[webcryto] Validate key usages during key creation.

content/child/webcrypto/platform_crypto.h

 // Copyright 2014 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 CONTENT_CHILD_WEBCRYPTO_PLATFORM_CRYPTO_H_
 #define CONTENT_CHILD_WEBCRYPTO_PLATFORM_CRYPTO_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 140 matching lines @@
                              const CryptoData& signature,
                              const CryptoData& data,
                              bool* signature_match);
 
 // |keylen_bytes| is the desired length of the key in bits.
 //
 // Preconditions:
 //  * algorithm.id() is for a symmetric key algorithm.
 //  * keylen_bytes is non-zero (TODO(eroman): revisit this).
 //  * For AES algorithms |keylen_bytes| is either 16, 24, or 32 bytes long.
+//  * usage_mask makes sense for the algorithm.
 Status GenerateSecretKey(const blink::WebCryptoAlgorithm& algorithm,
                          bool extractable,
                          blink::WebCryptoKeyUsageMask usage_mask,
                          unsigned keylen_bytes,
                          blink::WebCryptoKey* key);
 
 // Preconditions:
 //  * algorithm.id() is for an RSA algorithm.
 //  * public_exponent, modulus_length_bits and hash_or_null are the same as what
 //    is in algorithm. They are split out for convenience.
 //  * modulus_length_bits is not 0
 //  * public_exponent is not empty.
+//  * {public|private}_key_usage_mask make sense for the algorithm.
 Status GenerateRsaKeyPair(const blink::WebCryptoAlgorithm& algorithm,
                           bool extractable,
-                          blink::WebCryptoKeyUsageMask usage_mask,
+                          blink::WebCryptoKeyUsageMask public_key_usage_mask,
+                          blink::WebCryptoKeyUsageMask private_key_usage_mask,
                           unsigned int modulus_length_bits,
                           const CryptoData& public_exponent,
                           blink::WebCryptoKey* public_key,
                           blink::WebCryptoKey* private_key);
 
 // Preconditions:
 //  * |key| is non-null.
 //  * |algorithm.id()| is for a symmetric key algorithm.
 //  * For AES algorithms |key_data| is either 16, 24, or 32 bytes long.
+//  * usage_mask makes sense for the algorithm.
 // Note that this may be called from target Blink thread.
 Status ImportKeyRaw(const blink::WebCryptoAlgorithm& algorithm,
                     const CryptoData& key_data,
                     bool extractable,
                     blink::WebCryptoKeyUsageMask usage_mask,
                     blink::WebCryptoKey* key);
 
 // Preconditions:
 //  * algorithm.id() is for an RSA algorithm.
+//  * usage_mask makes sense for the algorithm.
 Status ImportRsaPublicKey(const blink::WebCryptoAlgorithm& algorithm,
                           bool extractable,
                           blink::WebCryptoKeyUsageMask usage_mask,
                           const CryptoData& modulus_data,
                           const CryptoData& exponent_data,
                           blink::WebCryptoKey* key);
 
 // Preconditions:
 //  * algorithm.id() is for an RSA algorithm.
 //  * modulus, public_exponent, and private_exponent will be non-empty. The
 //    others will either all be specified (non-empty), or all be unspecified
 //    (empty).
+//  * usage_mask makes sense for the algorithm.
 Status ImportRsaPrivateKey(const blink::WebCryptoAlgorithm& algorithm,
                            bool extractable,
                            blink::WebCryptoKeyUsageMask usage_mask,
                            const CryptoData& modulus,
                            const CryptoData& public_exponent,
                            const CryptoData& private_exponent,
                            const CryptoData& prime1,
                            const CryptoData& prime2,
                            const CryptoData& exponent1,
                            const CryptoData& exponent2,
                            const CryptoData& coefficient,
                            blink::WebCryptoKey* key);
 
 // Note that this may be called from target Blink thread.
+// Preconditions:
+//  * usage_mask makes sense for the algorithm.
 Status ImportKeySpki(const blink::WebCryptoAlgorithm& algorithm,
                      const CryptoData& key_data,
                      bool extractable,
                      blink::WebCryptoKeyUsageMask usage_mask,
                      blink::WebCryptoKey* key);
 
 // Note that this may be called from target Blink thread.
+// Preconditions:
+//  * usage_mask makes sense for the algorithm.
 Status ImportKeyPkcs8(const blink::WebCryptoAlgorithm& algorithm,
                       const CryptoData& key_data,
                       bool extractable,
                       blink::WebCryptoKeyUsageMask usage_mask,
                       blink::WebCryptoKey* key);
 
 // Preconditions:
 //  * |key| is non-null.
 Status ExportKeyRaw(SymKey* key, std::vector<uint8>* buffer);
 
@@ skipping 34 matching lines @@
 
 // Unwraps (decrypts) |wrapped_key_data| using AES-KW and places the results in
 // a WebCryptoKey. Raw key data remains inside NSS. This function should be used
 // when the input |wrapped_key_data| is known to result in symmetric raw key
 // data after AES-KW decryption.
 // Preconditions:
 //  * |wrapping_key| is non-null
 //  * |key| is non-null
 //  * |wrapped_key_data| is at least 24 bytes and a multiple of 8 bytes
 //  * |algorithm.id()| is for a symmetric key algorithm.
+//  * usage_mask makes sense for the algorithm.
 Status UnwrapSymKeyAesKw(const CryptoData& wrapped_key_data,
                          SymKey* wrapping_key,
                          const blink::WebCryptoAlgorithm& algorithm,
                          bool extractable,
                          blink::WebCryptoKeyUsageMask usage_mask,
                          blink::WebCryptoKey* key);
 
 // Performs AES-KW decryption on the input |data|. This function should be used
 // when the input |data| does not directly represent a key and should instead be
 // interpreted as generic bytes.
 // Preconditions:
 //  * |key| is non-null
 //  * |data| is at least 24 bytes and a multiple of 8 bytes
 //  * |buffer| is non-null.
 Status DecryptAesKw(SymKey* key,
                     const CryptoData& data,
                     std::vector<uint8>* buffer);
 
 }  // namespace platform
 
 }  // namespace webcrypto
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_WEBCRYPTO_PLATFORM_CRYPTO_H_