* [PATCH v3 1/2] crypto: ecdh - add privkey generation support
2017-05-30 14:52 [PATCH v3 0/2] crypto: ecdh - add privkey generation support Tudor Ambarus
@ 2017-05-30 14:52 ` Tudor Ambarus
2017-05-30 15:10 ` Stephan Müller
2017-05-30 14:52 ` [PATCH v3 2/2] crypto: testmgr - add genkey kpp test Tudor Ambarus
2017-06-10 4:18 ` [PATCH v3 0/2] crypto: ecdh - add privkey generation support Herbert Xu
2 siblings, 1 reply; 7+ messages in thread
From: Tudor Ambarus @ 2017-05-30 14:52 UTC (permalink / raw)
To: herbert, davem
Cc: linux-crypto, smueller, marcel, Nicolas.Ferre, Tudor Ambarus
Add support for generating ecc private keys.
Generation of ecc private keys is helpful in a user-space to kernel
ecdh offload because the keys are not revealed to user-space. Private
key generation is also helpful to implement forward secrecy.
If the user provides a NULL ecc private key, the kernel will generate it
and further use it for ecdh.
Move ecdh's object files below drbg's. drbg must be present in the kernel
at the time of calling.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
crypto/Kconfig | 1 +
crypto/Makefile | 9 +++++----
crypto/ecc.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
crypto/ecc.h | 14 ++++++++++++++
crypto/ecdh.c | 4 ++++
5 files changed, 80 insertions(+), 4 deletions(-)
diff --git a/crypto/Kconfig b/crypto/Kconfig
index aac4bc9..caa770e 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -130,6 +130,7 @@ config CRYPTO_DH
config CRYPTO_ECDH
tristate "ECDH algorithm"
select CRYTPO_KPP
+ select CRYPTO_RNG_DEFAULT
help
Generic implementation of the ECDH algorithm
diff --git a/crypto/Makefile b/crypto/Makefile
index 8a44057..d41f033 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -33,10 +33,6 @@ obj-$(CONFIG_CRYPTO_KPP2) += kpp.o
dh_generic-y := dh.o
dh_generic-y += dh_helper.o
obj-$(CONFIG_CRYPTO_DH) += dh_generic.o
-ecdh_generic-y := ecc.o
-ecdh_generic-y += ecdh.o
-ecdh_generic-y += ecdh_helper.o
-obj-$(CONFIG_CRYPTO_ECDH) += ecdh_generic.o
$(obj)/rsapubkey-asn1.o: $(obj)/rsapubkey-asn1.c $(obj)/rsapubkey-asn1.h
$(obj)/rsaprivkey-asn1.o: $(obj)/rsaprivkey-asn1.c $(obj)/rsaprivkey-asn1.h
@@ -138,6 +134,11 @@ obj-$(CONFIG_CRYPTO_USER_API_SKCIPHER) += algif_skcipher.o
obj-$(CONFIG_CRYPTO_USER_API_RNG) += algif_rng.o
obj-$(CONFIG_CRYPTO_USER_API_AEAD) += algif_aead.o
+ecdh_generic-y := ecc.o
+ecdh_generic-y += ecdh.o
+ecdh_generic-y += ecdh_helper.o
+obj-$(CONFIG_CRYPTO_ECDH) += ecdh_generic.o
+
#
# generic algorithms and the async_tx api
#
diff --git a/crypto/ecc.c b/crypto/ecc.c
index 6c33c43..633a9bc 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -29,6 +29,7 @@
#include <linux/swab.h>
#include <linux/fips.h>
#include <crypto/ecdh.h>
+#include <crypto/rng.h>
#include "ecc.h"
#include "ecc_curve_defs.h"
@@ -927,6 +928,61 @@ int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
return 0;
}
+/*
+ * ECC private keys are generated using the method of extra random bits,
+ * equivalent to that described in FIPS 186-4, Appendix B.4.1.
+ *
+ * d = (c mod(n–1)) + 1 where c is a string of random bits, 64 bits longer
+ * than requested
+ * 0 <= c mod(n-1) <= n-2 and implies that
+ * 1 <= d <= n-1
+ *
+ * This method generates a private key uniformly distributed in the range
+ * [1, n-1].
+ */
+int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey)
+{
+ const struct ecc_curve *curve = ecc_get_curve(curve_id);
+ u64 priv[ndigits];
+ unsigned int nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
+ unsigned int nbits = vli_num_bits(curve->n, ndigits);
+ int err;
+
+ /* Check that N is included in Table 1 of FIPS 186-4, section 6.1.1 */
+ if (nbits < 160)
+ return -EINVAL;
+
+ /*
+ * FIPS 186-4 recommends that the private key should be obtained from a
+ * RBG with a security strength equal to or greater than the security
+ * strength associated with N.
+ *
+ * The maximum security strength identified by NIST SP800-57pt1r4 for
+ * ECC is 256 (N >= 512).
+ *
+ * This condition is met by the default RNG because it selects a favored
+ * DRBG with a security strength of 256.
+ */
+ if (crypto_get_default_rng())
+ err = -EFAULT;
+
+ err = crypto_rng_get_bytes(crypto_default_rng, (u8 *)priv, nbytes);
+ crypto_put_default_rng();
+ if (err)
+ return err;
+
+ if (vli_is_zero(priv, ndigits))
+ return -EINVAL;
+
+ /* Make sure the private key is in the range [1, n-1]. */
+ if (vli_cmp(curve->n, priv, ndigits) != 1)
+ return -EINVAL;
+
+ ecc_swap_digits(priv, privkey, ndigits);
+
+ return 0;
+}
+
int ecc_make_pub_key(unsigned int curve_id, unsigned int ndigits,
const u64 *private_key, u64 *public_key)
{
diff --git a/crypto/ecc.h b/crypto/ecc.h
index e13fe88..e4fd449 100644
--- a/crypto/ecc.h
+++ b/crypto/ecc.h
@@ -44,6 +44,20 @@ int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
const u64 *private_key, unsigned int private_key_len);
/**
+ * ecc_gen_privkey() - Generates an ECC private key.
+ * The private key is a random integer in the range 0 < random < n, where n is a
+ * prime that is the order of the cyclic subgroup generated by the distinguished
+ * point G.
+ * @curve_id: id representing the curve to use
+ * @ndigits: curve number of digits
+ * @private_key: buffer for storing the generated private key
+ *
+ * Returns 0 if the private key was generated successfully, a negative value
+ * if an error occurred.
+ */
+int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey);
+
+/**
* ecc_make_pub_key() - Compute an ECC public key
*
* @curve_id: id representing the curve to use
diff --git a/crypto/ecdh.c b/crypto/ecdh.c
index 4aa0b0c..61c7708 100644
--- a/crypto/ecdh.c
+++ b/crypto/ecdh.c
@@ -55,6 +55,10 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
ctx->curve_id = params.curve_id;
ctx->ndigits = ndigits;
+ if (!params.key || !params.key_size)
+ return ecc_gen_privkey(ctx->curve_id, ctx->ndigits,
+ ctx->private_key);
+
if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits,
(const u64 *)params.key, params.key_size) < 0)
return -EINVAL;
--
2.7.4
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v3 2/2] crypto: testmgr - add genkey kpp test
2017-05-30 14:52 [PATCH v3 0/2] crypto: ecdh - add privkey generation support Tudor Ambarus
2017-05-30 14:52 ` [PATCH v3 1/2] " Tudor Ambarus
@ 2017-05-30 14:52 ` Tudor Ambarus
2017-06-10 4:18 ` [PATCH v3 0/2] crypto: ecdh - add privkey generation support Herbert Xu
2 siblings, 0 replies; 7+ messages in thread
From: Tudor Ambarus @ 2017-05-30 14:52 UTC (permalink / raw)
To: herbert, davem
Cc: linux-crypto, smueller, marcel, Nicolas.Ferre, Tudor Ambarus
The test considers a party that already has a private-public
key pair and a party that provides a NULL key. The kernel will
generate the private-public key pair for the latter, computes
the shared secret on both ends and verifies if it's the same.
The explicit private-public key pair was copied from
the previous test vector.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
crypto/testmgr.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++--------
crypto/testmgr.h | 47 +++++++++++++++++++++++++++++++++++
2 files changed, 112 insertions(+), 11 deletions(-)
diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index 6f5f3ed..5f8e683 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -1997,6 +1997,9 @@ static int do_test_kpp(struct crypto_kpp *tfm, const struct kpp_testvec *vec,
struct kpp_request *req;
void *input_buf = NULL;
void *output_buf = NULL;
+ void *a_public = NULL;
+ void *a_ss = NULL;
+ void *shared_secret = NULL;
struct tcrypt_result result;
unsigned int out_len_max;
int err = -ENOMEM;
@@ -2026,20 +2029,31 @@ static int do_test_kpp(struct crypto_kpp *tfm, const struct kpp_testvec *vec,
kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
tcrypt_complete, &result);
- /* Compute public key */
+ /* Compute party A's public key */
err = wait_async_op(&result, crypto_kpp_generate_public_key(req));
if (err) {
- pr_err("alg: %s: generate public key test failed. err %d\n",
+ pr_err("alg: %s: Party A: generate public key test failed. err %d\n",
alg, err);
goto free_output;
}
- /* Verify calculated public key */
- if (memcmp(vec->expected_a_public, sg_virt(req->dst),
- vec->expected_a_public_size)) {
- pr_err("alg: %s: generate public key test failed. Invalid output\n",
- alg);
- err = -EINVAL;
- goto free_output;
+
+ if (vec->genkey) {
+ /* Save party A's public key */
+ a_public = kzalloc(out_len_max, GFP_KERNEL);
+ if (!a_public) {
+ err = -ENOMEM;
+ goto free_output;
+ }
+ memcpy(a_public, sg_virt(req->dst), out_len_max);
+ } else {
+ /* Verify calculated public key */
+ if (memcmp(vec->expected_a_public, sg_virt(req->dst),
+ vec->expected_a_public_size)) {
+ pr_err("alg: %s: Party A: generate public key test failed. Invalid output\n",
+ alg);
+ err = -EINVAL;
+ goto free_output;
+ }
}
/* Calculate shared secret key by using counter part (b) public key. */
@@ -2058,15 +2072,53 @@ static int do_test_kpp(struct crypto_kpp *tfm, const struct kpp_testvec *vec,
tcrypt_complete, &result);
err = wait_async_op(&result, crypto_kpp_compute_shared_secret(req));
if (err) {
- pr_err("alg: %s: compute shard secret test failed. err %d\n",
+ pr_err("alg: %s: Party A: compute shared secret test failed. err %d\n",
alg, err);
goto free_all;
}
+
+ if (vec->genkey) {
+ /* Save the shared secret obtained by party A */
+ a_ss = kzalloc(vec->expected_ss_size, GFP_KERNEL);
+ if (!a_ss) {
+ err = -ENOMEM;
+ goto free_all;
+ }
+ memcpy(a_ss, sg_virt(req->dst), vec->expected_ss_size);
+
+ /*
+ * Calculate party B's shared secret by using party A's
+ * public key.
+ */
+ err = crypto_kpp_set_secret(tfm, vec->b_secret,
+ vec->b_secret_size);
+ if (err < 0)
+ goto free_all;
+
+ sg_init_one(&src, a_public, vec->expected_a_public_size);
+ sg_init_one(&dst, output_buf, out_len_max);
+ kpp_request_set_input(req, &src, vec->expected_a_public_size);
+ kpp_request_set_output(req, &dst, out_len_max);
+ kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+ tcrypt_complete, &result);
+ err = wait_async_op(&result,
+ crypto_kpp_compute_shared_secret(req));
+ if (err) {
+ pr_err("alg: %s: Party B: compute shared secret failed. err %d\n",
+ alg, err);
+ goto free_all;
+ }
+
+ shared_secret = a_ss;
+ } else {
+ shared_secret = (void *)vec->expected_ss;
+ }
+
/*
* verify shared secret from which the user will derive
* secret key by executing whatever hash it has chosen
*/
- if (memcmp(vec->expected_ss, sg_virt(req->dst),
+ if (memcmp(shared_secret, sg_virt(req->dst),
vec->expected_ss_size)) {
pr_err("alg: %s: compute shared secret test failed. Invalid output\n",
alg);
@@ -2074,8 +2126,10 @@ static int do_test_kpp(struct crypto_kpp *tfm, const struct kpp_testvec *vec,
}
free_all:
+ kfree(a_ss);
kfree(input_buf);
free_output:
+ kfree(a_public);
kfree(output_buf);
free_req:
kpp_request_free(req);
diff --git a/crypto/testmgr.h b/crypto/testmgr.h
index 4293573..db2e26c 100644
--- a/crypto/testmgr.h
+++ b/crypto/testmgr.h
@@ -137,13 +137,16 @@ struct akcipher_testvec {
struct kpp_testvec {
const unsigned char *secret;
+ const unsigned char *b_secret;
const unsigned char *b_public;
const unsigned char *expected_a_public;
const unsigned char *expected_ss;
unsigned short secret_size;
+ unsigned short b_secret_size;
unsigned short b_public_size;
unsigned short expected_a_public_size;
unsigned short expected_ss_size;
+ bool genkey;
};
static const char zeroed_string[48];
@@ -840,6 +843,50 @@ static const struct kpp_testvec ecdh_tv_template[] = {
.b_public_size = 64,
.expected_a_public_size = 64,
.expected_ss_size = 32
+ }, {
+ .secret =
+#ifdef __LITTLE_ENDIAN
+ "\x02\x00" /* type */
+ "\x08\x00" /* len */
+ "\x02\x00" /* curve_id */
+ "\x00\x00", /* key_size */
+#else
+ "\x00\x02" /* type */
+ "\x00\x08" /* len */
+ "\x00\x02" /* curve_id */
+ "\x00\x00", /* key_size */
+#endif
+ .b_secret =
+#ifdef __LITTLE_ENDIAN
+ "\x02\x00" /* type */
+ "\x28\x00" /* len */
+ "\x02\x00" /* curve_id */
+ "\x20\x00" /* key_size */
+#else
+ "\x00\x02" /* type */
+ "\x00\x28" /* len */
+ "\x00\x02" /* curve_id */
+ "\x00\x20" /* key_size */
+#endif
+ "\x24\xd1\x21\xeb\xe5\xcf\x2d\x83"
+ "\xf6\x62\x1b\x6e\x43\x84\x3a\xa3"
+ "\x8b\xe0\x86\xc3\x20\x19\xda\x92"
+ "\x50\x53\x03\xe1\xc0\xea\xb8\x82",
+ .b_public =
+ "\x1a\x7f\xeb\x52\x00\xbd\x3c\x31"
+ "\x7d\xb6\x70\xc1\x86\xa6\xc7\xc4"
+ "\x3b\xc5\x5f\x6c\x6f\x58\x3c\xf5"
+ "\xb6\x63\x82\x77\x33\x24\xa1\x5f"
+ "\x6a\xca\x43\x6f\xf7\x7e\xff\x02"
+ "\x37\x08\xcc\x40\x5e\x7a\xfd\x6a"
+ "\x6a\x02\x6e\x41\x87\x68\x38\x77"
+ "\xfa\xa9\x44\x43\x2d\xef\x09\xdf",
+ .secret_size = 8,
+ .b_secret_size = 40,
+ .b_public_size = 64,
+ .expected_a_public_size = 64,
+ .expected_ss_size = 32,
+ .genkey = true,
}
};
--
2.7.4
^ permalink raw reply related [flat|nested] 7+ messages in thread