mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 12:43:55 +08:00
222e83d2e0
Changed key initialization of tcp_fastopen cookies to net_get_random_once. If the user sets a custom key net_get_random_once must be called at least once to ensure we don't overwrite the user provided key when the first cookie is generated later on. Cc: Yuchung Cheng <ycheng@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
97 lines
2.4 KiB
C
97 lines
2.4 KiB
C
#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/tcp.h>
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#include <linux/rcupdate.h>
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#include <linux/rculist.h>
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#include <net/inetpeer.h>
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#include <net/tcp.h>
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int sysctl_tcp_fastopen __read_mostly;
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struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;
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static DEFINE_SPINLOCK(tcp_fastopen_ctx_lock);
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void tcp_fastopen_init_key_once(bool publish)
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{
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static u8 key[TCP_FASTOPEN_KEY_LENGTH];
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/* tcp_fastopen_reset_cipher publishes the new context
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* atomically, so we allow this race happening here.
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*
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* All call sites of tcp_fastopen_cookie_gen also check
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* for a valid cookie, so this is an acceptable risk.
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*/
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if (net_get_random_once(key, sizeof(key)) && publish)
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tcp_fastopen_reset_cipher(key, sizeof(key));
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}
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static void tcp_fastopen_ctx_free(struct rcu_head *head)
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{
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struct tcp_fastopen_context *ctx =
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container_of(head, struct tcp_fastopen_context, rcu);
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crypto_free_cipher(ctx->tfm);
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kfree(ctx);
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}
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int tcp_fastopen_reset_cipher(void *key, unsigned int len)
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{
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int err;
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struct tcp_fastopen_context *ctx, *octx;
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ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
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if (!ctx)
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return -ENOMEM;
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ctx->tfm = crypto_alloc_cipher("aes", 0, 0);
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if (IS_ERR(ctx->tfm)) {
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err = PTR_ERR(ctx->tfm);
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error: kfree(ctx);
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pr_err("TCP: TFO aes cipher alloc error: %d\n", err);
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return err;
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}
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err = crypto_cipher_setkey(ctx->tfm, key, len);
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if (err) {
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pr_err("TCP: TFO cipher key error: %d\n", err);
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crypto_free_cipher(ctx->tfm);
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goto error;
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}
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memcpy(ctx->key, key, len);
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spin_lock(&tcp_fastopen_ctx_lock);
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octx = rcu_dereference_protected(tcp_fastopen_ctx,
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lockdep_is_held(&tcp_fastopen_ctx_lock));
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rcu_assign_pointer(tcp_fastopen_ctx, ctx);
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spin_unlock(&tcp_fastopen_ctx_lock);
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if (octx)
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call_rcu(&octx->rcu, tcp_fastopen_ctx_free);
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return err;
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}
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/* Computes the fastopen cookie for the IP path.
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* The path is a 128 bits long (pad with zeros for IPv4).
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*
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* The caller must check foc->len to determine if a valid cookie
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* has been generated successfully.
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*/
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void tcp_fastopen_cookie_gen(__be32 src, __be32 dst,
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struct tcp_fastopen_cookie *foc)
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{
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__be32 path[4] = { src, dst, 0, 0 };
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struct tcp_fastopen_context *ctx;
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tcp_fastopen_init_key_once(true);
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rcu_read_lock();
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ctx = rcu_dereference(tcp_fastopen_ctx);
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if (ctx) {
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crypto_cipher_encrypt_one(ctx->tfm, foc->val, (__u8 *)path);
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foc->len = TCP_FASTOPEN_COOKIE_SIZE;
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}
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rcu_read_unlock();
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}
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