* new_record =
database_pb_.add_temporal_index_record();
new_record->set_origin_hash(origin_hash);
new_record->set_user_hash(user_hash);
new_record->set_temporal_index(least_used_index);
PersistDatabaseChanges();
return least_used_index;
}
void Attestation::FinalizeEndorsementData() {
// Only finalize endorsement data after install attributes are finalized.
if (install_attributes_->is_first_install())
return;
if (!database_pb_.has_credentials())
return;
TPMCredentials* credentials = database_pb_.mutable_credentials();
if (!credentials->has_endorsement_credential())
return;
if (!credentials->has_default_encrypted_endorsement_credential()) {
LOG(INFO) << "Attestation: Migrating endorsement data.";
if (!EncryptEndorsementCredential(
kDefaultPCA,
ConvertStringToBlob(credentials->endorsement_credential()),
credentials->mutable_default_encrypted_endorsement_credential())) {
LOG(ERROR) << "Attestation: Failed to encrypt EK cert.";
return;
}
}
if (!credentials->has_alternate_encrypted_endorsement_credential() &&
install_attributes_->Get(kAlternatePCAKeyAttributeName, NULL)) {
LOG(INFO) << "Attestation: Migrating endorsement data (alternate).";
if (!EncryptEndorsementCredential(
kAlternatePCA,
ConvertStringToBlob(credentials->endorsement_credential()),
credentials->mutable_alternate_encrypted_endorsement_credential())) {
LOG(ERROR) << "Attestation: Failed to encrypt EK cert (alternate).";
return;
}
}
LOG(INFO) << "Attestation: Clearing endorsement data.";
ClearString(credentials->mutable_endorsement_public_key());
credentials->clear_endorsement_public_key();
ClearString(credentials->mutable_endorsement_credential());
credentials->clear_endorsement_credential();
if (!PersistDatabaseChanges()) {
LOG(ERROR) << "Attestation: Failed to persist database changes.";
}
}
bool Attestation::IsTPMReady() {
if (!is_tpm_ready_ && tpm_)
is_tpm_ready_ = tpm_->IsEnabled() &&
tpm_->IsOwned() &&
!tpm_->IsBeingOwned();
return is_tpm_ready_;
}
void Attestation::RSADeleter::operator()(void* ptr) const {
if (ptr)
RSA_free(reinterpret_cast<RSA*>(ptr));
}
void Attestation::X509Deleter::operator()(void* ptr) const {
if (ptr)
X509_free(reinterpret_cast<X509*>(ptr));
}
void Attestation::EVP_PKEYDeleter::operator()(void* ptr) const {
if (ptr)
EVP_PKEY_free(reinterpret_cast<EVP_PKEY*>(ptr));
}
void Attestation::NETSCAPE_SPKIDeleter::operator()(void* ptr) const {
if (ptr)
NETSCAPE_SPKI_free(reinterpret_cast<NETSCAPE_SPKI*>(ptr));
}
}