1 files changed, 31 insertions, 66 deletions

diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 7d19fa4c8121..46b67128e1ca 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -7,6 +7,7 @@
 #include <linux/tcp.h>
 #include <linux/rcupdate.h>
 #include <linux/rculist.h>
+#include <linux/siphash.h>
 #include <net/inetpeer.h>
 #include <net/tcp.h>
 
@@ -37,14 +38,8 @@ static void tcp_fastopen_ctx_free(struct rcu_head *head)
 {
 	struct tcp_fastopen_context *ctx =
 	    container_of(head, struct tcp_fastopen_context, rcu);
-	int i;
 
-	/* We own ctx, thus no need to hold the Fastopen-lock */
-	for (i = 0; i < TCP_FASTOPEN_KEY_MAX; i++) {
-		if (ctx->tfm[i])
-			crypto_free_cipher(ctx->tfm[i]);
-	}
-	kfree(ctx);
+	kzfree(ctx);
 }
 
 void tcp_fastopen_destroy_cipher(struct sock *sk)
@@ -72,41 +67,6 @@ void tcp_fastopen_ctx_destroy(struct net *net)
 		call_rcu(&ctxt->rcu, tcp_fastopen_ctx_free);
 }
 
-static struct tcp_fastopen_context *tcp_fastopen_alloc_ctx(void *primary_key,
-							   void *backup_key,
-							   unsigned int len)
-{
-	struct tcp_fastopen_context *new_ctx;
-	void *key = primary_key;
-	int err, i;
-
-	new_ctx = kmalloc(sizeof(*new_ctx), GFP_KERNEL);
-	if (!new_ctx)
-		return ERR_PTR(-ENOMEM);
-	for (i = 0; i < TCP_FASTOPEN_KEY_MAX; i++)
-		new_ctx->tfm[i] = NULL;
-	for (i = 0; i < (backup_key ? 2 : 1); i++) {
-		new_ctx->tfm[i] = crypto_alloc_cipher("aes", 0, 0);
-		if (IS_ERR(new_ctx->tfm[i])) {
-			err = PTR_ERR(new_ctx->tfm[i]);
-			new_ctx->tfm[i] = NULL;
-			pr_err("TCP: TFO aes cipher alloc error: %d\n", err);
-			goto out;
-		}
-		err = crypto_cipher_setkey(new_ctx->tfm[i], key, len);
-		if (err) {
-			pr_err("TCP: TFO cipher key error: %d\n", err);
-			goto out;
-		}
-		memcpy(&new_ctx->key[i * TCP_FASTOPEN_KEY_LENGTH], key, len);
-		key = backup_key;
-	}
-	return new_ctx;
-out:
-	tcp_fastopen_ctx_free(&new_ctx->rcu);
-	return ERR_PTR(err);
-}
-
 int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk,
 			      void *primary_key, void *backup_key,
 			      unsigned int len)
@@ -115,11 +75,20 @@ int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk,
 	struct fastopen_queue *q;
 	int err = 0;
 
-	ctx = tcp_fastopen_alloc_ctx(primary_key, backup_key, len);
-	if (IS_ERR(ctx)) {
-		err = PTR_ERR(ctx);
+	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx) {
+		err = -ENOMEM;
 		goto out;
 	}
+
+	memcpy(ctx->key[0], primary_key, len);
+	if (backup_key) {
+		memcpy(ctx->key[1], backup_key, len);
+		ctx->num = 2;
+	} else {
+		ctx->num = 1;
+	}
+
 	spin_lock(&net->ipv4.tcp_fastopen_ctx_lock);
 	if (sk) {
 		q = &inet_csk(sk)->icsk_accept_queue.fastopenq;
@@ -141,31 +110,30 @@ out:
 
 static bool __tcp_fastopen_cookie_gen_cipher(struct request_sock *req,
 					     struct sk_buff *syn,
-					     struct crypto_cipher *tfm,
+					     const u8 *key,
 					     struct tcp_fastopen_cookie *foc)
 {
+	BUILD_BUG_ON(TCP_FASTOPEN_KEY_LENGTH != sizeof(siphash_key_t));
+	BUILD_BUG_ON(TCP_FASTOPEN_COOKIE_SIZE != sizeof(u64));
+
 	if (req->rsk_ops->family == AF_INET) {
 		const struct iphdr *iph = ip_hdr(syn);
-		__be32 path[4] = { iph->saddr, iph->daddr, 0, 0 };
 
-		crypto_cipher_encrypt_one(tfm, foc->val, (void *)path);
+		foc->val[0] = siphash(&iph->saddr,
+				      sizeof(iph->saddr) +
+				      sizeof(iph->daddr),
+				      (const siphash_key_t *)key);
 		foc->len = TCP_FASTOPEN_COOKIE_SIZE;
 		return true;
 	}
-
 #if IS_ENABLED(CONFIG_IPV6)
 	if (req->rsk_ops->family == AF_INET6) {
 		const struct ipv6hdr *ip6h = ipv6_hdr(syn);
-		struct tcp_fastopen_cookie tmp;
-		struct in6_addr *buf;
-		int i;
-
-		crypto_cipher_encrypt_one(tfm, tmp.val,
-					  (void *)&ip6h->saddr);
-		buf = &tmp.addr;
-		for (i = 0; i < 4; i++)
-			buf->s6_addr32[i] ^= ip6h->daddr.s6_addr32[i];
-		crypto_cipher_encrypt_one(tfm, foc->val, (void *)buf);
+
+		foc->val[0] = siphash(&ip6h->saddr,
+				      sizeof(ip6h->saddr) +
+				      sizeof(ip6h->daddr),
+				      (const siphash_key_t *)key);
 		foc->len = TCP_FASTOPEN_COOKIE_SIZE;
 		return true;
 	}
@@ -173,11 +141,8 @@ static bool __tcp_fastopen_cookie_gen_cipher(struct request_sock *req,
 	return false;
 }
 
-/* Generate the fastopen cookie by doing aes128 encryption on both
- * the source and destination addresses. Pad 0s for IPv4 or IPv4-mapped-IPv6
- * addresses. For the longer IPv6 addresses use CBC-MAC.
- *
- * XXX (TFO) - refactor when TCP_FASTOPEN_COOKIE_SIZE != AES_BLOCK_SIZE.
+/* Generate the fastopen cookie by applying SipHash to both the source and
+ * destination addresses.
  */
 static void tcp_fastopen_cookie_gen(struct sock *sk,
 				    struct request_sock *req,
@@ -189,7 +154,7 @@ static void tcp_fastopen_cookie_gen(struct sock *sk,
 	rcu_read_lock();
 	ctx = tcp_fastopen_get_ctx(sk);
 	if (ctx)
-		__tcp_fastopen_cookie_gen_cipher(req, syn, ctx->tfm[0], foc);
+		__tcp_fastopen_cookie_gen_cipher(req, syn, ctx->key[0], foc);
 	rcu_read_unlock();
 }
 
@@ -253,7 +218,7 @@ static int tcp_fastopen_cookie_gen_check(struct sock *sk,
 	if (!ctx)
 		goto out;
 	for (i = 0; i < tcp_fastopen_context_len(ctx); i++) {
-		__tcp_fastopen_cookie_gen_cipher(req, syn, ctx->tfm[i], foc);
+		__tcp_fastopen_cookie_gen_cipher(req, syn, ctx->key[i], foc);
 		if (tcp_fastopen_cookie_match(foc, orig)) {
 			ret = i + 1;
 			goto out;