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// Copyright (c) 2011 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 "update_engine/payload_signer.h"
#include <base/logging.h>
#include <base/string_split.h>
#include <base/string_util.h>
#include <openssl/pem.h>
#include "update_engine/delta_diff_generator.h"
#include "update_engine/delta_performer.h"
#include "update_engine/omaha_hash_calculator.h"
#include "update_engine/subprocess.h"
#include "update_engine/update_metadata.pb.h"
#include "update_engine/utils.h"
using std::string;
using std::vector;
namespace chromeos_update_engine {
const uint32_t kSignatureMessageVersion = 1;
namespace {
const char kRSA2048SHA256Padding[] = {
0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x31, 0x30,
0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05,
0x00, 0x04, 0x20
};
// Given a raw |signature|, packs it into a protobuf and serializes it into a
// binary blob. Returns true on success, false otherwise.
bool ConvertSignatureToProtobufBlob(const vector<char> signature,
vector<char>* out_signature_blob) {
// Pack it into a protobuf
Signatures out_message;
Signatures_Signature* sig_message = out_message.add_signatures();
sig_message->set_version(kSignatureMessageVersion);
sig_message->set_data(signature.data(), signature.size());
// Serialize protobuf
string serialized;
TEST_AND_RETURN_FALSE(out_message.AppendToString(&serialized));
out_signature_blob->insert(out_signature_blob->end(),
serialized.begin(),
serialized.end());
LOG(INFO) << "Signature blob size: " << out_signature_blob->size();
return true;
}
bool LoadPayload(const string& payload_path,
vector<char>* out_payload,
DeltaArchiveManifest* out_manifest,
uint64_t* out_metadata_size) {
vector<char> payload;
// Loads the payload and parses the manifest.
TEST_AND_RETURN_FALSE(utils::ReadFile(payload_path, &payload));
LOG(INFO) << "Payload size: " << payload.size();
TEST_AND_RETURN_FALSE(DeltaPerformer::ParsePayloadMetadata(
payload, out_manifest, out_metadata_size) ==
DeltaPerformer::kMetadataParseSuccess);
LOG(INFO) << "Metadata size: " << *out_metadata_size;
out_payload->swap(payload);
return true;
}
// Given an unsigned payload under |payload_path| and the |signature_blob_size|
// generates an updated payload that includes a dummy signature op in its
// manifest. Returns true on success, false otherwise.
bool AddSignatureOpToPayload(const string& payload_path,
int signature_blob_size,
vector<char>* out_payload) {
const int kProtobufOffset = 20;
const int kProtobufSizeOffset = 12;
// Loads the payload.
vector<char> payload;
DeltaArchiveManifest manifest;
uint64_t metadata_size;
TEST_AND_RETURN_FALSE(LoadPayload(
payload_path, &payload, &manifest, &metadata_size));
TEST_AND_RETURN_FALSE(!manifest.has_signatures_offset() &&
!manifest.has_signatures_size());
// Updates the manifest to include the signature operation.
DeltaDiffGenerator::AddSignatureOp(payload.size() - metadata_size,
signature_blob_size,
&manifest);
// Updates the payload to include the new manifest.
string serialized_manifest;
TEST_AND_RETURN_FALSE(manifest.AppendToString(&serialized_manifest));
LOG(INFO) << "Updated protobuf size: " << serialized_manifest.size();
payload.erase(payload.begin() + kProtobufOffset,
payload.begin() + metadata_size);
payload.insert(payload.begin() + kProtobufOffset,
serialized_manifest.begin(),
serialized_manifest.end());
// Updates the protobuf size.
uint64_t size_be = htobe64(serialized_manifest.size());
memcpy(&payload[kProtobufSizeOffset], &size_be, sizeof(size_be));
LOG(INFO) << "Updated payload size: " << payload.size();
out_payload->swap(payload);
return true;
}
} // namespace {}
bool PayloadSigner::SignHash(const vector<char>& hash,
const string& private_key_path,
vector<char>* out_signature) {
string sig_path;
TEST_AND_RETURN_FALSE(
utils::MakeTempFile("/tmp/signature.XXXXXX", &sig_path, NULL));
ScopedPathUnlinker sig_path_unlinker(sig_path);
string hash_path;
TEST_AND_RETURN_FALSE(
utils::MakeTempFile("/tmp/hash.XXXXXX", &hash_path, NULL));
ScopedPathUnlinker hash_path_unlinker(hash_path);
// We expect unpadded SHA256 hash coming in
TEST_AND_RETURN_FALSE(hash.size() == 32);
vector<char> padded_hash(hash);
PadRSA2048SHA256Hash(&padded_hash);
TEST_AND_RETURN_FALSE(utils::WriteFile(hash_path.c_str(),
padded_hash.data(),
padded_hash.size()));
// This runs on the server, so it's okay to cop out and call openssl
// executable rather than properly use the library
vector<string> cmd;
base::SplitString("/usr/bin/openssl rsautl -raw -sign -inkey x -in x -out x",
' ',
&cmd);
cmd[cmd.size() - 5] = private_key_path;
cmd[cmd.size() - 3] = hash_path;
cmd[cmd.size() - 1] = sig_path;
int return_code = 0;
TEST_AND_RETURN_FALSE(Subprocess::SynchronousExec(cmd, &return_code, NULL));
TEST_AND_RETURN_FALSE(return_code == 0);
vector<char> signature;
TEST_AND_RETURN_FALSE(utils::ReadFile(sig_path, &signature));
out_signature->swap(signature);
return true;
}
bool PayloadSigner::SignPayload(const string& unsigned_payload_path,
const string& private_key_path,
vector<char>* out_signature_blob) {
vector<char> hash_data;
TEST_AND_RETURN_FALSE(OmahaHashCalculator::RawHashOfFile(
unsigned_payload_path, -1, &hash_data) ==
utils::FileSize(unsigned_payload_path));
vector<char> signature;
TEST_AND_RETURN_FALSE(SignHash(hash_data, private_key_path, &signature));
TEST_AND_RETURN_FALSE(ConvertSignatureToProtobufBlob(signature,
out_signature_blob));
return true;
}
bool PayloadSigner::SignatureBlobLength(
const string& private_key_path,
uint64_t* out_length) {
DCHECK(out_length);
string x_path;
TEST_AND_RETURN_FALSE(
utils::MakeTempFile("/tmp/signed_data.XXXXXX", &x_path, NULL));
ScopedPathUnlinker x_path_unlinker(x_path);
TEST_AND_RETURN_FALSE(utils::WriteFile(x_path.c_str(), "x", 1));
vector<char> sig_blob;
TEST_AND_RETURN_FALSE(PayloadSigner::SignPayload(x_path,
private_key_path,
&sig_blob));
*out_length = sig_blob.size();
return true;
}
bool PayloadSigner::VerifySignature(const std::vector<char>& signature_blob,
const std::string& public_key_path,
std::vector<char>* out_hash_data) {
TEST_AND_RETURN_FALSE(!public_key_path.empty());
Signatures signatures;
TEST_AND_RETURN_FALSE(signatures.ParseFromArray(&signature_blob[0],
signature_blob.size()));
// Finds a signature that matches the current version.
int sig_index = 0;
for (; sig_index < signatures.signatures_size(); sig_index++) {
const Signatures_Signature& signature = signatures.signatures(sig_index);
if (signature.has_version() &&
signature.version() == kSignatureMessageVersion) {
break;
}
}
TEST_AND_RETURN_FALSE(sig_index < signatures.signatures_size());
const Signatures_Signature& signature = signatures.signatures(sig_index);
const string& sig_data = signature.data();
// The code below executes the equivalent of:
//
// openssl rsautl -verify -pubin -inkey |public_key_path|
// -in |sig_data| -out |out_hash_data|
// Loads the public key.
FILE* fpubkey = fopen(public_key_path.c_str(), "rb");
TEST_AND_RETURN_FALSE(fpubkey != NULL);
char dummy_password[] = { ' ', 0 }; // Ensure no password is read from stdin.
RSA* rsa = PEM_read_RSA_PUBKEY(fpubkey, NULL, NULL, dummy_password);
fclose(fpubkey);
TEST_AND_RETURN_FALSE(rsa != NULL);
unsigned int keysize = RSA_size(rsa);
if (sig_data.size() > 2 * keysize) {
LOG(ERROR) << "Signature size is too big for public key size.";
RSA_free(rsa);
return false;
}
// Decrypts the signature.
vector<char> hash_data(keysize);
int decrypt_size = RSA_public_decrypt(
sig_data.size(),
reinterpret_cast<const unsigned char*>(sig_data.data()),
reinterpret_cast<unsigned char*>(hash_data.data()),
rsa,
RSA_NO_PADDING);
RSA_free(rsa);
TEST_AND_RETURN_FALSE(decrypt_size > 0 &&
decrypt_size <= static_cast<int>(hash_data.size()));
hash_data.resize(decrypt_size);
out_hash_data->swap(hash_data);
return true;
}
bool PayloadSigner::VerifySignedPayload(const std::string& payload_path,
const std::string& public_key_path) {
vector<char> payload;
DeltaArchiveManifest manifest;
uint64_t metadata_size;
TEST_AND_RETURN_FALSE(LoadPayload(
payload_path, &payload, &manifest, &metadata_size));
TEST_AND_RETURN_FALSE(manifest.has_signatures_offset() &&
manifest.has_signatures_size());
CHECK_EQ(payload.size(),
metadata_size + manifest.signatures_offset() +
manifest.signatures_size());
vector<char> signature_blob(
payload.begin() + metadata_size + manifest.signatures_offset(),
payload.end());
vector<char> signed_hash;
TEST_AND_RETURN_FALSE(VerifySignature(
signature_blob, public_key_path, &signed_hash));
TEST_AND_RETURN_FALSE(!signed_hash.empty());
vector<char> hash;
TEST_AND_RETURN_FALSE(OmahaHashCalculator::RawHashOfBytes(
payload.data(), metadata_size + manifest.signatures_offset(), &hash));
PadRSA2048SHA256Hash(&hash);
TEST_AND_RETURN_FALSE(hash == signed_hash);
return true;
}
bool PayloadSigner::HashPayloadForSigning(const std::string& payload_path,
int signature_size,
vector<char>* out_hash_data) {
// TODO(petkov): Reduce memory usage -- the payload is manipulated in memory.
// Loads the payload and adds the signature op to it.
vector<char> signature(signature_size, 0);
vector<char> signature_blob;
TEST_AND_RETURN_FALSE(ConvertSignatureToProtobufBlob(signature,
&signature_blob));
vector<char> payload;
TEST_AND_RETURN_FALSE(AddSignatureOpToPayload(payload_path,
signature_blob.size(),
&payload));
// Calculates the hash on the updated payload. Note that the payload includes
// the signature op but doesn't include the signature blob at the end.
TEST_AND_RETURN_FALSE(OmahaHashCalculator::RawHashOfData(payload,
out_hash_data));
return true;
}
bool PayloadSigner::AddSignatureToPayload(const string& payload_path,
const vector<char>& signature,
const string& signed_payload_path) {
// TODO(petkov): Reduce memory usage -- the payload is manipulated in memory.
// Loads the payload and adds the signature op to it.
vector<char> signature_blob;
TEST_AND_RETURN_FALSE(ConvertSignatureToProtobufBlob(signature,
&signature_blob));
vector<char> payload;
TEST_AND_RETURN_FALSE(AddSignatureOpToPayload(payload_path,
signature_blob.size(),
&payload));
// Appends the signature blob to the end of the payload and writes the new
// payload.
payload.insert(payload.end(), signature_blob.begin(), signature_blob.end());
LOG(INFO) << "Signed payload size: " << payload.size();
TEST_AND_RETURN_FALSE(utils::WriteFile(signed_payload_path.c_str(),
payload.data(),
payload.size()));
return true;
}
bool PayloadSigner::PadRSA2048SHA256Hash(std::vector<char>* hash) {
TEST_AND_RETURN_FALSE(hash->size() == 32);
hash->insert(hash->begin(),
kRSA2048SHA256Padding,
kRSA2048SHA256Padding + sizeof(kRSA2048SHA256Padding));
TEST_AND_RETURN_FALSE(hash->size() == 256);
return true;
}
} // namespace chromeos_update_engine