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Applying Fedora patch openssh-9.0p1-evp-fips-ecdh.patch
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@beldmit
beldmit committed Sep 27, 2023
1 parent 7e46273 commit 3a04d1f
Showing 1 changed file with 104 additions and 25 deletions.
129 changes: 104 additions & 25 deletions kexecdh.c
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Original file line number Diff line number Diff line change
Expand Up @@ -35,17 +35,57 @@
#include <signal.h>

#include <openssl/ecdh.h>
#include <openssl/evp.h>
#include <openssl/core_names.h>
#include <openssl/param_build.h>
#include <openssl/err.h>

#include "sshkey.h"
#include "kex.h"
#include "sshbuf.h"
#include "digest.h"
#include "ssherr.h"
#include "log.h"

static int
kex_ecdh_dec_key_group(struct kex *, const struct sshbuf *, EC_KEY *key,
const EC_GROUP *, struct sshbuf **);

static EC_KEY *
generate_ec_keys(int ec_nid)
{
EC_KEY *client_key = NULL;
EVP_PKEY *pkey = NULL;
EVP_PKEY_CTX *ctx = NULL;
OSSL_PARAM_BLD *param_bld = NULL;
OSSL_PARAM *params = NULL;
const char *group_name;

if ((ctx = EVP_PKEY_CTX_new_from_name(NULL, "EC", NULL)) == NULL ||
(param_bld = OSSL_PARAM_BLD_new()) == NULL)
goto out;
if ((group_name = OSSL_EC_curve_nid2name(ec_nid)) == NULL ||
OSSL_PARAM_BLD_push_utf8_string(param_bld,
OSSL_PKEY_PARAM_GROUP_NAME, group_name, 0) != 1 ||
(params = OSSL_PARAM_BLD_to_param(param_bld)) == NULL) {
error_f("Could not create OSSL_PARAM");
goto out;
}
if (EVP_PKEY_keygen_init(ctx) != 1 ||
EVP_PKEY_CTX_set_params(ctx, params) != 1 ||
EVP_PKEY_generate(ctx, &pkey) != 1 ||
(client_key = EVP_PKEY_get1_EC_KEY(pkey)) == NULL) {
error_f("Could not generate ec keys");
goto out;
}
out:
EVP_PKEY_free(pkey);
EVP_PKEY_CTX_free(ctx);
OSSL_PARAM_BLD_free(param_bld);
OSSL_PARAM_free(params);
return client_key;
}

int
kex_ecdh_keypair(struct kex *kex)
{
Expand All @@ -55,11 +95,7 @@ kex_ecdh_keypair(struct kex *kex)
struct sshbuf *buf = NULL;
int r;

if ((client_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (EC_KEY_generate_key(client_key) != 1) {
if ((client_key = generate_ec_keys(kex->ec_nid)) == NULL) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
Expand Down Expand Up @@ -101,11 +137,7 @@ kex_ecdh_enc(struct kex *kex, const struct sshbuf *client_blob,
*server_blobp = NULL;
*shared_secretp = NULL;

if ((server_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (EC_KEY_generate_key(server_key) != 1) {
if ((server_key = generate_ec_keys(kex->ec_nid)) == NULL) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
Expand Down Expand Up @@ -140,11 +172,21 @@ kex_ecdh_dec_key_group(struct kex *kex, const struct sshbuf *ec_blob,
{
struct sshbuf *buf = NULL;
BIGNUM *shared_secret = NULL;
EC_POINT *dh_pub = NULL;
u_char *kbuf = NULL;
size_t klen = 0;
EVP_PKEY_CTX *ctx = NULL;
EVP_PKEY *pkey = NULL, *dh_pkey = NULL;
OSSL_PARAM_BLD *param_bld = NULL;
OSSL_PARAM *params = NULL;
u_char *kbuf = NULL, *pub = NULL;
size_t klen = 0, publen;
const char *group_name;
int r;

/* import EC_KEY to EVP_PKEY */
if ((r = ssh_create_evp_ec(key, kex->ec_nid, &pkey)) != 0) {
error_f("Could not create EVP_PKEY");
goto out;
}

*shared_secretp = NULL;

if ((buf = sshbuf_new()) == NULL) {
Expand All @@ -153,45 +195,82 @@ kex_ecdh_dec_key_group(struct kex *kex, const struct sshbuf *ec_blob,
}
if ((r = sshbuf_put_stringb(buf, ec_blob)) != 0)
goto out;
if ((dh_pub = EC_POINT_new(group)) == NULL) {

/* the public key is in the buffer in octet string UNCOMPRESSED
* format. See sshbuf_put_ec */
if ((r = sshbuf_get_string(buf, &pub, &publen)) != 0)
goto out;
sshbuf_reset(buf);
if ((ctx = EVP_PKEY_CTX_new_from_pkey(NULL, pkey, NULL)) == NULL ||
(param_bld = OSSL_PARAM_BLD_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshbuf_get_ec(buf, dh_pub, group)) != 0) {
if ((group_name = OSSL_EC_curve_nid2name(kex->ec_nid)) == NULL) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if (OSSL_PARAM_BLD_push_octet_string(param_bld,
OSSL_PKEY_PARAM_PUB_KEY, pub, publen) != 1 ||
OSSL_PARAM_BLD_push_utf8_string(param_bld,
OSSL_PKEY_PARAM_GROUP_NAME, group_name, 0) != 1 ||
(params = OSSL_PARAM_BLD_to_param(param_bld)) == NULL) {
error_f("Failed to set params for dh_pkey");
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
if (EVP_PKEY_fromdata_init(ctx) != 1 ||
EVP_PKEY_fromdata(ctx, &dh_pkey,
EVP_PKEY_PUBLIC_KEY, params) != 1 ||
EVP_PKEY_public_check(ctx) != 1) {
error_f("Peer public key import failed");
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
sshbuf_reset(buf);

#ifdef DEBUG_KEXECDH
fputs("public key:\n", stderr);
sshkey_dump_ec_point(group, dh_pub);
EVP_PKEY_print_public_fp(stderr, dh_pkey, 0, NULL);
#endif
if (sshkey_ec_validate_public(group, dh_pub) != 0) {
r = SSH_ERR_MESSAGE_INCOMPLETE;
EVP_PKEY_CTX_free(ctx);
ctx = NULL;
if ((ctx = EVP_PKEY_CTX_new_from_pkey(NULL, pkey, NULL)) == NULL ||
EVP_PKEY_derive_init(ctx) != 1 ||
EVP_PKEY_derive_set_peer(ctx, dh_pkey) != 1 ||
EVP_PKEY_derive(ctx, NULL, &klen) != 1) {
error_f("Failed to get derive information");
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
klen = (EC_GROUP_get_degree(group) + 7) / 8;
if ((kbuf = malloc(klen)) == NULL ||
(shared_secret = BN_new()) == NULL) {
if ((kbuf = malloc(klen)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if (ECDH_compute_key(kbuf, klen, dh_pub, key, NULL) != (int)klen ||
BN_bin2bn(kbuf, klen, shared_secret) == NULL) {
if (EVP_PKEY_derive(ctx, kbuf, &klen) != 1) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
#ifdef DEBUG_KEXECDH
dump_digest("shared secret", kbuf, klen);
#endif
if ((shared_secret = BN_new()) == NULL ||
(BN_bin2bn(kbuf, klen, shared_secret) == NULL)) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshbuf_put_bignum2(buf, shared_secret)) != 0)
goto out;
*shared_secretp = buf;
buf = NULL;
out:
EC_POINT_clear_free(dh_pub);
EVP_PKEY_CTX_free(ctx);
EVP_PKEY_free(pkey);
EVP_PKEY_free(dh_pkey);
OSSL_PARAM_BLD_free(param_bld);
OSSL_PARAM_free(params);
BN_clear_free(shared_secret);
freezero(kbuf, klen);
freezero(pub, publen);
sshbuf_free(buf);
return r;
}
Expand Down

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