1 files changed, 226 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/ccm.c b/core/lib/libtomcrypt/ccm.c
new file mode 100644
index 00000000..a7c06b9c
--- /dev/null
+++ b/core/lib/libtomcrypt/ccm.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright (c) 2014-2019, Linaro Limited
+ */
+
+#include <assert.h>
+#include <crypto/crypto.h>
+#include <crypto/crypto_impl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <tee_api_types.h>
+#include <tomcrypt.h>
+#include <util.h>
+
+#define TEE_CCM_KEY_MAX_LENGTH		32
+#define TEE_CCM_NONCE_MAX_LENGTH	13
+#define TEE_CCM_TAG_MAX_LENGTH		16
+
+struct tee_ccm_state {
+	struct crypto_authenc_ctx aectx;
+	ccm_state ctx;			/* the ccm state as defined by LTC */
+	size_t tag_len;			/* tag length */
+};
+
+static const struct crypto_authenc_ops aes_ccm_ops;
+
+TEE_Result crypto_aes_ccm_alloc_ctx(struct crypto_authenc_ctx **ctx_ret)
+{
+	struct tee_ccm_state *ctx = calloc(1, sizeof(*ctx));
+
+	if (!ctx)
+		return TEE_ERROR_OUT_OF_MEMORY;
+	ctx->aectx.ops = &aes_ccm_ops;
+
+	*ctx_ret = &ctx->aectx;
+	return TEE_SUCCESS;
+}
+
+static struct tee_ccm_state *to_tee_ccm_state(struct crypto_authenc_ctx *aectx)
+{
+	assert(aectx && aectx->ops == &aes_ccm_ops);
+
+	return container_of(aectx, struct tee_ccm_state, aectx);
+}
+
+static void crypto_aes_ccm_free_ctx(struct crypto_authenc_ctx *aectx)
+{
+	free(to_tee_ccm_state(aectx));
+}
+
+static void crypto_aes_ccm_copy_state(struct crypto_authenc_ctx *dst_aectx,
+				      struct crypto_authenc_ctx *src_aectx)
+{
+	struct tee_ccm_state *dst_ctx = to_tee_ccm_state(dst_aectx);
+	struct tee_ccm_state *src_ctx = to_tee_ccm_state(src_aectx);
+
+	dst_ctx->ctx = src_ctx->ctx;
+	dst_ctx->tag_len = src_ctx->tag_len;
+}
+
+static TEE_Result crypto_aes_ccm_init(struct crypto_authenc_ctx *aectx,
+				      TEE_OperationMode mode __unused,
+				      const uint8_t *key, size_t key_len,
+				      const uint8_t *nonce, size_t nonce_len,
+				      size_t tag_len, size_t aad_len,
+				      size_t payload_len)
+{
+	int ltc_res = 0;
+	int ltc_cipherindex = find_cipher("aes");
+	struct tee_ccm_state *ccm = to_tee_ccm_state(aectx);
+
+	if (ltc_cipherindex < 0)
+		return TEE_ERROR_NOT_SUPPORTED;
+
+	/* reset the state */
+	memset(&ccm->ctx, 0, sizeof(ccm->ctx));
+	ccm->tag_len = tag_len;
+
+	/* Check the key length */
+	if ((!key) || (key_len > TEE_CCM_KEY_MAX_LENGTH))
+		return TEE_ERROR_BAD_PARAMETERS;
+
+	/* check the nonce */
+	if (nonce_len > TEE_CCM_NONCE_MAX_LENGTH)
+		return TEE_ERROR_BAD_PARAMETERS;
+
+	/* check the tag len */
+	if ((tag_len < 4) || (tag_len > TEE_CCM_TAG_MAX_LENGTH) ||
+	    (tag_len % 2 != 0))
+		return TEE_ERROR_NOT_SUPPORTED;
+
+	ltc_res = ccm_init(&ccm->ctx, ltc_cipherindex, key, key_len,
+			   payload_len, tag_len, aad_len);
+	if (ltc_res != CRYPT_OK)
+		return TEE_ERROR_BAD_STATE;
+
+	/* Add the IV */
+	ltc_res = ccm_add_nonce(&ccm->ctx, nonce, nonce_len);
+	if (ltc_res != CRYPT_OK)
+		return TEE_ERROR_BAD_STATE;
+
+	return TEE_SUCCESS;
+}
+
+static TEE_Result crypto_aes_ccm_update_aad(struct crypto_authenc_ctx *aectx,
+					    const uint8_t *data, size_t len)
+{
+	struct tee_ccm_state *ccm = to_tee_ccm_state(aectx);
+	int ltc_res = 0;
+
+	/* Add the AAD (note: aad can be NULL if aadlen == 0) */
+	ltc_res = ccm_add_aad(&ccm->ctx, data, len);
+	if (ltc_res != CRYPT_OK)
+		return TEE_ERROR_BAD_STATE;
+
+	return TEE_SUCCESS;
+}
+
+static TEE_Result
+crypto_aes_ccm_update_payload(struct crypto_authenc_ctx *aectx,
+			      TEE_OperationMode mode, const uint8_t *src_data,
+			      size_t len, uint8_t *dst_data)
+{
+	int ltc_res = 0;
+	int dir = 0;
+	struct tee_ccm_state *ccm = to_tee_ccm_state(aectx);
+	unsigned char *pt = NULL;
+	unsigned char *ct = NULL;
+
+	if (mode == TEE_MODE_ENCRYPT) {
+		pt = (unsigned char *)src_data;
+		ct = dst_data;
+		dir = CCM_ENCRYPT;
+	} else {
+		pt = dst_data;
+		ct = (unsigned char *)src_data;
+		dir = CCM_DECRYPT;
+	}
+	ltc_res = ccm_process(&ccm->ctx, pt, len, ct, dir);
+	if (ltc_res != CRYPT_OK)
+		return TEE_ERROR_BAD_STATE;
+
+	return TEE_SUCCESS;
+}
+
+static TEE_Result crypto_aes_ccm_enc_final(struct crypto_authenc_ctx *aectx,
+					   const uint8_t *src_data,
+					   size_t len, uint8_t *dst_data,
+					   uint8_t *dst_tag,
+					   size_t *dst_tag_len)
+{
+	TEE_Result res = TEE_SUCCESS;
+	struct tee_ccm_state *ccm = to_tee_ccm_state(aectx);
+	int ltc_res = 0;
+
+	/* Finalize the remaining buffer */
+	res = crypto_aes_ccm_update_payload(aectx, TEE_MODE_ENCRYPT, src_data,
+					    len, dst_data);
+	if (res != TEE_SUCCESS)
+		return res;
+
+	/* Check the tag length */
+	if (*dst_tag_len < ccm->tag_len) {
+		*dst_tag_len = ccm->tag_len;
+		return TEE_ERROR_SHORT_BUFFER;
+	}
+	*dst_tag_len = ccm->tag_len;
+
+	/* Compute the tag */
+	ltc_res = ccm_done(&ccm->ctx, dst_tag,
+			   (unsigned long *)dst_tag_len);
+	if (ltc_res != CRYPT_OK)
+		return TEE_ERROR_BAD_STATE;
+
+	return TEE_SUCCESS;
+}
+
+static TEE_Result crypto_aes_ccm_dec_final(struct crypto_authenc_ctx *aectx,
+					   const uint8_t *src_data, size_t len,
+					   uint8_t *dst_data,
+					   const uint8_t *tag, size_t tag_len)
+{
+	TEE_Result res = TEE_ERROR_BAD_STATE;
+	struct tee_ccm_state *ccm = to_tee_ccm_state(aectx);
+	int ltc_res = 0;
+	uint8_t dst_tag[TEE_CCM_TAG_MAX_LENGTH] = { 0 };
+	unsigned long ltc_tag_len = tag_len;
+
+	if (tag_len == 0)
+		return TEE_ERROR_SHORT_BUFFER;
+	if (tag_len > TEE_CCM_TAG_MAX_LENGTH)
+		return TEE_ERROR_BAD_STATE;
+
+	/* Process the last buffer, if any */
+	res = crypto_aes_ccm_update_payload(aectx, TEE_MODE_DECRYPT, src_data,
+					    len, dst_data);
+	if (res != TEE_SUCCESS)
+		return res;
+
+	/* Finalize the authentication */
+	ltc_res = ccm_done(&ccm->ctx, dst_tag, &ltc_tag_len);
+	if (ltc_res != CRYPT_OK)
+		return TEE_ERROR_BAD_STATE;
+
+	if (consttime_memcmp(dst_tag, tag, tag_len) != 0)
+		res = TEE_ERROR_MAC_INVALID;
+	else
+		res = TEE_SUCCESS;
+	return res;
+}
+
+static void crypto_aes_ccm_final(struct crypto_authenc_ctx *aectx)
+{
+	ccm_reset(&to_tee_ccm_state(aectx)->ctx);
+}
+
+static const struct crypto_authenc_ops aes_ccm_ops = {
+	.init = crypto_aes_ccm_init,
+	.update_aad = crypto_aes_ccm_update_aad,
+	.update_payload = crypto_aes_ccm_update_payload,
+	.enc_final = crypto_aes_ccm_enc_final,
+	.dec_final = crypto_aes_ccm_dec_final,
+	.final = crypto_aes_ccm_final,
+	.free_ctx = crypto_aes_ccm_free_ctx,
+	.copy_state = crypto_aes_ccm_copy_state,
+};