aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--include/net/tcp.h41
-rw-r--r--include/uapi/linux/snmp.h1
-rw-r--r--net/ipv4/proc.c1
-rw-r--r--net/ipv4/sysctl_net_ipv4.c2
-rw-r--r--net/ipv4/tcp.c3
-rw-r--r--net/ipv4/tcp_fastopen.c172
6 files changed, 162 insertions, 58 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 985aa5db570c..0083a14fb64f 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1614,7 +1614,8 @@ void tcp_free_fastopen_req(struct tcp_sock *tp);
void tcp_fastopen_destroy_cipher(struct sock *sk);
void tcp_fastopen_ctx_destroy(struct net *net);
int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk,
- void *key, unsigned int len);
+ void *primary_key, void *backup_key,
+ unsigned int len);
void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb);
struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
struct request_sock *req,
@@ -1625,11 +1626,14 @@ bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss,
struct tcp_fastopen_cookie *cookie);
bool tcp_fastopen_defer_connect(struct sock *sk, int *err);
#define TCP_FASTOPEN_KEY_LENGTH 16
+#define TCP_FASTOPEN_KEY_MAX 2
+#define TCP_FASTOPEN_KEY_BUF_LENGTH \
+ (TCP_FASTOPEN_KEY_LENGTH * TCP_FASTOPEN_KEY_MAX)
/* Fastopen key context */
struct tcp_fastopen_context {
- struct crypto_cipher *tfm;
- __u8 key[TCP_FASTOPEN_KEY_LENGTH];
+ struct crypto_cipher *tfm[TCP_FASTOPEN_KEY_MAX];
+ __u8 key[TCP_FASTOPEN_KEY_BUF_LENGTH];
struct rcu_head rcu;
};
@@ -1639,6 +1643,37 @@ bool tcp_fastopen_active_should_disable(struct sock *sk);
void tcp_fastopen_active_disable_ofo_check(struct sock *sk);
void tcp_fastopen_active_detect_blackhole(struct sock *sk, bool expired);
+/* Caller needs to wrap with rcu_read_(un)lock() */
+static inline
+struct tcp_fastopen_context *tcp_fastopen_get_ctx(const struct sock *sk)
+{
+ struct tcp_fastopen_context *ctx;
+
+ ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx);
+ if (!ctx)
+ ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx);
+ return ctx;
+}
+
+static inline
+bool tcp_fastopen_cookie_match(const struct tcp_fastopen_cookie *foc,
+ const struct tcp_fastopen_cookie *orig)
+{
+ if (orig->len == TCP_FASTOPEN_COOKIE_SIZE &&
+ orig->len == foc->len &&
+ !memcmp(orig->val, foc->val, foc->len))
+ return true;
+ return false;
+}
+
+static inline
+int tcp_fastopen_context_len(const struct tcp_fastopen_context *ctx)
+{
+ if (ctx->tfm[1])
+ return 2;
+ return 1;
+}
+
/* Latencies incurred by various limits for a sender. They are
* chronograph-like stats that are mutually exclusive.
*/
diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
index 86dc24a96c90..74904e9d1b72 100644
--- a/include/uapi/linux/snmp.h
+++ b/include/uapi/linux/snmp.h
@@ -283,6 +283,7 @@ enum
LINUX_MIB_TCPACKCOMPRESSED, /* TCPAckCompressed */
LINUX_MIB_TCPZEROWINDOWDROP, /* TCPZeroWindowDrop */
LINUX_MIB_TCPRCVQDROP, /* TCPRcvQDrop */
+ LINUX_MIB_TCPFASTOPENPASSIVEALTKEY, /* TCPFastOpenPassiveAltKey */
__LINUX_MIB_MAX
};
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index b613572c6616..4746f963c439 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -291,6 +291,7 @@ static const struct snmp_mib snmp4_net_list[] = {
SNMP_MIB_ITEM("TCPAckCompressed", LINUX_MIB_TCPACKCOMPRESSED),
SNMP_MIB_ITEM("TCPZeroWindowDrop", LINUX_MIB_TCPZEROWINDOWDROP),
SNMP_MIB_ITEM("TCPRcvQDrop", LINUX_MIB_TCPRCVQDROP),
+ SNMP_MIB_ITEM("TCPFastOpenPassiveAltKey", LINUX_MIB_TCPFASTOPENPASSIVEALTKEY),
SNMP_MIB_SENTINEL
};
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 875867b64d6a..72dc8ca98d43 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -318,7 +318,7 @@ static int proc_tcp_fastopen_key(struct ctl_table *table, int write,
for (i = 0; i < ARRAY_SIZE(user_key); i++)
key[i] = cpu_to_le32(user_key[i]);
- tcp_fastopen_reset_cipher(net, NULL, key,
+ tcp_fastopen_reset_cipher(net, NULL, key, NULL,
TCP_FASTOPEN_KEY_LENGTH);
}
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 53d61ca3ac4b..bca51a351b0e 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2798,7 +2798,8 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
if (copy_from_user(key, optval, optlen))
return -EFAULT;
- return tcp_fastopen_reset_cipher(net, sk, key, sizeof(key));
+ return tcp_fastopen_reset_cipher(net, sk, key, NULL,
+ sizeof(key));
}
default:
/* fallthru */
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 3889ad28dd06..8e1580485c9e 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -30,14 +30,20 @@ void tcp_fastopen_init_key_once(struct net *net)
* for a valid cookie, so this is an acceptable risk.
*/
get_random_bytes(key, sizeof(key));
- tcp_fastopen_reset_cipher(net, NULL, key, sizeof(key));
+ tcp_fastopen_reset_cipher(net, NULL, key, NULL, sizeof(key));
}
static void tcp_fastopen_ctx_free(struct rcu_head *head)
{
struct tcp_fastopen_context *ctx =
container_of(head, struct tcp_fastopen_context, rcu);
- crypto_free_cipher(ctx->tfm);
+ 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);
}
@@ -66,33 +72,54 @@ void tcp_fastopen_ctx_destroy(struct net *net)
call_rcu(&ctxt->rcu, tcp_fastopen_ctx_free);
}
+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 *key, unsigned int len)
+ void *primary_key, void *backup_key,
+ unsigned int len)
{
struct tcp_fastopen_context *ctx, *octx;
struct fastopen_queue *q;
- int err;
+ int err = 0;
- ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
- if (!ctx)
- return -ENOMEM;
- ctx->tfm = crypto_alloc_cipher("aes", 0, 0);
-
- if (IS_ERR(ctx->tfm)) {
- err = PTR_ERR(ctx->tfm);
-error: kfree(ctx);
- pr_err("TCP: TFO aes cipher alloc error: %d\n", err);
- return err;
- }
- err = crypto_cipher_setkey(ctx->tfm, key, len);
- if (err) {
- pr_err("TCP: TFO cipher key error: %d\n", err);
- crypto_free_cipher(ctx->tfm);
- goto error;
+ ctx = tcp_fastopen_alloc_ctx(primary_key, backup_key, len);
+ if (IS_ERR(ctx)) {
+ err = PTR_ERR(ctx);
+ goto out;
}
- memcpy(ctx->key, key, len);
-
-
spin_lock(&net->ipv4.tcp_fastopen_ctx_lock);
if (sk) {
q = &inet_csk(sk)->icsk_accept_queue.fastopenq;
@@ -108,6 +135,7 @@ error: kfree(ctx);
if (octx)
call_rcu(&octx->rcu, tcp_fastopen_ctx_free);
+out:
return err;
}
@@ -151,25 +179,20 @@ static bool __tcp_fastopen_cookie_gen_cipher(struct request_sock *req,
*
* XXX (TFO) - refactor when TCP_FASTOPEN_COOKIE_SIZE != AES_BLOCK_SIZE.
*/
-static bool tcp_fastopen_cookie_gen(struct sock *sk,
+static void tcp_fastopen_cookie_gen(struct sock *sk,
struct request_sock *req,
struct sk_buff *syn,
struct tcp_fastopen_cookie *foc)
{
struct tcp_fastopen_context *ctx;
- bool ok = false;
rcu_read_lock();
- ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx);
- if (!ctx)
- ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx);
+ ctx = tcp_fastopen_get_ctx(sk);
if (ctx)
- ok = __tcp_fastopen_cookie_gen_cipher(req, syn, ctx->tfm, foc);
+ __tcp_fastopen_cookie_gen_cipher(req, syn, ctx->tfm[0], foc);
rcu_read_unlock();
- return ok;
}
-
/* If an incoming SYN or SYNACK frame contains a payload and/or FIN,
* queue this additional data / FIN.
*/
@@ -213,6 +236,35 @@ void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb)
tcp_fin(sk);
}
+/* returns 0 - no key match, 1 for primary, 2 for backup */
+static int tcp_fastopen_cookie_gen_check(struct sock *sk,
+ struct request_sock *req,
+ struct sk_buff *syn,
+ struct tcp_fastopen_cookie *orig,
+ struct tcp_fastopen_cookie *valid_foc)
+{
+ struct tcp_fastopen_cookie search_foc = { .len = -1 };
+ struct tcp_fastopen_cookie *foc = valid_foc;
+ struct tcp_fastopen_context *ctx;
+ int i, ret = 0;
+
+ rcu_read_lock();
+ ctx = tcp_fastopen_get_ctx(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);
+ if (tcp_fastopen_cookie_match(foc, orig)) {
+ ret = i + 1;
+ goto out;
+ }
+ foc = &search_foc;
+ }
+out:
+ rcu_read_unlock();
+ return ret;
+}
+
static struct sock *tcp_fastopen_create_child(struct sock *sk,
struct sk_buff *skb,
struct request_sock *req)
@@ -332,6 +384,7 @@ struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
int tcp_fastopen = sock_net(sk)->ipv4.sysctl_tcp_fastopen;
struct tcp_fastopen_cookie valid_foc = { .len = -1 };
struct sock *child;
+ int ret = 0;
if (foc->len == 0) /* Client requests a cookie */
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENCOOKIEREQD);
@@ -347,31 +400,44 @@ struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
tcp_fastopen_no_cookie(sk, dst, TFO_SERVER_COOKIE_NOT_REQD))
goto fastopen;
- if (foc->len >= 0 && /* Client presents or requests a cookie */
- tcp_fastopen_cookie_gen(sk, req, skb, &valid_foc) &&
- foc->len == TCP_FASTOPEN_COOKIE_SIZE &&
- foc->len == valid_foc.len &&
- !memcmp(foc->val, valid_foc.val, foc->len)) {
- /* Cookie is valid. Create a (full) child socket to accept
- * the data in SYN before returning a SYN-ACK to ack the
- * data. If we fail to create the socket, fall back and
- * ack the ISN only but includes the same cookie.
- *
- * Note: Data-less SYN with valid cookie is allowed to send
- * data in SYN_RECV state.
- */
+ if (foc->len == 0) {
+ /* Client requests a cookie. */
+ tcp_fastopen_cookie_gen(sk, req, skb, &valid_foc);
+ } else if (foc->len > 0) {
+ ret = tcp_fastopen_cookie_gen_check(sk, req, skb, foc,
+ &valid_foc);
+ if (!ret) {
+ NET_INC_STATS(sock_net(sk),
+ LINUX_MIB_TCPFASTOPENPASSIVEFAIL);
+ } else {
+ /* Cookie is valid. Create a (full) child socket to
+ * accept the data in SYN before returning a SYN-ACK to
+ * ack the data. If we fail to create the socket, fall
+ * back and ack the ISN only but includes the same
+ * cookie.
+ *
+ * Note: Data-less SYN with valid cookie is allowed to
+ * send data in SYN_RECV state.
+ */
fastopen:
- child = tcp_fastopen_create_child(sk, skb, req);
- if (child) {
- foc->len = -1;
+ child = tcp_fastopen_create_child(sk, skb, req);
+ if (child) {
+ if (ret == 2) {
+ valid_foc.exp = foc->exp;
+ *foc = valid_foc;
+ NET_INC_STATS(sock_net(sk),
+ LINUX_MIB_TCPFASTOPENPASSIVEALTKEY);
+ } else {
+ foc->len = -1;
+ }
+ NET_INC_STATS(sock_net(sk),
+ LINUX_MIB_TCPFASTOPENPASSIVE);
+ return child;
+ }
NET_INC_STATS(sock_net(sk),
- LINUX_MIB_TCPFASTOPENPASSIVE);
- return child;
+ LINUX_MIB_TCPFASTOPENPASSIVEFAIL);
}
- NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVEFAIL);
- } else if (foc->len > 0) /* Client presents an invalid cookie */
- NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVEFAIL);
-
+ }
valid_foc.exp = foc->exp;
*foc = valid_foc;
return NULL;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.