[PATCH v4 01/21] net/tcp: Prepare tcp_md5sig_pool for TCP-AO
From: Dmitry Safonov
Date: Wed Feb 15 2023 - 13:34:08 EST
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.
[1]: https://lore.kernel.org/all/20230118214111.394416-1-dima@xxxxxxxxxx/T/#u
Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
---
include/net/tcp.h | 48 ++++--
net/ipv4/Kconfig | 4 +
net/ipv4/Makefile | 1 +
net/ipv4/tcp.c | 103 +++---------
net/ipv4/tcp_ipv4.c | 97 +++++++-----
net/ipv4/tcp_minisocks.c | 21 ++-
net/ipv4/tcp_sigpool.c | 333 +++++++++++++++++++++++++++++++++++++++
net/ipv6/tcp_ipv6.c | 58 +++----
8 files changed, 493 insertions(+), 172 deletions(-)
create mode 100644 net/ipv4/tcp_sigpool.c
diff --git a/include/net/tcp.h b/include/net/tcp.h
index db9f828e9d1e..e77080003800 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1664,12 +1664,35 @@ 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);
+/**
+ * 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 +1748,14 @@ 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_skb_data(struct tcp_sigpool *hp,
+ const struct sk_buff *skb, unsigned int header_len);
+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 af7d2cf490fb..de8ba8cdc056 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -61,6 +61,7 @@ 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 33f559f491c8..5522c5ac24bc 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4413,98 +4413,42 @@ 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(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);
+ size_t scratch_size;
+ int ret;
- 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) {
+ tcp_md5_sigpool_id = ret;
+ 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;
}
+EXPORT_SYMBOL(tcp_md5_alloc_sigpool);
-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(tcp_md5_sigpool_id);
}
-EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
+EXPORT_SYMBOL(tcp_md5_release_sigpool);
-
-/**
- * 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(tcp_md5_sigpool_id);
}
-EXPORT_SYMBOL(tcp_get_md5sig_pool);
+EXPORT_SYMBOL(tcp_md5_add_sigpool);
-int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
+int tcp_md5_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->md5_req;
+ 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;
@@ -4538,16 +4482,17 @@ int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
}
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 8320d0ecb13a..6701af5922cb 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_md5_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;
}
@@ -2285,6 +2286,18 @@ 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);
@@ -2309,10 +2322,12 @@ 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 e002f2e1d4f2..0219c0e5e2df 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..2fbd6795ced6
--- /dev/null
+++ b/net/ipv4/tcp_sigpool.c
@@ -0,0 +1,333 @@
+// 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 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)
+{
+ size_t ret = 0;
+
+ /* slow-path */
+ mutex_lock(&cpool_mutex);
+ if (cpool[id].alg)
+ ret = strscpy(buf, cpool[id].alg, buf_len);
+ mutex_unlock(&cpool_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(tcp_sigpool_algo);
+
+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 11b736a76bd7..116319d56ab2 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -672,7 +672,7 @@ 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)
@@ -693,39 +693,36 @@ 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;
}
@@ -736,8 +733,7 @@ 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 */
@@ -749,30 +745,28 @@ 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_md5_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;
}
--
2.39.1