tls: store iv directly within cipher_context

TLS_MAX_IV_SIZE + TLS_MAX_SALT_SIZE is 20B, we don't get much benefit
in cipher_context's size and can simplify the init code a bit.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tls.h

@@ -62,6 +62,7 @@ struct tls_rec;
 #define TLS_AAD_SPACE_SIZE		13
 
 #define TLS_MAX_IV_SIZE			16
+#define TLS_MAX_SALT_SIZE		4
 #define TLS_TAG_SIZE			16
 #define TLS_MAX_REC_SEQ_SIZE		8
 #define TLS_MAX_AAD_SIZE		TLS_AAD_SPACE_SIZE
@@ -193,7 +194,7 @@ enum tls_context_flags {
 };
 
 struct cipher_context {
-	char *iv;
+	char iv[TLS_MAX_IV_SIZE + TLS_MAX_SALT_SIZE];
 	char rec_seq[TLS_MAX_REC_SEQ_SIZE];
 };
 

net/tls/tls_device.c

@@ -56,10 +56,8 @@ static struct page *dummy_page;
 
 static void tls_device_free_ctx(struct tls_context *ctx)
 {
-	if (ctx->tx_conf == TLS_HW) {
+	if (ctx->tx_conf == TLS_HW)
 		kfree(tls_offload_ctx_tx(ctx));
-		kfree(ctx->tx.iv);
-	}
 
 	if (ctx->rx_conf == TLS_HW)
 		kfree(tls_offload_ctx_rx(ctx));
@@ -1088,11 +1086,6 @@ int tls_set_device_offload(struct sock *sk, struct tls_context *ctx)
 	prot->overhead_size = prot->prepend_size + prot->tag_size;
 	prot->iv_size = cipher_desc->iv;
 	prot->salt_size = cipher_desc->salt;
-	ctx->tx.iv = kmalloc(cipher_desc->iv + cipher_desc->salt, GFP_KERNEL);
-	if (!ctx->tx.iv) {
-		rc = -ENOMEM;
-		goto release_netdev;
-	}
 
 	memcpy(ctx->tx.iv + cipher_desc->salt, iv, cipher_desc->iv);
 
@@ -1102,7 +1095,7 @@ int tls_set_device_offload(struct sock *sk, struct tls_context *ctx)
 	start_marker_record = kmalloc(sizeof(*start_marker_record), GFP_KERNEL);
 	if (!start_marker_record) {
 		rc = -ENOMEM;
-		goto free_iv;
+		goto release_netdev;
 	}
 
 	offload_ctx = kzalloc(TLS_OFFLOAD_CONTEXT_SIZE_TX, GFP_KERNEL);
@@ -1187,8 +1180,6 @@ int tls_set_device_offload(struct sock *sk, struct tls_context *ctx)
 	ctx->priv_ctx_tx = NULL;
 free_marker_record:
 	kfree(start_marker_record);
-free_iv:
-	kfree(ctx->tx.iv);
 release_netdev:
 	dev_put(netdev);
 	return rc;

net/tls/tls_main.c

@@ -60,6 +60,7 @@ enum {
 
 #define CHECK_CIPHER_DESC(cipher,ci)				\
 	static_assert(cipher ## _IV_SIZE <= TLS_MAX_IV_SIZE);		\
+	static_assert(cipher ## _SALT_SIZE <= TLS_MAX_SALT_SIZE);		\
 	static_assert(cipher ## _REC_SEQ_SIZE <= TLS_MAX_REC_SEQ_SIZE);	\
 	static_assert(cipher ## _TAG_SIZE == TLS_TAG_SIZE);		\
 	static_assert(sizeof_field(struct ci, iv) == cipher ## _IV_SIZE);	\
@@ -344,7 +345,6 @@ static void tls_sk_proto_cleanup(struct sock *sk,
 
 	/* We need these for tls_sw_fallback handling of other packets */
 	if (ctx->tx_conf == TLS_SW) {
-		kfree(ctx->tx.iv);
 		tls_sw_release_resources_tx(sk);
 		TLS_DEC_STATS(sock_net(sk), LINUX_MIB_TLSCURRTXSW);
 	} else if (ctx->tx_conf == TLS_HW) {

net/tls/tls_sw.c

@@ -2467,8 +2467,6 @@ void tls_sw_release_resources_rx(struct sock *sk)
 	struct tls_context *tls_ctx = tls_get_ctx(sk);
 	struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
 
-	kfree(tls_ctx->rx.iv);
-
 	if (ctx->aead_recv) {
 		__skb_queue_purge(&ctx->rx_list);
 		crypto_free_aead(ctx->aead_recv);
@@ -2682,11 +2680,7 @@ int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx)
 			      prot->tag_size + prot->tail_size;
 	prot->iv_size = cipher_desc->iv;
 	prot->salt_size = cipher_desc->salt;
-	cctx->iv = kmalloc(cipher_desc->iv + cipher_desc->salt, GFP_KERNEL);
-	if (!cctx->iv) {
-		rc = -ENOMEM;
-		goto free_priv;
-	}
+
 	/* Note: 128 & 256 bit salt are the same size */
 	prot->rec_seq_size = cipher_desc->rec_seq;
 	memcpy(cctx->iv, salt, cipher_desc->salt);
@@ -2698,7 +2692,7 @@ int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx)
 		if (IS_ERR(*aead)) {
 			rc = PTR_ERR(*aead);
 			*aead = NULL;
-			goto free_iv;
+			goto free_priv;
 		}
 	}
 
@@ -2730,9 +2724,6 @@ int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx, int tx)
 free_aead:
 	crypto_free_aead(*aead);
 	*aead = NULL;
-free_iv:
-	kfree(cctx->iv);
-	cctx->iv = NULL;
 free_priv:
 	if (tx) {
 		kfree(ctx->priv_ctx_tx);