[net-next 0/5] Add CHACHA20-POLY1305 cipher to Kernel TLS

[net-next 0/5] Add CHACHA20-POLY1305 cipher to Kernel TLS

[Vadim Fedorenko]

RFC 7905 defines usage of ChaCha20-Poly1305 in TLS connections. This
cipher is widely used nowadays and it's good to have a support for it
in TLS connections in kernel

Vadim Fedorenko (5):
  net/tls: make inline helpers protocol-aware
  net/tls: add CHACHA20-POLY1305 specific defines and structures
  net/tls: add CHACHA20-POLY1305 specific behavior
  net/tls: add CHACHA20-POLY1305 configuration
  selftests/tls: add CHACHA20-POLY1305 to tls selftests

 include/net/tls.h                 | 32 ++++++++++++++++---------------
 include/uapi/linux/tls.h          | 15 +++++++++++++++
 net/tls/tls_device.c              |  2 +-
 net/tls/tls_device_fallback.c     | 13 +++++++------
 net/tls/tls_main.c                |  3 +++
 net/tls/tls_sw.c                  | 36 ++++++++++++++++++++++++++---------
 tools/testing/selftests/net/tls.c | 40 ++++++++++++++++++++++++++++++++-------
 7 files changed, 103 insertions(+), 38 deletions(-)

-- 
1.8.3.1

[net-next 1/5] net/tls: make inline helpers protocol-aware

[Vadim Fedorenko]

Inline functions defined in tls.h have a lot of AES-specific
constants. Remove these constants and change argument to struct
tls_prot_info to have an access to cipher type in later patches

Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
---
 include/net/tls.h             | 26 ++++++++++++--------------
 net/tls/tls_device.c          |  2 +-
 net/tls/tls_device_fallback.c | 13 +++++++------
 net/tls/tls_sw.c              | 12 +++++-------
 4 files changed, 25 insertions(+), 28 deletions(-)

diff --git a/include/net/tls.h b/include/net/tls.h
index cf14730..d04ce73 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -502,31 +502,30 @@ static inline void tls_advance_record_sn(struct sock *sk,
 		tls_err_abort(sk, EBADMSG);
 
 	if (prot->version != TLS_1_3_VERSION)
-		tls_bigint_increment(ctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
+		tls_bigint_increment(ctx->iv + prot->salt_size,
 				     prot->iv_size);
 }
 
 static inline void tls_fill_prepend(struct tls_context *ctx,
 			     char *buf,
 			     size_t plaintext_len,
-			     unsigned char record_type,
-			     int version)
+			     unsigned char record_type)
 {
 	struct tls_prot_info *prot = &ctx->prot_info;
 	size_t pkt_len, iv_size = prot->iv_size;
 
 	pkt_len = plaintext_len + prot->tag_size;
-	if (version != TLS_1_3_VERSION) {
+	if (prot->version != TLS_1_3_VERSION) {
 		pkt_len += iv_size;
 
 		memcpy(buf + TLS_NONCE_OFFSET,
-		       ctx->tx.iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, iv_size);
+		       ctx->tx.iv + prot->salt_size, iv_size);
 	}
 
 	/* we cover nonce explicit here as well, so buf should be of
 	 * size KTLS_DTLS_HEADER_SIZE + KTLS_DTLS_NONCE_EXPLICIT_SIZE
 	 */
-	buf[0] = version == TLS_1_3_VERSION ?
+	buf[0] = prot->version == TLS_1_3_VERSION ?
 		   TLS_RECORD_TYPE_DATA : record_type;
 	/* Note that VERSION must be TLS_1_2 for both TLS1.2 and TLS1.3 */
 	buf[1] = TLS_1_2_VERSION_MINOR;
@@ -539,18 +538,17 @@ static inline void tls_fill_prepend(struct tls_context *ctx,
 static inline void tls_make_aad(char *buf,
 				size_t size,
 				char *record_sequence,
-				int record_sequence_size,
 				unsigned char record_type,
-				int version)
+				struct tls_prot_info *prot)
 {
-	if (version != TLS_1_3_VERSION) {
-		memcpy(buf, record_sequence, record_sequence_size);
+	if (prot->version != TLS_1_3_VERSION) {
+		memcpy(buf, record_sequence, prot->rec_seq_size);
 		buf += 8;
 	} else {
-		size += TLS_CIPHER_AES_GCM_128_TAG_SIZE;
+		size += prot->tag_size;
 	}
 
-	buf[0] = version == TLS_1_3_VERSION ?
+	buf[0] = prot->version == TLS_1_3_VERSION ?
 		  TLS_RECORD_TYPE_DATA : record_type;
 	buf[1] = TLS_1_2_VERSION_MAJOR;
 	buf[2] = TLS_1_2_VERSION_MINOR;
@@ -558,11 +556,11 @@ static inline void tls_make_aad(char *buf,
 	buf[4] = size & 0xFF;
 }
 
-static inline void xor_iv_with_seq(int version, char *iv, char *seq)
+static inline void xor_iv_with_seq(struct tls_prot_info *prot, char *iv, char *seq)
 {
 	int i;
 
-	if (version == TLS_1_3_VERSION) {
+	if (prot->version == TLS_1_3_VERSION) {
 		for (i = 0; i < 8; i++)
 			iv[i + 4] ^= seq[i];
 	}
diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index 54d3e16..6f93ad5 100644
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -327,7 +327,7 @@ static int tls_device_record_close(struct sock *sk,
 	/* fill prepend */
 	tls_fill_prepend(ctx, skb_frag_address(&record->frags[0]),
 			 record->len - prot->overhead_size,
-			 record_type, prot->version);
+			 record_type);
 	return ret;
 }
 
diff --git a/net/tls/tls_device_fallback.c b/net/tls/tls_device_fallback.c
index 2889533..d946817 100644
--- a/net/tls/tls_device_fallback.c
+++ b/net/tls/tls_device_fallback.c
@@ -49,7 +49,8 @@ static int tls_enc_record(struct aead_request *aead_req,
 			  struct crypto_aead *aead, char *aad,
 			  char *iv, __be64 rcd_sn,
 			  struct scatter_walk *in,
-			  struct scatter_walk *out, int *in_len)
+			  struct scatter_walk *out, int *in_len,
+			  struct tls_prot_info *prot)
 {
 	unsigned char buf[TLS_HEADER_SIZE + TLS_CIPHER_AES_GCM_128_IV_SIZE];
 	struct scatterlist sg_in[3];
@@ -73,8 +74,7 @@ static int tls_enc_record(struct aead_request *aead_req,
 	len -= TLS_CIPHER_AES_GCM_128_IV_SIZE;
 
 	tls_make_aad(aad, len - TLS_CIPHER_AES_GCM_128_TAG_SIZE,
-		(char *)&rcd_sn, sizeof(rcd_sn), buf[0],
-		TLS_1_2_VERSION);
+		(char *)&rcd_sn, buf[0], prot);
 
 	memcpy(iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, buf + TLS_HEADER_SIZE,
 	       TLS_CIPHER_AES_GCM_128_IV_SIZE);
@@ -140,7 +140,7 @@ static struct aead_request *tls_alloc_aead_request(struct crypto_aead *aead,
 static int tls_enc_records(struct aead_request *aead_req,
 			   struct crypto_aead *aead, struct scatterlist *sg_in,
 			   struct scatterlist *sg_out, char *aad, char *iv,
-			   u64 rcd_sn, int len)
+			   u64 rcd_sn, int len, struct tls_prot_info *prot)
 {
 	struct scatter_walk out, in;
 	int rc;
@@ -150,7 +150,7 @@ static int tls_enc_records(struct aead_request *aead_req,
 
 	do {
 		rc = tls_enc_record(aead_req, aead, aad, iv,
-				    cpu_to_be64(rcd_sn), &in, &out, &len);
+				    cpu_to_be64(rcd_sn), &in, &out, &len, prot);
 		rcd_sn++;
 
 	} while (rc == 0 && len);
@@ -348,7 +348,8 @@ static struct sk_buff *tls_enc_skb(struct tls_context *tls_ctx,
 		    payload_len, sync_size, dummy_buf);
 
 	if (tls_enc_records(aead_req, ctx->aead_send, sg_in, sg_out, aad, iv,
-			    rcd_sn, sync_size + payload_len) < 0)
+			    rcd_sn, sync_size + payload_len,
+			    &tls_ctx->prot_info) < 0)
 		goto free_nskb;
 
 	complete_skb(nskb, skb, tcp_payload_offset);
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 2fe9e2c..6bc757a 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -505,7 +505,7 @@ static int tls_do_encryption(struct sock *sk,
 	memcpy(&rec->iv_data[iv_offset], tls_ctx->tx.iv,
 	       prot->iv_size + prot->salt_size);
 
-	xor_iv_with_seq(prot->version, rec->iv_data, tls_ctx->tx.rec_seq);
+	xor_iv_with_seq(prot, rec->iv_data, tls_ctx->tx.rec_seq);
 
 	sge->offset += prot->prepend_size;
 	sge->length -= prot->prepend_size;
@@ -748,14 +748,13 @@ static int tls_push_record(struct sock *sk, int flags,
 	sg_chain(rec->sg_aead_out, 2, &msg_en->sg.data[i]);
 
 	tls_make_aad(rec->aad_space, msg_pl->sg.size + prot->tail_size,
-		     tls_ctx->tx.rec_seq, prot->rec_seq_size,
-		     record_type, prot->version);
+		     tls_ctx->tx.rec_seq, record_type, prot);
 
 	tls_fill_prepend(tls_ctx,
 			 page_address(sg_page(&msg_en->sg.data[i])) +
 			 msg_en->sg.data[i].offset,
 			 msg_pl->sg.size + prot->tail_size,
-			 record_type, prot->version);
+			 record_type);
 
 	tls_ctx->pending_open_record_frags = false;
 
@@ -1471,13 +1470,12 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
 	else
 		memcpy(iv + iv_offset, tls_ctx->rx.iv, prot->salt_size);
 
-	xor_iv_with_seq(prot->version, iv, tls_ctx->rx.rec_seq);
+	xor_iv_with_seq(prot, iv, tls_ctx->rx.rec_seq);
 
 	/* Prepare AAD */
 	tls_make_aad(aad, rxm->full_len - prot->overhead_size +
 		     prot->tail_size,
-		     tls_ctx->rx.rec_seq, prot->rec_seq_size,
-		     ctx->control, prot->version);
+		     tls_ctx->rx.rec_seq, ctx->control, prot);
 
 	/* Prepare sgin */
 	sg_init_table(sgin, n_sgin);
-- 
1.8.3.1

[net-next 2/5] net/tls: add CHACHA20-POLY1305 specific defines and structures

[Vadim Fedorenko]

To provide support for ChaCha-Poly cipher we need to define
specific constants and structures.

Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
---
 include/net/tls.h        |  1 +
 include/uapi/linux/tls.h | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/include/net/tls.h b/include/net/tls.h
index d04ce73..e4e9c2a 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -211,6 +211,7 @@ struct cipher_context {
 	union {
 		struct tls12_crypto_info_aes_gcm_128 aes_gcm_128;
 		struct tls12_crypto_info_aes_gcm_256 aes_gcm_256;
+		struct tls12_crypto_info_chacha20_poly1305 chacha20_poly1305;
 	};
 };
 
diff --git a/include/uapi/linux/tls.h b/include/uapi/linux/tls.h
index bcd2869..0d54bae 100644
--- a/include/uapi/linux/tls.h
+++ b/include/uapi/linux/tls.h
@@ -77,6 +77,13 @@
 #define TLS_CIPHER_AES_CCM_128_TAG_SIZE		16
 #define TLS_CIPHER_AES_CCM_128_REC_SEQ_SIZE		8
 
+#define TLS_CIPHER_CHACHA20_POLY1305			54
+#define TLS_CIPHER_CHACHA20_POLY1305_IV_SIZE		12
+#define TLS_CIPHER_CHACHA20_POLY1305_KEY_SIZE	32
+#define TLS_CIPHER_CHACHA20_POLY1305_SALT_SIZE		0
+#define TLS_CIPHER_CHACHA20_POLY1305_TAG_SIZE	16
+#define TLS_CIPHER_CHACHA20_POLY1305_REC_SEQ_SIZE	8
+
 #define TLS_SET_RECORD_TYPE	1
 #define TLS_GET_RECORD_TYPE	2
 
@@ -109,6 +116,14 @@ struct tls12_crypto_info_aes_ccm_128 {
 	unsigned char rec_seq[TLS_CIPHER_AES_CCM_128_REC_SEQ_SIZE];
 };
 
+struct tls12_crypto_info_chacha20_poly1305 {
+	struct tls_crypto_info info;
+	unsigned char iv[TLS_CIPHER_CHACHA20_POLY1305_IV_SIZE];
+	unsigned char key[TLS_CIPHER_CHACHA20_POLY1305_KEY_SIZE];
+	unsigned char salt[TLS_CIPHER_CHACHA20_POLY1305_SALT_SIZE];
+	unsigned char rec_seq[TLS_CIPHER_CHACHA20_POLY1305_REC_SEQ_SIZE];
+};
+
 enum {
 	TLS_INFO_UNSPEC,
 	TLS_INFO_VERSION,
-- 
1.8.3.1

[net-next 3/5] net/tls: add CHACHA20-POLY1305 specific behavior

[Vadim Fedorenko]

RFC 7905 defines special behavior for ChaCha-Poly TLS sessions.
The differences are in the calculation of nonce and the absence
of explicit IV. This behavior is like TLSv1.3 partly.

Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
---
 include/net/tls.h | 9 ++++++---
 net/tls/tls_sw.c  | 6 ++++--
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/include/net/tls.h b/include/net/tls.h
index e4e9c2a..b2637ed 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -502,7 +502,8 @@ static inline void tls_advance_record_sn(struct sock *sk,
 	if (tls_bigint_increment(ctx->rec_seq, prot->rec_seq_size))
 		tls_err_abort(sk, EBADMSG);
 
-	if (prot->version != TLS_1_3_VERSION)
+	if (prot->version != TLS_1_3_VERSION &&
+	    prot->cipher_type != TLS_CIPHER_CHACHA20_POLY1305)
 		tls_bigint_increment(ctx->iv + prot->salt_size,
 				     prot->iv_size);
 }
@@ -516,7 +517,8 @@ static inline void tls_fill_prepend(struct tls_context *ctx,
 	size_t pkt_len, iv_size = prot->iv_size;
 
 	pkt_len = plaintext_len + prot->tag_size;
-	if (prot->version != TLS_1_3_VERSION) {
+	if (prot->version != TLS_1_3_VERSION &&
+	    prot->cipher_type != TLS_CIPHER_CHACHA20_POLY1305) {
 		pkt_len += iv_size;
 
 		memcpy(buf + TLS_NONCE_OFFSET,
@@ -561,7 +563,8 @@ static inline void xor_iv_with_seq(struct tls_prot_info *prot, char *iv, char *s
 {
 	int i;
 
-	if (prot->version == TLS_1_3_VERSION) {
+	if (prot->version == TLS_1_3_VERSION ||
+	    prot->cipher_type == TLS_CIPHER_CHACHA20_POLY1305) {
 		for (i = 0; i < 8; i++)
 			iv[i + 4] ^= seq[i];
 	}
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 6bc757a..b4eefdb 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -1464,7 +1464,8 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
 		kfree(mem);
 		return err;
 	}
-	if (prot->version == TLS_1_3_VERSION)
+	if (prot->version == TLS_1_3_VERSION ||
+	    prot->cipher_type == TLS_CIPHER_CHACHA20_POLY1305)
 		memcpy(iv + iv_offset, tls_ctx->rx.iv,
 		       crypto_aead_ivsize(ctx->aead_recv));
 	else
@@ -2068,7 +2069,8 @@ static int tls_read_size(struct strparser *strp, struct sk_buff *skb)
 	data_len = ((header[4] & 0xFF) | (header[3] << 8));
 
 	cipher_overhead = prot->tag_size;
-	if (prot->version != TLS_1_3_VERSION)
+	if (prot->version != TLS_1_3_VERSION &&
+	    prot->cipher_type != TLS_CIPHER_CHACHA20_POLY1305)
 		cipher_overhead += prot->iv_size;
 
 	if (data_len > TLS_MAX_PAYLOAD_SIZE + cipher_overhead +
-- 
1.8.3.1

[net-next 4/5] net/tls: add CHACHA20-POLY1305 configuration

[Vadim Fedorenko]

Add ChaCha-Poly specific configuration code.

Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
---
 net/tls/tls_main.c |  3 +++
 net/tls/tls_sw.c   | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 8d93cea..47b7c53 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -521,6 +521,9 @@ static int do_tls_setsockopt_conf(struct sock *sk, sockptr_t optval,
 	case TLS_CIPHER_AES_CCM_128:
 		optsize = sizeof(struct tls12_crypto_info_aes_ccm_128);
 		break;
+	case TLS_CIPHER_CHACHA20_POLY1305:
+		optsize = sizeof(struct tls12_crypto_info_chacha20_poly1305);
+		break;
 	default:
 		rc = -EINVAL;
 		goto err_crypto_info;
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index b4eefdb..6bb33d5 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2290,6 +2290,7 @@ int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx)
 	struct tls12_crypto_info_aes_gcm_128 *gcm_128_info;
 	struct tls12_crypto_info_aes_gcm_256 *gcm_256_info;
 	struct tls12_crypto_info_aes_ccm_128 *ccm_128_info;
+	struct tls12_crypto_info_chacha20_poly1305 *chacha20_poly1305_info;
 	struct tls_sw_context_tx *sw_ctx_tx = NULL;
 	struct tls_sw_context_rx *sw_ctx_rx = NULL;
 	struct cipher_context *cctx;
@@ -2402,6 +2403,23 @@ int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx)
 		cipher_name = "ccm(aes)";
 		break;
 	}
+	case TLS_CIPHER_CHACHA20_POLY1305: {
+		nonce_size = 0;
+		tag_size = TLS_CIPHER_CHACHA20_POLY1305_TAG_SIZE;
+		iv_size = TLS_CIPHER_CHACHA20_POLY1305_IV_SIZE;
+		iv = ((struct tls12_crypto_info_chacha20_poly1305 *)crypto_info)->iv;
+		rec_seq_size = TLS_CIPHER_CHACHA20_POLY1305_REC_SEQ_SIZE;
+		rec_seq =
+		((struct tls12_crypto_info_chacha20_poly1305 *)crypto_info)->rec_seq;
+		chacha20_poly1305_info =
+		(struct tls12_crypto_info_chacha20_poly1305 *)crypto_info;
+		keysize = TLS_CIPHER_CHACHA20_POLY1305_KEY_SIZE;
+		key = chacha20_poly1305_info->key;
+		salt = chacha20_poly1305_info->salt;
+		salt_size = TLS_CIPHER_CHACHA20_POLY1305_SALT_SIZE;
+		cipher_name = "rfc7539(chacha20,poly1305)";
+		break;
+	}
 	default:
 		rc = -EINVAL;
 		goto free_priv;
-- 
1.8.3.1

[net-next 5/5] selftests/tls: add CHACHA20-POLY1305 to tls selftests

[Vadim Fedorenko]

Add new cipher as a variant of standart tls selftests

Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru>
---
 tools/testing/selftests/net/tls.c | 40 ++++++++++++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/net/tls.c b/tools/testing/selftests/net/tls.c
index b599f1f..49d8ade 100644
--- a/tools/testing/selftests/net/tls.c
+++ b/tools/testing/selftests/net/tls.c
@@ -103,32 +103,58 @@
 
 FIXTURE_VARIANT(tls)
 {
-	unsigned int tls_version;
+	u16 tls_version;
+	u16 cipher_type;
 };
 
-FIXTURE_VARIANT_ADD(tls, 12)
+FIXTURE_VARIANT_ADD(tls, 12_gcm)
 {
 	.tls_version = TLS_1_2_VERSION,
+	.cipher_type = TLS_CIPHER_AES_GCM_128,
 };
 
-FIXTURE_VARIANT_ADD(tls, 13)
+FIXTURE_VARIANT_ADD(tls, 13_gcm)
 {
 	.tls_version = TLS_1_3_VERSION,
+	.cipher_type = TLS_CIPHER_AES_GCM_128,
+};
+
+FIXTURE_VARIANT_ADD(tls, 12_chacha)
+{
+	.tls_version = TLS_1_2_VERSION,
+	.cipher_type = TLS_CIPHER_CHACHA20_POLY1305,
+};
+
+FIXTURE_VARIANT_ADD(tls, 13_chacha)
+{
+	.tls_version = TLS_1_3_VERSION,
+	.cipher_type = TLS_CIPHER_CHACHA20_POLY1305,
 };
 
 FIXTURE_SETUP(tls)
 {
-	struct tls12_crypto_info_aes_gcm_128 tls12;
+	union tls_crypto_context tls12;
 	struct sockaddr_in addr;
 	socklen_t len;
 	int sfd, ret;
+	size_t tls12_sz;
 
 	self->notls = false;
 	len = sizeof(addr);
 
 	memset(&tls12, 0, sizeof(tls12));
 	tls12.info.version = variant->tls_version;
-	tls12.info.cipher_type = TLS_CIPHER_AES_GCM_128;
+	tls12.info.cipher_type = variant->cipher_type;
+	switch(variant->cipher_type) {
+	case TLS_CIPHER_CHACHA20_POLY1305:
+		tls12_sz = sizeof(tls12_crypto_info_chacha20_poly1305);
+		break;
+	case TLS_CIPHER_AES_GCM_128:
+		tls12_sz = sizeof(tls12_crypto_info_aes_gcm_128);
+		break;
+	default:
+		tls12_sz = 0;
+	}
 
 	addr.sin_family = AF_INET;
 	addr.sin_addr.s_addr = htonl(INADDR_ANY);
@@ -156,7 +182,7 @@
 
 	if (!self->notls) {
 		ret = setsockopt(self->fd, SOL_TLS, TLS_TX, &tls12,
-				 sizeof(tls12));
+				 tls12_sz);
 		ASSERT_EQ(ret, 0);
 	}
 
@@ -169,7 +195,7 @@
 		ASSERT_EQ(ret, 0);
 
 		ret = setsockopt(self->cfd, SOL_TLS, TLS_RX, &tls12,
-				 sizeof(tls12));
+				 tls12_sz);
 		ASSERT_EQ(ret, 0);
 	}
 
-- 
1.8.3.1

Re: [net-next 4/5] net/tls: add CHACHA20-POLY1305 configuration

[Jakub Kicinski]

The series LGTM, great to see chacha support!

One nit here, and when you post v2 would you mind ccing crypto?

From TLS perspective I think this code is ready to be merged, but
my crypto knowledge is close to none, so best if we give crypto
folks a chance to take a look.

On Sun, 22 Nov 2020 04:57:44 +0300 Vadim Fedorenko wrote:
> +	case TLS_CIPHER_CHACHA20_POLY1305: {
> +		nonce_size = 0;
> +		tag_size = TLS_CIPHER_CHACHA20_POLY1305_TAG_SIZE;
> +		iv_size = TLS_CIPHER_CHACHA20_POLY1305_IV_SIZE;
> +		iv = ((struct tls12_crypto_info_chacha20_poly1305 *)crypto_info)->iv;

[1]

> +		rec_seq_size = TLS_CIPHER_CHACHA20_POLY1305_REC_SEQ_SIZE;
> +		rec_seq =
> +		((struct tls12_crypto_info_chacha20_poly1305 *)crypto_info)->rec_seq;

[2]

> +		chacha20_poly1305_info =
> +		(struct tls12_crypto_info_chacha20_poly1305 *)crypto_info;

Move this line up, and use it in [1] and [2].

You can also make it:

	chacha20_poly1305_info = (void *)crypto_info;

> +		keysize = TLS_CIPHER_CHACHA20_POLY1305_KEY_SIZE;
> +		key = chacha20_poly1305_info->key;
> +		salt = chacha20_poly1305_info->salt;
> +		salt_size = TLS_CIPHER_CHACHA20_POLY1305_SALT_SIZE;
> +		cipher_name = "rfc7539(chacha20,poly1305)";
> +		break;
> +	}