Add utility for generating KDF contexts

Starting in v19, OEMCrypto implementers will need to implement KDF generation in OEMCrypto.  To make it easier, this adds a utility to generate them based on the request context.

PiperOrigin-RevId: 572693987
Change-Id: Ife382bf35ceede508499e3677de115ef12999dcc

libwvdrmengine/oemcrypto/odk/include/odk.h

@@ -55,6 +55,9 @@
  *
  * @defgroup common_types Common Types
  * Enumerations and structures that are used by several OEMCrypto and ODK
+ *
+ * @defgroup odk_derivation Key Derivation Utils
+ * Utilities and constants relating to key derivation.
  * functions.
  *********************************************************************/
 
@@ -784,6 +787,83 @@ bool CheckApiVersionAtMost(const ODK_NonceValues* nonce_values,
 
 /// @}
 
+/// @addtogroup odk_derivation
+/// @{
+
+/**
+ * Contains the key label for the Mac key derivation.  This contains
+ * |ODK_MacKeyLabelWithZeroLength| number of bytes.
+ */
+extern const uint8_t ODK_MacKeyLabelWithZero[];
+
+/** Contains the number of bytes in |ODK_MacKeyLabelWithZero|. */
+extern const size_t ODK_MacKeyLabelWithZeroLength;
+
+/**
+ * Contains the key label for the Encryption key derivation.  This contains
+ * |ODK_EncKeyLabelWithZeroLength| number of bytes.
+ */
+extern const uint8_t ODK_EncKeyLabelWithZero[];
+
+/** Contains the number of bytes in |ODK_EncKeyLabelWithZero|. */
+extern const size_t ODK_EncKeyLabelWithZeroLength;
+
+/**
+ * Contains the suffix bytes (NIST 800-108 key length) for Mac key derivation.
+ * This value is appended after the context string.  This contains
+ * ODK_MacKeySuffixLength number of bytes.
+ */
+extern const uint8_t ODK_MacKeySuffix[];
+
+/** Contains the number of bytes in |ODK_MacKeySuffix|. */
+extern const size_t ODK_MacKeySuffixLength;
+
+/**
+ * Contains the suffix bytes (NIST 800-108 key length) for Encryption key
+ * derivation.  This value is appended after the context string.  This contains
+ * ODK_EncKeySuffixLength number of bytes.
+ */
+extern const uint8_t ODK_EncKeySuffix[];
+
+/** Contains the number of bytes in |ODK_EncKeySuffix|. */
+extern const size_t ODK_EncKeySuffixLength;
+
+/**
+ * Generates the key-derivation contexts for the license exchange based on the
+ * given context value.
+ *
+ * NOTE: if the mac_key_context/enc_key_context pointer are null and/or input
+ * mac_key_context_length/enc_key_context_length is zero, this function returns
+ * OEMCrypto_ERROR_SHORT_BUFFER and sets output
+ * mac_key_context_length/enc_key_context_length to the size needed.
+ *
+ * @param[in] context: pointer to the context buffer.
+ * @param[in] context_length: the length of the context buffer.
+ * @param[out] mac_key_context: an output buffer to contain the MAC key context.
+ * @param[in,out] mac_key_context_length: on input, contains the number of bytes
+ *       in |mac_key_context|; on return, will contain the context length.
+ * @param[out] enc_key_context: an output buffer to contain the encryption key
+ *       context.
+ * @param[in,out] enc_key_context_length: on input, contains the number of bytes
+ *       in |enc_key_context|; on return, will contain the context length.
+ *
+ * @retval OEMCrypto_SUCCESS
+ * @retval OEMCrypto_ERROR_SHORT_BUFFER: mac_key_context_length or
+ *         enc_key_context_length is too small
+ * @retval OEMCrypto_ERROR_INVALID_CONTEXT
+ *
+ * @version
+ * This method is new in version 19 of the API.
+ */
+OEMCryptoResult ODK_GenerateKeyContexts(const uint8_t* context,
+                                        size_t context_length,
+                                        uint8_t* mac_key_context,
+                                        size_t* mac_key_context_length,
+                                        uint8_t* enc_key_context,
+                                        size_t* enc_key_context_length);
+
+/// @}
+
 #ifdef __cplusplus
 }
 #endif

libwvdrmengine/oemcrypto/odk/include/odk_structs.h

@@ -19,7 +19,7 @@ extern "C" {
 #define ODK_MINOR_VERSION 0
 
 /* ODK Version string. Date changed automatically on each release. */
-#define ODK_RELEASE_DATE "ODK v19.0 2023-10-09"
+#define ODK_RELEASE_DATE "ODK v19.0 2023-10-11"
 
 /* The lowest version number for an ODK message. */
 #define ODK_FIRST_VERSION 16