diff mbox series

[5/5] tcp/md5: Make more generic tcp_sig_pool

Message ID 20211105014953.972946-6-dima@arista.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series tcp/md5: Generic tcp_sig_pool | expand

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netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 1092 this patch: 1094
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netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 1101 this patch: 1103
netdev/checkpatch warning CHECK: Alignment should match open parenthesis CHECK: Comparison to NULL could be written "!hash" CHECK: Comparison to NULL could be written "!per_cpu_ptr" WARNING: data_race without comment
netdev/kdoc fail Errors and warnings before: 0 this patch: 2
netdev/source_inline success Was 0 now: 0
netdev/tree_selection success Guessing tree name failed - patch did not apply, async

Commit Message

Dmitry Safonov Nov. 5, 2021, 1:49 a.m. UTC 
Convert tcp_md5sig_pool to more generic tcp_sig_pool.
Now tcp_sig_pool_alloc(const char *alg) can be used to allocate per-cpu
ahash request for different hashing algorithms besides md5.
tcp_sig_pool_get() and tcp_sig_pool_put() should be used to get
ahash_request and scratch area.

Make tcp_sig_pool reusable for TCP Authentication Option support
(TCP-AO, RFC5925), where RFC5926[1] requires HMAC-SHA1 and AES-128_CMAC
hashing at least.

Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 include/net/tcp.h        |  24 +++--
 net/ipv4/tcp.c           | 192 +++++++++++++++++++++++++++------------
 net/ipv4/tcp_ipv4.c      |  46 +++++-----
 net/ipv4/tcp_minisocks.c |   4 +-
 net/ipv6/tcp_ipv6.c      |  44 ++++-----
 5 files changed, 197 insertions(+), 113 deletions(-)

Comments

Leonard Crestez Nov. 5, 2021, 9:54 a.m. UTC | #1 
On 11/5/21 3:49 AM, Dmitry Safonov wrote:
> Convert tcp_md5sig_pool to more generic tcp_sig_pool.
> Now tcp_sig_pool_alloc(const char *alg) can be used to allocate per-cpu
> ahash request for different hashing algorithms besides md5.
> tcp_sig_pool_get() and tcp_sig_pool_put() should be used to get
> ahash_request and scratch area.

This pool pattern is a workaround for crypto-api only being able to 
allocate transforms from user context.

It would be useful for this "one-transform-per-cpu" object to be part of 
crypto api itself, there is nothing TCP-specific here other than the 
size of scratch buffer.

> Make tcp_sig_pool reusable for TCP Authentication Option support
> (TCP-AO, RFC5925), where RFC5926[1] requires HMAC-SHA1 and AES-128_CMAC
> hashing at least.
Additional work would be required to support options of arbitrary size 
and I don't think anyone would use non-standard crypto algorithms.

Is RFC5926 conformance really insufficient?

My knowledge of cryptography doesn't go much beyond "data goes in 
signature goes out" but there are many recent arguments from that cipher 
agility is outright harmful and recent protocols like WireGuard don't 
support any algorithm choices.

> +#define TCP_SIG_POOL_MAX		8
> +static struct tcp_sig_pool_priv_t {
> +	struct tcp_sig_crypto		cryptos[TCP_SIG_POOL_MAX];
> +	unsigned int			cryptos_nr;
> +} tcp_sig_pool_priv = {
> +	.cryptos_nr = 1,
> +	.cryptos[TCP_MD5_SIG_ID].alg = "md5",
> +};

Why an array of 8? Better to use an arbitrary list.

--
Regards,
Leonard
Dmitry Safonov Nov. 5, 2021, 1:59 p.m. UTC | #2 
On 11/5/21 09:54, Leonard Crestez wrote:
> On 11/5/21 3:49 AM, Dmitry Safonov wrote:
>> Convert tcp_md5sig_pool to more generic tcp_sig_pool.
>> Now tcp_sig_pool_alloc(const char *alg) can be used to allocate per-cpu
>> ahash request for different hashing algorithms besides md5.
>> tcp_sig_pool_get() and tcp_sig_pool_put() should be used to get
>> ahash_request and scratch area.
> 
> This pool pattern is a workaround for crypto-api only being able to
> allocate transforms from user context.
>> It would be useful for this "one-transform-per-cpu" object to be part of
> crypto api itself, there is nothing TCP-specific here other than the
> size of scratch buffer.

Agree, it would be nice to have something like this as a part of crypto.
The intention here is to reuse md5 sig pool, rather than introduce
another similar one.

>> Make tcp_sig_pool reusable for TCP Authentication Option support
>> (TCP-AO, RFC5925), where RFC5926[1] requires HMAC-SHA1 and AES-128_CMAC
>> hashing at least.
> Additional work would be required to support options of arbitrary size
> and I don't think anyone would use non-standard crypto algorithms.
> 
> Is RFC5926 conformance really insufficient?

For the resulting hash, the scratch buffer can be used.

Honestly, I just don't see much benefit in introducing more code and
structures in order to limit hash algorithms. If anything,

:if (strcmp("hmac(sha1)", opts.algo) && strcmp("cmac(aes)", opts.algo))
:       return -EPROTONOSUPPORT;

and passing the string straight to crypto seems to be better than adding
new structures.

On the other side, those two hashes MUST be supported to comply with
RFC, other may. As user can already configure conflicting receive/send
ids for MKTs, I don't see a point not allowing any hash algorithm
supported by crypto.

> My knowledge of cryptography doesn't go much beyond "data goes in
> signature goes out" but there are many recent arguments from that cipher
> agility is outright harmful and recent protocols like WireGuard don't
> support any algorithm choices.

You already limit usage when root-enabled sysctl is triggered, I don't
see big concerns here.

> 
>> +#define TCP_SIG_POOL_MAX        8
>> +static struct tcp_sig_pool_priv_t {
>> +    struct tcp_sig_crypto        cryptos[TCP_SIG_POOL_MAX];
>> +    unsigned int            cryptos_nr;
>> +} tcp_sig_pool_priv = {
>> +    .cryptos_nr = 1,
>> +    .cryptos[TCP_MD5_SIG_ID].alg = "md5",
>> +};
> 
> Why an array of 8? Better to use an arbitrary list.

Some reasonable limit, may be 16 or whatever in order to avoid
dynamically (re-)allocating the array and keeping O(1) lookups.

Thanks,
          Dmitry
Leonard Crestez Nov. 5, 2021, 4:53 p.m. UTC | #3 
On 11/5/21 3:59 PM, Dmitry Safonov wrote:
> On 11/5/21 09:54, Leonard Crestez wrote:
>> On 11/5/21 3:49 AM, Dmitry Safonov wrote:
>>> Convert tcp_md5sig_pool to more generic tcp_sig_pool.
>>> Now tcp_sig_pool_alloc(const char *alg) can be used to allocate per-cpu
>>> ahash request for different hashing algorithms besides md5.
>>> tcp_sig_pool_get() and tcp_sig_pool_put() should be used to get
>>> ahash_request and scratch area.
>>
>> This pool pattern is a workaround for crypto-api only being able to
>> allocate transforms from user context.
>>> It would be useful for this "one-transform-per-cpu" object to be part of
>> crypto api itself, there is nothing TCP-specific here other than the
>> size of scratch buffer.
> 
> Agree, it would be nice to have something like this as a part of crypto.
> The intention here is to reuse md5 sig pool, rather than introduce
> another similar one.
> 
>>> Make tcp_sig_pool reusable for TCP Authentication Option support
>>> (TCP-AO, RFC5925), where RFC5926[1] requires HMAC-SHA1 and AES-128_CMAC
>>> hashing at least.
>> Additional work would be required to support options of arbitrary size
>> and I don't think anyone would use non-standard crypto algorithms.
>>
>> Is RFC5926 conformance really insufficient?
> 
> For the resulting hash, the scratch buffer can be used.
> 
> Honestly, I just don't see much benefit in introducing more code and
> structures in order to limit hash algorithms. If anything,
> 
> :if (strcmp("hmac(sha1)", opts.algo) && strcmp("cmac(aes)", opts.algo))
> :       return -EPROTONOSUPPORT;
> 
> and passing the string straight to crypto seems to be better than adding
> new structures.
> 
> On the other side, those two hashes MUST be supported to comply with
> RFC, other may. As user can already configure conflicting receive/send
> ids for MKTs, I don't see a point not allowing any hash algorithm
> supported by crypto.

The algorithm enum controls not just the algorithm but the length in 
bytes of the traffic key and signatures. Supporting arbitrary algorithms 
requires supporting arbitrary byte lengths everywhere and increasing a 
couple of stack allocations (including some in the TCP core).

An earlier version actually had u8 fields for the length but those were 
later removed.

Adding this is not difficult but requires careful testing of the new 
corner cases. All this will be for functionality is never going to be used.

>> My knowledge of cryptography doesn't go much beyond "data goes in
>> signature goes out" but there are many recent arguments from that cipher
>> agility is outright harmful and recent protocols like WireGuard don't
>> support any algorithm choices.
> 
> You already limit usage when root-enabled sysctl is triggered, I don't
> see big concerns here.
> 
>>
>>> +#define TCP_SIG_POOL_MAX        8
>>> +static struct tcp_sig_pool_priv_t {
>>> +    struct tcp_sig_crypto        cryptos[TCP_SIG_POOL_MAX];
>>> +    unsigned int            cryptos_nr;
>>> +} tcp_sig_pool_priv = {
>>> +    .cryptos_nr = 1,
>>> +    .cryptos[TCP_MD5_SIG_ID].alg = "md5",
>>> +};
>>
>> Why an array of 8? Better to use an arbitrary list.
> 
> Some reasonable limit, may be 16 or whatever in order to avoid
> dynamically (re-)allocating the array and keeping O(1) lookups.

Defining an arbitrary array length limit is an underhanded way of making 
lookup O(1).
Herbert Xu Nov. 6, 2021, 3:43 a.m. UTC | #4 
On Fri, Nov 05, 2021 at 01:59:35PM +0000, Dmitry Safonov wrote:
> On 11/5/21 09:54, Leonard Crestez wrote:
>
> > This pool pattern is a workaround for crypto-api only being able to
> > allocate transforms from user context.
> >> It would be useful for this "one-transform-per-cpu" object to be part of
> > crypto api itself, there is nothing TCP-specific here other than the
> > size of scratch buffer.
> 
> Agree, it would be nice to have something like this as a part of crypto.
> The intention here is to reuse md5 sig pool, rather than introduce
> another similar one.

As I said before, I'm happy to see the ahash/shash interface modified
so that we allow the key to be in the request object in addition to the
tfm.  However, I don't really have the time to work on that and
nobody else from the crypto side seems interested in this.

So if you guys have the time and are willing to work on it then I'm
more than happy to help you.

Cheers,
diff mbox series

Patch

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 27eb71dd7ff8..2d868ce8736d 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1628,10 +1628,10 @@  union tcp_md5sum_block {
 #endif
 };
 
-/* - pool: digest algorithm, hash description and scratch buffer */
-struct tcp_md5sig_pool {
-	struct ahash_request	*md5_req;
+struct tcp_sig_pool {
+	struct ahash_request	*req;
 	void			*scratch;
+#define SCRATCH_SIZE (sizeof(union tcp_md5sum_block) + sizeof(struct tcphdr))
 };
 
 /* - functions */
@@ -1671,18 +1671,24 @@  tcp_md5_do_lookup(const struct sock *sk, int l3index,
 #define tcp_twsk_md5_key(twsk)	NULL
 #endif
 
-bool tcp_md5sig_pool_alloc(void);
-bool tcp_md5sig_pool_ready(void);
 
-struct tcp_md5sig_pool *tcp_md5sig_pool_get(void);
-static inline void tcp_md5sig_pool_put(void)
+/* TCP MD5 supports only one hash function, set MD5 id in stone
+ * to avoid needless storing MD5 id in (struct tcp_md5sig_info).
+ */
+#define TCP_MD5_SIG_ID		0
+
+int tcp_sig_pool_alloc(const char *alg);
+bool tcp_sig_pool_ready(unsigned int id);
+
+int tcp_sig_pool_get(unsigned int id, struct tcp_sig_pool *tsp);
+static inline void tcp_sig_pool_put(void)
 {
 	local_bh_enable();
 }
 
-int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *,
+int tcp_md5_hash_skb_data(struct tcp_sig_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_sig_pool *hp,
 		     const struct tcp_md5sig_key *key);
 
 /* From tcp_fastopen.c */
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 8d8692fc9cd5..8307c7b91d09 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4253,32 +4253,79 @@  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;
+struct tcp_sig_crypto {
+	struct ahash_request * __percpu	*req;
+	const char			*alg;
+	bool				ready;
+};
+
+#define TCP_SIG_POOL_MAX		8
+static struct tcp_sig_pool_priv_t {
+	struct tcp_sig_crypto		cryptos[TCP_SIG_POOL_MAX];
+	unsigned int			cryptos_nr;
+} tcp_sig_pool_priv = {
+	.cryptos_nr = 1,
+	.cryptos[TCP_MD5_SIG_ID].alg = "md5",
+};
+
+static DEFINE_PER_CPU(void *, tcp_sig_pool_scratch);
+static DEFINE_MUTEX(tcp_sig_pool_mutex);
 
-static void __tcp_md5sig_pool_alloc(void)
+static int tcp_sig_pool_alloc_scrath(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_sig_pool_scratch, cpu);
+
+		if (scratch)
+			continue;
+
+		scratch = kmalloc_node(SCRATCH_SIZE, GFP_KERNEL,
+					cpu_to_node(cpu));
+		if (!scratch)
+			return -ENOMEM;
+		per_cpu(tcp_sig_pool_scratch, cpu) = scratch;
+	}
+	return 0;
+}
+
+bool tcp_sig_pool_ready(unsigned int id)
+{
+	return tcp_sig_pool_priv.cryptos[id].ready;
+}
+EXPORT_SYMBOL(tcp_sig_pool_ready);
+
+static int __tcp_sig_pool_alloc(struct tcp_sig_crypto *crypto, const char *alg)
+{
+	struct crypto_ahash *hash;
+	bool needs_key;
+	int cpu, ret = -ENOMEM;
+
+	crypto->alg = kstrdup(alg, GFP_KERNEL);
+	if (!crypto->alg)
+		return -ENOMEM;
+
+	crypto->req = alloc_percpu(struct ahash_request *);
+	if (!crypto->req)
+		goto out_free_alg;
+
+	hash = crypto_alloc_ahash(alg, 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(hash)) {
+		ret = PTR_ERR(hash);
+		goto out_free_req;
+	}
+
+	/* If hash has .setkey(), allocate ahash per-cpu, not only request */
+	needs_key = crypto_ahash_get_flags(hash) & CRYPTO_TFM_NEED_KEY;
 
 	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)
-				goto out_free;
-			per_cpu(tcp_md5sig_pool, cpu).scratch = scratch;
-		}
+		if (hash == NULL)
+			hash = crypto_alloc_ahash(alg, 0, CRYPTO_ALG_ASYNC);
+		if (IS_ERR(hash))
+			goto out_free;
 
 		req = ahash_request_alloc(hash, GFP_KERNEL);
 		if (!req)
@@ -4286,75 +4333,106 @@  static void __tcp_md5sig_pool_alloc(void)
 
 		ahash_request_set_callback(req, 0, NULL, NULL);
 
-		per_cpu(tcp_md5sig_pool, cpu).md5_req = req;
+		*per_cpu_ptr(crypto->req, cpu) = req;
+
+		if (needs_key)
+			hash = NULL;
 	}
-	/* before setting tcp_md5sig_pool_populated, we must commit all writes
-	 * to memory. See smp_rmb() in tcp_md5sig_pool_get()
+	/* before setting crypto->ready, we must commit all writes
+	 * to memory. See smp_rmb() in tcp_sig_pool_get()
 	 */
 	smp_wmb();
-	tcp_md5sig_pool_populated = true;
-	return;
+	crypto->ready = true;
+	return 0;
 
 out_free:
+	if (!IS_ERR_OR_NULL(hash) && needs_key)
+		crypto_free_ahash(hash);
+
 	for_each_possible_cpu(cpu) {
-		if (per_cpu(tcp_md5sig_pool, cpu).md5_req == NULL)
+		if (*per_cpu_ptr(crypto->req, cpu) == NULL)
 			break;
-		ahash_request_free(per_cpu(tcp_md5sig_pool, cpu).md5_req);
-		per_cpu(tcp_md5sig_pool, cpu).md5_req = NULL;
+		hash = crypto_ahash_reqtfm(*per_cpu_ptr(crypto->req, cpu));
+		ahash_request_free(*per_cpu_ptr(crypto->req, cpu));
+		if (needs_key) {
+			crypto_free_ahash(hash);
+			hash = NULL;
+		}
 	}
-	crypto_free_ahash(hash);
+
+	if (hash)
+		crypto_free_ahash(hash);
+out_free_req:
+	free_percpu(crypto->req);
+out_free_alg:
+	kfree(crypto->alg);
+	return ret;
 }
 
-bool tcp_md5sig_pool_alloc(void)
+int tcp_sig_pool_alloc(const char *alg)
 {
-	if (unlikely(!tcp_md5sig_pool_populated)) {
-		mutex_lock(&tcp_md5sig_mutex);
+	unsigned int i, err;
 
-		if (!tcp_md5sig_pool_populated) {
-			__tcp_md5sig_pool_alloc();
-			if (tcp_md5sig_pool_populated)
-				static_branch_inc(&tcp_md5_needed);
-		}
+	/* slow-path: once per setsockopt() */
+	mutex_lock(&tcp_sig_pool_mutex);
 
-		mutex_unlock(&tcp_md5sig_mutex);
+	err = tcp_sig_pool_alloc_scrath();
+	if (err)
+		goto out;
+
+	for (i = 0; i < tcp_sig_pool_priv.cryptos_nr; i++) {
+		if (!strcmp(tcp_sig_pool_priv.cryptos[i].alg, alg))
+			break;
 	}
-	return tcp_md5sig_pool_populated;
-}
-EXPORT_SYMBOL(tcp_md5sig_pool_alloc);
 
-bool tcp_md5sig_pool_ready(void)
-{
-	return tcp_md5sig_pool_populated;
+	if (i >= TCP_SIG_POOL_MAX) {
+		i = -ENOSPC;
+		goto out;
+	}
+
+	if (tcp_sig_pool_priv.cryptos[i].ready)
+		goto out;
+
+	err = __tcp_sig_pool_alloc(&tcp_sig_pool_priv.cryptos[i], alg);
+	if (!err && i == TCP_MD5_SIG_ID)
+		static_branch_inc(&tcp_md5_needed);
+
+out:
+	mutex_unlock(&tcp_sig_pool_mutex);
+	return err ?: i;
 }
-EXPORT_SYMBOL(tcp_md5sig_pool_ready);
+EXPORT_SYMBOL(tcp_sig_pool_alloc);
 
 /**
- *	tcp_md5sig_pool_get - get md5sig_pool for this user
+ *	tcp_sig_pool_get - get tcp_sig_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_md5sig_pool_get(void)
+int tcp_sig_pool_get(unsigned int id, struct tcp_sig_pool *tsp)
 {
 	local_bh_disable();
 
-	if (tcp_md5sig_pool_populated) {
-		/* coupled with smp_wmb() in __tcp_md5sig_pool_alloc() */
-		smp_rmb();
-		return this_cpu_ptr(&tcp_md5sig_pool);
+	if (id > tcp_sig_pool_priv.cryptos_nr || !tcp_sig_pool_ready(id)) {
+		local_bh_enable();
+		return -EINVAL;
 	}
-	local_bh_enable();
-	return NULL;
+
+	/* coupled with smp_wmb() in __tcp_sig_pool_alloc() */
+	smp_rmb();
+	tsp->req = *this_cpu_ptr(tcp_sig_pool_priv.cryptos[id].req);
+	tsp->scratch = this_cpu_ptr(&tcp_sig_pool_scratch);
+	return 0;
 }
-EXPORT_SYMBOL(tcp_md5sig_pool_get);
+EXPORT_SYMBOL(tcp_sig_pool_get);
 
-int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
+int tcp_md5_hash_skb_data(struct tcp_sig_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;
+	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;
@@ -4388,16 +4466,16 @@  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_sig_pool *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 44db9afa17fc..7e18806c6d82 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1190,7 +1190,7 @@  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 (WARN_ON_ONCE(!tcp_md5sig_pool_ready())) {
+	if (WARN_ON_ONCE(!tcp_sig_pool_ready(TCP_MD5_SIG_ID))) {
 		sock_kfree_s(sk, key, sizeof(*key));
 		return -ENOMEM;
 	}
@@ -1249,6 +1249,7 @@  static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
 	u8 prefixlen = 32;
 	int l3index = 0;
 	u8 flags;
+	int err;
 
 	if (optlen < sizeof(cmd))
 		return -EINVAL;
@@ -1294,14 +1295,15 @@  static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 		return -EINVAL;
 
-	if (!tcp_md5sig_pool_alloc())
-		return -ENOMEM;
+	err = tcp_sig_pool_alloc("md5");
+	if (err < 0 || WARN_ON_ONCE(err != TCP_MD5_SIG_ID))
+		return err;
 
 	return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
 			      cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 }
 
-static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
+static int tcp_v4_md5_hash_headers(struct tcp_sig_pool *hp,
 				   __be32 daddr, __be32 saddr,
 				   const struct tcphdr *th, int nbytes)
 {
@@ -1321,37 +1323,36 @@  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 tcp_sig_pool hp;
 	struct ahash_request *req;
 
-	hp = tcp_md5sig_pool_get();
-	if (!hp)
+	if (tcp_sig_pool_get(TCP_MD5_SIG_ID, &hp))
 		goto clear_hash_noput;
-	req = hp->md5_req;
+	req = hp.req;
 
 	if (crypto_ahash_init(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))
 		goto clear_hash;
 
-	tcp_md5sig_pool_put();
+	tcp_sig_pool_put();
 	return 0;
 
 clear_hash:
-	tcp_md5sig_pool_put();
+	tcp_sig_pool_put();
 clear_hash_noput:
 	memset(md5_hash, 0, 16);
 	return 1;
@@ -1361,7 +1362,7 @@  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 tcp_sig_pool hp;
 	struct ahash_request *req;
 	const struct tcphdr *th = tcp_hdr(skb);
 	__be32 saddr, daddr;
@@ -1375,29 +1376,28 @@  int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
 		daddr = iph->daddr;
 	}
 
-	hp = tcp_md5sig_pool_get();
-	if (!hp)
+	if (tcp_sig_pool_get(TCP_MD5_SIG_ID, &hp))
 		goto clear_hash_noput;
-	req = hp->md5_req;
+	req = hp.req;
 
 	if (crypto_ahash_init(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))
 		goto clear_hash;
 
-	tcp_md5sig_pool_put();
+	tcp_sig_pool_put();
 	return 0;
 
 clear_hash:
-	tcp_md5sig_pool_put();
+	tcp_sig_pool_put();
 clear_hash_noput:
 	memset(md5_hash, 0, 16);
 	return 1;
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index c99cdb529902..7bfc5a42ce98 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -293,10 +293,10 @@  void tcp_time_wait(struct sock *sk, int state, int timeo)
 			tcptw->tw_md5_key = NULL;
 			if (static_branch_unlikely(&tcp_md5_needed)) {
 				struct tcp_md5sig_key *key;
-				bool err = WARN_ON(!tcp_md5sig_pool_ready());
+				bool err = !tcp_sig_pool_ready(TCP_MD5_SIG_ID);
 
 				key = tp->af_specific->md5_lookup(sk, sk);
-				if (key && !err) {
+				if (key && !WARN_ON(err)) {
 					tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC);
 					WARN_ON_ONCE(tcptw->tw_md5_key == NULL);
 				}
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 9147f9f69196..0abc28937058 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -603,6 +603,7 @@  static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
 	int l3index = 0;
 	u8 prefixlen;
 	u8 flags;
+	int err;
 
 	if (optlen < sizeof(cmd))
 		return -EINVAL;
@@ -654,8 +655,9 @@  static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
 		return -EINVAL;
 
-	if (!tcp_md5sig_pool_alloc())
-		return -ENOMEM;
+	err = tcp_sig_pool_alloc("md5");
+	if (err < 0 || WARN_ON_ONCE(err != TCP_MD5_SIG_ID))
+		return err;
 
 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
@@ -668,7 +670,7 @@  static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
 			      cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 }
 
-static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
+static int tcp_v6_md5_hash_headers(struct tcp_sig_pool *hp,
 				   const struct in6_addr *daddr,
 				   const struct in6_addr *saddr,
 				   const struct tcphdr *th, int nbytes)
@@ -689,38 +691,37 @@  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 tcp_sig_pool hp;
 	struct ahash_request *req;
 
-	hp = tcp_md5sig_pool_get();
-	if (!hp)
+	if (tcp_sig_pool_get(TCP_MD5_SIG_ID, &hp))
 		goto clear_hash_noput;
-	req = hp->md5_req;
+	req = hp.req;
 
 	if (crypto_ahash_init(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))
 		goto clear_hash;
 
-	tcp_md5sig_pool_put();
+	tcp_sig_pool_put();
 	return 0;
 
 clear_hash:
-	tcp_md5sig_pool_put();
+	tcp_sig_pool_put();
 clear_hash_noput:
 	memset(md5_hash, 0, 16);
 	return 1;
@@ -732,7 +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 tcp_sig_pool hp;
 	struct ahash_request *req;
 	const struct tcphdr *th = tcp_hdr(skb);
 
@@ -745,29 +746,28 @@  static int tcp_v6_md5_hash_skb(char *md5_hash,
 		daddr = &ip6h->daddr;
 	}
 
-	hp = tcp_md5sig_pool_get();
-	if (!hp)
+	if (tcp_sig_pool_get(TCP_MD5_SIG_ID, &hp))
 		goto clear_hash_noput;
-	req = hp->md5_req;
+	req = hp.req;
 
 	if (crypto_ahash_init(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))
 		goto clear_hash;
 
-	tcp_md5sig_pool_put();
+	tcp_sig_pool_put();
 	return 0;
 
 clear_hash:
-	tcp_md5sig_pool_put();
+	tcp_sig_pool_put();
 clear_hash_noput:
 	memset(md5_hash, 0, 16);
 	return 1;