content/child/webcrypto/openssl/rsa_sign_openssl.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 "content/child/webcrypto/crypto_data.h"
   7 #include "content/child/webcrypto/openssl/key_openssl.h"
   8 #include "content/child/webcrypto/openssl/rsa_sign_openssl.h"
   9 #include "content/child/webcrypto/openssl/util_openssl.h"
  10 #include "content/child/webcrypto/status.h"
  11 #include "crypto/openssl_util.h"
  12 #include "crypto/scoped_openssl_types.h"
  13 #include "third_party/WebKit/public/platform/WebCryptoKeyAlgorithm.h"
  14
  15 namespace content {
  16
  17 namespace webcrypto {
  18
  19 namespace {
  20
  21 // Extracts the OpenSSL key and digest from a WebCrypto key. The returned
  22 // pointers will remain valid as long as |key| is alive.
  23 Status GetPKeyAndDigest(const blink::WebCryptoKey& key,
  24                         EVP_PKEY** pkey,
  25                         const EVP_MD** digest) {
  26   *pkey = AsymKeyOpenSsl::Cast(key)->key();
  27
  28   *digest = GetDigest(key.algorithm().rsaHashedParams()->hash().id());
  29   if (!*digest)
  30     return Status::ErrorUnsupported();
  31
  32   return Status::Success();
  33 }
  34
  35 // Sets the PSS parameters on |pctx| if the key is for RSA-PSS.
  36 //
  37 // Otherwise returns Success without doing anything.
  38 Status ApplyRsaPssOptions(const blink::WebCryptoKey& key,
  39                           const EVP_MD* const mgf_digest,
  40                           unsigned int salt_length_bytes,
  41                           EVP_PKEY_CTX* pctx) {
  42   // Only apply RSA-PSS options if the key is for RSA-PSS.
  43   if (key.algorithm().id() != blink::WebCryptoAlgorithmIdRsaPss) {
  44     DCHECK_EQ(0u, salt_length_bytes);
  45     DCHECK_EQ(blink::WebCryptoAlgorithmIdRsaSsaPkcs1v1_5, key.algorithm().id());
  46     return Status::Success();
  47   }
  48
  49   // BoringSSL takes a signed int for the salt length, and interprets
  50   // negative values in a special manner. Make sure not to silently underflow.
  51   base::CheckedNumeric<int> salt_length_bytes_int(salt_length_bytes);
  52   if (!salt_length_bytes_int.IsValid()) {
  53     // TODO(eroman): Give a better error message.
  54     return Status::OperationError();
  55   }
  56
  57   if (1 != EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) ||
  58       1 != EVP_PKEY_CTX_set_rsa_mgf1_md(pctx, mgf_digest) ||
  59       1 != EVP_PKEY_CTX_set_rsa_pss_saltlen(
  60                pctx, salt_length_bytes_int.ValueOrDie())) {
  61     return Status::OperationError();
  62   }
  63
  64   return Status::Success();
  65 }
  66
  67 }  // namespace
  68
  69 Status RsaSign(const blink::WebCryptoKey& key,
  70                unsigned int pss_salt_length_bytes,
  71                const CryptoData& data,
  72                std::vector<uint8_t>* buffer) {
  73   if (key.type() != blink::WebCryptoKeyTypePrivate)
  74     return Status::ErrorUnexpectedKeyType();
  75
  76   crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
  77   crypto::ScopedEVP_MD_CTX ctx(EVP_MD_CTX_create());
  78   EVP_PKEY_CTX* pctx = NULL;  // Owned by |ctx|.
  79
  80   EVP_PKEY* private_key = NULL;
  81   const EVP_MD* digest = NULL;
  82   Status status = GetPKeyAndDigest(key, &private_key, &digest);
  83   if (status.IsError())
  84     return status;
  85
  86   // NOTE: A call to EVP_DigestSignFinal() with a NULL second parameter
  87   // returns a maximum allocation size, while the call without a NULL returns
  88   // the real one, which may be smaller.
  89   size_t sig_len = 0;
  90   if (!ctx.get() ||
  91       !EVP_DigestSignInit(ctx.get(), &pctx, digest, NULL, private_key)) {
  92     return Status::OperationError();
  93   }
  94
  95   // Set PSS-specific options (if applicable).
  96   status = ApplyRsaPssOptions(key, digest, pss_salt_length_bytes, pctx);
  97   if (status.IsError())
  98     return status;
  99
 100   if (!EVP_DigestSignUpdate(ctx.get(), data.bytes(), data.byte_length()) ||
 101       !EVP_DigestSignFinal(ctx.get(), NULL, &sig_len)) {
 102     return Status::OperationError();
 103   }
 104
 105   buffer->resize(sig_len);
 106   if (!EVP_DigestSignFinal(ctx.get(), &buffer->front(), &sig_len))
 107     return Status::OperationError();
 108
 109   buffer->resize(sig_len);
 110   return Status::Success();
 111 }
 112
 113 Status RsaVerify(const blink::WebCryptoKey& key,
 114                  unsigned int pss_salt_length_bytes,
 115                  const CryptoData& signature,
 116                  const CryptoData& data,
 117                  bool* signature_match) {
 118   if (key.type() != blink::WebCryptoKeyTypePublic)
 119     return Status::ErrorUnexpectedKeyType();
 120
 121   crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
 122   crypto::ScopedEVP_MD_CTX ctx(EVP_MD_CTX_create());
 123   EVP_PKEY_CTX* pctx = NULL;  // Owned by |ctx|.
 124
 125   EVP_PKEY* public_key = NULL;
 126   const EVP_MD* digest = NULL;
 127   Status status = GetPKeyAndDigest(key, &public_key, &digest);
 128   if (status.IsError())
 129     return status;
 130
 131   if (!EVP_DigestVerifyInit(ctx.get(), &pctx, digest, NULL, public_key))
 132     return Status::OperationError();
 133
 134   // Set PSS-specific options (if applicable).
 135   status = ApplyRsaPssOptions(key, digest, pss_salt_length_bytes, pctx);
 136   if (status.IsError())
 137     return status;
 138
 139   if (!EVP_DigestVerifyUpdate(ctx.get(), data.bytes(), data.byte_length()))
 140     return Status::OperationError();
 141
 142   *signature_match = 1 == EVP_DigestVerifyFinal(ctx.get(), signature.bytes(),
 143                                                 signature.byte_length());
 144   return Status::Success();
 145 }
 146
 147 }  // namespace webcrypto
 148
 149 }  // namespace content