crypto: dh - SP800-56A rev 3 local public key validation

After the generation of a local public key, SP800-56A rev 3 section
5.6.2.1.3 mandates a validation of that key with a full validation
compliant to section 5.6.2.3.1.

Only if the full validation passes, the key is allowed to be used.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Stephan Müller 2020-07-20 19:08:52 +02:00 коммит произвёл Herbert Xu
Родитель 90fa9ae51c
Коммит 2ed5ba61cc
1 изменённых файлов: 33 добавлений и 24 удалений

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@ -180,32 +180,41 @@ static int dh_compute_value(struct kpp_request *req)
if (ret)
goto err_free_base;
/* SP800-56A rev3 5.7.1.1 check: Validation of shared secret */
if (fips_enabled && req->src) {
MPI pone;
if (fips_enabled) {
/* SP800-56A rev3 5.7.1.1 check: Validation of shared secret */
if (req->src) {
MPI pone;
/* z <= 1 */
if (mpi_cmp_ui(val, 1) < 1) {
ret = -EBADMSG;
goto err_free_base;
/* z <= 1 */
if (mpi_cmp_ui(val, 1) < 1) {
ret = -EBADMSG;
goto err_free_base;
}
/* z == p - 1 */
pone = mpi_alloc(0);
if (!pone) {
ret = -ENOMEM;
goto err_free_base;
}
ret = mpi_sub_ui(pone, ctx->p, 1);
if (!ret && !mpi_cmp(pone, val))
ret = -EBADMSG;
mpi_free(pone);
if (ret)
goto err_free_base;
/* SP800-56A rev 3 5.6.2.1.3 key check */
} else {
if (dh_is_pubkey_valid(ctx, val)) {
ret = -EAGAIN;
goto err_free_val;
}
}
/* z == p - 1 */
pone = mpi_alloc(0);
if (!pone) {
ret = -ENOMEM;
goto err_free_base;
}
ret = mpi_sub_ui(pone, ctx->p, 1);
if (!ret && !mpi_cmp(pone, val))
ret = -EBADMSG;
mpi_free(pone);
if (ret)
goto err_free_base;
}
ret = mpi_write_to_sgl(val, req->dst, req->dst_len, &sign);