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systemd/SOURCES/0609-openssl-add-ecc_edch.p...

111 lines
4.7 KiB

From 5d8a176526175a9d7bf762c46245492bf056bdc8 Mon Sep 17 00:00:00 2001
From: Dan Streetman <ddstreet@ieee.org>
Date: Fri, 7 Jul 2023 10:11:07 -0400
Subject: [PATCH] openssl: add ecc_edch()
Add function to perform ECC EDCH.
(cherry picked from commit 779b80d8039ae3925ce6a52f97f9d53586ae931e)
Related: RHEL-16182
---
src/shared/openssl-util.c | 42 +++++++++++++++++++++++++++++++++++++++
src/shared/openssl-util.h | 2 ++
src/test/test-openssl.c | 19 ++++++++++++++++++
3 files changed, 63 insertions(+)
diff --git a/src/shared/openssl-util.c b/src/shared/openssl-util.c
index 19ec385bf0..c8eadd9c63 100644
--- a/src/shared/openssl-util.c
+++ b/src/shared/openssl-util.c
@@ -894,6 +894,48 @@ int ecc_pkey_new(int curve_id, EVP_PKEY **ret) {
return 0;
}
+/* Perform ECDH to derive an ECC shared secret between the provided private key and public peer key. For two
+ * keys, this will result in the same shared secret in either direction; ECDH using Alice's private key and
+ * Bob's public (peer) key will result in the same shared secret as ECDH using Bob's private key and Alice's
+ * public (peer) key. On success, this returns 0 and provides the shared secret; otherwise this returns an
+ * error. */
+int ecc_ecdh(const EVP_PKEY *private_pkey,
+ const EVP_PKEY *peer_pkey,
+ void **ret_shared_secret,
+ size_t *ret_shared_secret_size) {
+
+ assert(private_pkey);
+ assert(peer_pkey);
+ assert(ret_shared_secret);
+ assert(ret_shared_secret_size);
+
+ _cleanup_(EVP_PKEY_CTX_freep) EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new((EVP_PKEY*) private_pkey, NULL);
+ if (!ctx)
+ return log_openssl_errors("Failed to create new EVP_PKEY_CTX");
+
+ if (EVP_PKEY_derive_init(ctx) <= 0)
+ return log_openssl_errors("Failed to initialize EVP_PKEY_CTX");
+
+ if (EVP_PKEY_derive_set_peer(ctx, (EVP_PKEY*) peer_pkey) <= 0)
+ return log_openssl_errors("Failed to set ECC derive peer");
+
+ size_t shared_secret_size;
+ if (EVP_PKEY_derive(ctx, NULL, &shared_secret_size) <= 0)
+ return log_openssl_errors("Failed to get ECC shared secret size");
+
+ _cleanup_free_ void *shared_secret = malloc(shared_secret_size);
+ if (!shared_secret)
+ return log_oom_debug();
+
+ if (EVP_PKEY_derive(ctx, (unsigned char*) shared_secret, &shared_secret_size) <= 0)
+ return log_openssl_errors("Failed to derive ECC shared secret");
+
+ *ret_shared_secret = TAKE_PTR(shared_secret);
+ *ret_shared_secret_size = shared_secret_size;
+
+ return 0;
+}
+
int pubkey_fingerprint(EVP_PKEY *pk, const EVP_MD *md, void **ret, size_t *ret_size) {
_cleanup_(EVP_MD_CTX_freep) EVP_MD_CTX* m = NULL;
_cleanup_free_ void *d = NULL, *h = NULL;
diff --git a/src/shared/openssl-util.h b/src/shared/openssl-util.h
index 2e894fba80..0fea0c5df0 100644
--- a/src/shared/openssl-util.h
+++ b/src/shared/openssl-util.h
@@ -104,6 +104,8 @@ int ecc_pkey_to_curve_x_y(const EVP_PKEY *pkey, int *ret_curve_id, void **ret_x,
int ecc_pkey_new(int curve_id, EVP_PKEY **ret);
+int ecc_ecdh(const EVP_PKEY *private_pkey, const EVP_PKEY *peer_pkey, void **ret_shared_secret, size_t *ret_shared_secret_size);
+
int pubkey_fingerprint(EVP_PKEY *pk, const EVP_MD *md, void **ret, size_t *ret_size);
#else
diff --git a/src/test/test-openssl.c b/src/test/test-openssl.c
index 9d2a1ad0c2..1653c0dc9d 100644
--- a/src/test/test-openssl.c
+++ b/src/test/test-openssl.c
@@ -425,4 +425,23 @@ TEST(openssl_cipher) {
/* expected= */ NULL);
}
+TEST(ecc_ecdh) {
+ _cleanup_(EVP_PKEY_freep) EVP_PKEY *pkeyA = NULL, *pkeyB = NULL, *pkeyC = NULL;
+ _cleanup_free_ void *secretAB = NULL, *secretBA = NULL, *secretAC = NULL, *secretCA = NULL;
+ size_t secretAB_size, secretBA_size, secretAC_size, secretCA_size;
+
+ assert_se(ecc_pkey_new(NID_X9_62_prime256v1, &pkeyA) >= 0);
+ assert_se(ecc_pkey_new(NID_X9_62_prime256v1, &pkeyB) >= 0);
+ assert_se(ecc_pkey_new(NID_X9_62_prime256v1, &pkeyC) >= 0);
+
+ assert_se(ecc_ecdh(pkeyA, pkeyB, &secretAB, &secretAB_size) >= 0);
+ assert_se(ecc_ecdh(pkeyB, pkeyA, &secretBA, &secretBA_size) >= 0);
+ assert_se(ecc_ecdh(pkeyA, pkeyC, &secretAC, &secretAC_size) >= 0);
+ assert_se(ecc_ecdh(pkeyC, pkeyA, &secretCA, &secretCA_size) >= 0);
+
+ assert_se(memcmp_nn(secretAB, secretAB_size, secretBA, secretBA_size) == 0);
+ assert_se(memcmp_nn(secretAC, secretAC_size, secretCA, secretCA_size) == 0);
+ assert_se(memcmp_nn(secretAC, secretAC_size, secretAB, secretAB_size) != 0);
+}
+
DEFINE_TEST_MAIN(LOG_DEBUG);