components/webcrypto/algorithms/rsa_sign.cc

   1 // Copyright 2014 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/numerics/safe_math.h"
   6 #include "base/stl_util.h"
   7 #include "components/webcrypto/algorithms/rsa_sign.h"
   8 #include "components/webcrypto/algorithms/util_openssl.h"
   9 #include "components/webcrypto/crypto_data.h"
  10 #include "components/webcrypto/key.h"
  11 #include "components/webcrypto/status.h"
  12 #include "crypto/openssl_util.h"
  13 #include "crypto/scoped_openssl_types.h"
  14 #include "third_party/WebKit/public/platform/WebCryptoKeyAlgorithm.h"
  15
  16 namespace webcrypto {
  17
  18 namespace {
  19
  20 // Extracts the OpenSSL key and digest from a WebCrypto key. The returned
  21 // pointers will remain valid as long as |key| is alive.
  22 Status GetPKeyAndDigest(const blink::WebCryptoKey& key,
  23                         EVP_PKEY** pkey,
  24                         const EVP_MD** digest) {
  25   *pkey = GetEVP_PKEY(key);
  26
  27   *digest = GetDigest(key.algorithm().rsaHashedParams()->hash().id());
  28   if (!*digest)
  29     return Status::ErrorUnsupported();
  30
  31   return Status::Success();
  32 }
  33
  34 // Sets the PSS parameters on |pctx| if the key is for RSA-PSS.
  35 //
  36 // Otherwise returns Success without doing anything.
  37 Status ApplyRsaPssOptions(const blink::WebCryptoKey& key,
  38                           const EVP_MD* const mgf_digest,
  39                           unsigned int salt_length_bytes,
  40                           EVP_PKEY_CTX* pctx) {
  41   // Only apply RSA-PSS options if the key is for RSA-PSS.
  42   if (key.algorithm().id() != blink::WebCryptoAlgorithmIdRsaPss) {
  43     DCHECK_EQ(0u, salt_length_bytes);
  44     DCHECK_EQ(blink::WebCryptoAlgorithmIdRsaSsaPkcs1v1_5, key.algorithm().id());
  45     return Status::Success();
  46   }
  47
  48   // BoringSSL takes a signed int for the salt length, and interprets
  49   // negative values in a special manner. Make sure not to silently underflow.
  50   base::CheckedNumeric<int> salt_length_bytes_int(salt_length_bytes);
  51   if (!salt_length_bytes_int.IsValid()) {
  52     // TODO(eroman): Give a better error message.
  53     return Status::OperationError();
  54   }
  55
  56   if (1 != EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) ||
  57       1 != EVP_PKEY_CTX_set_rsa_mgf1_md(pctx, mgf_digest) ||
  58       1 != EVP_PKEY_CTX_set_rsa_pss_saltlen(
  59                pctx, salt_length_bytes_int.ValueOrDie())) {
  60     return Status::OperationError();
  61   }
  62
  63   return Status::Success();
  64 }
  65
  66 }  // namespace
  67
  68 Status RsaSign(const blink::WebCryptoKey& key,
  69                unsigned int pss_salt_length_bytes,
  70                const CryptoData& data,
  71                std::vector<uint8_t>* buffer) {
  72   if (key.type() != blink::WebCryptoKeyTypePrivate)
  73     return Status::ErrorUnexpectedKeyType();
  74
  75   crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
  76   crypto::ScopedEVP_MD_CTX ctx(EVP_MD_CTX_create());
  77   EVP_PKEY_CTX* pctx = NULL;  // Owned by |ctx|.
  78
  79   EVP_PKEY* private_key = NULL;
  80   const EVP_MD* digest = NULL;
  81   Status status = GetPKeyAndDigest(key, &private_key, &digest);
  82   if (status.IsError())
  83     return status;
  84
  85   // NOTE: A call to EVP_DigestSignFinal() with a NULL second parameter
  86   // returns a maximum allocation size, while the call without a NULL returns
  87   // the real one, which may be smaller.
  88   size_t sig_len = 0;
  89   if (!ctx.get() ||
  90       !EVP_DigestSignInit(ctx.get(), &pctx, digest, NULL, private_key)) {
  91     return Status::OperationError();
  92   }
  93
  94   // Set PSS-specific options (if applicable).
  95   status = ApplyRsaPssOptions(key, digest, pss_salt_length_bytes, pctx);
  96   if (status.IsError())
  97     return status;
  98
  99   if (!EVP_DigestSignUpdate(ctx.get(), data.bytes(), data.byte_length()) ||
 100       !EVP_DigestSignFinal(ctx.get(), NULL, &sig_len)) {
 101     return Status::OperationError();
 102   }
 103
 104   buffer->resize(sig_len);
 105   if (!EVP_DigestSignFinal(ctx.get(), vector_as_array(buffer), &sig_len))
 106     return Status::OperationError();
 107
 108   buffer->resize(sig_len);
 109   return Status::Success();
 110 }
 111
 112 Status RsaVerify(const blink::WebCryptoKey& key,
 113                  unsigned int pss_salt_length_bytes,
 114                  const CryptoData& signature,
 115                  const CryptoData& data,
 116                  bool* signature_match) {
 117   if (key.type() != blink::WebCryptoKeyTypePublic)
 118     return Status::ErrorUnexpectedKeyType();
 119
 120   crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
 121   crypto::ScopedEVP_MD_CTX ctx(EVP_MD_CTX_create());
 122   EVP_PKEY_CTX* pctx = NULL;  // Owned by |ctx|.
 123
 124   EVP_PKEY* public_key = NULL;
 125   const EVP_MD* digest = NULL;
 126   Status status = GetPKeyAndDigest(key, &public_key, &digest);
 127   if (status.IsError())
 128     return status;
 129
 130   if (!EVP_DigestVerifyInit(ctx.get(), &pctx, digest, NULL, public_key))
 131     return Status::OperationError();
 132
 133   // Set PSS-specific options (if applicable).
 134   status = ApplyRsaPssOptions(key, digest, pss_salt_length_bytes, pctx);
 135   if (status.IsError())
 136     return status;
 137
 138   if (!EVP_DigestVerifyUpdate(ctx.get(), data.bytes(), data.byte_length()))
 139     return Status::OperationError();
 140
 141   *signature_match = 1 == EVP_DigestVerifyFinal(ctx.get(), signature.bytes(),
 142                                                 signature.byte_length());
 143   return Status::Success();
 144 }
 145
 146 }  // namespace webcrypto