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openssl/providers/implementations/ciphers/ciphercommon_gcm.c

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/*
* Copyright 2019-2021 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
*/
/* Dispatch functions for gcm mode */
#include <openssl/rand.h>
#include <openssl/proverr.h>
#include "prov/ciphercommon.h"
#include "prov/ciphercommon_gcm.h"
#include "prov/providercommon.h"
#include "prov/provider_ctx.h"
static int gcm_tls_init(PROV_GCM_CTX *dat, unsigned char *aad, size_t aad_len);
static int gcm_tls_iv_set_fixed(PROV_GCM_CTX *ctx, unsigned char *iv,
size_t len);
static int gcm_tls_cipher(PROV_GCM_CTX *ctx, unsigned char *out, size_t *padlen,
const unsigned char *in, size_t len);
static int gcm_cipher_internal(PROV_GCM_CTX *ctx, unsigned char *out,
size_t *padlen, const unsigned char *in,
size_t len);
/*
* Called from EVP_CipherInit when there is currently no context via
* the new_ctx() function
*/
void ossl_gcm_initctx(void *provctx, PROV_GCM_CTX *ctx, size_t keybits,
const PROV_GCM_HW *hw)
{
ctx->pad = 1;
ctx->mode = EVP_CIPH_GCM_MODE;
ctx->taglen = UNINITIALISED_SIZET;
ctx->tls_aad_len = UNINITIALISED_SIZET;
ctx->ivlen = (EVP_GCM_TLS_FIXED_IV_LEN + EVP_GCM_TLS_EXPLICIT_IV_LEN);
ctx->keylen = keybits / 8;
ctx->hw = hw;
ctx->libctx = PROV_LIBCTX_OF(provctx);
}
/*
* Called by EVP_CipherInit via the _einit and _dinit functions
*/
static int gcm_init(void *vctx, const unsigned char *key, size_t keylen,
const unsigned char *iv, size_t ivlen,
const OSSL_PARAM params[], int enc)
{
PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
if (!ossl_prov_is_running())
return 0;
ctx->enc = enc;
if (iv != NULL) {
if (ivlen == 0 || ivlen > sizeof(ctx->iv)) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
return 0;
}
ctx->ivlen = ivlen;
memcpy(ctx->iv, iv, ivlen);
ctx->iv_state = IV_STATE_BUFFERED;
}
if (key != NULL) {
if (keylen != ctx->keylen) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
return 0;
}
if (!ctx->hw->setkey(ctx, key, ctx->keylen))
return 0;
ctx->tls_enc_records = 0;
}
return ossl_gcm_set_ctx_params(ctx, params);
}
int ossl_gcm_einit(void *vctx, const unsigned char *key, size_t keylen,
const unsigned char *iv, size_t ivlen,
const OSSL_PARAM params[])
{
return gcm_init(vctx, key, keylen, iv, ivlen, params, 1);
}
int ossl_gcm_dinit(void *vctx, const unsigned char *key, size_t keylen,
const unsigned char *iv, size_t ivlen,
const OSSL_PARAM params[])
{
return gcm_init(vctx, key, keylen, iv, ivlen, params, 0);
}
/* increment counter (64-bit int) by 1 */
static void ctr64_inc(unsigned char *counter)
{
int n = 8;
unsigned char c;
do {
--n;
c = counter[n];
++c;
counter[n] = c;
if (c > 0)
return;
} while (n > 0);
}
static int getivgen(PROV_GCM_CTX *ctx, unsigned char *out, size_t olen)
{
if (!ctx->iv_gen
|| !ctx->key_set
|| !ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen))
return 0;
if (olen == 0 || olen > ctx->ivlen)
olen = ctx->ivlen;
memcpy(out, ctx->iv + ctx->ivlen - olen, olen);
/*
* Invocation field will be at least 8 bytes in size and so no need
* to check wrap around or increment more than last 8 bytes.
*/
ctr64_inc(ctx->iv + ctx->ivlen - 8);
ctx->iv_state = IV_STATE_COPIED;
return 1;
}
static int setivinv(PROV_GCM_CTX *ctx, unsigned char *in, size_t inl)
{
if (!ctx->iv_gen
|| !ctx->key_set
|| ctx->enc)
return 0;
memcpy(ctx->iv + ctx->ivlen - inl, in, inl);
if (!ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen))
return 0;
ctx->iv_state = IV_STATE_COPIED;
return 1;
}
int ossl_gcm_get_ctx_params(void *vctx, OSSL_PARAM params[])
{
PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
OSSL_PARAM *p;
size_t sz;
int type;
for (p = params; p->key != NULL; p++) {
type = ossl_param_find_pidx(p->key);
switch (type) {
default:
break;
case PIDX_CIPHER_PARAM_IVLEN:
if (!OSSL_PARAM_set_size_t(p, ctx->ivlen)) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
return 0;
}
break;
case PIDX_CIPHER_PARAM_KEYLEN:
if (!OSSL_PARAM_set_size_t(p, ctx->keylen)) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
return 0;
}
break;
case PIDX_CIPHER_PARAM_AEAD_TAGLEN:
{
size_t taglen = (ctx->taglen != UNINITIALISED_SIZET) ? ctx->taglen :
GCM_TAG_MAX_SIZE;
if (!OSSL_PARAM_set_size_t(p, taglen)) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
return 0;
}
}
break;
case PIDX_CIPHER_PARAM_IV:
if (ctx->iv_state == IV_STATE_UNINITIALISED)
return 0;
if (ctx->ivlen > p->data_size) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
return 0;
}
if (!OSSL_PARAM_set_octet_string(p, ctx->iv, ctx->ivlen)
&& !OSSL_PARAM_set_octet_ptr(p, &ctx->iv, ctx->ivlen)) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
return 0;
}
break;
case PIDX_CIPHER_PARAM_UPDATED_IV:
if (ctx->iv_state == IV_STATE_UNINITIALISED)
return 0;
if (ctx->ivlen > p->data_size) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
return 0;
}
if (!OSSL_PARAM_set_octet_string(p, ctx->iv, ctx->ivlen)
&& !OSSL_PARAM_set_octet_ptr(p, &ctx->iv, ctx->ivlen)) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
return 0;
}
break;
case PIDX_CIPHER_PARAM_AEAD_TLS1_AAD_PAD:
if (!OSSL_PARAM_set_size_t(p, ctx->tls_aad_pad_sz)) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
return 0;
}
break;
case PIDX_CIPHER_PARAM_AEAD_TAG:
sz = p->data_size;
if (sz == 0
|| sz > EVP_GCM_TLS_TAG_LEN
|| !ctx->enc
|| ctx->taglen == UNINITIALISED_SIZET) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG);
return 0;
}
if (!OSSL_PARAM_set_octet_string(p, ctx->buf, sz)) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
return 0;
}
break;
case PIDX_CIPHER_PARAM_AEAD_TLS1_GET_IV_GEN:
if (p->data == NULL
|| p->data_type != OSSL_PARAM_OCTET_STRING
|| !getivgen(ctx, p->data, p->data_size))
return 0;
break;
}
}
return 1;
}
int ossl_gcm_set_ctx_params(void *vctx, const OSSL_PARAM params[])
{
PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
const OSSL_PARAM *p;
size_t sz;
void *vp;
int type;
if (params == NULL)
return 1;
for (p = params; p->key != NULL; p++) {
type = ossl_param_find_pidx(p->key);
switch (type) {
default:
break;
case PIDX_CIPHER_PARAM_AEAD_TAG:
vp = ctx->buf;
if (!OSSL_PARAM_get_octet_string(p, &vp, EVP_GCM_TLS_TAG_LEN, &sz)) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
return 0;
}
if (sz == 0 || ctx->enc) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG);
return 0;
}
ctx->taglen = sz;
break;
case PIDX_CIPHER_PARAM_AEAD_IVLEN:
if (!OSSL_PARAM_get_size_t(p, &sz)) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
return 0;
}
if (sz == 0 || sz > sizeof(ctx->iv)) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
return 0;
}
ctx->ivlen = sz;
break;
case PIDX_CIPHER_PARAM_AEAD_TLS1_AAD:
if (p->data_type != OSSL_PARAM_OCTET_STRING) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
return 0;
}
sz = gcm_tls_init(ctx, p->data, p->data_size);
if (sz == 0) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_AAD);
return 0;
}
ctx->tls_aad_pad_sz = sz;
break;
case PIDX_CIPHER_PARAM_AEAD_TLS1_IV_FIXED:
if (p->data_type != OSSL_PARAM_OCTET_STRING) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
return 0;
}
if (gcm_tls_iv_set_fixed(ctx, p->data, p->data_size) == 0) {
ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
return 0;
}
break;
case PIDX_CIPHER_PARAM_AEAD_TLS1_SET_IV_INV:
if (p->data == NULL
|| p->data_type != OSSL_PARAM_OCTET_STRING
|| !setivinv(ctx, p->data, p->data_size))
return 0;
break;
}
}
return 1;
}
int ossl_gcm_stream_update(void *vctx, unsigned char *out, size_t *outl,
size_t outsize, const unsigned char *in, size_t inl)
{
PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
if (inl == 0) {
*outl = 0;
return 1;
}
if (outsize < inl) {
ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
return 0;
}
if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0) {
ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
return 0;
}
return 1;
}
int ossl_gcm_stream_final(void *vctx, unsigned char *out, size_t *outl,
size_t outsize)
{
PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
int i;
if (!ossl_prov_is_running())
return 0;
i = gcm_cipher_internal(ctx, out, outl, NULL, 0);
if (i <= 0)
return 0;
*outl = 0;
return 1;
}
int ossl_gcm_cipher(void *vctx,
unsigned char *out, size_t *outl, size_t outsize,
const unsigned char *in, size_t inl)
{
PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
if (!ossl_prov_is_running())
return 0;
if (outsize < inl) {
ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
return 0;
}
if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0)
return 0;
*outl = inl;
return 1;
}
/*
* See SP800-38D (GCM) Section 8 "Uniqueness requirement on IVS and keys"
*
* See also 8.2.2 RBG-based construction.
* Random construction consists of a free field (which can be NULL) and a
* random field which will use a DRBG that can return at least 96 bits of
* entropy strength. (The DRBG must be seeded by the FIPS module).
*/
static int gcm_iv_generate(PROV_GCM_CTX *ctx, int offset)
{
int sz = ctx->ivlen - offset;
/* Must be at least 96 bits */
if (sz <= 0 || ctx->ivlen < GCM_IV_DEFAULT_SIZE)
return 0;
/* Use DRBG to generate random iv */
if (RAND_bytes_ex(ctx->libctx, ctx->iv + offset, sz, 0) <= 0)
return 0;
ctx->iv_state = IV_STATE_BUFFERED;
ctx->iv_gen_rand = 1;
return 1;
}
static int gcm_cipher_internal(PROV_GCM_CTX *ctx, unsigned char *out,
size_t *padlen, const unsigned char *in,
size_t len)
{
size_t olen = 0;
int rv = 0;
const PROV_GCM_HW *hw = ctx->hw;
if (ctx->tls_aad_len != UNINITIALISED_SIZET)
return gcm_tls_cipher(ctx, out, padlen, in, len);
if (!ctx->key_set || ctx->iv_state == IV_STATE_FINISHED)
goto err;
/*
* FIPS requires generation of AES-GCM IV's inside the FIPS module.
* The IV can still be set externally (the security policy will state that
* this is not FIPS compliant). There are some applications
* where setting the IV externally is the only option available.
*/
if (ctx->iv_state == IV_STATE_UNINITIALISED) {
if (!ctx->enc || !gcm_iv_generate(ctx, 0))
goto err;
}
if (ctx->iv_state == IV_STATE_BUFFERED) {
if (!hw->setiv(ctx, ctx->iv, ctx->ivlen))
goto err;
ctx->iv_state = IV_STATE_COPIED;
}
if (in != NULL) {
/* The input is AAD if out is NULL */
if (out == NULL) {
if (!hw->aadupdate(ctx, in, len))
goto err;
} else {
/* The input is ciphertext OR plaintext */
if (!hw->cipherupdate(ctx, in, len, out))
goto err;
}
} else {
/* The tag must be set before actually decrypting data */
if (!ctx->enc && ctx->taglen == UNINITIALISED_SIZET)
goto err;
if (!hw->cipherfinal(ctx, ctx->buf))
goto err;
ctx->iv_state = IV_STATE_FINISHED; /* Don't reuse the IV */
goto finish;
}
olen = len;
finish:
rv = 1;
err:
*padlen = olen;
return rv;
}
static int gcm_tls_init(PROV_GCM_CTX *dat, unsigned char *aad, size_t aad_len)
{
unsigned char *buf;
size_t len;
if (!ossl_prov_is_running() || aad_len != EVP_AEAD_TLS1_AAD_LEN)
return 0;
/* Save the aad for later use. */
buf = dat->buf;
memcpy(buf, aad, aad_len);
dat->tls_aad_len = aad_len;
len = buf[aad_len - 2] << 8 | buf[aad_len - 1];
/* Correct length for explicit iv. */
if (len < EVP_GCM_TLS_EXPLICIT_IV_LEN)
return 0;
len -= EVP_GCM_TLS_EXPLICIT_IV_LEN;
/* If decrypting correct for tag too. */
if (!dat->enc) {
if (len < EVP_GCM_TLS_TAG_LEN)
return 0;
len -= EVP_GCM_TLS_TAG_LEN;
}
buf[aad_len - 2] = (unsigned char)(len >> 8);
buf[aad_len - 1] = (unsigned char)(len & 0xff);
/* Extra padding: tag appended to record. */
return EVP_GCM_TLS_TAG_LEN;
}
static int gcm_tls_iv_set_fixed(PROV_GCM_CTX *ctx, unsigned char *iv,
size_t len)
{
/* Special case: -1 length restores whole IV */
if (len == (size_t)-1) {
memcpy(ctx->iv, iv, ctx->ivlen);
ctx->iv_gen = 1;
ctx->iv_state = IV_STATE_BUFFERED;
return 1;
}
/* Fixed field must be at least 4 bytes and invocation field at least 8 */
if ((len < EVP_GCM_TLS_FIXED_IV_LEN)
|| (ctx->ivlen - (int)len) < EVP_GCM_TLS_EXPLICIT_IV_LEN)
return 0;
if (len > 0)
memcpy(ctx->iv, iv, len);
if (ctx->enc
&& RAND_bytes_ex(ctx->libctx, ctx->iv + len, ctx->ivlen - len, 0) <= 0)
return 0;
ctx->iv_gen = 1;
ctx->iv_state = IV_STATE_BUFFERED;
return 1;
}
/*
* Handle TLS GCM packet format. This consists of the last portion of the IV
* followed by the payload and finally the tag. On encrypt generate IV,
* encrypt payload and write the tag. On verify retrieve IV, decrypt payload
* and verify tag.
*/
static int gcm_tls_cipher(PROV_GCM_CTX *ctx, unsigned char *out, size_t *padlen,
const unsigned char *in, size_t len)
{
int rv = 0;
size_t arg = EVP_GCM_TLS_EXPLICIT_IV_LEN;
size_t plen = 0;
unsigned char *tag = NULL;
if (!ossl_prov_is_running() || !ctx->key_set)
goto err;
/* Encrypt/decrypt must be performed in place */
if (out != in || len < (EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN))
goto err;
/*
* Check for too many keys as per FIPS 140-2 IG A.5 "Key/IV Pair Uniqueness
* Requirements from SP 800-38D". The requirements is for one party to the
* communication to fail after 2^64 - 1 keys. We do this on the encrypting
* side only.
*/
if (ctx->enc && ++ctx->tls_enc_records == 0) {
ERR_raise(ERR_LIB_PROV, PROV_R_TOO_MANY_RECORDS);
goto err;
}
/*
* Set IV from start of buffer or generate IV and write to start of
* buffer.
*/
if (ctx->enc) {
if (!getivgen(ctx, out, arg))
goto err;
} else {
if (!setivinv(ctx, out, arg))
goto err;
}
/* Fix buffer and length to point to payload */
in += EVP_GCM_TLS_EXPLICIT_IV_LEN;
out += EVP_GCM_TLS_EXPLICIT_IV_LEN;
len -= EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN;
tag = ctx->enc ? out + len : (unsigned char *)in + len;
if (!ctx->hw->oneshot(ctx, ctx->buf, ctx->tls_aad_len, in, len, out, tag,
EVP_GCM_TLS_TAG_LEN)) {
if (!ctx->enc)
OPENSSL_cleanse(out, len);
goto err;
}
if (ctx->enc)
plen = len + EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN;
else
plen = len;
rv = 1;
err:
ctx->iv_state = IV_STATE_FINISHED;
ctx->tls_aad_len = UNINITIALISED_SIZET;
*padlen = plen;
return rv;
}
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