Add SignatureVerifier::VerifyInitRSAPSS for verifying RSA-PSS signatures.

crypto/signature_verifier_openssl.cc

 // 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 "crypto/signature_verifier.h"
 
 #include <openssl/evp.h>
 #include <openssl/x509.h>
 
 #include <vector>
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/stl_util.h"
 #include "crypto/openssl_util.h"
 
 namespace crypto {
 
+namespace {
+
+const EVP_MD* ToOpenSSLDigest(SignatureVerifier::HashAlgorithm hash_alg) {
+  switch (hash_alg) {
+    case SignatureVerifier::SHA1:
+      return EVP_sha1();
+    case SignatureVerifier::SHA256:
+      return EVP_sha256();
+  }
+}
+
+}  // namespace
+
 struct SignatureVerifier::VerifyContext {
-  ScopedOpenSSL<EVP_PKEY, EVP_PKEY_free> public_key;
   ScopedOpenSSL<EVP_MD_CTX, EVP_MD_CTX_destroy> ctx;
 };
 
 SignatureVerifier::SignatureVerifier()
     : verify_context_(NULL) {
 }
 
 SignatureVerifier::~SignatureVerifier() {
   Reset();
 }
 
-bool SignatureVerifier::VerifyInit(const uint8* signature_algorithm,
-                                   int signature_algorithm_len,
+bool SignatureVerifier::CommonInit(const EVP_MD* digest,
                                    const uint8* signature,
                                    int signature_len,
                                    const uint8* public_key_info,
-                                   int public_key_info_len) {
-  DCHECK(!verify_context_);
+                                   int public_key_info_len,
+                                   EVP_PKEY_CTX** pkey_ctx) {
+  if (verify_context_)
+    return false;
+
   verify_context_ = new VerifyContext;
   OpenSSLErrStackTracer err_tracer(FROM_HERE);

[wtc, 2013/06/27 02:23:51]

rsleevi: I am not familiar with OpenSSLErrStackTracer.
Could you please doublecheck all uses of OpenSSLErrStackTracer
in this file? In particular, do we need to use
OpenSSLErrStackTracer in CommonInit(), whose callers
already use OpenSSLErrStackTracer?

[Ryan Sleevi, 2013/06/27 16:51:08]

Ah, as long as both callers have an err tracer, no, it's not needed.

Basically, any time you're calling an OpenSSL function, you want to make sure
that at unwind time, there's at least a tracer on the stack.

 
-  ScopedOpenSSL<X509_ALGOR, X509_ALGOR_free> algorithm(
-      d2i_X509_ALGOR(NULL, &signature_algorithm, signature_algorithm_len));
-  if (!algorithm.get())
-    return false;
-
-  const EVP_MD* digest = EVP_get_digestbyobj(algorithm.get()->algorithm);
-  DCHECK(digest);
-
   signature_.assign(signature, signature + signature_len);
 
   // BIO_new_mem_buf is not const aware, but it does not modify the buffer.
   char* data = reinterpret_cast<char*>(const_cast<uint8*>(public_key_info));
   ScopedOpenSSL<BIO, BIO_free_all> bio(BIO_new_mem_buf(data,
                                                        public_key_info_len));
   if (!bio.get())
     return false;
 
-  verify_context_->public_key.reset(d2i_PUBKEY_bio(bio.get(), NULL));
-  if (!verify_context_->public_key.get())
+  ScopedOpenSSL<EVP_PKEY, EVP_PKEY_free> public_key(
+      d2i_PUBKEY_bio(bio.get(), NULL));
+  if (!public_key.get())
     return false;
 
   verify_context_->ctx.reset(EVP_MD_CTX_create());
-  int rv = EVP_VerifyInit_ex(verify_context_->ctx.get(), digest, NULL);
+  int rv = EVP_DigestVerifyInit(verify_context_->ctx.get(), pkey_ctx,
+                                digest, NULL, public_key.get());
+  return rv == 1;
+}
+
+bool SignatureVerifier::VerifyInit(const uint8* signature_algorithm,
+                                   int signature_algorithm_len,
+                                   const uint8* signature,
+                                   int signature_len,
+                                   const uint8* public_key_info,
+                                   int public_key_info_len) {
+  OpenSSLErrStackTracer err_tracer(FROM_HERE);
+  ScopedOpenSSL<X509_ALGOR, X509_ALGOR_free> algorithm(
+      d2i_X509_ALGOR(NULL, &signature_algorithm, signature_algorithm_len));
+  if (!algorithm.get())
+    return false;
+  const EVP_MD* digest = EVP_get_digestbyobj(algorithm.get()->algorithm);
+  if (!digest)
+    return false;
+
+  return CommonInit(digest, signature, signature_len, public_key_info,
+                    public_key_info_len, NULL);
+}
+
+bool SignatureVerifier::VerifyInitRSAPSS(HashAlgorithm hash_alg,
+                                         HashAlgorithm mask_hash_alg,
+                                         int salt_len,
+                                         const uint8* signature,
+                                         int signature_len,
+                                         const uint8* public_key_info,
+                                         int public_key_info_len) {
+  OpenSSLErrStackTracer err_tracer(FROM_HERE);
+  const EVP_MD* digest = ToOpenSSLDigest(hash_alg);
+  DCHECK(digest);
+
+  EVP_PKEY_CTX* pkey_ctx;
+  if (!CommonInit(digest, signature, signature_len, public_key_info,
+                  public_key_info_len, &pkey_ctx)) {
+    return false;
+  }
+
+  int rv = EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, RSA_PKCS1_PSS_PADDING);
+  if (rv != 1)
+    return false;
+  rv = EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx,
+                                    ToOpenSSLDigest(mask_hash_alg));
+  if (rv != 1)
+    return false;
+  rv = EVP_PKEY_CTX_set_rsa_pss_saltlen(pkey_ctx, salt_len);
   return rv == 1;
 }
 
 void SignatureVerifier::VerifyUpdate(const uint8* data_part,
                                      int data_part_len) {
   DCHECK(verify_context_);
   OpenSSLErrStackTracer err_tracer(FROM_HERE);
-  int rv = EVP_VerifyUpdate(verify_context_->ctx.get(),
-                            data_part, data_part_len);
+  int rv = EVP_DigestVerifyUpdate(verify_context_->ctx.get(),
+                                  data_part, data_part_len);
   DCHECK_EQ(rv, 1);
 }
 
 bool SignatureVerifier::VerifyFinal() {
   DCHECK(verify_context_);
   OpenSSLErrStackTracer err_tracer(FROM_HERE);
-  int rv = EVP_VerifyFinal(verify_context_->ctx.get(),
-                           vector_as_array(&signature_), signature_.size(),
-                           verify_context_->public_key.get());
+  int rv = EVP_DigestVerifyFinal(verify_context_->ctx.get(),
+                                 vector_as_array(&signature_),
+                                 signature_.size());
   DCHECK_GE(rv, 0);
   Reset();
   return rv == 1;
 }
 
 void SignatureVerifier::Reset() {
   delete verify_context_;
   verify_context_ = NULL;
   signature_.clear();
 }
 
 }  // namespace crypto