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Message-ID: <20231004223629.166300-2-dima@arista.com> Date: Wed, 4 Oct 2023 23:36:05 +0100 From: Dmitry Safonov <dima@...sta.com> To: David Ahern <dsahern@...nel.org>, Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>, Jakub Kicinski <kuba@...nel.org>, "David S. Miller" <davem@...emloft.net> Cc: linux-kernel@...r.kernel.org, Dmitry Safonov <dima@...sta.com>, Andy Lutomirski <luto@...capital.net>, Ard Biesheuvel <ardb@...nel.org>, Bob Gilligan <gilligan@...sta.com>, Dan Carpenter <error27@...il.com>, David Laight <David.Laight@...lab.com>, Dmitry Safonov <0x7f454c46@...il.com>, Donald Cassidy <dcassidy@...hat.com>, Eric Biggers <ebiggers@...nel.org>, "Eric W. Biederman" <ebiederm@...ssion.com>, Francesco Ruggeri <fruggeri05@...il.com>, "Gaillardetz, Dominik" <dgaillar@...na.com>, Herbert Xu <herbert@...dor.apana.org.au>, Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>, Ivan Delalande <colona@...sta.com>, Leonard Crestez <cdleonard@...il.com>, "Nassiri, Mohammad" <mnassiri@...na.com>, Salam Noureddine <noureddine@...sta.com>, Simon Horman <simon.horman@...igine.com>, "Tetreault, Francois" <ftetreau@...na.com>, netdev@...r.kernel.org, Steen Hegelund <Steen.Hegelund@...rochip.com> Subject: [PATCH v13 net-next 01/23] net/tcp: Prepare tcp_md5sig_pool for TCP-AO TCP-AO, similarly to TCP-MD5, needs to allocate tfms on a slow-path, which is setsockopt() and use crypto ahash requests on fast paths, which are RX/TX softirqs. Also, it needs a temporary/scratch buffer for preparing the hash. Rework tcp_md5sig_pool in order to support other hashing algorithms than MD5. It will make it possible to share pre-allocated crypto_ahash descriptors and scratch area between all TCP hash users. Internally tcp_sigpool calls crypto_clone_ahash() API over pre-allocated crypto ahash tfm. Kudos to Herbert, who provided this new crypto API. I was a little concerned over GFP_ATOMIC allocations of ahash and crypto_request in RX/TX (see tcp_sigpool_start()), so I benchmarked both "backends" with different algorithms, using patched version of iperf3[2]. On my laptop with i7-7600U @ 2.80GHz: clone-tfm per-CPU-requests TCP-MD5 2.25 Gbits/sec 2.30 Gbits/sec TCP-AO(hmac(sha1)) 2.53 Gbits/sec 2.54 Gbits/sec TCP-AO(hmac(sha512)) 1.67 Gbits/sec 1.64 Gbits/sec TCP-AO(hmac(sha384)) 1.77 Gbits/sec 1.80 Gbits/sec TCP-AO(hmac(sha224)) 1.29 Gbits/sec 1.30 Gbits/sec TCP-AO(hmac(sha3-512)) 481 Mbits/sec 480 Mbits/sec TCP-AO(hmac(md5)) 2.07 Gbits/sec 2.12 Gbits/sec TCP-AO(hmac(rmd160)) 1.01 Gbits/sec 995 Mbits/sec TCP-AO(cmac(aes128)) [not supporetd yet] 2.11 Gbits/sec So, it seems that my concerns don't have strong grounds and per-CPU crypto_request allocation can be dropped/removed from tcp_sigpool once ciphers get crypto_clone_ahash() support. [1]: https://lore.kernel.org/all/ZDefxOq6Ax0JeTRH@gondor.apana.org.au/T/#u [2]: https://github.com/0x7f454c46/iperf/tree/tcp-md5-ao Signed-off-by: Dmitry Safonov <dima@...sta.com> Reviewed-by: Steen Hegelund <Steen.Hegelund@...rochip.com> Acked-by: David Ahern <dsahern@...nel.org> --- include/net/tcp.h | 50 ++++-- net/ipv4/Kconfig | 4 + net/ipv4/Makefile | 1 + net/ipv4/tcp.c | 145 +++------------- net/ipv4/tcp_ipv4.c | 97 ++++++----- net/ipv4/tcp_minisocks.c | 21 ++- net/ipv4/tcp_sigpool.c | 358 +++++++++++++++++++++++++++++++++++++++ net/ipv6/tcp_ipv6.c | 60 +++---- 8 files changed, 525 insertions(+), 211 deletions(-) create mode 100644 net/ipv4/tcp_sigpool.c diff --git a/include/net/tcp.h b/include/net/tcp.h index af9cb37fbe53..1a8213cd2763 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1701,12 +1701,39 @@ union tcp_md5sum_block { #endif }; -/* - pool: digest algorithm, hash description and scratch buffer */ -struct tcp_md5sig_pool { - struct ahash_request *md5_req; - void *scratch; +/* + * struct tcp_sigpool - per-CPU pool of ahash_requests + * @scratch: per-CPU temporary area, that can be used between + * tcp_sigpool_start() and tcp_sigpool_end() to perform + * crypto request + * @req: pre-allocated ahash request + */ +struct tcp_sigpool { + void *scratch; + struct ahash_request *req; }; +int tcp_sigpool_alloc_ahash(const char *alg, size_t scratch_size); +void tcp_sigpool_get(unsigned int id); +void tcp_sigpool_release(unsigned int id); +int tcp_sigpool_hash_skb_data(struct tcp_sigpool *hp, + const struct sk_buff *skb, + unsigned int header_len); + +/** + * tcp_sigpool_start - disable bh and start using tcp_sigpool_ahash + * @id: tcp_sigpool that was previously allocated by tcp_sigpool_alloc_ahash() + * @c: returned tcp_sigpool for usage (uninitialized on failure) + * + * Returns 0 on success, error otherwise. + */ +int tcp_sigpool_start(unsigned int id, struct tcp_sigpool *c); +/** + * tcp_sigpool_end - enable bh and stop using tcp_sigpool + * @c: tcp_sigpool context that was returned by tcp_sigpool_start() + */ +void tcp_sigpool_end(struct tcp_sigpool *c); +size_t tcp_sigpool_algo(unsigned int id, char *buf, size_t buf_len); /* - functions */ int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, const struct sock *sk, const struct sk_buff *skb); @@ -1762,17 +1789,12 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, #define tcp_twsk_md5_key(twsk) NULL #endif -bool tcp_alloc_md5sig_pool(void); +int tcp_md5_alloc_sigpool(void); +void tcp_md5_release_sigpool(void); +void tcp_md5_add_sigpool(void); +extern int tcp_md5_sigpool_id; -struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); -static inline void tcp_put_md5sig_pool(void) -{ - local_bh_enable(); -} - -int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, - unsigned int header_len); -int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, +int tcp_md5_hash_key(struct tcp_sigpool *hp, const struct tcp_md5sig_key *key); /* From tcp_fastopen.c */ diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig index 2dfb12230f08..89e2ab023272 100644 --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -741,10 +741,14 @@ config DEFAULT_TCP_CONG default "bbr" if DEFAULT_BBR default "cubic" +config TCP_SIGPOOL + tristate + config TCP_MD5SIG bool "TCP: MD5 Signature Option support (RFC2385)" select CRYPTO select CRYPTO_MD5 + select TCP_SIGPOOL help RFC2385 specifies a method of giving MD5 protection to TCP sessions. Its main (only?) use is to protect BGP sessions between core routers diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile index b18ba8ef93ad..cd760793cfcb 100644 --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -62,6 +62,7 @@ obj-$(CONFIG_TCP_CONG_SCALABLE) += tcp_scalable.o obj-$(CONFIG_TCP_CONG_LP) += tcp_lp.o obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o +obj-$(CONFIG_TCP_SIGPOOL) += tcp_sigpool.o obj-$(CONFIG_NET_SOCK_MSG) += tcp_bpf.o obj-$(CONFIG_BPF_SYSCALL) += udp_bpf.o obj-$(CONFIG_NETLABEL) += cipso_ipv4.o diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index e54f91eb943b..72e7e3e9f236 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4299,141 +4299,52 @@ int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, EXPORT_SYMBOL(tcp_getsockopt); #ifdef CONFIG_TCP_MD5SIG -static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool); -static DEFINE_MUTEX(tcp_md5sig_mutex); -static bool tcp_md5sig_pool_populated = false; +int tcp_md5_sigpool_id = -1; +EXPORT_SYMBOL_GPL(tcp_md5_sigpool_id); -static void __tcp_alloc_md5sig_pool(void) +int tcp_md5_alloc_sigpool(void) { - struct crypto_ahash *hash; - int cpu; + size_t scratch_size; + int ret; - hash = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC); - if (IS_ERR(hash)) - return; - - for_each_possible_cpu(cpu) { - void *scratch = per_cpu(tcp_md5sig_pool, cpu).scratch; - struct ahash_request *req; - - if (!scratch) { - scratch = kmalloc_node(sizeof(union tcp_md5sum_block) + - sizeof(struct tcphdr), - GFP_KERNEL, - cpu_to_node(cpu)); - if (!scratch) - return; - per_cpu(tcp_md5sig_pool, cpu).scratch = scratch; - } - if (per_cpu(tcp_md5sig_pool, cpu).md5_req) - continue; - - req = ahash_request_alloc(hash, GFP_KERNEL); - if (!req) - return; - - ahash_request_set_callback(req, 0, NULL, NULL); - - per_cpu(tcp_md5sig_pool, cpu).md5_req = req; + scratch_size = sizeof(union tcp_md5sum_block) + sizeof(struct tcphdr); + ret = tcp_sigpool_alloc_ahash("md5", scratch_size); + if (ret >= 0) { + /* As long as any md5 sigpool was allocated, the return + * id would stay the same. Re-write the id only for the case + * when previously all MD5 keys were deleted and this call + * allocates the first MD5 key, which may return a different + * sigpool id than was used previously. + */ + WRITE_ONCE(tcp_md5_sigpool_id, ret); /* Avoids the compiler potentially being smart here */ + return 0; } - /* before setting tcp_md5sig_pool_populated, we must commit all writes - * to memory. See smp_rmb() in tcp_get_md5sig_pool() - */ - smp_wmb(); - /* Paired with READ_ONCE() from tcp_alloc_md5sig_pool() - * and tcp_get_md5sig_pool(). - */ - WRITE_ONCE(tcp_md5sig_pool_populated, true); + return ret; } -bool tcp_alloc_md5sig_pool(void) +void tcp_md5_release_sigpool(void) { - /* Paired with WRITE_ONCE() from __tcp_alloc_md5sig_pool() */ - if (unlikely(!READ_ONCE(tcp_md5sig_pool_populated))) { - mutex_lock(&tcp_md5sig_mutex); - - if (!tcp_md5sig_pool_populated) - __tcp_alloc_md5sig_pool(); - - mutex_unlock(&tcp_md5sig_mutex); - } - /* Paired with WRITE_ONCE() from __tcp_alloc_md5sig_pool() */ - return READ_ONCE(tcp_md5sig_pool_populated); + tcp_sigpool_release(READ_ONCE(tcp_md5_sigpool_id)); } -EXPORT_SYMBOL(tcp_alloc_md5sig_pool); - -/** - * tcp_get_md5sig_pool - get md5sig_pool for this user - * - * We use percpu structure, so if we succeed, we exit with preemption - * and BH disabled, to make sure another thread or softirq handling - * wont try to get same context. - */ -struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) +void tcp_md5_add_sigpool(void) { - local_bh_disable(); - - /* Paired with WRITE_ONCE() from __tcp_alloc_md5sig_pool() */ - if (READ_ONCE(tcp_md5sig_pool_populated)) { - /* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */ - smp_rmb(); - return this_cpu_ptr(&tcp_md5sig_pool); - } - local_bh_enable(); - return NULL; + tcp_sigpool_get(READ_ONCE(tcp_md5_sigpool_id)); } -EXPORT_SYMBOL(tcp_get_md5sig_pool); -int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, - const struct sk_buff *skb, unsigned int header_len) -{ - struct scatterlist sg; - const struct tcphdr *tp = tcp_hdr(skb); - struct ahash_request *req = hp->md5_req; - unsigned int i; - const unsigned int head_data_len = skb_headlen(skb) > header_len ? - skb_headlen(skb) - header_len : 0; - const struct skb_shared_info *shi = skb_shinfo(skb); - struct sk_buff *frag_iter; - - sg_init_table(&sg, 1); - - sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len); - ahash_request_set_crypt(req, &sg, NULL, head_data_len); - if (crypto_ahash_update(req)) - return 1; - - for (i = 0; i < shi->nr_frags; ++i) { - const skb_frag_t *f = &shi->frags[i]; - unsigned int offset = skb_frag_off(f); - struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT); - - sg_set_page(&sg, page, skb_frag_size(f), - offset_in_page(offset)); - ahash_request_set_crypt(req, &sg, NULL, skb_frag_size(f)); - if (crypto_ahash_update(req)) - return 1; - } - - skb_walk_frags(skb, frag_iter) - if (tcp_md5_hash_skb_data(hp, frag_iter, 0)) - return 1; - - return 0; -} -EXPORT_SYMBOL(tcp_md5_hash_skb_data); - -int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key) +int tcp_md5_hash_key(struct tcp_sigpool *hp, + const struct tcp_md5sig_key *key) { u8 keylen = READ_ONCE(key->keylen); /* paired with WRITE_ONCE() in tcp_md5_do_add */ struct scatterlist sg; sg_init_one(&sg, key->key, keylen); - ahash_request_set_crypt(hp->md5_req, &sg, NULL, keylen); + ahash_request_set_crypt(hp->req, &sg, NULL, keylen); - /* We use data_race() because tcp_md5_do_add() might change key->key under us */ - return data_race(crypto_ahash_update(hp->md5_req)); + /* We use data_race() because tcp_md5_do_add() might change + * key->key under us + */ + return data_race(crypto_ahash_update(hp->req)); } EXPORT_SYMBOL(tcp_md5_hash_key); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index a441740616d7..8b9d2b2ca89f 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1220,10 +1220,6 @@ static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, key = sock_kmalloc(sk, sizeof(*key), gfp | __GFP_ZERO); if (!key) return -ENOMEM; - if (!tcp_alloc_md5sig_pool()) { - sock_kfree_s(sk, key, sizeof(*key)); - return -ENOMEM; - } memcpy(key->key, newkey, newkeylen); key->keylen = newkeylen; @@ -1245,15 +1241,21 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, struct tcp_sock *tp = tcp_sk(sk); if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) { - if (tcp_md5sig_info_add(sk, GFP_KERNEL)) + if (tcp_md5_alloc_sigpool()) return -ENOMEM; + if (tcp_md5sig_info_add(sk, GFP_KERNEL)) { + tcp_md5_release_sigpool(); + return -ENOMEM; + } + if (!static_branch_inc(&tcp_md5_needed.key)) { struct tcp_md5sig_info *md5sig; md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk)); rcu_assign_pointer(tp->md5sig_info, NULL); kfree_rcu(md5sig, rcu); + tcp_md5_release_sigpool(); return -EUSERS; } } @@ -1270,8 +1272,12 @@ int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, struct tcp_sock *tp = tcp_sk(sk); if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) { - if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) + tcp_md5_add_sigpool(); + + if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) { + tcp_md5_release_sigpool(); return -ENOMEM; + } if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) { struct tcp_md5sig_info *md5sig; @@ -1280,6 +1286,7 @@ int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, net_warn_ratelimited("Too many TCP-MD5 keys in the system\n"); rcu_assign_pointer(tp->md5sig_info, NULL); kfree_rcu(md5sig, rcu); + tcp_md5_release_sigpool(); return -EUSERS; } } @@ -1379,7 +1386,7 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, cmd.tcpm_key, cmd.tcpm_keylen); } -static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp, +static int tcp_v4_md5_hash_headers(struct tcp_sigpool *hp, __be32 daddr, __be32 saddr, const struct tcphdr *th, int nbytes) { @@ -1399,38 +1406,35 @@ static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp, _th->check = 0; sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th)); - ahash_request_set_crypt(hp->md5_req, &sg, NULL, + ahash_request_set_crypt(hp->req, &sg, NULL, sizeof(*bp) + sizeof(*th)); - return crypto_ahash_update(hp->md5_req); + return crypto_ahash_update(hp->req); } static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, __be32 daddr, __be32 saddr, const struct tcphdr *th) { - struct tcp_md5sig_pool *hp; - struct ahash_request *req; + struct tcp_sigpool hp; - hp = tcp_get_md5sig_pool(); - if (!hp) - goto clear_hash_noput; - req = hp->md5_req; + if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp)) + goto clear_hash_nostart; - if (crypto_ahash_init(req)) + if (crypto_ahash_init(hp.req)) goto clear_hash; - if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2)) + if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2)) goto clear_hash; - if (tcp_md5_hash_key(hp, key)) + if (tcp_md5_hash_key(&hp, key)) goto clear_hash; - ahash_request_set_crypt(req, NULL, md5_hash, 0); - if (crypto_ahash_final(req)) + ahash_request_set_crypt(hp.req, NULL, md5_hash, 0); + if (crypto_ahash_final(hp.req)) goto clear_hash; - tcp_put_md5sig_pool(); + tcp_sigpool_end(&hp); return 0; clear_hash: - tcp_put_md5sig_pool(); -clear_hash_noput: + tcp_sigpool_end(&hp); +clear_hash_nostart: memset(md5_hash, 0, 16); return 1; } @@ -1439,9 +1443,8 @@ int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, const struct sock *sk, const struct sk_buff *skb) { - struct tcp_md5sig_pool *hp; - struct ahash_request *req; const struct tcphdr *th = tcp_hdr(skb); + struct tcp_sigpool hp; __be32 saddr, daddr; if (sk) { /* valid for establish/request sockets */ @@ -1453,30 +1456,28 @@ int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, daddr = iph->daddr; } - hp = tcp_get_md5sig_pool(); - if (!hp) - goto clear_hash_noput; - req = hp->md5_req; + if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp)) + goto clear_hash_nostart; - if (crypto_ahash_init(req)) + if (crypto_ahash_init(hp.req)) goto clear_hash; - if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len)) + if (tcp_v4_md5_hash_headers(&hp, daddr, saddr, th, skb->len)) goto clear_hash; - if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) + if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2)) goto clear_hash; - if (tcp_md5_hash_key(hp, key)) + if (tcp_md5_hash_key(&hp, key)) goto clear_hash; - ahash_request_set_crypt(req, NULL, md5_hash, 0); - if (crypto_ahash_final(req)) + ahash_request_set_crypt(hp.req, NULL, md5_hash, 0); + if (crypto_ahash_final(hp.req)) goto clear_hash; - tcp_put_md5sig_pool(); + tcp_sigpool_end(&hp); return 0; clear_hash: - tcp_put_md5sig_pool(); -clear_hash_noput: + tcp_sigpool_end(&hp); +clear_hash_nostart: memset(md5_hash, 0, 16); return 1; } @@ -2294,6 +2295,18 @@ static int tcp_v4_init_sock(struct sock *sk) return 0; } +#ifdef CONFIG_TCP_MD5SIG +static void tcp_md5sig_info_free_rcu(struct rcu_head *head) +{ + struct tcp_md5sig_info *md5sig; + + md5sig = container_of(head, struct tcp_md5sig_info, rcu); + kfree(md5sig); + static_branch_slow_dec_deferred(&tcp_md5_needed); + tcp_md5_release_sigpool(); +} +#endif + void tcp_v4_destroy_sock(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); @@ -2318,10 +2331,12 @@ void tcp_v4_destroy_sock(struct sock *sk) #ifdef CONFIG_TCP_MD5SIG /* Clean up the MD5 key list, if any */ if (tp->md5sig_info) { + struct tcp_md5sig_info *md5sig; + + md5sig = rcu_dereference_protected(tp->md5sig_info, 1); tcp_clear_md5_list(sk); - kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu); - tp->md5sig_info = NULL; - static_branch_slow_dec_deferred(&tcp_md5_needed); + call_rcu(&md5sig->rcu, tcp_md5sig_info_free_rcu); + rcu_assign_pointer(tp->md5sig_info, NULL); } #endif diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 3f87611077ef..37aff812ca18 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -261,10 +261,9 @@ static void tcp_time_wait_init(struct sock *sk, struct tcp_timewait_sock *tcptw) tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC); if (!tcptw->tw_md5_key) return; - if (!tcp_alloc_md5sig_pool()) - goto out_free; if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) goto out_free; + tcp_md5_add_sigpool(); } return; out_free: @@ -348,16 +347,26 @@ void tcp_time_wait(struct sock *sk, int state, int timeo) } EXPORT_SYMBOL(tcp_time_wait); +#ifdef CONFIG_TCP_MD5SIG +static void tcp_md5_twsk_free_rcu(struct rcu_head *head) +{ + struct tcp_md5sig_key *key; + + key = container_of(head, struct tcp_md5sig_key, rcu); + kfree(key); + static_branch_slow_dec_deferred(&tcp_md5_needed); + tcp_md5_release_sigpool(); +} +#endif + void tcp_twsk_destructor(struct sock *sk) { #ifdef CONFIG_TCP_MD5SIG if (static_branch_unlikely(&tcp_md5_needed.key)) { struct tcp_timewait_sock *twsk = tcp_twsk(sk); - if (twsk->tw_md5_key) { - kfree_rcu(twsk->tw_md5_key, rcu); - static_branch_slow_dec_deferred(&tcp_md5_needed); - } + if (twsk->tw_md5_key) + call_rcu(&twsk->tw_md5_key->rcu, tcp_md5_twsk_free_rcu); } #endif } diff --git a/net/ipv4/tcp_sigpool.c b/net/ipv4/tcp_sigpool.c new file mode 100644 index 000000000000..65a8eaae2fec --- /dev/null +++ b/net/ipv4/tcp_sigpool.c @@ -0,0 +1,358 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <crypto/hash.h> +#include <linux/cpu.h> +#include <linux/kref.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/percpu.h> +#include <linux/workqueue.h> +#include <net/tcp.h> + +static size_t __scratch_size; +static DEFINE_PER_CPU(void __rcu *, sigpool_scratch); + +struct sigpool_entry { + struct crypto_ahash *hash; + const char *alg; + struct kref kref; + uint16_t needs_key:1, + reserved:15; +}; + +#define CPOOL_SIZE (PAGE_SIZE / sizeof(struct sigpool_entry)) +static struct sigpool_entry cpool[CPOOL_SIZE]; +static unsigned int cpool_populated; +static DEFINE_MUTEX(cpool_mutex); + +/* Slow-path */ +struct scratches_to_free { + struct rcu_head rcu; + unsigned int cnt; + void *scratches[]; +}; + +static void free_old_scratches(struct rcu_head *head) +{ + struct scratches_to_free *stf; + + stf = container_of(head, struct scratches_to_free, rcu); + while (stf->cnt--) + kfree(stf->scratches[stf->cnt]); + kfree(stf); +} + +/** + * sigpool_reserve_scratch - re-allocates scratch buffer, slow-path + * @size: request size for the scratch/temp buffer + */ +static int sigpool_reserve_scratch(size_t size) +{ + struct scratches_to_free *stf; + size_t stf_sz = struct_size(stf, scratches, num_possible_cpus()); + int cpu, err = 0; + + lockdep_assert_held(&cpool_mutex); + if (__scratch_size >= size) + return 0; + + stf = kmalloc(stf_sz, GFP_KERNEL); + if (!stf) + return -ENOMEM; + stf->cnt = 0; + + size = max(size, __scratch_size); + cpus_read_lock(); + for_each_possible_cpu(cpu) { + void *scratch, *old_scratch; + + scratch = kmalloc_node(size, GFP_KERNEL, cpu_to_node(cpu)); + if (!scratch) { + err = -ENOMEM; + break; + } + + old_scratch = rcu_replace_pointer(per_cpu(sigpool_scratch, cpu), + scratch, lockdep_is_held(&cpool_mutex)); + if (!cpu_online(cpu) || !old_scratch) { + kfree(old_scratch); + continue; + } + stf->scratches[stf->cnt++] = old_scratch; + } + cpus_read_unlock(); + if (!err) + __scratch_size = size; + + call_rcu(&stf->rcu, free_old_scratches); + return err; +} + +static void sigpool_scratch_free(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + kfree(rcu_replace_pointer(per_cpu(sigpool_scratch, cpu), + NULL, lockdep_is_held(&cpool_mutex))); + __scratch_size = 0; +} + +static int __cpool_try_clone(struct crypto_ahash *hash) +{ + struct crypto_ahash *tmp; + + tmp = crypto_clone_ahash(hash); + if (IS_ERR(tmp)) + return PTR_ERR(tmp); + + crypto_free_ahash(tmp); + return 0; +} + +static int __cpool_alloc_ahash(struct sigpool_entry *e, const char *alg) +{ + struct crypto_ahash *cpu0_hash; + int ret; + + e->alg = kstrdup(alg, GFP_KERNEL); + if (!e->alg) + return -ENOMEM; + + cpu0_hash = crypto_alloc_ahash(alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(cpu0_hash)) { + ret = PTR_ERR(cpu0_hash); + goto out_free_alg; + } + + e->needs_key = crypto_ahash_get_flags(cpu0_hash) & CRYPTO_TFM_NEED_KEY; + + ret = __cpool_try_clone(cpu0_hash); + if (ret) + goto out_free_cpu0_hash; + e->hash = cpu0_hash; + kref_init(&e->kref); + return 0; + +out_free_cpu0_hash: + crypto_free_ahash(cpu0_hash); +out_free_alg: + kfree(e->alg); + e->alg = NULL; + return ret; +} + +/** + * tcp_sigpool_alloc_ahash - allocates pool for ahash requests + * @alg: name of async hash algorithm + * @scratch_size: reserve a tcp_sigpool::scratch buffer of this size + */ +int tcp_sigpool_alloc_ahash(const char *alg, size_t scratch_size) +{ + int i, ret; + + /* slow-path */ + mutex_lock(&cpool_mutex); + ret = sigpool_reserve_scratch(scratch_size); + if (ret) + goto out; + for (i = 0; i < cpool_populated; i++) { + if (!cpool[i].alg) + continue; + if (strcmp(cpool[i].alg, alg)) + continue; + + if (kref_read(&cpool[i].kref) > 0) + kref_get(&cpool[i].kref); + else + kref_init(&cpool[i].kref); + ret = i; + goto out; + } + + for (i = 0; i < cpool_populated; i++) { + if (!cpool[i].alg) + break; + } + if (i >= CPOOL_SIZE) { + ret = -ENOSPC; + goto out; + } + + ret = __cpool_alloc_ahash(&cpool[i], alg); + if (!ret) { + ret = i; + if (i == cpool_populated) + cpool_populated++; + } +out: + mutex_unlock(&cpool_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(tcp_sigpool_alloc_ahash); + +static void __cpool_free_entry(struct sigpool_entry *e) +{ + crypto_free_ahash(e->hash); + kfree(e->alg); + memset(e, 0, sizeof(*e)); +} + +static void cpool_cleanup_work_cb(struct work_struct *work) +{ + bool free_scratch = true; + unsigned int i; + + mutex_lock(&cpool_mutex); + for (i = 0; i < cpool_populated; i++) { + if (kref_read(&cpool[i].kref) > 0) { + free_scratch = false; + continue; + } + if (!cpool[i].alg) + continue; + __cpool_free_entry(&cpool[i]); + } + if (free_scratch) + sigpool_scratch_free(); + mutex_unlock(&cpool_mutex); +} + +static DECLARE_WORK(cpool_cleanup_work, cpool_cleanup_work_cb); +static void cpool_schedule_cleanup(struct kref *kref) +{ + schedule_work(&cpool_cleanup_work); +} + +/** + * tcp_sigpool_release - decreases number of users for a pool. If it was + * the last user of the pool, releases any memory that was consumed. + * @id: tcp_sigpool that was previously allocated by tcp_sigpool_alloc_ahash() + */ +void tcp_sigpool_release(unsigned int id) +{ + if (WARN_ON_ONCE(id > cpool_populated || !cpool[id].alg)) + return; + + /* slow-path */ + kref_put(&cpool[id].kref, cpool_schedule_cleanup); +} +EXPORT_SYMBOL_GPL(tcp_sigpool_release); + +/** + * tcp_sigpool_get - increases number of users (refcounter) for a pool + * @id: tcp_sigpool that was previously allocated by tcp_sigpool_alloc_ahash() + */ +void tcp_sigpool_get(unsigned int id) +{ + if (WARN_ON_ONCE(id > cpool_populated || !cpool[id].alg)) + return; + kref_get(&cpool[id].kref); +} +EXPORT_SYMBOL_GPL(tcp_sigpool_get); + +int tcp_sigpool_start(unsigned int id, struct tcp_sigpool *c) __cond_acquires(RCU_BH) +{ + struct crypto_ahash *hash; + + rcu_read_lock_bh(); + if (WARN_ON_ONCE(id > cpool_populated || !cpool[id].alg)) { + rcu_read_unlock_bh(); + return -EINVAL; + } + + hash = crypto_clone_ahash(cpool[id].hash); + if (IS_ERR(hash)) { + rcu_read_unlock_bh(); + return PTR_ERR(hash); + } + + c->req = ahash_request_alloc(hash, GFP_ATOMIC); + if (!c->req) { + crypto_free_ahash(hash); + rcu_read_unlock_bh(); + return -ENOMEM; + } + ahash_request_set_callback(c->req, 0, NULL, NULL); + + /* Pairs with tcp_sigpool_reserve_scratch(), scratch area is + * valid (allocated) until tcp_sigpool_end(). + */ + c->scratch = rcu_dereference_bh(*this_cpu_ptr(&sigpool_scratch)); + return 0; +} +EXPORT_SYMBOL_GPL(tcp_sigpool_start); + +void tcp_sigpool_end(struct tcp_sigpool *c) __releases(RCU_BH) +{ + struct crypto_ahash *hash = crypto_ahash_reqtfm(c->req); + + rcu_read_unlock_bh(); + ahash_request_free(c->req); + crypto_free_ahash(hash); +} +EXPORT_SYMBOL_GPL(tcp_sigpool_end); + +/** + * tcp_sigpool_algo - return algorithm of tcp_sigpool + * @id: tcp_sigpool that was previously allocated by tcp_sigpool_alloc_ahash() + * @buf: buffer to return name of algorithm + * @buf_len: size of @buf + */ +size_t tcp_sigpool_algo(unsigned int id, char *buf, size_t buf_len) +{ + if (WARN_ON_ONCE(id > cpool_populated || !cpool[id].alg)) + return -EINVAL; + + return strscpy(buf, cpool[id].alg, buf_len); +} +EXPORT_SYMBOL_GPL(tcp_sigpool_algo); + +/** + * tcp_sigpool_hash_skb_data - hash data in skb with initialized tcp_sigpool + * @hp: tcp_sigpool pointer + * @skb: buffer to add sign for + * @header_len: TCP header length for this segment + */ +int tcp_sigpool_hash_skb_data(struct tcp_sigpool *hp, + const struct sk_buff *skb, + unsigned int header_len) +{ + const unsigned int head_data_len = skb_headlen(skb) > header_len ? + skb_headlen(skb) - header_len : 0; + const struct skb_shared_info *shi = skb_shinfo(skb); + const struct tcphdr *tp = tcp_hdr(skb); + struct ahash_request *req = hp->req; + struct sk_buff *frag_iter; + struct scatterlist sg; + unsigned int i; + + sg_init_table(&sg, 1); + + sg_set_buf(&sg, ((u8 *)tp) + header_len, head_data_len); + ahash_request_set_crypt(req, &sg, NULL, head_data_len); + if (crypto_ahash_update(req)) + return 1; + + for (i = 0; i < shi->nr_frags; ++i) { + const skb_frag_t *f = &shi->frags[i]; + unsigned int offset = skb_frag_off(f); + struct page *page; + + page = skb_frag_page(f) + (offset >> PAGE_SHIFT); + sg_set_page(&sg, page, skb_frag_size(f), offset_in_page(offset)); + ahash_request_set_crypt(req, &sg, NULL, skb_frag_size(f)); + if (crypto_ahash_update(req)) + return 1; + } + + skb_walk_frags(skb, frag_iter) + if (tcp_sigpool_hash_skb_data(hp, frag_iter, 0)) + return 1; + + return 0; +} +EXPORT_SYMBOL(tcp_sigpool_hash_skb_data); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Per-CPU pool of crypto requests"); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 8a6e2e97f673..183fd1543255 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -670,7 +670,7 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, int optname, cmd.tcpm_key, cmd.tcpm_keylen); } -static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp, +static int tcp_v6_md5_hash_headers(struct tcp_sigpool *hp, const struct in6_addr *daddr, const struct in6_addr *saddr, const struct tcphdr *th, int nbytes) @@ -691,39 +691,36 @@ static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp, _th->check = 0; sg_init_one(&sg, bp, sizeof(*bp) + sizeof(*th)); - ahash_request_set_crypt(hp->md5_req, &sg, NULL, + ahash_request_set_crypt(hp->req, &sg, NULL, sizeof(*bp) + sizeof(*th)); - return crypto_ahash_update(hp->md5_req); + return crypto_ahash_update(hp->req); } static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, const struct in6_addr *daddr, struct in6_addr *saddr, const struct tcphdr *th) { - struct tcp_md5sig_pool *hp; - struct ahash_request *req; + struct tcp_sigpool hp; - hp = tcp_get_md5sig_pool(); - if (!hp) - goto clear_hash_noput; - req = hp->md5_req; + if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp)) + goto clear_hash_nostart; - if (crypto_ahash_init(req)) + if (crypto_ahash_init(hp.req)) goto clear_hash; - if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, th->doff << 2)) + if (tcp_v6_md5_hash_headers(&hp, daddr, saddr, th, th->doff << 2)) goto clear_hash; - if (tcp_md5_hash_key(hp, key)) + if (tcp_md5_hash_key(&hp, key)) goto clear_hash; - ahash_request_set_crypt(req, NULL, md5_hash, 0); - if (crypto_ahash_final(req)) + ahash_request_set_crypt(hp.req, NULL, md5_hash, 0); + if (crypto_ahash_final(hp.req)) goto clear_hash; - tcp_put_md5sig_pool(); + tcp_sigpool_end(&hp); return 0; clear_hash: - tcp_put_md5sig_pool(); -clear_hash_noput: + tcp_sigpool_end(&hp); +clear_hash_nostart: memset(md5_hash, 0, 16); return 1; } @@ -733,10 +730,9 @@ static int tcp_v6_md5_hash_skb(char *md5_hash, const struct sock *sk, const struct sk_buff *skb) { - const struct in6_addr *saddr, *daddr; - struct tcp_md5sig_pool *hp; - struct ahash_request *req; const struct tcphdr *th = tcp_hdr(skb); + const struct in6_addr *saddr, *daddr; + struct tcp_sigpool hp; if (sk) { /* valid for establish/request sockets */ saddr = &sk->sk_v6_rcv_saddr; @@ -747,30 +743,28 @@ static int tcp_v6_md5_hash_skb(char *md5_hash, daddr = &ip6h->daddr; } - hp = tcp_get_md5sig_pool(); - if (!hp) - goto clear_hash_noput; - req = hp->md5_req; + if (tcp_sigpool_start(tcp_md5_sigpool_id, &hp)) + goto clear_hash_nostart; - if (crypto_ahash_init(req)) + if (crypto_ahash_init(hp.req)) goto clear_hash; - if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len)) + if (tcp_v6_md5_hash_headers(&hp, daddr, saddr, th, skb->len)) goto clear_hash; - if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) + if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2)) goto clear_hash; - if (tcp_md5_hash_key(hp, key)) + if (tcp_md5_hash_key(&hp, key)) goto clear_hash; - ahash_request_set_crypt(req, NULL, md5_hash, 0); - if (crypto_ahash_final(req)) + ahash_request_set_crypt(hp.req, NULL, md5_hash, 0); + if (crypto_ahash_final(hp.req)) goto clear_hash; - tcp_put_md5sig_pool(); + tcp_sigpool_end(&hp); return 0; clear_hash: - tcp_put_md5sig_pool(); -clear_hash_noput: + tcp_sigpool_end(&hp); +clear_hash_nostart: memset(md5_hash, 0, 16); return 1; } -- 2.42.0
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