diff options
Diffstat (limited to 'net/ipv4/tcp_fastopen.c')
| -rw-r--r-- | net/ipv4/tcp_fastopen.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index ab7bd35bb31..f195d9316e5 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -8,12 +8,26 @@ #include <net/inetpeer.h> #include <net/tcp.h> -int sysctl_tcp_fastopen __read_mostly; +int sysctl_tcp_fastopen __read_mostly = TFO_CLIENT_ENABLE; struct tcp_fastopen_context __rcu *tcp_fastopen_ctx; static DEFINE_SPINLOCK(tcp_fastopen_ctx_lock); +void tcp_fastopen_init_key_once(bool publish) +{ + static u8 key[TCP_FASTOPEN_KEY_LENGTH]; + + /* tcp_fastopen_reset_cipher publishes the new context + * atomically, so we allow this race happening here. + * + * All call sites of tcp_fastopen_cookie_gen also check + * for a valid cookie, so this is an acceptable risk. + */ + if (net_get_random_once(key, sizeof(key)) && publish) + tcp_fastopen_reset_cipher(key, sizeof(key)); +} + static void tcp_fastopen_ctx_free(struct rcu_head *head) { struct tcp_fastopen_context *ctx = @@ -70,6 +84,8 @@ void tcp_fastopen_cookie_gen(__be32 src, __be32 dst, __be32 path[4] = { src, dst, 0, 0 }; struct tcp_fastopen_context *ctx; + tcp_fastopen_init_key_once(true); + rcu_read_lock(); ctx = rcu_dereference(tcp_fastopen_ctx); if (ctx) { @@ -78,14 +94,3 @@ void tcp_fastopen_cookie_gen(__be32 src, __be32 dst, } rcu_read_unlock(); } - -static int __init tcp_fastopen_init(void) -{ - __u8 key[TCP_FASTOPEN_KEY_LENGTH]; - - get_random_bytes(key, sizeof(key)); - tcp_fastopen_reset_cipher(key, sizeof(key)); - return 0; -} - -late_initcall(tcp_fastopen_init); |