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Miller" Cc: Dmitry Safonov , Andy Lutomirski , Ard Biesheuvel , Bob Gilligan , Dan Carpenter , David Laight , Dmitry Safonov <0x7f454c46@gmail.com>, Eric Biggers , "Eric W. Biederman" , Francesco Ruggeri , Herbert Xu , Hideaki YOSHIFUJI , Ivan Delalande , Leonard Crestez , Salam Noureddine , netdev@vger.kernel.org Subject: [PATCH v5 01/21] [draft] net/tcp: Prepare tcp_md5sig_pool for TCP-AO Date: Mon, 3 Apr 2023 22:34:00 +0100 Message-Id: <20230403213420.1576559-2-dima@arista.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230403213420.1576559-1-dima@arista.com> References: <20230403213420.1576559-1-dima@arista.com> MIME-Version: 1.0 X-Spam-Status: No, score=-0.2 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1762192589866823272?= X-GMAIL-MSGID: =?utf-8?q?1762192589866823272?= 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. It as well needs a temporary/scratch buffer for preparing the hashing request. Extend tcp_md5sig_pool to support other hashing algorithms than MD5. Move it in a separate file. This patch was previously submitted as more generic crypto_pool [1], but Herbert nacked making it generic crypto API. His view is that crypto requests should be atomically allocated on fast-paths. So, in this version I don't move this pool anywhere outside TCP, only extending it for TCP-AO use-case. It can be converted once there will be per-request hashing crypto keys. NOTE: This is a draft version of the patch: in discussion with Herbert [2] he asks to wait for his per-request setkey changes, which he expects to be ready during v6.3 development (to be in v6.4 kernel). When they will be in linux-next, I'm going to rework this patch to use one tfm for each hashing algo with crypto requests dynamically allocated in RX/TX using kmalloc(). Sending this patch to make buildbots happy as well as for anyone who wants to try/test TCP-AO. [1]: https://lore.kernel.org/all/20230118214111.394416-1-dima@arista.com/T/#u [2]: https://lore.kernel.org/all/c4224fa7-c206-17d3-641b-6f3f53dd813d@arista.com/T/#u Signed-off-by: Dmitry Safonov --- include/net/tcp.h | 49 +++-- net/ipv4/Kconfig | 4 + net/ipv4/Makefile | 1 + net/ipv4/tcp.c | 135 ++------------ net/ipv4/tcp_ipv4.c | 97 +++++----- net/ipv4/tcp_minisocks.c | 21 ++- net/ipv4/tcp_sigpool.c | 375 +++++++++++++++++++++++++++++++++++++++ net/ipv6/tcp_ipv6.c | 58 +++--- 8 files changed, 531 insertions(+), 209 deletions(-) create mode 100644 net/ipv4/tcp_sigpool.c diff --git a/include/net/tcp.h b/include/net/tcp.h index db9f828e9d1e..0283abb6df4d 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1664,12 +1664,38 @@ 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) + */ +int tcp_sigpool_start(unsigned int id, struct tcp_sigpool *c); +/** + * tcp_sigpool_end - enable bh and stop using tcp_sigpool + */ +static inline void tcp_sigpool_end(void) +{ + rcu_read_unlock_bh(); +} +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); @@ -1725,17 +1751,12 @@ 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); - -struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); -static inline void tcp_put_md5sig_pool(void) -{ - local_bh_enable(); -} +int tcp_md5_alloc_sigpool(void); +void tcp_md5_release_sigpool(void); +void tcp_md5_add_sigpool(void); +extern int tcp_md5_sigpool_id; -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 880277c9fd07..035f3ad733c0 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 288693981b00..055ce5fbc425 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4414,141 +4414,44 @@ 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; - - 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; - } - /* 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); -} - -bool tcp_alloc_md5sig_pool(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(); + size_t scratch_size; + int ret; - mutex_unlock(&tcp_md5sig_mutex); + scratch_size = sizeof(union tcp_md5sum_block) + sizeof(struct tcphdr); + ret = tcp_sigpool_alloc_ahash("md5", scratch_size); + if (ret >= 0) { + tcp_md5_sigpool_id = ret; + return 0; } - /* Paired with WRITE_ONCE() from __tcp_alloc_md5sig_pool() */ - return READ_ONCE(tcp_md5sig_pool_populated); + return ret; } -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_release_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_release(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) +void tcp_md5_add_sigpool(void) { - 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; + tcp_sigpool_get(tcp_md5_sigpool_id); } -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)); + 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 ea370afa70ed..b6ac2cd77ee4 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1212,10 +1212,6 @@ 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; @@ -1237,8 +1233,13 @@ 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; @@ -1246,6 +1247,7 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, 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; } } @@ -1262,8 +1264,12 @@ 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; @@ -1272,6 +1278,7 @@ 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; } } @@ -1371,7 +1378,7 @@ 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) { @@ -1391,38 +1398,35 @@ 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(); return 0; clear_hash: - tcp_put_md5sig_pool(); -clear_hash_noput: + tcp_sigpool_end(); +clear_hash_nostart: memset(md5_hash, 0, 16); return 1; } @@ -1431,8 +1435,7 @@ 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; + struct tcp_sigpool hp; const struct tcphdr *th = tcp_hdr(skb); __be32 saddr, daddr; @@ -1445,30 +1448,28 @@ 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(); return 0; clear_hash: - tcp_put_md5sig_pool(); -clear_hash_noput: + tcp_sigpool_end(); +clear_hash_nostart: memset(md5_hash, 0, 16); return 1; } @@ -2286,6 +2287,18 @@ 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); @@ -2310,10 +2323,12 @@ 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 9a7ef7732c24..da6952fbeb83 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: @@ -349,16 +348,26 @@ 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..7cb7f2391cdc --- /dev/null +++ b/net/ipv4/tcp_sigpool.c @@ -0,0 +1,375 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include +#include +#include +#include +#include +#include +#include +#include + +static unsigned long __scratch_size; +static DEFINE_PER_CPU(void __rcu *, sigpool_scratch); + +struct sigpool_entry { + struct ahash_request * __percpu *req; + const char *alg; + struct kref kref; + bool needs_key; +}; + +#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_alloc_ahash(struct sigpool_entry *e, const char *alg) +{ + struct crypto_ahash *hash, *cpu0_hash; + int cpu, ret = -ENOMEM; + + e->alg = kstrdup(alg, GFP_KERNEL); + if (!e->alg) + return -ENOMEM; + + e->req = alloc_percpu(struct ahash_request *); + if (!e->req) + goto out_free_alg; + + cpu0_hash = crypto_alloc_ahash(alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(cpu0_hash)) { + ret = PTR_ERR(cpu0_hash); + goto out_free_req; + } + + /* If hash has .setkey(), allocate ahash per-CPU, not only request */ + e->needs_key = crypto_ahash_get_flags(cpu0_hash) & CRYPTO_TFM_NEED_KEY; + + hash = cpu0_hash; + for_each_possible_cpu(cpu) { + struct ahash_request *req; + + /* If ahash has a key - it has to be allocated per-CPU. + * In such case re-use for CPU0 hash that just have been + * allocated above. + */ + if (!hash) + hash = crypto_alloc_ahash(alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hash)) + goto out_free_per_cpu; + + req = ahash_request_alloc(hash, GFP_KERNEL); + if (!req) + goto out_free_hash; + + ahash_request_set_callback(req, 0, NULL, NULL); + + *per_cpu_ptr(e->req, cpu) = req; + + if (e->needs_key) + hash = NULL; + } + kref_init(&e->kref); + return 0; + +out_free_hash: + if (hash != cpu0_hash) + crypto_free_ahash(hash); + +out_free_per_cpu: + for_each_possible_cpu(cpu) { + struct ahash_request *req = *per_cpu_ptr(e->req, cpu); + struct crypto_ahash *pcpu_hash; + + if (!req) + break; + pcpu_hash = crypto_ahash_reqtfm(req); + ahash_request_free(req); + /* hash per-CPU, e->needs_key == true */ + if (pcpu_hash != cpu0_hash) + crypto_free_ahash(pcpu_hash); + } + + crypto_free_ahash(cpu0_hash); +out_free_req: + free_percpu(e->req); +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 && !strcmp(cpool[i].alg, alg)) { + 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) +{ + struct crypto_ahash *hash = NULL; + int cpu; + + for_each_possible_cpu(cpu) { + if (*per_cpu_ptr(e->req, cpu) == NULL) + continue; + + hash = crypto_ahash_reqtfm(*per_cpu_ptr(e->req, cpu)); + ahash_request_free(*per_cpu_ptr(e->req, cpu)); + if (e->needs_key) { + crypto_free_ahash(hash); + hash = NULL; + } + } + if (hash) + crypto_free_ahash(hash); + free_percpu(e->req); + kfree(e->alg); + memset(e, 0, sizeof(*e)); +} + +static void cpool_cleanup_work_cb(struct work_struct *work) +{ + unsigned int i; + bool free_scratch = true; + + 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) +{ + rcu_read_lock_bh(); + if (WARN_ON_ONCE(id > cpool_populated || !cpool[id].alg)) { + rcu_read_unlock_bh(); + return -EINVAL; + } + c->req = *this_cpu_ptr(cpool[id].req); + /* 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); + +/** + * 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) +{ + struct scatterlist sg; + const struct tcphdr *tp = tcp_hdr(skb); + struct ahash_request *req = hp->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_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 1bf93b61aa06..60fe9ade2e61 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -673,7 +673,7 @@ 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) @@ -694,39 +694,36 @@ 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(); return 0; clear_hash: - tcp_put_md5sig_pool(); -clear_hash_noput: + tcp_sigpool_end(); +clear_hash_nostart: memset(md5_hash, 0, 16); return 1; } @@ -737,8 +734,7 @@ static int tcp_v6_md5_hash_skb(char *md5_hash, const struct sk_buff *skb) { const struct in6_addr *saddr, *daddr; - struct tcp_md5sig_pool *hp; - struct ahash_request *req; + struct tcp_sigpool hp; const struct tcphdr *th = tcp_hdr(skb); if (sk) { /* valid for establish/request sockets */ @@ -750,30 +746,28 @@ 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(); return 0; clear_hash: - tcp_put_md5sig_pool(); -clear_hash_noput: + tcp_sigpool_end(); +clear_hash_nostart: memset(md5_hash, 0, 16); return 1; }