include: crypto: Add Galois/Counter Mode (GCM) support

Add support for AES Galois/Counter Mode of Operation to the Crypto API.

Signed-off-by: Markus Fuchs <[email protected]>

Author: mrfuchs

include/crypto/cipher.h

@@ -268,4 +268,26 @@ static inline int cipher_ccm_op(struct cipher_ctx *ctx,
 	return ctx->ops.ccm_crypt_hndlr(ctx, pkt, nonce);
 }
 
+/*
+ * @brief Perform Galois/Counter Mode (GCM) crypto operation
+ *
+ * @param[in]  ctx       Pointer to the crypto context of this op.
+ * @param[in/out]  pkt   Structure holding the input/output, Associated
+ *			 Data (AD) and auth tag buffer pointers.
+ * @param[in]  nonce     Nonce for the operation. Same nonce value should not
+ *			 be reused across multiple operations (within a
+ *			 session context) for security.
+ *
+ * @return 0 on success, negative errno code on fail.
+ */
+static inline int cipher_gcm_op(struct cipher_ctx *ctx,
+				struct cipher_aead_pkt *pkt, u8_t *nonce)
+{
+	__ASSERT(ctx->ops.cipher_mode == CRYPTO_CIPHER_MODE_GCM, "GCM mode "
+		 "session invoking a different mode handler");
+
+	pkt->pkt->ctx = ctx;
+	return ctx->ops.gcm_crypt_hndlr(ctx, pkt, nonce);
+}
+
 #endif /* ZEPHYR_INCLUDE_CRYPTO_CIPHER_H_ */

include/crypto/cipher_structs.h

@@ -38,6 +38,7 @@ enum cipher_mode {
 	CRYPTO_CIPHER_MODE_CBC = 2,
 	CRYPTO_CIPHER_MODE_CTR = 3,
 	CRYPTO_CIPHER_MODE_CCM = 4,
+	CRYPTO_CIPHER_MODE_GCM = 5,
 };
 
 /* Forward declarations */
@@ -59,6 +60,9 @@ typedef int (*ctr_op_t)(struct cipher_ctx *ctx, struct cipher_pkt *pkt,
 typedef int (*ccm_op_t)(struct cipher_ctx *ctx, struct cipher_aead_pkt *pkt,
 			 u8_t *nonce);
 
+typedef int (*gcm_op_t)(struct cipher_ctx *ctx, struct cipher_aead_pkt *pkt,
+			 u8_t *nonce);
+
 struct cipher_ops {
 
 	enum cipher_mode cipher_mode;
@@ -68,6 +72,7 @@ struct cipher_ops {
 		cbc_op_t	cbc_crypt_hndlr;
 		ctr_op_t	ctr_crypt_hndlr;
 		ccm_op_t	ccm_crypt_hndlr;
+		gcm_op_t	gcm_crypt_hndlr;
 	};
 };
 
@@ -83,6 +88,11 @@ struct ctr_params {
 	u32_t ctr_len;
 };
 
+struct gcm_params {
+	u16_t tag_len;
+	u16_t nonce_len;
+};
+
 /* Structure encoding session parameters. Refer to comments for individual
  * fields to know the contract in terms of who fills what and when w.r.t
  * begin_session() call.
@@ -132,6 +142,7 @@ struct cipher_ctx {
 	union {
 		struct ccm_params ccm_info;
 		struct ctr_params ctr_info;
+		struct gcm_params gcm_info;
 	} mode_params;
 
 	/* Cryptographic keylength in bytes. To be populated by the app