pkey_mac.c
/*
* Copyright 2018-2020 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <string.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/engine.h>
#include <openssl/params.h>
#include <openssl/core_names.h>
#include "crypto/evp.h"
#include "evp_local.h"
/* MAC PKEY context structure */
typedef struct {
EVP_MAC_CTX *ctx;
/*
* We know of two MAC types:
*
* 1. those who take a secret in raw form, i.e. raw data as a
* ASN1_OCTET_STRING embedded in a EVP_PKEY. So far, that's
* all of them but CMAC.
* 2. those who take a secret with associated cipher in very generic
* form, i.e. a complete EVP_MAC_CTX embedded in a PKEY. So far,
* only CMAC does this.
*
* (one might wonder why the second form isn't used for all)
*/
#define MAC_TYPE_RAW 1 /* HMAC like MAC type (all but CMAC so far) */
#define MAC_TYPE_MAC 2 /* CMAC like MAC type (only CMAC known so far) */
int type;
/* The following is only used for MAC_TYPE_RAW implementations */
struct {
const EVP_MD *md; /* temp storage of MD */
ASN1_OCTET_STRING ktmp; /* temp storage for key */
} raw_data;
} MAC_PKEY_CTX;
static void pkey_mac_cleanup(EVP_PKEY_CTX *ctx);
static int pkey_mac_init(EVP_PKEY_CTX *ctx)
{
MAC_PKEY_CTX *hctx;
/* We're being smart and using the same base NIDs for PKEY and for MAC */
int nid = ctx->pmeth->pkey_id;
EVP_MAC *mac;
ERR_set_mark();
mac = EVP_MAC_fetch(ctx->libctx, OBJ_nid2sn(nid), ctx->propquery);
ERR_pop_to_mark();
/*
* mac == NULL may actually be ok in some situations. In an
* EVP_PKEY_new_mac_key() call a temporary EVP_PKEY_CTX is created with
* default libctx. We don't actually need the underlying MAC to be present
* to successfully set the key in that case. The resulting EVP_PKEY could
* then be used in some other libctx where the MAC *is* present
*/
if ((hctx = OPENSSL_zalloc(sizeof(*hctx))) == NULL) {
EVPerr(EVP_F_PKEY_MAC_INIT, ERR_R_MALLOC_FAILURE);
return 0;
}
if (mac != NULL) {
hctx->ctx = EVP_MAC_CTX_new(mac);
if (hctx->ctx == NULL) {
OPENSSL_free(hctx);
return 0;
}
}
if (nid == EVP_PKEY_CMAC) {
hctx->type = MAC_TYPE_MAC;
} else {
hctx->type = MAC_TYPE_RAW;
hctx->raw_data.ktmp.type = V_ASN1_OCTET_STRING;
}
pkey_mac_cleanup(ctx);
EVP_PKEY_CTX_set_data(ctx, hctx);
ctx->keygen_info_count = 0;
return 1;
}
static int pkey_mac_copy(EVP_PKEY_CTX *dst, const EVP_PKEY_CTX *src)
{
MAC_PKEY_CTX *sctx, *dctx;
sctx = EVP_PKEY_CTX_get_data(src);
if (sctx->ctx == NULL) {
/* This actually means the fetch failed during the init call */
EVPerr(0, EVP_R_FETCH_FAILED);
return 0;
}
if (sctx->ctx->data == NULL)
return 0;
dctx = OPENSSL_zalloc(sizeof(*dctx));
if (dctx == NULL) {
EVPerr(EVP_F_PKEY_MAC_COPY, ERR_R_MALLOC_FAILURE);
return 0;
}
EVP_PKEY_CTX_set_data(dst, dctx);
dst->keygen_info_count = 0;
dctx->ctx = EVP_MAC_CTX_dup(sctx->ctx);
if (dctx->ctx == NULL)
goto err;
/*
* Normally, nothing special would be done with the MAC method. In
* this particular case, though, the MAC method was fetched internally
* by pkey_mac_init() above or by EVP_PKEY_new_CMAC_key() and passed
* via the EVP_MAC_CTX, so it is effectively like every new EVP_MAC_CTX
* fetches the MAC method anew in this case. Therefore, its reference
* count must be adjusted here.
*/
if (!EVP_MAC_up_ref(EVP_MAC_CTX_mac(dctx->ctx)))
goto err;
dctx->type = sctx->type;
switch (dctx->type) {
case MAC_TYPE_RAW:
dctx->raw_data.md = sctx->raw_data.md;
if (ASN1_STRING_get0_data(&sctx->raw_data.ktmp) != NULL &&
!ASN1_STRING_copy(&dctx->raw_data.ktmp, &sctx->raw_data.ktmp))
goto err;
break;
case MAC_TYPE_MAC:
/* Nothing more to do */
break;
default:
/* This should be dead code */
return 0;
}
return 1;
err:
pkey_mac_cleanup(dst);
return 0;
}
static void pkey_mac_cleanup(EVP_PKEY_CTX *ctx)
{
/*
* For the exact same reasons the MAC reference count is incremented
* in pkey_mac_copy() above, it must be explicitly freed here.
*/
MAC_PKEY_CTX *hctx = ctx == NULL ? NULL : EVP_PKEY_CTX_get_data(ctx);
if (hctx != NULL) {
EVP_MAC *mac = hctx->ctx != NULL ? EVP_MAC_CTX_mac(hctx->ctx) : NULL;
switch (hctx->type) {
case MAC_TYPE_RAW:
OPENSSL_clear_free(hctx->raw_data.ktmp.data,
hctx->raw_data.ktmp.length);
break;
}
EVP_MAC_CTX_free(hctx->ctx);
EVP_MAC_free(mac);
OPENSSL_free(hctx);
EVP_PKEY_CTX_set_data(ctx, NULL);
}
}
static int pkey_mac_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
{
MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);
int nid = ctx->pmeth->pkey_id;
switch (hctx->type) {
case MAC_TYPE_RAW:
{
ASN1_OCTET_STRING *hkey = NULL;
if (!hctx->raw_data.ktmp.data)
return 0;
hkey = ASN1_OCTET_STRING_dup(&hctx->raw_data.ktmp);
if (!hkey)
return 0;
EVP_PKEY_assign(pkey, nid, hkey);
}
break;
case MAC_TYPE_MAC:
{
EVP_MAC_CTX *cmkey;
if (hctx->ctx == NULL) {
/* This actually means the fetch failed during the init call */
EVPerr(0, EVP_R_FETCH_FAILED);
return 0;
}
cmkey = EVP_MAC_CTX_dup(hctx->ctx);
if (cmkey == NULL)
return 0;
if (!EVP_MAC_up_ref(EVP_MAC_CTX_mac(hctx->ctx)))
return 0;
EVP_PKEY_assign(pkey, nid, cmkey);
}
break;
default:
/* This should be dead code */
return 0;
}
return 1;
}
static int int_update(EVP_MD_CTX *ctx, const void *data, size_t count)
{
MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(EVP_MD_CTX_pkey_ctx(ctx));
if (!EVP_MAC_update(hctx->ctx, data, count))
return 0;
return 1;
}
static int pkey_mac_signctx_init(EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx)
{
MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);
ASN1_OCTET_STRING *key = NULL;
int rv = 1;
/*
* For MACs with the EVP_PKEY_FLAG_SIGCTX_CUSTOM flag set and that
* gets the key passed as an ASN.1 OCTET STRING, we set the key here,
* as this may be only time it's set during a DigestSign.
*
* MACs that pass around the key in form of EVP_MAC_CTX are setting
* the key through other mechanisms. (this is only CMAC for now)
*/
int set_key =
hctx->type == MAC_TYPE_RAW
&& (ctx->pmeth->flags & EVP_PKEY_FLAG_SIGCTX_CUSTOM) != 0;
if (hctx->ctx == NULL) {
/* This actually means the fetch failed during the init call */
EVPerr(0, EVP_R_FETCH_FAILED);
return 0;
}
if (set_key) {
if (!EVP_MAC_is_a(EVP_MAC_CTX_mac(hctx->ctx),
OBJ_nid2sn(EVP_PKEY_id(EVP_PKEY_CTX_get0_pkey(ctx)))))
return 0;
key = EVP_PKEY_get0(EVP_PKEY_CTX_get0_pkey(ctx));
if (key == NULL)
return 0;
}
EVP_MD_CTX_set_flags(mctx, EVP_MD_CTX_FLAG_NO_INIT);
EVP_MD_CTX_set_update_fn(mctx, int_update);
/* Some MACs don't support this control... that's fine */
{
OSSL_PARAM params[3];
size_t params_n = 0;
int flags = EVP_MD_CTX_test_flags(mctx, ~EVP_MD_CTX_FLAG_NO_INIT);
/* TODO(3.0) "flags" isn't quite right, i.e. a quick hack for now */
params[params_n++] =
OSSL_PARAM_construct_int(OSSL_MAC_PARAM_FLAGS, &flags);
if (set_key)
params[params_n++] =
OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
key->data, key->length);
params[params_n++] = OSSL_PARAM_construct_end();
rv = EVP_MAC_CTX_set_params(hctx->ctx, params);
}
return rv;
}
static int pkey_mac_signctx(EVP_PKEY_CTX *ctx, unsigned char *sig,
size_t *siglen, EVP_MD_CTX *mctx)
{
MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);
return EVP_MAC_final(hctx->ctx, sig, siglen, EVP_MAC_size(hctx->ctx));
}
static int pkey_mac_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
{
MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);
switch (type) {
case EVP_PKEY_CTRL_CIPHER:
switch (hctx->type) {
case MAC_TYPE_RAW:
return -2; /* The raw types don't support ciphers */
case MAC_TYPE_MAC:
{
OSSL_PARAM params[3];
size_t params_n = 0;
char *ciphname = (char *)OBJ_nid2sn(EVP_CIPHER_nid(p2));
#ifndef OPENSSL_NO_ENGINE
char *engineid = (char *)ENGINE_get_id(ctx->engine);
params[params_n++] =
OSSL_PARAM_construct_utf8_string("engine", engineid, 0);
#endif
params[params_n++] =
OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_CIPHER,
ciphname, 0);
params[params_n] = OSSL_PARAM_construct_end();
if (hctx->ctx == NULL) {
/*
* This actually means the fetch failed during the init call
*/
EVPerr(0, EVP_R_FETCH_FAILED);
return 0;
}
if (!EVP_MAC_CTX_set_params(hctx->ctx, params)
|| !EVP_MAC_init(hctx->ctx))
return 0;
}
break;
default:
/* This should be dead code */
return 0;
}
break;
case EVP_PKEY_CTRL_MD:
switch (hctx->type) {
case MAC_TYPE_RAW:
hctx->raw_data.md = p2;
break;
case MAC_TYPE_MAC: {
EVP_MAC_CTX *new_mac_ctx;
if (ctx->pkey == NULL)
return 0;
new_mac_ctx = EVP_MAC_CTX_dup(ctx->pkey->pkey.ptr);
if (new_mac_ctx == NULL)
return 0;
EVP_MAC_CTX_free(hctx->ctx);
hctx->ctx = new_mac_ctx;
}
break;
default:
/* This should be dead code */
return 0;
}
break;
case EVP_PKEY_CTRL_SET_DIGEST_SIZE:
{
OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
size_t size = (size_t)p1;
size_t verify = 0;
/*
* We verify that the length is actually set by getting back
* the same parameter and checking that it matches what we
* tried to set.
* TODO(3.0) when we have a more direct mechanism to check if
* a parameter was used, we must refactor this to use that.
*/
params[0] =
OSSL_PARAM_construct_size_t(OSSL_MAC_PARAM_SIZE, &size);
if (hctx->ctx == NULL) {
/*
* This actually means the fetch failed during the init call
*/
EVPerr(0, EVP_R_FETCH_FAILED);
return 0;
}
if (!EVP_MAC_CTX_set_params(hctx->ctx, params))
return 0;
params[0] =
OSSL_PARAM_construct_size_t(OSSL_MAC_PARAM_SIZE, &verify);
if (!EVP_MAC_CTX_get_params(hctx->ctx, params))
return 0;
/*
* Since EVP_MAC_CTX_{get,set}_params() returned successfully,
* we can only assume that the size was ignored, i.e. this
* control is unsupported.
*/
if (verify != size)
return -2;
}
break;
case EVP_PKEY_CTRL_SET_MAC_KEY:
switch (hctx->type) {
case MAC_TYPE_RAW:
if ((!p2 && p1 > 0) || (p1 < -1))
return 0;
if (!ASN1_OCTET_STRING_set(&hctx->raw_data.ktmp, p2, p1))
return 0;
break;
case MAC_TYPE_MAC:
{
OSSL_PARAM params[2];
size_t params_n = 0;
params[params_n++] =
OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
p2, p1);
params[params_n] = OSSL_PARAM_construct_end();
if (hctx->ctx == NULL) {
/*
* This actually means the fetch failed during the init call
*/
EVPerr(0, EVP_R_FETCH_FAILED);
return 0;
}
return EVP_MAC_CTX_set_params(hctx->ctx, params);
}
break;
default:
/* This should be dead code */
return 0;
}
break;
case EVP_PKEY_CTRL_DIGESTINIT:
switch (hctx->type) {
case MAC_TYPE_RAW:
if (hctx->ctx == NULL) {
/* This actually means the fetch failed during the init call */
EVPerr(0, EVP_R_FETCH_FAILED);
return 0;
}
/* Ensure that we have attached the implementation */
if (!EVP_MAC_init(hctx->ctx))
return 0;
{
ASN1_OCTET_STRING *key =
(ASN1_OCTET_STRING *)ctx->pkey->pkey.ptr;
OSSL_PARAM params[4];
size_t params_n = 0;
char *mdname =
(char *)OBJ_nid2sn(EVP_MD_nid(hctx->raw_data.md));
#ifndef OPENSSL_NO_ENGINE
char *engineid = ctx->engine == NULL
? NULL : (char *)ENGINE_get_id(ctx->engine);
if (engineid != NULL)
params[params_n++] =
OSSL_PARAM_construct_utf8_string("engine", engineid, 0);
#endif
params[params_n++] =
OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_DIGEST,
mdname, 0);
params[params_n++] =
OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
key->data, key->length);
params[params_n] = OSSL_PARAM_construct_end();
return EVP_MAC_CTX_set_params(hctx->ctx, params);
}
break;
case MAC_TYPE_MAC:
return -2; /* The mac types don't support ciphers */
default:
/* This should be dead code */
return 0;
}
break;
default:
return -2;
}
return 1;
}
static int pkey_mac_ctrl_str(EVP_PKEY_CTX *ctx,
const char *type, const char *value)
{
MAC_PKEY_CTX *hctx = EVP_PKEY_CTX_get_data(ctx);
const EVP_MAC *mac = EVP_MAC_CTX_mac(hctx->ctx);
OSSL_PARAM params[2];
int ok = 0;
/*
* Translation of some control names that are equivalent to a single
* parameter name.
*
* "md" and "digest" are the same thing, we use the single "digest"
*
* "digestsize" was a setting control in siphash, but naming wise,
* it's really the same as "size".
*/
if (strcmp(type, "md") == 0)
type = OSSL_MAC_PARAM_DIGEST;
else if (strcmp(type, "digestsize") == 0)
type = OSSL_MAC_PARAM_SIZE;
if (!OSSL_PARAM_allocate_from_text(¶ms[0],
EVP_MAC_settable_ctx_params(mac),
type, value, strlen(value) + 1, NULL))
return 0;
params[1] = OSSL_PARAM_construct_end();
if (hctx->ctx == NULL) {
/* This actually means the fetch failed during the init call */
EVPerr(0, EVP_R_FETCH_FAILED);
return 0;
}
ok = EVP_MAC_CTX_set_params(hctx->ctx, params);
OPENSSL_free(params[0].data);
return ok;
}
static const EVP_PKEY_METHOD cmac_pkey_meth = {
EVP_PKEY_CMAC,
EVP_PKEY_FLAG_SIGCTX_CUSTOM,
pkey_mac_init,
pkey_mac_copy,
pkey_mac_cleanup,
0, 0,
0,
pkey_mac_keygen,
0, 0,
0, 0,
0, 0,
pkey_mac_signctx_init,
pkey_mac_signctx,
0, 0,
0, 0,
0, 0,
0, 0,
pkey_mac_ctrl,
pkey_mac_ctrl_str
};
const EVP_PKEY_METHOD *cmac_pkey_method(void)
{
return &cmac_pkey_meth;
}
static const EVP_PKEY_METHOD hmac_pkey_meth = {
EVP_PKEY_HMAC,
0,
pkey_mac_init,
pkey_mac_copy,
pkey_mac_cleanup,
0, 0,
0,
pkey_mac_keygen,
0, 0,
0, 0,
0, 0,
pkey_mac_signctx_init,
pkey_mac_signctx,
0, 0,
0, 0,
0, 0,
0, 0,
pkey_mac_ctrl,
pkey_mac_ctrl_str
};
const EVP_PKEY_METHOD *hmac_pkey_method(void)
{
return &hmac_pkey_meth;
}
static const EVP_PKEY_METHOD siphash_pkey_meth = {
EVP_PKEY_SIPHASH,
EVP_PKEY_FLAG_SIGCTX_CUSTOM,
pkey_mac_init,
pkey_mac_copy,
pkey_mac_cleanup,
0, 0,
0,
pkey_mac_keygen,
0, 0,
0, 0,
0, 0,
pkey_mac_signctx_init,
pkey_mac_signctx,
0, 0,
0, 0,
0, 0,
0, 0,
pkey_mac_ctrl,
pkey_mac_ctrl_str
};
const EVP_PKEY_METHOD *siphash_pkey_method(void)
{
return &siphash_pkey_meth;
}
static const EVP_PKEY_METHOD poly1305_pkey_meth = {
EVP_PKEY_POLY1305,
EVP_PKEY_FLAG_SIGCTX_CUSTOM,
pkey_mac_init,
pkey_mac_copy,
pkey_mac_cleanup,
0, 0,
0,
pkey_mac_keygen,
0, 0,
0, 0,
0, 0,
pkey_mac_signctx_init,
pkey_mac_signctx,
0, 0,
0, 0,
0, 0,
0, 0,
pkey_mac_ctrl,
pkey_mac_ctrl_str
};
const EVP_PKEY_METHOD *poly1305_pkey_method(void)
{
return &poly1305_pkey_meth;
}
