| Index: base/crypto/symmetric_key_win.cc
|
| ===================================================================
|
| --- base/crypto/symmetric_key_win.cc (revision 80572)
|
| +++ base/crypto/symmetric_key_win.cc (working copy)
|
| @@ -1,536 +0,0 @@
|
| -// Copyright (c) 2011 The Chromium 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 "base/crypto/symmetric_key.h"
|
| -
|
| -#include <winsock2.h> // For htonl.
|
| -
|
| -#include <vector>
|
| -
|
| -// TODO(wtc): replace scoped_array by std::vector.
|
| -#include "base/memory/scoped_ptr.h"
|
| -
|
| -namespace base {
|
| -
|
| -namespace {
|
| -
|
| -// The following is a non-public Microsoft header documented in MSDN under
|
| -// CryptImportKey / CryptExportKey. Following the header is the byte array of
|
| -// the actual plaintext key.
|
| -struct PlaintextBlobHeader {
|
| - BLOBHEADER hdr;
|
| - DWORD cbKeySize;
|
| -};
|
| -
|
| -// CryptoAPI makes use of three distinct ALG_IDs for AES, rather than just
|
| -// CALG_AES (which exists, but depending on the functions you are calling, may
|
| -// result in function failure, whereas the subtype would succeed).
|
| -ALG_ID GetAESAlgIDForKeySize(size_t key_size_in_bits) {
|
| - // Only AES-128/-192/-256 is supported in CryptoAPI.
|
| - switch (key_size_in_bits) {
|
| - case 128:
|
| - return CALG_AES_128;
|
| - case 192:
|
| - return CALG_AES_192;
|
| - case 256:
|
| - return CALG_AES_256;
|
| - default:
|
| - NOTREACHED();
|
| - return 0;
|
| - }
|
| -};
|
| -
|
| -// Imports a raw/plaintext key of |key_size| stored in |*key_data| into a new
|
| -// key created for the specified |provider|. |alg| contains the algorithm of
|
| -// the key being imported.
|
| -// If |key_data| is intended to be used as an HMAC key, then |alg| should be
|
| -// CALG_HMAC.
|
| -// If successful, returns true and stores the imported key in |*key|.
|
| -// TODO(wtc): use this function in hmac_win.cc.
|
| -bool ImportRawKey(HCRYPTPROV provider,
|
| - ALG_ID alg,
|
| - const void* key_data, DWORD key_size,
|
| - ScopedHCRYPTKEY* key) {
|
| - DCHECK_GT(key_size, 0);
|
| -
|
| - DWORD actual_size = sizeof(PlaintextBlobHeader) + key_size;
|
| - std::vector<BYTE> tmp_data(actual_size);
|
| - BYTE* actual_key = &tmp_data[0];
|
| - memcpy(actual_key + sizeof(PlaintextBlobHeader), key_data, key_size);
|
| - PlaintextBlobHeader* key_header =
|
| - reinterpret_cast<PlaintextBlobHeader*>(actual_key);
|
| - memset(key_header, 0, sizeof(PlaintextBlobHeader));
|
| -
|
| - key_header->hdr.bType = PLAINTEXTKEYBLOB;
|
| - key_header->hdr.bVersion = CUR_BLOB_VERSION;
|
| - key_header->hdr.aiKeyAlg = alg;
|
| -
|
| - key_header->cbKeySize = key_size;
|
| -
|
| - HCRYPTKEY unsafe_key = NULL;
|
| - DWORD flags = CRYPT_EXPORTABLE;
|
| - if (alg == CALG_HMAC) {
|
| - // Though it may appear odd that IPSEC and RC2 are being used, this is
|
| - // done in accordance with Microsoft's FIPS 140-2 Security Policy for the
|
| - // RSA Enhanced Provider, as the approved means of using arbitrary HMAC
|
| - // key material.
|
| - key_header->hdr.aiKeyAlg = CALG_RC2;
|
| - flags |= CRYPT_IPSEC_HMAC_KEY;
|
| - }
|
| -
|
| - BOOL ok =
|
| - CryptImportKey(provider, actual_key, actual_size, 0, flags, &unsafe_key);
|
| -
|
| - // Clean up the temporary copy of key, regardless of whether it was imported
|
| - // sucessfully or not.
|
| - SecureZeroMemory(actual_key, actual_size);
|
| -
|
| - if (!ok)
|
| - return false;
|
| -
|
| - key->reset(unsafe_key);
|
| - return true;
|
| -}
|
| -
|
| -// Attempts to generate a random AES key of |key_size_in_bits|. Returns true
|
| -// if generation is successful, storing the generated key in |*key| and the
|
| -// key provider (CSP) in |*provider|.
|
| -bool GenerateAESKey(size_t key_size_in_bits,
|
| - ScopedHCRYPTPROV* provider,
|
| - ScopedHCRYPTKEY* key) {
|
| - DCHECK(provider);
|
| - DCHECK(key);
|
| -
|
| - ALG_ID alg = GetAESAlgIDForKeySize(key_size_in_bits);
|
| - if (alg == 0)
|
| - return false;
|
| -
|
| - ScopedHCRYPTPROV safe_provider;
|
| - // Note: The only time NULL is safe to be passed as pszContainer is when
|
| - // dwFlags contains CRYPT_VERIFYCONTEXT, as all keys generated and/or used
|
| - // will be treated as ephemeral keys and not persisted.
|
| - BOOL ok = CryptAcquireContext(safe_provider.receive(), NULL, NULL,
|
| - PROV_RSA_AES, CRYPT_VERIFYCONTEXT);
|
| - if (!ok)
|
| - return false;
|
| -
|
| - ScopedHCRYPTKEY safe_key;
|
| - // In the FIPS 140-2 Security Policy for CAPI on XP/Vista+, Microsoft notes
|
| - // that CryptGenKey makes use of the same functionality exposed via
|
| - // CryptGenRandom. The reason this is being used, as opposed to
|
| - // CryptGenRandom and CryptImportKey is for compliance with the security
|
| - // policy
|
| - ok = CryptGenKey(safe_provider.get(), alg, CRYPT_EXPORTABLE,
|
| - safe_key.receive());
|
| - if (!ok)
|
| - return false;
|
| -
|
| - key->swap(safe_key);
|
| - provider->swap(safe_provider);
|
| -
|
| - return true;
|
| -}
|
| -
|
| -// Returns true if the HMAC key size meets the requirement of FIPS 198
|
| -// Section 3. |alg| is the hash function used in the HMAC.
|
| -bool CheckHMACKeySize(size_t key_size_in_bits, ALG_ID alg) {
|
| - DWORD hash_size = 0;
|
| - switch (alg) {
|
| - case CALG_SHA1:
|
| - hash_size = 20;
|
| - break;
|
| - case CALG_SHA_256:
|
| - hash_size = 32;
|
| - break;
|
| - case CALG_SHA_384:
|
| - hash_size = 48;
|
| - break;
|
| - case CALG_SHA_512:
|
| - hash_size = 64;
|
| - break;
|
| - }
|
| - if (hash_size == 0)
|
| - return false;
|
| -
|
| - // An HMAC key must be >= L/2, where L is the output size of the hash
|
| - // function being used.
|
| - return (key_size_in_bits >= (hash_size / 2 * 8) &&
|
| - (key_size_in_bits % 8) == 0);
|
| -}
|
| -
|
| -// Attempts to generate a random, |key_size_in_bits|-long HMAC key, for use
|
| -// with the hash function |alg|.
|
| -// |key_size_in_bits| must be >= 1/2 the hash size of |alg| for security.
|
| -// Returns true if generation is successful, storing the generated key in
|
| -// |*key| and the key provider (CSP) in |*provider|.
|
| -bool GenerateHMACKey(size_t key_size_in_bits,
|
| - ALG_ID alg,
|
| - ScopedHCRYPTPROV* provider,
|
| - ScopedHCRYPTKEY* key,
|
| - scoped_array<BYTE>* raw_key) {
|
| - DCHECK(provider);
|
| - DCHECK(key);
|
| - DCHECK(raw_key);
|
| -
|
| - if (!CheckHMACKeySize(key_size_in_bits, alg))
|
| - return false;
|
| -
|
| - ScopedHCRYPTPROV safe_provider;
|
| - // See comment in GenerateAESKey as to why NULL is acceptable for the
|
| - // container name.
|
| - BOOL ok = CryptAcquireContext(safe_provider.receive(), NULL, NULL,
|
| - PROV_RSA_FULL, CRYPT_VERIFYCONTEXT);
|
| - if (!ok)
|
| - return false;
|
| -
|
| - DWORD key_size_in_bytes = key_size_in_bits / 8;
|
| - scoped_array<BYTE> random(new BYTE[key_size_in_bytes]);
|
| - ok = CryptGenRandom(safe_provider, key_size_in_bytes, random.get());
|
| - if (!ok)
|
| - return false;
|
| -
|
| - ScopedHCRYPTKEY safe_key;
|
| - bool rv = ImportRawKey(safe_provider, CALG_HMAC, random.get(),
|
| - key_size_in_bytes, &safe_key);
|
| - if (rv) {
|
| - key->swap(safe_key);
|
| - provider->swap(safe_provider);
|
| - raw_key->swap(random);
|
| - }
|
| -
|
| - SecureZeroMemory(random.get(), key_size_in_bytes);
|
| - return rv;
|
| -}
|
| -
|
| -// Attempts to create an HMAC hash instance using the specified |provider|
|
| -// and |key|. The inner hash function will be |hash_alg|. If successful,
|
| -// returns true and stores the hash in |*hash|.
|
| -// TODO(wtc): use this function in hmac_win.cc.
|
| -bool CreateHMACHash(HCRYPTPROV provider,
|
| - HCRYPTKEY key,
|
| - ALG_ID hash_alg,
|
| - ScopedHCRYPTHASH* hash) {
|
| - ScopedHCRYPTHASH safe_hash;
|
| - BOOL ok = CryptCreateHash(provider, CALG_HMAC, key, 0, safe_hash.receive());
|
| - if (!ok)
|
| - return false;
|
| -
|
| - HMAC_INFO hmac_info;
|
| - memset(&hmac_info, 0, sizeof(hmac_info));
|
| - hmac_info.HashAlgid = hash_alg;
|
| -
|
| - ok = CryptSetHashParam(safe_hash, HP_HMAC_INFO,
|
| - reinterpret_cast<const BYTE*>(&hmac_info), 0);
|
| - if (!ok)
|
| - return false;
|
| -
|
| - hash->swap(safe_hash);
|
| - return true;
|
| -}
|
| -
|
| -// Computes a block of the derived key using the PBKDF2 function F for the
|
| -// specified |block_index| using the PRF |hash|, writing the output to
|
| -// |output_buf|.
|
| -// |output_buf| must have enough space to accomodate the output of the PRF
|
| -// specified by |hash|.
|
| -// Returns true if the block was successfully computed.
|
| -bool ComputePBKDF2Block(HCRYPTHASH hash,
|
| - DWORD hash_size,
|
| - const std::string& salt,
|
| - size_t iterations,
|
| - uint32 block_index,
|
| - BYTE* output_buf) {
|
| - // From RFC 2898:
|
| - // 3. <snip> The function F is defined as the exclusive-or sum of the first
|
| - // c iterates of the underlying pseudorandom function PRF applied to the
|
| - // password P and the concatenation of the salt S and the block index i:
|
| - // F (P, S, c, i) = U_1 \xor U_2 \xor ... \xor U_c
|
| - // where
|
| - // U_1 = PRF(P, S || INT (i))
|
| - // U_2 = PRF(P, U_1)
|
| - // ...
|
| - // U_c = PRF(P, U_{c-1})
|
| - ScopedHCRYPTHASH safe_hash;
|
| - BOOL ok = CryptDuplicateHash(hash, NULL, 0, safe_hash.receive());
|
| - if (!ok)
|
| - return false;
|
| -
|
| - // Iteration U_1: Compute PRF for S.
|
| - ok = CryptHashData(safe_hash, reinterpret_cast<const BYTE*>(salt.data()),
|
| - salt.size(), 0);
|
| - if (!ok)
|
| - return false;
|
| -
|
| - // Iteration U_1: and append (big-endian) INT (i).
|
| - uint32 big_endian_block_index = htonl(block_index);
|
| - ok = CryptHashData(safe_hash,
|
| - reinterpret_cast<BYTE*>(&big_endian_block_index),
|
| - sizeof(big_endian_block_index), 0);
|
| -
|
| - std::vector<BYTE> hash_value(hash_size);
|
| -
|
| - DWORD size = hash_size;
|
| - ok = CryptGetHashParam(safe_hash, HP_HASHVAL, &hash_value[0], &size, 0);
|
| - if (!ok || size != hash_size)
|
| - return false;
|
| -
|
| - memcpy(output_buf, &hash_value[0], hash_size);
|
| -
|
| - // Iteration 2 - c: Compute U_{iteration} by applying the PRF to
|
| - // U_{iteration - 1}, then xor the resultant hash with |output|, which
|
| - // contains U_1 ^ U_2 ^ ... ^ U_{iteration - 1}.
|
| - for (size_t iteration = 2; iteration <= iterations; ++iteration) {
|
| - safe_hash.reset();
|
| - ok = CryptDuplicateHash(hash, NULL, 0, safe_hash.receive());
|
| - if (!ok)
|
| - return false;
|
| -
|
| - ok = CryptHashData(safe_hash, &hash_value[0], hash_size, 0);
|
| - if (!ok)
|
| - return false;
|
| -
|
| - size = hash_size;
|
| - ok = CryptGetHashParam(safe_hash, HP_HASHVAL, &hash_value[0], &size, 0);
|
| - if (!ok || size != hash_size)
|
| - return false;
|
| -
|
| - for (int i = 0; i < hash_size; ++i)
|
| - output_buf[i] ^= hash_value[i];
|
| - }
|
| -
|
| - return true;
|
| -}
|
| -
|
| -} // namespace
|
| -
|
| -SymmetricKey::~SymmetricKey() {
|
| - // TODO(wtc): create a "secure" string type that zeroes itself in the
|
| - // destructor.
|
| - if (!raw_key_.empty())
|
| - SecureZeroMemory(const_cast<char *>(raw_key_.data()), raw_key_.size());
|
| -}
|
| -
|
| -// static
|
| -SymmetricKey* SymmetricKey::GenerateRandomKey(Algorithm algorithm,
|
| - size_t key_size_in_bits) {
|
| - DCHECK_GE(key_size_in_bits, 8);
|
| -
|
| - ScopedHCRYPTPROV provider;
|
| - ScopedHCRYPTKEY key;
|
| -
|
| - bool ok = false;
|
| - scoped_array<BYTE> raw_key;
|
| -
|
| - switch (algorithm) {
|
| - case AES:
|
| - ok = GenerateAESKey(key_size_in_bits, &provider, &key);
|
| - break;
|
| - case HMAC_SHA1:
|
| - ok = GenerateHMACKey(key_size_in_bits, CALG_SHA1, &provider,
|
| - &key, &raw_key);
|
| - break;
|
| - }
|
| -
|
| - if (!ok) {
|
| - NOTREACHED();
|
| - return NULL;
|
| - }
|
| -
|
| - size_t key_size_in_bytes = key_size_in_bits / 8;
|
| - if (raw_key == NULL)
|
| - key_size_in_bytes = 0;
|
| -
|
| - SymmetricKey* result = new SymmetricKey(provider.release(),
|
| - key.release(),
|
| - raw_key.get(),
|
| - key_size_in_bytes);
|
| - if (raw_key != NULL)
|
| - SecureZeroMemory(raw_key.get(), key_size_in_bytes);
|
| -
|
| - return result;
|
| -}
|
| -
|
| -// static
|
| -SymmetricKey* SymmetricKey::DeriveKeyFromPassword(Algorithm algorithm,
|
| - const std::string& password,
|
| - const std::string& salt,
|
| - size_t iterations,
|
| - size_t key_size_in_bits) {
|
| - // CryptoAPI lacks routines to perform PBKDF2 derivation as specified
|
| - // in RFC 2898, so it must be manually implemented. Only HMAC-SHA1 is
|
| - // supported as the PRF.
|
| -
|
| - // While not used until the end, sanity-check the input before proceeding
|
| - // with the expensive computation.
|
| - DWORD provider_type = 0;
|
| - ALG_ID alg = 0;
|
| - switch (algorithm) {
|
| - case AES:
|
| - provider_type = PROV_RSA_AES;
|
| - alg = GetAESAlgIDForKeySize(key_size_in_bits);
|
| - break;
|
| - case HMAC_SHA1:
|
| - provider_type = PROV_RSA_FULL;
|
| - alg = CALG_HMAC;
|
| - break;
|
| - default:
|
| - NOTREACHED();
|
| - break;
|
| - }
|
| - if (provider_type == 0 || alg == 0)
|
| - return NULL;
|
| -
|
| - ScopedHCRYPTPROV provider;
|
| - BOOL ok = CryptAcquireContext(provider.receive(), NULL, NULL, provider_type,
|
| - CRYPT_VERIFYCONTEXT);
|
| - if (!ok)
|
| - return NULL;
|
| -
|
| - // Convert the user password into a key suitable to be fed into the PRF
|
| - // function.
|
| - ScopedHCRYPTKEY password_as_key;
|
| - BYTE* password_as_bytes =
|
| - const_cast<BYTE*>(reinterpret_cast<const BYTE*>(password.data()));
|
| - if (!ImportRawKey(provider, CALG_HMAC, password_as_bytes,
|
| - password.size(), &password_as_key))
|
| - return NULL;
|
| -
|
| - // Configure the PRF function. Only HMAC variants are supported, with the
|
| - // only hash function supported being SHA1.
|
| - // TODO(rsleevi): Support SHA-256 on XP SP3+.
|
| - ScopedHCRYPTHASH prf;
|
| - if (!CreateHMACHash(provider, password_as_key, CALG_SHA1, &prf))
|
| - return NULL;
|
| -
|
| - DWORD hLen = 0;
|
| - DWORD param_size = sizeof(hLen);
|
| - ok = CryptGetHashParam(prf, HP_HASHSIZE,
|
| - reinterpret_cast<BYTE*>(&hLen), ¶m_size, 0);
|
| - if (!ok || hLen == 0)
|
| - return NULL;
|
| -
|
| - // 1. If dkLen > (2^32 - 1) * hLen, output "derived key too long" and stop.
|
| - size_t dkLen = key_size_in_bits / 8;
|
| - DCHECK_GT(dkLen, 0);
|
| -
|
| - if ((dkLen / hLen) > 0xFFFFFFFF) {
|
| - DLOG(ERROR) << "Derived key too long.";
|
| - return NULL;
|
| - }
|
| -
|
| - // 2. Let l be the number of hLen-octet blocks in the derived key,
|
| - // rounding up, and let r be the number of octets in the last
|
| - // block:
|
| - size_t L = (dkLen + hLen - 1) / hLen;
|
| - DCHECK_GT(L, 0);
|
| -
|
| - size_t total_generated_size = L * hLen;
|
| - std::vector<BYTE> generated_key(total_generated_size);
|
| - BYTE* block_offset = &generated_key[0];
|
| -
|
| - // 3. For each block of the derived key apply the function F defined below
|
| - // to the password P, the salt S, the iteration count c, and the block
|
| - // index to compute the block:
|
| - // T_1 = F (P, S, c, 1)
|
| - // T_2 = F (P, S, c, 2)
|
| - // ...
|
| - // T_l = F (P, S, c, l)
|
| - // <snip>
|
| - // 4. Concatenate the blocks and extract the first dkLen octets to produce
|
| - // a derived key DK:
|
| - // DK = T_1 || T_2 || ... || T_l<0..r-1>
|
| - for (uint32 block_index = 1; block_index <= L; ++block_index) {
|
| - if (!ComputePBKDF2Block(prf, hLen, salt, iterations, block_index,
|
| - block_offset))
|
| - return NULL;
|
| - block_offset += hLen;
|
| - }
|
| -
|
| - // Convert the derived key bytes into a key handle for the desired algorithm.
|
| - ScopedHCRYPTKEY key;
|
| - if (!ImportRawKey(provider, alg, &generated_key[0], dkLen, &key))
|
| - return NULL;
|
| -
|
| - SymmetricKey* result = new SymmetricKey(provider.release(), key.release(),
|
| - &generated_key[0], dkLen);
|
| -
|
| - SecureZeroMemory(&generated_key[0], total_generated_size);
|
| -
|
| - return result;
|
| -}
|
| -
|
| -// static
|
| -SymmetricKey* SymmetricKey::Import(Algorithm algorithm,
|
| - const std::string& raw_key) {
|
| - DWORD provider_type = 0;
|
| - ALG_ID alg = 0;
|
| - switch (algorithm) {
|
| - case AES:
|
| - provider_type = PROV_RSA_AES;
|
| - alg = GetAESAlgIDForKeySize(raw_key.size() * 8);
|
| - break;
|
| - case HMAC_SHA1:
|
| - provider_type = PROV_RSA_FULL;
|
| - alg = CALG_HMAC;
|
| - break;
|
| - default:
|
| - NOTREACHED();
|
| - break;
|
| - }
|
| - if (provider_type == 0 || alg == 0)
|
| - return NULL;
|
| -
|
| - ScopedHCRYPTPROV provider;
|
| - BOOL ok = CryptAcquireContext(provider.receive(), NULL, NULL, provider_type,
|
| - CRYPT_VERIFYCONTEXT);
|
| - if (!ok)
|
| - return NULL;
|
| -
|
| - ScopedHCRYPTKEY key;
|
| - if (!ImportRawKey(provider, alg, raw_key.data(), raw_key.size(), &key))
|
| - return NULL;
|
| -
|
| - return new SymmetricKey(provider.release(), key.release(),
|
| - raw_key.data(), raw_key.size());
|
| -}
|
| -
|
| -bool SymmetricKey::GetRawKey(std::string* raw_key) {
|
| - // Short circuit for when the key was supplied to the constructor.
|
| - if (!raw_key_.empty()) {
|
| - *raw_key = raw_key_;
|
| - return true;
|
| - }
|
| -
|
| - DWORD size = 0;
|
| - BOOL ok = CryptExportKey(key_, 0, PLAINTEXTKEYBLOB, 0, NULL, &size);
|
| - if (!ok)
|
| - return false;
|
| -
|
| - std::vector<BYTE> result(size);
|
| -
|
| - ok = CryptExportKey(key_, 0, PLAINTEXTKEYBLOB, 0, &result[0], &size);
|
| - if (!ok)
|
| - return false;
|
| -
|
| - PlaintextBlobHeader* header =
|
| - reinterpret_cast<PlaintextBlobHeader*>(&result[0]);
|
| - raw_key->assign(reinterpret_cast<char*>(&result[sizeof(*header)]),
|
| - header->cbKeySize);
|
| -
|
| - SecureZeroMemory(&result[0], size);
|
| -
|
| - return true;
|
| -}
|
| -
|
| -SymmetricKey::SymmetricKey(HCRYPTPROV provider,
|
| - HCRYPTKEY key,
|
| - const void* key_data, size_t key_size_in_bytes)
|
| - : provider_(provider), key_(key) {
|
| - if (key_data) {
|
| - raw_key_.assign(reinterpret_cast<const char*>(key_data),
|
| - key_size_in_bytes);
|
| - }
|
| -}
|
| -
|
| -} // namespace base
|
|
|