forked from Minki/linux
149479d019
Encrypt the cookie with both server and client IPv4 addresses, such that multi-homed server will grant different cookies based on both the source and destination IPs. No client change is needed since cookie is opaque to the client. Signed-off-by: Yuchung Cheng <ycheng@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
92 lines
2.2 KiB
C
92 lines
2.2 KiB
C
#include <linux/err.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/list.h>
|
|
#include <linux/tcp.h>
|
|
#include <linux/rcupdate.h>
|
|
#include <linux/rculist.h>
|
|
#include <net/inetpeer.h>
|
|
#include <net/tcp.h>
|
|
|
|
int sysctl_tcp_fastopen __read_mostly;
|
|
|
|
struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;
|
|
|
|
static DEFINE_SPINLOCK(tcp_fastopen_ctx_lock);
|
|
|
|
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);
|
|
kfree(ctx);
|
|
}
|
|
|
|
int tcp_fastopen_reset_cipher(void *key, unsigned int len)
|
|
{
|
|
int err;
|
|
struct tcp_fastopen_context *ctx, *octx;
|
|
|
|
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;
|
|
}
|
|
memcpy(ctx->key, key, len);
|
|
|
|
spin_lock(&tcp_fastopen_ctx_lock);
|
|
|
|
octx = rcu_dereference_protected(tcp_fastopen_ctx,
|
|
lockdep_is_held(&tcp_fastopen_ctx_lock));
|
|
rcu_assign_pointer(tcp_fastopen_ctx, ctx);
|
|
spin_unlock(&tcp_fastopen_ctx_lock);
|
|
|
|
if (octx)
|
|
call_rcu(&octx->rcu, tcp_fastopen_ctx_free);
|
|
return err;
|
|
}
|
|
|
|
/* Computes the fastopen cookie for the IP path.
|
|
* The path is a 128 bits long (pad with zeros for IPv4).
|
|
*
|
|
* The caller must check foc->len to determine if a valid cookie
|
|
* has been generated successfully.
|
|
*/
|
|
void tcp_fastopen_cookie_gen(__be32 src, __be32 dst,
|
|
struct tcp_fastopen_cookie *foc)
|
|
{
|
|
__be32 path[4] = { src, dst, 0, 0 };
|
|
struct tcp_fastopen_context *ctx;
|
|
|
|
rcu_read_lock();
|
|
ctx = rcu_dereference(tcp_fastopen_ctx);
|
|
if (ctx) {
|
|
crypto_cipher_encrypt_one(ctx->tfm, foc->val, (__u8 *)path);
|
|
foc->len = TCP_FASTOPEN_COOKIE_SIZE;
|
|
}
|
|
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);
|