Bluetooth: move ecdh allocation outside of ecdh_helper

Before this change, a new crypto tfm was allocated, each time,
for both key generation and shared secret computation.

Allocate a single tfm for both cases.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/ecdh_helper.c

@@ -23,7 +23,6 @@
 #include "ecdh_helper.h"
 
 #include <linux/scatterlist.h>
-#include <crypto/kpp.h>
 #include <crypto/ecdh.h>
 
 struct ecdh_completion {
@@ -50,10 +49,9 @@ static inline void swap_digits(u64 *in, u64 *out, unsigned int ndigits)
 		out[i] = __swab64(in[ndigits - 1 - i]);
 }
 
-bool compute_ecdh_secret(const u8 public_key[64], const u8 private_key[32],
-			 u8 secret[32])
+bool compute_ecdh_secret(struct crypto_kpp *tfm, const u8 public_key[64],
+			 const u8 private_key[32], u8 secret[32])
 {
-	struct crypto_kpp *tfm;
 	struct kpp_request *req;
 	struct ecdh p;
 	struct ecdh_completion result;
@@ -66,16 +64,9 @@ bool compute_ecdh_secret(const u8 public_key[64], const u8 private_key[32],
 	if (!tmp)
 		return false;
 
-	tfm = crypto_alloc_kpp("ecdh", CRYPTO_ALG_INTERNAL, 0);
-	if (IS_ERR(tfm)) {
-		pr_err("alg: kpp: Failed to load tfm for kpp: %ld\n",
-		       PTR_ERR(tfm));
-		goto free_tmp;
-	}
-
 	req = kpp_request_alloc(tfm, GFP_KERNEL);
 	if (!req)
-		goto free_kpp;
+		goto free_tmp;
 
 	init_completion(&result.completion);
 
@@ -126,16 +117,14 @@ free_all:
 	kzfree(buf);
 free_req:
 	kpp_request_free(req);
-free_kpp:
-	crypto_free_kpp(tfm);
 free_tmp:
 	kfree(tmp);
 	return (err == 0);
 }
 
-bool generate_ecdh_keys(u8 public_key[64], u8 private_key[32])
+bool generate_ecdh_keys(struct crypto_kpp *tfm, u8 public_key[64],
+			u8 private_key[32])
 {
-	struct crypto_kpp *tfm;
 	struct kpp_request *req;
 	struct ecdh p;
 	struct ecdh_completion result;
@@ -150,16 +139,9 @@ bool generate_ecdh_keys(u8 public_key[64], u8 private_key[32])
 	if (!tmp)
 		return false;
 
-	tfm = crypto_alloc_kpp("ecdh", CRYPTO_ALG_INTERNAL, 0);
-	if (IS_ERR(tfm)) {
-		pr_err("alg: kpp: Failed to load tfm for kpp: %ld\n",
-		       PTR_ERR(tfm));
-		goto free_tmp;
-	}
-
 	req = kpp_request_alloc(tfm, GFP_KERNEL);
 	if (!req)
-		goto free_kpp;
+		goto free_tmp;
 
 	init_completion(&result.completion);
 
@@ -218,8 +200,6 @@ free_all:
 	kzfree(buf);
 free_req:
 	kpp_request_free(req);
-free_kpp:
-	crypto_free_kpp(tfm);
 free_tmp:
 	kfree(tmp);
 	return (err == 0);

net/bluetooth/ecdh_helper.h

@@ -20,8 +20,10 @@
  * COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
  * SOFTWARE IS DISCLAIMED.
  */
+#include <crypto/kpp.h>
 #include <linux/types.h>
 
-bool compute_ecdh_secret(const u8 pub_a[64], const u8 priv_b[32],
-			 u8 secret[32]);
-bool generate_ecdh_keys(u8 public_key[64], u8 private_key[32]);
+bool compute_ecdh_secret(struct crypto_kpp *tfm, const u8 pub_a[64],
+			 const u8 priv_b[32], u8 secret[32]);
+bool generate_ecdh_keys(struct crypto_kpp *tfm, u8 public_key[64],
+			u8 private_key[32]);

net/bluetooth/selftest.c

@@ -138,9 +138,9 @@ static const u8 dhkey_3[32] __initconst = {
 	0x7c, 0x1c, 0xf9, 0x49, 0xe6, 0xd7, 0xaa, 0x70,
 };
 
-static int __init test_ecdh_sample(const u8 priv_a[32], const u8 priv_b[32],
-				   const u8 pub_a[64], const u8 pub_b[64],
-				   const u8 dhkey[32])
+static int __init test_ecdh_sample(struct crypto_kpp *tfm, const u8 priv_a[32],
+				   const u8 priv_b[32], const u8 pub_a[64],
+				   const u8 pub_b[64], const u8 dhkey[32])
 {
 	u8 *tmp, *dhkey_a, *dhkey_b;
 	int ret = 0;
@@ -152,8 +152,8 @@ static int __init test_ecdh_sample(const u8 priv_a[32], const u8 priv_b[32],
 	dhkey_a = &tmp[0];
 	dhkey_b = &tmp[32];
 
-	compute_ecdh_secret(pub_b, priv_a, dhkey_a);
-	compute_ecdh_secret(pub_a, priv_b, dhkey_b);
+	compute_ecdh_secret(tfm, pub_b, priv_a, dhkey_a);
+	compute_ecdh_secret(tfm, pub_a, priv_b, dhkey_b);
 
 	if (memcmp(dhkey_a, dhkey, 32)) {
 		ret = -EINVAL;
@@ -185,30 +185,43 @@ static const struct file_operations test_ecdh_fops = {
 
 static int __init test_ecdh(void)
 {
+	struct crypto_kpp *tfm;
 	ktime_t calltime, delta, rettime;
 	unsigned long long duration;
 	int err;
 
 	calltime = ktime_get();
 
-	err = test_ecdh_sample(priv_a_1, priv_b_1, pub_a_1, pub_b_1, dhkey_1);
+	tfm = crypto_alloc_kpp("ecdh", CRYPTO_ALG_INTERNAL, 0);
+	if (IS_ERR(tfm)) {
+		BT_ERR("Unable to create ECDH crypto context");
+		err = PTR_ERR(tfm);
+		goto done;
+	}
+
+	err = test_ecdh_sample(tfm, priv_a_1, priv_b_1, pub_a_1, pub_b_1,
+			       dhkey_1);
 	if (err) {
 		BT_ERR("ECDH sample 1 failed");
 		goto done;
 	}
 
-	err = test_ecdh_sample(priv_a_2, priv_b_2, pub_a_2, pub_b_2, dhkey_2);
+	err = test_ecdh_sample(tfm, priv_a_2, priv_b_2, pub_a_2, pub_b_2,
+			       dhkey_2);
 	if (err) {
 		BT_ERR("ECDH sample 2 failed");
 		goto done;
 	}
 
-	err = test_ecdh_sample(priv_a_3, priv_a_3, pub_a_3, pub_a_3, dhkey_3);
+	err = test_ecdh_sample(tfm, priv_a_3, priv_a_3, pub_a_3, pub_a_3,
+			       dhkey_3);
 	if (err) {
 		BT_ERR("ECDH sample 3 failed");
 		goto done;
 	}
 
+	crypto_free_kpp(tfm);
+
 	rettime = ktime_get();
 	delta = ktime_sub(rettime, calltime);
 	duration = (unsigned long long) ktime_to_ns(delta) >> 10;

net/bluetooth/smp.c

@@ -26,6 +26,7 @@
 #include <crypto/algapi.h>
 #include <crypto/b128ops.h>
 #include <crypto/hash.h>
+#include <crypto/kpp.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -92,6 +93,7 @@ struct smp_dev {
 
 	struct crypto_cipher	*tfm_aes;
 	struct crypto_shash	*tfm_cmac;
+	struct crypto_kpp	*tfm_ecdh;
 };
 
 struct smp_chan {
@@ -131,6 +133,7 @@ struct smp_chan {
 
 	struct crypto_cipher	*tfm_aes;
 	struct crypto_shash	*tfm_cmac;
+	struct crypto_kpp	*tfm_ecdh;
 };
 
 /* These debug key values are defined in the SMP section of the core
@@ -574,7 +577,8 @@ int smp_generate_oob(struct hci_dev *hdev, u8 hash[16], u8 rand[16])
 			get_random_bytes(smp->local_sk, 32);
 
 			/* Generate local key pair for Secure Connections */
-			if (!generate_ecdh_keys(smp->local_pk, smp->local_sk))
+			if (!generate_ecdh_keys(smp->tfm_ecdh, smp->local_pk,
+						smp->local_sk))
 				return -EIO;
 
 			/* This is unlikely, but we need to check that
@@ -771,6 +775,7 @@ static void smp_chan_destroy(struct l2cap_conn *conn)
 
 	crypto_free_cipher(smp->tfm_aes);
 	crypto_free_shash(smp->tfm_cmac);
+	crypto_free_kpp(smp->tfm_ecdh);
 
 	/* Ensure that we don't leave any debug key around if debug key
 	 * support hasn't been explicitly enabled.
@@ -1391,16 +1396,19 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
 	smp->tfm_aes = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
 	if (IS_ERR(smp->tfm_aes)) {
 		BT_ERR("Unable to create AES crypto context");
-		kzfree(smp);
-		return NULL;
+		goto zfree_smp;
 	}
 
 	smp->tfm_cmac = crypto_alloc_shash("cmac(aes)", 0, 0);
 	if (IS_ERR(smp->tfm_cmac)) {
 		BT_ERR("Unable to create CMAC crypto context");
-		crypto_free_cipher(smp->tfm_aes);
-		kzfree(smp);
-		return NULL;
+		goto free_cipher;
+	}
+
+	smp->tfm_ecdh = crypto_alloc_kpp("ecdh", CRYPTO_ALG_INTERNAL, 0);
+	if (IS_ERR(smp->tfm_ecdh)) {
+		BT_ERR("Unable to create ECDH crypto context");
+		goto free_shash;
 	}
 
 	smp->conn = conn;
@@ -1413,6 +1421,14 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
 	hci_conn_hold(conn->hcon);
 
 	return smp;
+
+free_shash:
+	crypto_free_shash(smp->tfm_cmac);
+free_cipher:
+	crypto_free_cipher(smp->tfm_aes);
+zfree_smp:
+	kzfree(smp);
+	return NULL;
 }
 
 static int sc_mackey_and_ltk(struct smp_chan *smp, u8 mackey[16], u8 ltk[16])
@@ -1903,7 +1919,8 @@ static u8 sc_send_public_key(struct smp_chan *smp)
 			get_random_bytes(smp->local_sk, 32);
 
 			/* Generate local key pair for Secure Connections */
-			if (!generate_ecdh_keys(smp->local_pk, smp->local_sk))
+			if (!generate_ecdh_keys(smp->tfm_ecdh, smp->local_pk,
+						smp->local_sk))
 				return SMP_UNSPECIFIED;
 
 			/* This is unlikely, but we need to check that
@@ -2677,7 +2694,8 @@ static int smp_cmd_public_key(struct l2cap_conn *conn, struct sk_buff *skb)
 	SMP_DBG("Remote Public Key X: %32phN", smp->remote_pk);
 	SMP_DBG("Remote Public Key Y: %32phN", smp->remote_pk + 32);
 
-	if (!compute_ecdh_secret(smp->remote_pk, smp->local_sk, smp->dhkey))
+	if (!compute_ecdh_secret(smp->tfm_ecdh, smp->remote_pk, smp->local_sk,
+				 smp->dhkey))
 		return SMP_UNSPECIFIED;
 
 	SMP_DBG("DHKey %32phN", smp->dhkey);
@@ -3169,6 +3187,7 @@ static struct l2cap_chan *smp_add_cid(struct hci_dev *hdev, u16 cid)
 	struct smp_dev *smp;
 	struct crypto_cipher *tfm_aes;
 	struct crypto_shash *tfm_cmac;
+	struct crypto_kpp *tfm_ecdh;
 
 	if (cid == L2CAP_CID_SMP_BREDR) {
 		smp = NULL;
@@ -3194,8 +3213,18 @@ static struct l2cap_chan *smp_add_cid(struct hci_dev *hdev, u16 cid)
 		return ERR_CAST(tfm_cmac);
 	}
 
+	tfm_ecdh = crypto_alloc_kpp("ecdh", CRYPTO_ALG_INTERNAL, 0);
+	if (IS_ERR(tfm_ecdh)) {
+		BT_ERR("Unable to create ECDH crypto context");
+		crypto_free_shash(tfm_cmac);
+		crypto_free_cipher(tfm_aes);
+		kzfree(smp);
+		return ERR_CAST(tfm_ecdh);
+	}
+
 	smp->tfm_aes = tfm_aes;
 	smp->tfm_cmac = tfm_cmac;
+	smp->tfm_ecdh = tfm_ecdh;
 	smp->min_key_size = SMP_MIN_ENC_KEY_SIZE;
 	smp->max_key_size = SMP_MAX_ENC_KEY_SIZE;
 
@@ -3205,6 +3234,7 @@ create_chan:
 		if (smp) {
 			crypto_free_cipher(smp->tfm_aes);
 			crypto_free_shash(smp->tfm_cmac);
+			crypto_free_kpp(smp->tfm_ecdh);
 			kzfree(smp);
 		}
 		return ERR_PTR(-ENOMEM);
@@ -3252,6 +3282,7 @@ static void smp_del_chan(struct l2cap_chan *chan)
 		chan->data = NULL;
 		crypto_free_cipher(smp->tfm_aes);
 		crypto_free_shash(smp->tfm_cmac);
+		crypto_free_kpp(smp->tfm_ecdh);
 		kzfree(smp);
 	}
 
@@ -3498,13 +3529,13 @@ static inline void swap_digits(u64 *in, u64 *out, unsigned int ndigits)
 		out[i] = __swab64(in[ndigits - 1 - i]);
 }
 
-static int __init test_debug_key(void)
+static int __init test_debug_key(struct crypto_kpp *tfm_ecdh)
 {
 	u8 pk[64], sk[32];
 
 	swap_digits((u64 *)debug_sk, (u64 *)sk, 4);
 
-	if (!generate_ecdh_keys(pk, sk))
+	if (!generate_ecdh_keys(tfm_ecdh, pk, sk))
 		return -EINVAL;
 
 	if (crypto_memneq(sk, debug_sk, 32))
@@ -3763,7 +3794,8 @@ static const struct file_operations test_smp_fops = {
 };
 
 static int __init run_selftests(struct crypto_cipher *tfm_aes,
-				struct crypto_shash *tfm_cmac)
+				struct crypto_shash *tfm_cmac,
+				struct crypto_kpp *tfm_ecdh)
 {
 	ktime_t calltime, delta, rettime;
 	unsigned long long duration;
@@ -3771,7 +3803,7 @@ static int __init run_selftests(struct crypto_cipher *tfm_aes,
 
 	calltime = ktime_get();
 
-	err = test_debug_key();
+	err = test_debug_key(tfm_ecdh);
 	if (err) {
 		BT_ERR("debug_key test failed");
 		goto done;
@@ -3848,6 +3880,7 @@ int __init bt_selftest_smp(void)
 {
 	struct crypto_cipher *tfm_aes;
 	struct crypto_shash *tfm_cmac;
+	struct crypto_kpp *tfm_ecdh;
 	int err;
 
 	tfm_aes = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
@@ -3863,10 +3896,19 @@ int __init bt_selftest_smp(void)
 		return PTR_ERR(tfm_cmac);
 	}
 
-	err = run_selftests(tfm_aes, tfm_cmac);
+	tfm_ecdh = crypto_alloc_kpp("ecdh", CRYPTO_ALG_INTERNAL, 0);
+	if (IS_ERR(tfm_ecdh)) {
+		BT_ERR("Unable to create ECDH crypto context");
+		crypto_free_shash(tfm_cmac);
+		crypto_free_cipher(tfm_aes);
+		return PTR_ERR(tfm_ecdh);
+	}
+
+	err = run_selftests(tfm_aes, tfm_cmac, tfm_ecdh);
 
 	crypto_free_shash(tfm_cmac);
 	crypto_free_cipher(tfm_aes);
+	crypto_free_kpp(tfm_ecdh);
 
 	return err;
 }