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ecdh: Rewrite to use OSSL_PARAM_BLD

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and improve debug logs and error checking. Thanks Norbert for the hints.

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Norbert Pocs <npocs@redhat.com>
This commit is contained in:
Jakub Jelen
2023-01-18 13:12:34 +01:00
parent 6d34718f89
commit bc2e99dc3f
1 changed files with 79 additions and 28 deletions
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107
src/ecdh_crypto.c
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@@ -35,7 +35,9 @@
#define NISTP384 NID_secp384r1
#define NISTP521 NID_secp521r1
#else
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/param_build.h>
#include <openssl/params.h>
#include <openssl/core_names.h>
#include "libcrypto-compat.h"
@@ -132,9 +134,9 @@ ssh_string ssh_ecdh_generate(ssh_session session)
rc = OSSL_PARAM_get_octet_string_ptr(pubkey_param,
(const void**)&pubkey,
&pubkey_len);
OSSL_PARAM_free(out_params);
if (rc != 1) {
SSH_LOG(SSH_LOG_TRACE, "Failed to read public key");
OSSL_PARAM_free(out_params);
EVP_PKEY_free(key);
return NULL;
}
@@ -142,9 +144,28 @@ ssh_string ssh_ecdh_generate(ssh_session session)
/* Convert the data to low-level representation */
nid = pki_key_ecgroup_name_to_nid(curve);
group = EC_GROUP_new_by_curve_name_ex(NULL, NULL, nid);
if (group == NULL) {
ssh_set_error(session,
SSH_FATAL,
"Could not create group: %s",
ERR_error_string(ERR_get_error(), NULL));
OSSL_PARAM_free(out_params);
EVP_PKEY_free(key);
return NULL;
}
point = EC_POINT_new(group);
if (point == NULL) {
ssh_set_error(session,
SSH_FATAL,
"Could not create point: %s",
ERR_error_string(ERR_get_error(), NULL));
OSSL_PARAM_free(out_params);
EVP_PKEY_free(key);
return NULL;
}
rc = EC_POINT_oct2point(group, (EC_POINT *)point, pubkey, pubkey_len, NULL);
if (group == NULL || point == NULL || rc != 1) {
OSSL_PARAM_free(out_params);
if (rc != 1) {
SSH_LOG(SSH_LOG_TRACE, "Failed to export public key");
EVP_PKEY_free(key);
return NULL;
@@ -262,31 +283,27 @@ int ecdh_build_k(ssh_session session)
void *secret = NULL;
size_t secret_len;
int rc;
OSSL_PARAM params[3];
ssh_string peer_pubkey = NULL;
OSSL_PARAM_BLD *param_bld = OSSL_PARAM_BLD_new();
EVP_PKEY_CTX *dh_ctx = EVP_PKEY_CTX_new_from_pkey(NULL,
next_crypto->ecdh_privkey,
NULL);
EVP_PKEY_CTX *pubkey_ctx = EVP_PKEY_CTX_new_from_pkey(NULL,
next_crypto->ecdh_privkey,
NULL);
if (dh_ctx == NULL || pubkey_ctx == NULL) {
if (dh_ctx == NULL || param_bld == NULL) {
ssh_set_error_oom(session);
EVP_PKEY_CTX_free(dh_ctx);
EVP_PKEY_CTX_free(pubkey_ctx);
OSSL_PARAM_BLD_free(param_bld);
return -1;
}
rc = EVP_PKEY_derive_init(dh_ctx);
if (rc != 1) {
ssh_set_error(session,
SSH_FATAL,
"Could not init PKEY derive: %s",
ERR_error_string(ERR_get_error(), NULL));
EVP_PKEY_CTX_free(dh_ctx);
EVP_PKEY_CTX_free(pubkey_ctx);
return -1;
}
rc = EVP_PKEY_fromdata_init(pubkey_ctx);
if (rc != 1) {
EVP_PKEY_CTX_free(dh_ctx);
EVP_PKEY_CTX_free(pubkey_ctx);
OSSL_PARAM_BLD_free(param_bld);
return -1;
}
@@ -295,26 +312,51 @@ int ecdh_build_k(ssh_session session)
} else {
peer_pubkey = next_crypto->ecdh_server_pubkey;
}
params[0] = OSSL_PARAM_construct_octet_string(OSSL_PKEY_PARAM_PUB_KEY,
ssh_string_data(peer_pubkey),
ssh_string_len(peer_pubkey));
curve = ecdh_kex_type_to_curve(next_crypto->kex_type);
params[1] = OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_GROUP_NAME,
(char *)curve,
strlen(curve));
params[2] = OSSL_PARAM_construct_end();
rc = EVP_PKEY_fromdata(pubkey_ctx, &pubkey, EVP_PKEY_PUBLIC_KEY, params);
rc = OSSL_PARAM_BLD_push_octet_string(param_bld,
OSSL_PKEY_PARAM_PUB_KEY,
ssh_string_data(peer_pubkey),
ssh_string_len(peer_pubkey));
if (rc != 1) {
ssh_set_error(session,
SSH_FATAL,
"Could not push the pub key: %s",
ERR_error_string(ERR_get_error(), NULL));
EVP_PKEY_CTX_free(dh_ctx);
EVP_PKEY_CTX_free(pubkey_ctx);
OSSL_PARAM_BLD_free(param_bld);
return -1;
}
curve = ecdh_kex_type_to_curve(next_crypto->kex_type);
rc = OSSL_PARAM_BLD_push_utf8_string(param_bld,
OSSL_PKEY_PARAM_GROUP_NAME,
(char *)curve,
strlen(curve));
if (rc != 1) {
ssh_set_error(session,
SSH_FATAL,
"Could not push the group name: %s",
ERR_error_string(ERR_get_error(), NULL));
EVP_PKEY_CTX_free(dh_ctx);
OSSL_PARAM_BLD_free(param_bld);
return -1;
}
EVP_PKEY_CTX_free(pubkey_ctx);
rc = evp_build_pkey("EC", param_bld, &pubkey, EVP_PKEY_PUBLIC_KEY);
OSSL_PARAM_BLD_free(param_bld);
if (rc != SSH_OK) {
ssh_set_error(session,
SSH_FATAL,
"Could not build the pkey: %s",
ERR_error_string(ERR_get_error(), NULL));
EVP_PKEY_CTX_free(dh_ctx);
return -1;
}
rc = EVP_PKEY_derive_set_peer(dh_ctx, pubkey);
if (rc != 1) {
ssh_set_error(session,
SSH_FATAL,
"Could not set peer pubkey: %s",
ERR_error_string(ERR_get_error(), NULL));
EVP_PKEY_CTX_free(dh_ctx);
return -1;
}
@@ -322,18 +364,27 @@ int ecdh_build_k(ssh_session session)
/* get the max length of the secret */
rc = EVP_PKEY_derive(dh_ctx, NULL, &secret_len);
if (rc != 1) {
ssh_set_error(session,
SSH_FATAL,
"Could not set peer pubkey: %s",
ERR_error_string(ERR_get_error(), NULL));
EVP_PKEY_CTX_free(dh_ctx);
return -1;
}
secret = malloc(secret_len);
if (secret == NULL) {
ssh_set_error_oom(session);
EVP_PKEY_CTX_free(dh_ctx);
return -1;
}
rc = EVP_PKEY_derive(dh_ctx, secret, &secret_len);
if (rc != 1) {
ssh_set_error(session,
SSH_FATAL,
"Could not derive shared key: %s",
ERR_error_string(ERR_get_error(), NULL));
EVP_PKEY_CTX_free(dh_ctx);
return -1;
}