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      1 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "base/crypto/signature_verifier.h"
      6 
      7 #include <stdlib.h>
      8 
      9 #include "base/crypto/cssm_init.h"
     10 #include "base/logging.h"
     11 
     12 namespace base {
     13 
     14 SignatureVerifier::SignatureVerifier() : csp_handle_(0), sig_handle_(0) {
     15   EnsureCSSMInit();
     16 
     17   static CSSM_VERSION version = {2, 0};
     18   CSSM_RETURN crtn;
     19   crtn = CSSM_ModuleAttach(&gGuidAppleCSP, &version, &kCssmMemoryFunctions, 0,
     20                            CSSM_SERVICE_CSP, 0, CSSM_KEY_HIERARCHY_NONE,
     21                            NULL, 0, NULL, &csp_handle_);
     22   DCHECK(crtn == CSSM_OK);
     23 }
     24 
     25 SignatureVerifier::~SignatureVerifier() {
     26   Reset();
     27   if (csp_handle_) {
     28     CSSM_RETURN crtn = CSSM_ModuleDetach(csp_handle_);
     29     DCHECK(crtn == CSSM_OK);
     30   }
     31 }
     32 
     33 bool SignatureVerifier::VerifyInit(const uint8* signature_algorithm,
     34                                    int signature_algorithm_len,
     35                                    const uint8* signature,
     36                                    int signature_len,
     37                                    const uint8* public_key_info,
     38                                    int public_key_info_len) {
     39   signature_.assign(signature, signature + signature_len);
     40   public_key_info_.assign(public_key_info,
     41                           public_key_info + public_key_info_len);
     42 
     43   CSSM_ALGORITHMS key_alg = CSSM_ALGID_RSA;  // TODO(wtc): hardcoded.
     44 
     45   memset(&public_key_, 0, sizeof(public_key_));
     46   public_key_.KeyData.Data = const_cast<uint8*>(&public_key_info_[0]);
     47   public_key_.KeyData.Length = public_key_info_.size();
     48   public_key_.KeyHeader.HeaderVersion = CSSM_KEYHEADER_VERSION;
     49   public_key_.KeyHeader.BlobType = CSSM_KEYBLOB_RAW;
     50   public_key_.KeyHeader.Format = CSSM_KEYBLOB_RAW_FORMAT_X509;
     51   public_key_.KeyHeader.AlgorithmId = key_alg;
     52   public_key_.KeyHeader.KeyClass = CSSM_KEYCLASS_PUBLIC_KEY;
     53   public_key_.KeyHeader.KeyAttr = CSSM_KEYATTR_EXTRACTABLE;
     54   public_key_.KeyHeader.KeyUsage = CSSM_KEYUSE_VERIFY;
     55   CSSM_KEY_SIZE key_size;
     56   CSSM_RETURN crtn;
     57   crtn = CSSM_QueryKeySizeInBits(csp_handle_, NULL, &public_key_, &key_size);
     58   if (crtn) {
     59     NOTREACHED() << "CSSM_QueryKeySizeInBits failed: " << crtn;
     60     return false;
     61   }
     62   public_key_.KeyHeader.LogicalKeySizeInBits = key_size.LogicalKeySizeInBits;
     63 
     64   // TODO(wtc): decode signature_algorithm...
     65   CSSM_ALGORITHMS sig_alg = CSSM_ALGID_SHA1WithRSA;
     66 
     67   crtn = CSSM_CSP_CreateSignatureContext(csp_handle_, sig_alg, NULL,
     68                                          &public_key_, &sig_handle_);
     69   if (crtn) {
     70     NOTREACHED();
     71     return false;
     72   }
     73   crtn = CSSM_VerifyDataInit(sig_handle_);
     74   if (crtn) {
     75     NOTREACHED();
     76     return false;
     77   }
     78   return true;
     79 }
     80 
     81 void SignatureVerifier::VerifyUpdate(const uint8* data_part,
     82                                      int data_part_len) {
     83   CSSM_DATA data;
     84   data.Data = const_cast<uint8*>(data_part);
     85   data.Length = data_part_len;
     86   CSSM_RETURN crtn = CSSM_VerifyDataUpdate(sig_handle_, &data, 1);
     87   DCHECK(crtn == CSSM_OK);
     88 }
     89 
     90 bool SignatureVerifier::VerifyFinal() {
     91   CSSM_DATA sig;
     92   sig.Data = const_cast<uint8*>(&signature_[0]);
     93   sig.Length = signature_.size();
     94   CSSM_RETURN crtn = CSSM_VerifyDataFinal(sig_handle_, &sig);
     95   Reset();
     96 
     97   // crtn is CSSMERR_CSP_VERIFY_FAILED if signature verification fails.
     98   return (crtn == CSSM_OK);
     99 }
    100 
    101 void SignatureVerifier::Reset() {
    102   CSSM_RETURN crtn;
    103   if (sig_handle_) {
    104     crtn = CSSM_DeleteContext(sig_handle_);
    105     DCHECK(crtn == CSSM_OK);
    106     sig_handle_ = 0;
    107   }
    108   signature_.clear();
    109 
    110   // Can't call CSSM_FreeKey on public_key_ because we constructed
    111   // public_key_ manually.
    112 }
    113 
    114 }  // namespace base
    115 
    116