Sign self-signed certs with SHA256.

net/cert/x509_util.h

 // Copyright (c) 2012 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.
 
 #ifndef NET_CERT_X509_UTIL_H_
 #define NET_CERT_X509_UTIL_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "base/time/time.h"
+#include "crypto/hmac.h"
 #include "net/base/net_export.h"
 
 namespace crypto {
 class ECPrivateKey;
 class RSAPrivateKey;
 }
 
 namespace net {
 
 class X509Certificate;
 
 namespace x509_util {
 
 // Returns true if the times can be used to create an X.509 certificate.
 // Certificates can accept dates from Jan 1st, 1 to Dec 31, 9999.  A bug in NSS
 // limited the range to 1950-9999
 // (https://bugzilla.mozilla.org/show_bug.cgi?id=786531).  This function will
 // return whether it is supported by the currently used crypto library.
 NET_EXPORT_PRIVATE bool IsSupportedValidityRange(base::Time not_valid_before,
                                                  base::Time not_valid_after);
 
-// Creates a server bound certificate containing the public key in |key|.
+// Creates a private keypair and server bound certificate.
 // Domain, serial number and validity period are given as
 // parameters. The certificate is signed by the private key in |key|.
-// The hashing algorithm for the signature is SHA-1.
+// The signature algorithm may be updated periodically to match best practices.
 //
 // See Internet Draft draft-balfanz-tls-obc-00 for more details:
 // http://tools.ietf.org/html/draft-balfanz-tls-obc-00
-NET_EXPORT_PRIVATE bool CreateDomainBoundCertEC(
+NET_EXPORT_PRIVATE bool CreateKeyAndDomainBoundCertEC(
+    const std::string& domain,
+    uint32 serial_number,
+    base::Time not_valid_before,
+    base::Time not_valid_after,
+    crypto::ECPrivateKey** key,

[Ryan Sleevi, 2013/10/18 22:45:23]

Pass a scoped_ptr<crypto::ECPrivateKey>*, rather than a pointer-pointer.

[bemasc, 2013/10/19 00:47:45]

Done.

+    std::string* der_cert);
+
+// Helper function for CreateKeyAndDomainBoundCertEC
+NET_EXPORT_PRIVATE bool CreateDomainBoundCertECInternal(
     crypto::ECPrivateKey* key,
+    crypto::HMAC::HashAlgorithm alg,

[Ryan Sleevi, 2013/10/18 22:45:23]

The dependency on crypto::HMAC is wrong here.

Likewise, you don't need to expose this in a public header.

[bemasc, 2013/10/19 00:47:45]

I'm not sure what you mean.
In light of the new design, I've removed "Internal" from the name.

[Ryan Sleevi, 2013/10/21 17:56:14]

I meant that X.509 has nothing to do with HMAC. You're just overloading it
because it has hash names.

I see us either moving crypto::HMAC::HashAlgorithm into crypto/, or making a
specific hash algorithm for the cert. Having crypto::HashTo[EVP/OidTag] in
crypto_util_openssl/crypto_util_nss is one approach, so that these functions can
use it, or simply defining a new enum for the supported *cert* hash algs.

Considering that there are other types of cert types that don't align with HMAC
(eg: RSA-PSS), I don't want us to overload the enum.

     const std::string& domain,
     uint32 serial_number,
     base::Time not_valid_before,
     base::Time not_valid_after,
     std::string* der_cert);
 
-// Create a self-signed certificate containing the public key in |key|.
+// Creates a public-private keypair and a self-signed certificate.
 // Subject, serial number and validity period are given as parameters.
-// The certificate is signed by the private key in |key|. The hashing
-// algorithm for the signature is SHA-1.
+// The certificate is signed by the private key in |key|. The key length and
+// signature algorithm may be updated periodically to match best practices.
 //
 // |subject| is a distinguished name defined in RFC4514 with _only_ a CN
 // component, as in:
 //   CN=Michael Wong
 //
 // SECURITY WARNING
 //
 // Using self-signed certificates has the following security risks:
 // 1. Encryption without authentication and thus vulnerable to
 //    man-in-the-middle attacks.
 // 2. Self-signed certificates cannot be revoked.
 //
 // Use this certificate only after the above risks are acknowledged.
-NET_EXPORT bool CreateSelfSignedCert(crypto::RSAPrivateKey* key,
-                                     const std::string& subject,
-                                     uint32 serial_number,
-                                     base::Time not_valid_before,
-                                     base::Time not_valid_after,
-                                     std::string* der_cert);
+NET_EXPORT bool CreateKeyAndSelfSignedCert(const std::string& subject,
+                                           uint32 serial_number,
+                                           base::Time not_valid_before,
+                                           base::Time not_valid_after,
+                                           crypto::RSAPrivateKey** key,

[Ryan Sleevi, 2013/10/18 22:45:23]

ditto scoped_ptr

[bemasc, 2013/10/19 00:47:45]

Done.

+                                           std::string* der_cert);
+
+// Helper function for CreateKeyAndSelfSignedCert.
+NET_EXPORT_PRIVATE bool CreateSelfSignedCertInternal(
+    crypto::RSAPrivateKey* key,
+    crypto::HMAC::HashAlgorithm alg,
+    const std::string& subject,
+    uint32 serial_number,
+    base::Time not_valid_before,
+    base::Time not_valid_after,
+    std::string* der_cert);
+
+// Legacy certificate signing function.  This function is preserved here because
+// best practices suggest that keys signed with one hash algorithm should not be
+// signed again later with a different algorithm.  Eventually, all users of this

[Ryan Sleevi, 2013/10/18 22:45:23]

You're not signing keys, you're signing data with a key.

because you should not re-use a key for signing data with multiple signature
algorithms or parameters.

[bemasc, 2013/10/19 00:47:45]

Done.

[bemasc, 2013/10/19 00:47:45]

Removed this function.

+// function should migrate to CreateKeyAndSelfSignedCert.
+NET_EXPORT bool CreateSha1SelfSignedCert(crypto::RSAPrivateKey* key,
+                                         const std::string& subject,
+                                         uint32 serial_number,
+                                         base::Time not_valid_before,
+                                         base::Time not_valid_after,
+                                         std::string* der_cert);
 
 // Comparator for use in STL algorithms that will sort client certificates by
 // order of preference.
 // Returns true if |a| is more preferable than |b|, allowing it to be used
 // with any algorithm that compares according to strict weak ordering.
 //
 // Criteria include:
 // - Prefer certificates that have a longer validity period (later
 //   expiration dates)
 // - If equal, prefer certificates that were issued more recently
 // - If equal, prefer shorter chains (if available)
 class NET_EXPORT_PRIVATE ClientCertSorter {
  public:
   ClientCertSorter();
 
   bool operator()(
       const scoped_refptr<X509Certificate>& a,
       const scoped_refptr<X509Certificate>& b) const;
 
  private:
   base::Time now_;
 };
 
 } // namespace x509_util
 
 } // namespace net
 
 #endif  // NET_CERT_X509_UTIL_H_