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mbedtls/library/pkparse.c
Valerio Setti fbbafa0d2d pkparse: do not set key algorithm for Montgomery keys in pk_ecc_set_key() 
Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
2023-12-06 10:07:34 +01:00

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/*
* Public Key layer for parsing key files and structures
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#include "common.h"
#if defined(MBEDTLS_PK_PARSE_C)
#include "mbedtls/pk.h"
#include "mbedtls/asn1.h"
#include "mbedtls/oid.h"
#include "mbedtls/platform_util.h"
#include "mbedtls/platform.h"
#include "mbedtls/error.h"
#include <string.h>
#if defined(MBEDTLS_USE_PSA_CRYPTO)
#include "mbedtls/psa_util.h"
#include "psa/crypto.h"
#endif
/* Key types */
#if defined(MBEDTLS_RSA_C)
#include "mbedtls/rsa.h"
#endif
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
#include "mbedtls/ecp.h"
#include "pk_internal.h"
#endif
/* Extended formats */
#if defined(MBEDTLS_PEM_PARSE_C)
#include "mbedtls/pem.h"
#endif
#if defined(MBEDTLS_PKCS5_C)
#include "mbedtls/pkcs5.h"
#endif
#if defined(MBEDTLS_PKCS12_C)
#include "mbedtls/pkcs12.h"
#endif
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
/***********************************************************************
*
* ECC setters
*
* 1. This is an abstraction layer around MBEDTLS_PK_USE_PSA_EC_DATA:
* this macro will not appear outside this section.
* 2. All inputs are raw: no metadata, no ASN.1 until the next section.
*
**********************************************************************/
/*
* Set the group used by this key.
*
* [in/out] pk: in: must have been pk_setup() to an ECC type
* out: will have group (curve) information set
* [in] grp_in: a supported group ID (not NONE)
*/
static int pk_ecc_set_group(mbedtls_pk_context *pk, mbedtls_ecp_group_id grp_id)
{
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
size_t ec_bits;
psa_ecc_family_t ec_family = mbedtls_ecc_group_to_psa(grp_id, &ec_bits);
/* group may already be initialized; if so, make sure IDs match */
if ((pk->ec_family != 0 && pk->ec_family != ec_family) ||
(pk->ec_bits != 0 && pk->ec_bits != ec_bits)) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
/* set group */
pk->ec_family = ec_family;
pk->ec_bits = ec_bits;
return 0;
#else /* MBEDTLS_PK_USE_PSA_EC_DATA */
mbedtls_ecp_keypair *ecp = mbedtls_pk_ec_rw(*pk);
/* grp may already be initialized; if so, make sure IDs match */
if (mbedtls_pk_ec_ro(*pk)->grp.id != MBEDTLS_ECP_DP_NONE &&
mbedtls_pk_ec_ro(*pk)->grp.id != grp_id) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
/* set group */
return mbedtls_ecp_group_load(&(ecp->grp), grp_id);
#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
}
/*
* Set the private key material
*
* [in/out] pk: in: must have the group set already, see pk_ecc_set_group().
* out: will have the private key set.
* [in] key, key_len: the raw private key (no ASN.1 wrapping).
*/
static int pk_ecc_set_key(mbedtls_pk_context *pk,
unsigned char *key, size_t key_len)
{
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
psa_key_usage_t flags;
psa_status_t status;
psa_set_key_type(&attributes, PSA_KEY_TYPE_ECC_KEY_PAIR(pk->ec_family));
if (pk->ec_family == PSA_ECC_FAMILY_MONTGOMERY) {
/* Do not set algorithm here because Montgomery keys cannot do ECDSA and
* the PK module cannot do ECDH. When the key will be used in TLS for
* ECDH, it will be exported and then re-imported with proper flags
* and algorithm. */
flags = PSA_KEY_USAGE_EXPORT;
} else {
psa_set_key_algorithm(&attributes,
MBEDTLS_PK_PSA_ALG_ECDSA_MAYBE_DET(PSA_ALG_ANY_HASH));
flags = PSA_KEY_USAGE_SIGN_HASH | PSA_KEY_USAGE_SIGN_MESSAGE |
PSA_KEY_USAGE_EXPORT;
}
psa_set_key_usage_flags(&attributes, flags);
status = psa_import_key(&attributes, key, key_len, &pk->priv_id);
return psa_pk_status_to_mbedtls(status);
#else /* MBEDTLS_PK_USE_PSA_EC_DATA */
mbedtls_ecp_keypair *eck = mbedtls_pk_ec_rw(*pk);
int ret = mbedtls_ecp_read_key(eck->grp.id, eck, key, key_len);
if (ret != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
return 0;
#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
}
/*
* Derive a public key from its private counterpart.
* Computationally intensive, only use when public key is not available.
*
* [in/out] pk: in: must have the private key set, see pk_ecc_set_key().
* out: will have the public key set.
* [in] prv, prv_len: the raw private key (see note below).
* [in] f_rng, p_rng: RNG function and context.
*
* Note: the private key information is always available from pk,
* however for convenience the serialized version is also passed,
* as it's available at each calling site, and useful in some configs
* (as otherwise we would have to re-serialize it from the pk context).
*
* There are three implementations of this function:
* 1. MBEDTLS_PK_USE_PSA_EC_DATA,
* 2. MBEDTLS_USE_PSA_CRYPTO but not MBEDTLS_PK_USE_PSA_EC_DATA,
* 3. not MBEDTLS_USE_PSA_CRYPTO.
*/
static int pk_ecc_set_pubkey_from_prv(mbedtls_pk_context *pk,
const unsigned char *prv, size_t prv_len,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
(void) f_rng;
(void) p_rng;
(void) prv;
(void) prv_len;
psa_status_t status;
status = psa_export_public_key(pk->priv_id, pk->pub_raw, sizeof(pk->pub_raw),
&pk->pub_raw_len);
return psa_pk_status_to_mbedtls(status);
#elif defined(MBEDTLS_USE_PSA_CRYPTO) /* && !MBEDTLS_PK_USE_PSA_EC_DATA */
(void) f_rng;
(void) p_rng;
psa_status_t status;
mbedtls_ecp_keypair *eck = (mbedtls_ecp_keypair *) pk->pk_ctx;
size_t curve_bits;
psa_ecc_family_t curve = mbedtls_ecc_group_to_psa(eck->grp.id, &curve_bits);
/* Import private key into PSA, from serialized input */
mbedtls_svc_key_id_t key_id = MBEDTLS_SVC_KEY_ID_INIT;
psa_key_attributes_t key_attr = PSA_KEY_ATTRIBUTES_INIT;
psa_set_key_type(&key_attr, PSA_KEY_TYPE_ECC_KEY_PAIR(curve));
psa_set_key_usage_flags(&key_attr, PSA_KEY_USAGE_EXPORT);
status = psa_import_key(&key_attr, prv, prv_len, &key_id);
if (status != PSA_SUCCESS) {
return psa_pk_status_to_mbedtls(status);
}
/* Export public key from PSA */
unsigned char pub[MBEDTLS_PSA_MAX_EC_PUBKEY_LENGTH];
size_t pub_len;
status = psa_export_public_key(key_id, pub, sizeof(pub), &pub_len);
psa_status_t destruction_status = psa_destroy_key(key_id);
if (status != PSA_SUCCESS) {
return psa_pk_status_to_mbedtls(status);
} else if (destruction_status != PSA_SUCCESS) {
return psa_pk_status_to_mbedtls(destruction_status);
}
/* Load serialized public key into ecp_keypair structure */
return mbedtls_ecp_point_read_binary(&eck->grp, &eck->Q, pub, pub_len);
#else /* MBEDTLS_USE_PSA_CRYPTO */
(void) prv;
(void) prv_len;
mbedtls_ecp_keypair *eck = (mbedtls_ecp_keypair *) pk->pk_ctx;
return mbedtls_ecp_mul(&eck->grp, &eck->Q, &eck->d, &eck->grp.G, f_rng, p_rng);
#endif /* MBEDTLS_USE_PSA_CRYPTO */
}
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
/*
* Set the public key: fallback using ECP_LIGHT in the USE_PSA_EC_DATA case.
*
* Normally, when MBEDTLS_PK_USE_PSA_EC_DATA is enabled, we only use PSA
* functions to handle keys. However, currently psa_import_key() does not
* support compressed points. In case that support was explicitly requested,
* this fallback uses ECP functions to get the job done. This is the reason
* why MBEDTLS_PK_PARSE_EC_COMPRESSED auto-enables MBEDTLS_ECP_LIGHT.
*
* [in/out] pk: in: must have the group set, see pk_ecc_set_group().
* out: will have the public key set.
* [in] pub, pub_len: the public key as an ECPoint,
* in any format supported by ECP.
*
* Return:
* - 0 on success;
* - MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the format is potentially valid
* but not supported;
* - another error code otherwise.
*/
static int pk_ecc_set_pubkey_psa_ecp_fallback(mbedtls_pk_context *pk,
const unsigned char *pub,
size_t pub_len)
{
#if !defined(MBEDTLS_PK_PARSE_EC_COMPRESSED)
(void) pk;
(void) pub;
(void) pub_len;
return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE;
#else /* MBEDTLS_PK_PARSE_EC_COMPRESSED */
mbedtls_ecp_keypair ecp_key;
mbedtls_ecp_group_id ecp_group_id;
int ret;
ecp_group_id = mbedtls_ecc_group_of_psa(pk->ec_family, pk->ec_bits, 0);
mbedtls_ecp_keypair_init(&ecp_key);
ret = mbedtls_ecp_group_load(&(ecp_key.grp), ecp_group_id);
if (ret != 0) {
goto exit;
}
ret = mbedtls_ecp_point_read_binary(&(ecp_key.grp), &ecp_key.Q,
pub, pub_len);
if (ret != 0) {
goto exit;
}
ret = mbedtls_ecp_point_write_binary(&(ecp_key.grp), &ecp_key.Q,
MBEDTLS_ECP_PF_UNCOMPRESSED,
&pk->pub_raw_len, pk->pub_raw,
sizeof(pk->pub_raw));
exit:
mbedtls_ecp_keypair_free(&ecp_key);
return ret;
#endif /* MBEDTLS_PK_PARSE_EC_COMPRESSED */
}
#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
/*
* Set the public key.
*
* [in/out] pk: in: must have its group set, see pk_ecc_set_group().
* out: will have the public key set.
* [in] pub, pub_len: the raw public key (an ECPoint).
*
* Return:
* - 0 on success;
* - MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE if the format is potentially valid
* but not supported;
* - another error code otherwise.
*/
static int pk_ecc_set_pubkey(mbedtls_pk_context *pk,
const unsigned char *pub, size_t pub_len)
{
#if defined(MBEDTLS_PK_USE_PSA_EC_DATA)
/* Load the key */
if (!PSA_ECC_FAMILY_IS_WEIERSTRASS(pk->ec_family) || *pub == 0x04) {
/* Format directly supported by PSA:
* - non-Weierstrass curves that only have one format;
* - uncompressed format for Weierstrass curves. */
if (pub_len > sizeof(pk->pub_raw)) {
return MBEDTLS_ERR_PK_BUFFER_TOO_SMALL;
}
memcpy(pk->pub_raw, pub, pub_len);
pk->pub_raw_len = pub_len;
} else {
/* Other format, try the fallback */
int ret = pk_ecc_set_pubkey_psa_ecp_fallback(pk, pub, pub_len);
if (ret != 0) {
return ret;
}
}
/* Validate the key by trying to import it */
mbedtls_svc_key_id_t key_id = MBEDTLS_SVC_KEY_ID_INIT;
psa_key_attributes_t key_attrs = PSA_KEY_ATTRIBUTES_INIT;
psa_set_key_usage_flags(&key_attrs, 0);
psa_set_key_type(&key_attrs, PSA_KEY_TYPE_ECC_PUBLIC_KEY(pk->ec_family));
psa_set_key_bits(&key_attrs, pk->ec_bits);
if ((psa_import_key(&key_attrs, pk->pub_raw, pk->pub_raw_len,
&key_id) != PSA_SUCCESS) ||
(psa_destroy_key(key_id) != PSA_SUCCESS)) {
return MBEDTLS_ERR_PK_INVALID_PUBKEY;
}
return 0;
#else /* MBEDTLS_PK_USE_PSA_EC_DATA */
int ret;
mbedtls_ecp_keypair *ec_key = (mbedtls_ecp_keypair *) pk->pk_ctx;
ret = mbedtls_ecp_point_read_binary(&ec_key->grp, &ec_key->Q, pub, pub_len);
if (ret != 0) {
return ret;
}
return mbedtls_ecp_check_pubkey(&ec_key->grp, &ec_key->Q);
#endif /* MBEDTLS_PK_USE_PSA_EC_DATA */
}
/***********************************************************************
*
* Low-level ECC parsing: optional support for SpecifiedECDomain
*
* There are two functions here that are used by the rest of the code:
* - pk_ecc_tag_is_speficied_ec_domain()
* - pk_ecc_group_id_from_specified()
*
* All the other functions are internal to this section.
*
* The two "public" functions have a dummy variant provided
* in configs without MBEDTLS_PK_PARSE_EC_EXTENDED. This acts as an
* abstraction layer for this macro, which should not appear outside
* this section.
*
**********************************************************************/
#if !defined(MBEDTLS_PK_PARSE_EC_EXTENDED)
/* See the "real" version for documentation */
static int pk_ecc_tag_is_specified_ec_domain(int tag)
{
(void) tag;
return 0;
}
/* See the "real" version for documentation */
static int pk_ecc_group_id_from_specified(const mbedtls_asn1_buf *params,
mbedtls_ecp_group_id *grp_id)
{
(void) params;
(void) grp_id;
return MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE;
}
#else /* MBEDTLS_PK_PARSE_EC_EXTENDED */
/*
* Tell if the passed tag might be the start of SpecifiedECDomain
* (that is, a sequence).
*/
static int pk_ecc_tag_is_specified_ec_domain(int tag)
{
return tag == (MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
}
/*
* Parse a SpecifiedECDomain (SEC 1 C.2) and (mostly) fill the group with it.
* WARNING: the resulting group should only be used with
* pk_ecc_group_id_from_specified(), since its base point may not be set correctly
* if it was encoded compressed.
*
* SpecifiedECDomain ::= SEQUENCE {
* version SpecifiedECDomainVersion(ecdpVer1 | ecdpVer2 | ecdpVer3, ...),
* fieldID FieldID {{FieldTypes}},
* curve Curve,
* base ECPoint,
* order INTEGER,
* cofactor INTEGER OPTIONAL,
* hash HashAlgorithm OPTIONAL,
* ...
* }
*
* We only support prime-field as field type, and ignore hash and cofactor.
*/
static int pk_group_from_specified(const mbedtls_asn1_buf *params, mbedtls_ecp_group *grp)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *p = params->p;
const unsigned char *const end = params->p + params->len;
const unsigned char *end_field, *end_curve;
size_t len;
int ver;
/* SpecifiedECDomainVersion ::= INTEGER { 1, 2, 3 } */
if ((ret = mbedtls_asn1_get_int(&p, end, &ver)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
if (ver < 1 || ver > 3) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
/*
* FieldID { FIELD-ID:IOSet } ::= SEQUENCE { -- Finite field
* fieldType FIELD-ID.&id({IOSet}),
* parameters FIELD-ID.&Type({IOSet}{@fieldType})
* }
*/
if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
return ret;
}
end_field = p + len;
/*
* FIELD-ID ::= TYPE-IDENTIFIER
* FieldTypes FIELD-ID ::= {
* { Prime-p IDENTIFIED BY prime-field } |
* { Characteristic-two IDENTIFIED BY characteristic-two-field }
* }
* prime-field OBJECT IDENTIFIER ::= { id-fieldType 1 }
*/
if ((ret = mbedtls_asn1_get_tag(&p, end_field, &len, MBEDTLS_ASN1_OID)) != 0) {
return ret;
}
if (len != MBEDTLS_OID_SIZE(MBEDTLS_OID_ANSI_X9_62_PRIME_FIELD) ||
memcmp(p, MBEDTLS_OID_ANSI_X9_62_PRIME_FIELD, len) != 0) {
return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
}
p += len;
/* Prime-p ::= INTEGER -- Field of size p. */
if ((ret = mbedtls_asn1_get_mpi(&p, end_field, &grp->P)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
grp->pbits = mbedtls_mpi_bitlen(&grp->P);
if (p != end_field) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
/*
* Curve ::= SEQUENCE {
* a FieldElement,
* b FieldElement,
* seed BIT STRING OPTIONAL
* -- Shall be present if used in SpecifiedECDomain
* -- with version equal to ecdpVer2 or ecdpVer3
* }
*/
if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
return ret;
}
end_curve = p + len;
/*
* FieldElement ::= OCTET STRING
* containing an integer in the case of a prime field
*/
if ((ret = mbedtls_asn1_get_tag(&p, end_curve, &len, MBEDTLS_ASN1_OCTET_STRING)) != 0 ||
(ret = mbedtls_mpi_read_binary(&grp->A, p, len)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
p += len;
if ((ret = mbedtls_asn1_get_tag(&p, end_curve, &len, MBEDTLS_ASN1_OCTET_STRING)) != 0 ||
(ret = mbedtls_mpi_read_binary(&grp->B, p, len)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
p += len;
/* Ignore seed BIT STRING OPTIONAL */
if ((ret = mbedtls_asn1_get_tag(&p, end_curve, &len, MBEDTLS_ASN1_BIT_STRING)) == 0) {
p += len;
}
if (p != end_curve) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
/*
* ECPoint ::= OCTET STRING
*/
if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
if ((ret = mbedtls_ecp_point_read_binary(grp, &grp->G,
(const unsigned char *) p, len)) != 0) {
/*
* If we can't read the point because it's compressed, cheat by
* reading only the X coordinate and the parity bit of Y.
*/
if (ret != MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE ||
(p[0] != 0x02 && p[0] != 0x03) ||
len != mbedtls_mpi_size(&grp->P) + 1 ||
mbedtls_mpi_read_binary(&grp->G.X, p + 1, len - 1) != 0 ||
mbedtls_mpi_lset(&grp->G.Y, p[0] - 2) != 0 ||
mbedtls_mpi_lset(&grp->G.Z, 1) != 0) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
}
p += len;
/*
* order INTEGER
*/
if ((ret = mbedtls_asn1_get_mpi(&p, end, &grp->N)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
grp->nbits = mbedtls_mpi_bitlen(&grp->N);
/*
* Allow optional elements by purposefully not enforcing p == end here.
*/
return 0;
}
/*
* Find the group id associated with an (almost filled) group as generated by
* pk_group_from_specified(), or return an error if unknown.
*/
static int pk_group_id_from_group(const mbedtls_ecp_group *grp, mbedtls_ecp_group_id *grp_id)
{
int ret = 0;
mbedtls_ecp_group ref;
const mbedtls_ecp_group_id *id;
mbedtls_ecp_group_init(&ref);
for (id = mbedtls_ecp_grp_id_list(); *id != MBEDTLS_ECP_DP_NONE; id++) {
/* Load the group associated to that id */
mbedtls_ecp_group_free(&ref);
MBEDTLS_MPI_CHK(mbedtls_ecp_group_load(&ref, *id));
/* Compare to the group we were given, starting with easy tests */
if (grp->pbits == ref.pbits && grp->nbits == ref.nbits &&
mbedtls_mpi_cmp_mpi(&grp->P, &ref.P) == 0 &&
mbedtls_mpi_cmp_mpi(&grp->A, &ref.A) == 0 &&
mbedtls_mpi_cmp_mpi(&grp->B, &ref.B) == 0 &&
mbedtls_mpi_cmp_mpi(&grp->N, &ref.N) == 0 &&
mbedtls_mpi_cmp_mpi(&grp->G.X, &ref.G.X) == 0 &&
mbedtls_mpi_cmp_mpi(&grp->G.Z, &ref.G.Z) == 0 &&
/* For Y we may only know the parity bit, so compare only that */
mbedtls_mpi_get_bit(&grp->G.Y, 0) == mbedtls_mpi_get_bit(&ref.G.Y, 0)) {
break;
}
}
cleanup:
mbedtls_ecp_group_free(&ref);
*grp_id = *id;
if (ret == 0 && *id == MBEDTLS_ECP_DP_NONE) {
ret = MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE;
}
return ret;
}
/*
* Parse a SpecifiedECDomain (SEC 1 C.2) and find the associated group ID
*/
static int pk_ecc_group_id_from_specified(const mbedtls_asn1_buf *params,
mbedtls_ecp_group_id *grp_id)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_ecp_group grp;
mbedtls_ecp_group_init(&grp);
if ((ret = pk_group_from_specified(params, &grp)) != 0) {
goto cleanup;
}
ret = pk_group_id_from_group(&grp, grp_id);
cleanup:
/* The API respecting lifecycle for mbedtls_ecp_group struct is
* _init(), _load() and _free(). In pk_ecc_group_id_from_specified() the
* temporary grp breaks that flow and it's members are populated
* by pk_group_id_from_group(). As such mbedtls_ecp_group_free()
* which is assuming a group populated by _setup() may not clean-up
* properly -> Manually free it's members.
*/
mbedtls_mpi_free(&grp.N);
mbedtls_mpi_free(&grp.P);
mbedtls_mpi_free(&grp.A);
mbedtls_mpi_free(&grp.B);
mbedtls_ecp_point_free(&grp.G);
return ret;
}
#endif /* MBEDTLS_PK_PARSE_EC_EXTENDED */
/***********************************************************************
*
* Unsorted (yet!) from this point on until the next section header
*
**********************************************************************/
/* Minimally parse an ECParameters buffer to and mbedtls_asn1_buf
*
* ECParameters ::= CHOICE {
* namedCurve OBJECT IDENTIFIER
* specifiedCurve SpecifiedECDomain -- = SEQUENCE { ... }
* -- implicitCurve NULL
* }
*/
static int pk_get_ecparams(unsigned char **p, const unsigned char *end,
mbedtls_asn1_buf *params)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
if (end - *p < 1) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT,
MBEDTLS_ERR_ASN1_OUT_OF_DATA);
}
/* Acceptable tags: OID for namedCurve, or specifiedECDomain */
params->tag = **p;
if (params->tag != MBEDTLS_ASN1_OID &&
!pk_ecc_tag_is_specified_ec_domain(params->tag)) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT,
MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);
}
if ((ret = mbedtls_asn1_get_tag(p, end, &params->len, params->tag)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
params->p = *p;
*p += params->len;
if (*p != end) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
return 0;
}
/*
* Use EC parameters to initialise an EC group
*
* ECParameters ::= CHOICE {
* namedCurve OBJECT IDENTIFIER
* specifiedCurve SpecifiedECDomain -- = SEQUENCE { ... }
* -- implicitCurve NULL
*/
static int pk_use_ecparams(const mbedtls_asn1_buf *params, mbedtls_pk_context *pk)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_ecp_group_id grp_id;
if (params->tag == MBEDTLS_ASN1_OID) {
if (mbedtls_oid_get_ec_grp(params, &grp_id) != 0) {
return MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE;
}
} else {
ret = pk_ecc_group_id_from_specified(params, &grp_id);
if (ret != 0) {
return ret;
}
}
return pk_ecc_set_group(pk, grp_id);
}
#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
/*
* Load an RFC8410 EC key, which doesn't have any parameters
*/
static int pk_use_ecparams_rfc8410(const mbedtls_asn1_buf *params,
mbedtls_ecp_group_id grp_id,
mbedtls_pk_context *pk)
{
if (params->tag != 0 || params->len != 0) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
return pk_ecc_set_group(pk, grp_id);
}
/*
* Parse an RFC 8410 encoded private EC key
*
* CurvePrivateKey ::= OCTET STRING
*/
static int pk_parse_key_rfc8410_der(mbedtls_pk_context *pk,
unsigned char *key, size_t keylen, const unsigned char *end,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len;
if ((ret = mbedtls_asn1_get_tag(&key, (key + keylen), &len, MBEDTLS_ASN1_OCTET_STRING)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
if (key + len != end) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
/*
* Load the private key
*/
ret = pk_ecc_set_key(pk, key, len);
if (ret != 0) {
return ret;
}
/* pk_parse_key_pkcs8_unencrypted_der() only supports version 1 PKCS8 keys,
* which never contain a public key. As such, derive the public key
* unconditionally. */
if ((ret = pk_ecc_set_pubkey_from_prv(pk, key, len, f_rng, p_rng)) != 0) {
return ret;
}
return 0;
}
#endif /* MBEDTLS_PK_HAVE_RFC8410_CURVES */
#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
#if defined(MBEDTLS_RSA_C)
/*
* RSAPublicKey ::= SEQUENCE {
* modulus INTEGER, -- n
* publicExponent INTEGER -- e
* }
*/
static int pk_get_rsapubkey(unsigned char **p,
const unsigned char *end,
mbedtls_rsa_context *rsa)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len;
if ((ret = mbedtls_asn1_get_tag(p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_PUBKEY, ret);
}
if (*p + len != end) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_PUBKEY,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
/* Import N */
if ((ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_PUBKEY, ret);
}
if ((ret = mbedtls_rsa_import_raw(rsa, *p, len, NULL, 0, NULL, 0,
NULL, 0, NULL, 0)) != 0) {
return MBEDTLS_ERR_PK_INVALID_PUBKEY;
}
*p += len;
/* Import E */
if ((ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_PUBKEY, ret);
}
if ((ret = mbedtls_rsa_import_raw(rsa, NULL, 0, NULL, 0, NULL, 0,
NULL, 0, *p, len)) != 0) {
return MBEDTLS_ERR_PK_INVALID_PUBKEY;
}
*p += len;
if (mbedtls_rsa_complete(rsa) != 0 ||
mbedtls_rsa_check_pubkey(rsa) != 0) {
return MBEDTLS_ERR_PK_INVALID_PUBKEY;
}
if (*p != end) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_PUBKEY,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
return 0;
}
#endif /* MBEDTLS_RSA_C */
/* Get a PK algorithm identifier
*
* AlgorithmIdentifier ::= SEQUENCE {
* algorithm OBJECT IDENTIFIER,
* parameters ANY DEFINED BY algorithm OPTIONAL }
*/
static int pk_get_pk_alg(unsigned char **p,
const unsigned char *end,
mbedtls_pk_type_t *pk_alg, mbedtls_asn1_buf *params,
mbedtls_ecp_group_id *ec_grp_id)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_asn1_buf alg_oid;
memset(params, 0, sizeof(mbedtls_asn1_buf));
if ((ret = mbedtls_asn1_get_alg(p, end, &alg_oid, params)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_ALG, ret);
}
ret = mbedtls_oid_get_pk_alg(&alg_oid, pk_alg);
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
if (ret == MBEDTLS_ERR_OID_NOT_FOUND) {
ret = mbedtls_oid_get_ec_grp_algid(&alg_oid, ec_grp_id);
if (ret == 0) {
*pk_alg = MBEDTLS_PK_ECKEY;
}
}
#else
(void) ec_grp_id;
#endif
if (ret != 0) {
return MBEDTLS_ERR_PK_UNKNOWN_PK_ALG;
}
/*
* No parameters with RSA (only for EC)
*/
if (*pk_alg == MBEDTLS_PK_RSA &&
((params->tag != MBEDTLS_ASN1_NULL && params->tag != 0) ||
params->len != 0)) {
return MBEDTLS_ERR_PK_INVALID_ALG;
}
return 0;
}
/* Helper for Montgomery curves */
#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
#define MBEDTLS_PK_IS_RFC8410_GROUP_ID(id) \
((id == MBEDTLS_ECP_DP_CURVE25519) || (id == MBEDTLS_ECP_DP_CURVE448))
#endif /* MBEDTLS_PK_HAVE_RFC8410_CURVES */
/*
* SubjectPublicKeyInfo ::= SEQUENCE {
* algorithm AlgorithmIdentifier,
* subjectPublicKey BIT STRING }
*/
int mbedtls_pk_parse_subpubkey(unsigned char **p, const unsigned char *end,
mbedtls_pk_context *pk)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len;
mbedtls_asn1_buf alg_params;
mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE;
mbedtls_ecp_group_id ec_grp_id = MBEDTLS_ECP_DP_NONE;
const mbedtls_pk_info_t *pk_info;
if ((ret = mbedtls_asn1_get_tag(p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
end = *p + len;
if ((ret = pk_get_pk_alg(p, end, &pk_alg, &alg_params, &ec_grp_id)) != 0) {
return ret;
}
if ((ret = mbedtls_asn1_get_bitstring_null(p, end, &len)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_PUBKEY, ret);
}
if (*p + len != end) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_PUBKEY,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
if ((pk_info = mbedtls_pk_info_from_type(pk_alg)) == NULL) {
return MBEDTLS_ERR_PK_UNKNOWN_PK_ALG;
}
if ((ret = mbedtls_pk_setup(pk, pk_info)) != 0) {
return ret;
}
#if defined(MBEDTLS_RSA_C)
if (pk_alg == MBEDTLS_PK_RSA) {
ret = pk_get_rsapubkey(p, end, mbedtls_pk_rsa(*pk));
} else
#endif /* MBEDTLS_RSA_C */
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
if (pk_alg == MBEDTLS_PK_ECKEY_DH || pk_alg == MBEDTLS_PK_ECKEY) {
#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
if (MBEDTLS_PK_IS_RFC8410_GROUP_ID(ec_grp_id)) {
ret = pk_use_ecparams_rfc8410(&alg_params, ec_grp_id, pk);
} else
#endif
{
ret = pk_use_ecparams(&alg_params, pk);
}
if (ret == 0) {
ret = pk_ecc_set_pubkey(pk, *p, (size_t) (end - *p));
*p += end - *p;
}
} else
#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
ret = MBEDTLS_ERR_PK_UNKNOWN_PK_ALG;
if (ret == 0 && *p != end) {
ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_PUBKEY,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
if (ret != 0) {
mbedtls_pk_free(pk);
}
return ret;
}
#if defined(MBEDTLS_RSA_C)
/*
* Wrapper around mbedtls_asn1_get_mpi() that rejects zero.
*
* The value zero is:
* - never a valid value for an RSA parameter
* - interpreted as "omitted, please reconstruct" by mbedtls_rsa_complete().
*
* Since values can't be omitted in PKCS#1, passing a zero value to
* rsa_complete() would be incorrect, so reject zero values early.
*/
static int asn1_get_nonzero_mpi(unsigned char **p,
const unsigned char *end,
mbedtls_mpi *X)
{
int ret;
ret = mbedtls_asn1_get_mpi(p, end, X);
if (ret != 0) {
return ret;
}
if (mbedtls_mpi_cmp_int(X, 0) == 0) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
return 0;
}
/*
* Parse a PKCS#1 encoded private RSA key
*/
static int pk_parse_key_pkcs1_der(mbedtls_rsa_context *rsa,
const unsigned char *key,
size_t keylen)
{
int ret, version;
size_t len;
unsigned char *p, *end;
mbedtls_mpi T;
mbedtls_mpi_init(&T);
p = (unsigned char *) key;
end = p + keylen;
/*
* This function parses the RSAPrivateKey (PKCS#1)
*
* RSAPrivateKey ::= SEQUENCE {
* version Version,
* modulus INTEGER, -- n
* publicExponent INTEGER, -- e
* privateExponent INTEGER, -- d
* prime1 INTEGER, -- p
* prime2 INTEGER, -- q
* exponent1 INTEGER, -- d mod (p-1)
* exponent2 INTEGER, -- d mod (q-1)
* coefficient INTEGER, -- (inverse of q) mod p
* otherPrimeInfos OtherPrimeInfos OPTIONAL
* }
*/
if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
end = p + len;
if ((ret = mbedtls_asn1_get_int(&p, end, &version)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
if (version != 0) {
return MBEDTLS_ERR_PK_KEY_INVALID_VERSION;
}
/* Import N */
if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
(ret = mbedtls_rsa_import(rsa, &T, NULL, NULL,
NULL, NULL)) != 0) {
goto cleanup;
}
/* Import E */
if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
(ret = mbedtls_rsa_import(rsa, NULL, NULL, NULL,
NULL, &T)) != 0) {
goto cleanup;
}
/* Import D */
if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
(ret = mbedtls_rsa_import(rsa, NULL, NULL, NULL,
&T, NULL)) != 0) {
goto cleanup;
}
/* Import P */
if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
(ret = mbedtls_rsa_import(rsa, NULL, &T, NULL,
NULL, NULL)) != 0) {
goto cleanup;
}
/* Import Q */
if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
(ret = mbedtls_rsa_import(rsa, NULL, NULL, &T,
NULL, NULL)) != 0) {
goto cleanup;
}
#if !defined(MBEDTLS_RSA_NO_CRT) && !defined(MBEDTLS_RSA_ALT)
/*
* The RSA CRT parameters DP, DQ and QP are nominally redundant, in
* that they can be easily recomputed from D, P and Q. However by
* parsing them from the PKCS1 structure it is possible to avoid
* recalculating them which both reduces the overhead of loading
* RSA private keys into memory and also avoids side channels which
* can arise when computing those values, since all of D, P, and Q
* are secret. See https://eprint.iacr.org/2020/055 for a
* description of one such attack.
*/
/* Import DP */
if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
(ret = mbedtls_mpi_copy(&rsa->DP, &T)) != 0) {
goto cleanup;
}
/* Import DQ */
if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
(ret = mbedtls_mpi_copy(&rsa->DQ, &T)) != 0) {
goto cleanup;
}
/* Import QP */
if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
(ret = mbedtls_mpi_copy(&rsa->QP, &T)) != 0) {
goto cleanup;
}
#else
/* Verify existence of the CRT params */
if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
(ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 ||
(ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0) {
goto cleanup;
}
#endif
/* rsa_complete() doesn't complete anything with the default
* implementation but is still called:
* - for the benefit of alternative implementation that may want to
* pre-compute stuff beyond what's provided (eg Montgomery factors)
* - as is also sanity-checks the key
*
* Furthermore, we also check the public part for consistency with
* mbedtls_pk_parse_pubkey(), as it includes size minima for example.
*/
if ((ret = mbedtls_rsa_complete(rsa)) != 0 ||
(ret = mbedtls_rsa_check_pubkey(rsa)) != 0) {
goto cleanup;
}
if (p != end) {
ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
cleanup:
mbedtls_mpi_free(&T);
if (ret != 0) {
/* Wrap error code if it's coming from a lower level */
if ((ret & 0xff80) == 0) {
ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
} else {
ret = MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
mbedtls_rsa_free(rsa);
}
return ret;
}
#endif /* MBEDTLS_RSA_C */
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
/*
* Parse a SEC1 encoded private EC key
*/
static int pk_parse_key_sec1_der(mbedtls_pk_context *pk,
const unsigned char *key, size_t keylen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
int version, pubkey_done;
size_t len, d_len;
mbedtls_asn1_buf params = { 0, 0, NULL };
unsigned char *p = (unsigned char *) key;
unsigned char *d;
unsigned char *end = p + keylen;
unsigned char *end2;
/*
* RFC 5915, or SEC1 Appendix C.4
*
* ECPrivateKey ::= SEQUENCE {
* version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
* privateKey OCTET STRING,
* parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
* publicKey [1] BIT STRING OPTIONAL
* }
*/
if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
end = p + len;
if ((ret = mbedtls_asn1_get_int(&p, end, &version)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
if (version != 1) {
return MBEDTLS_ERR_PK_KEY_INVALID_VERSION;
}
if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
/* Keep a reference to the position fo the private key. It will be used
* later in this function. */
d = p;
d_len = len;
p += len;
pubkey_done = 0;
if (p != end) {
/*
* Is 'parameters' present?
*/
if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED |
0)) == 0) {
if ((ret = pk_get_ecparams(&p, p + len, &params)) != 0 ||
(ret = pk_use_ecparams(&params, pk)) != 0) {
return ret;
}
} else if (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
}
/*
* Load the private key
*/
ret = pk_ecc_set_key(pk, d, d_len);
if (ret != 0) {
return ret;
}
if (p != end) {
/*
* Is 'publickey' present? If not, or if we can't read it (eg because it
* is compressed), create it from the private key.
*/
if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED |
1)) == 0) {
end2 = p + len;
if ((ret = mbedtls_asn1_get_bitstring_null(&p, end2, &len)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
if (p + len != end2) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
if ((ret = pk_ecc_set_pubkey(pk, p, (size_t) (end2 - p))) == 0) {
pubkey_done = 1;
} else {
/*
* The only acceptable failure mode of pk_ecc_set_pubkey() above
* is if the point format is not recognized.
*/
if (ret != MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
}
} else if (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
}
if (!pubkey_done) {
if ((ret = pk_ecc_set_pubkey_from_prv(pk, d, d_len, f_rng, p_rng)) != 0) {
return ret;
}
}
return 0;
}
#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
/***********************************************************************
*
* PKCS#8 parsing functions
*
**********************************************************************/
/*
* Parse an unencrypted PKCS#8 encoded private key
*
* Notes:
*
* - This function does not own the key buffer. It is the
* responsibility of the caller to take care of zeroizing
* and freeing it after use.
*
* - The function is responsible for freeing the provided
* PK context on failure.
*
*/
static int pk_parse_key_pkcs8_unencrypted_der(
mbedtls_pk_context *pk,
const unsigned char *key, size_t keylen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
int ret, version;
size_t len;
mbedtls_asn1_buf params;
unsigned char *p = (unsigned char *) key;
unsigned char *end = p + keylen;
mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE;
mbedtls_ecp_group_id ec_grp_id = MBEDTLS_ECP_DP_NONE;
const mbedtls_pk_info_t *pk_info;
#if !defined(MBEDTLS_PK_HAVE_ECC_KEYS)
(void) f_rng;
(void) p_rng;
#endif
/*
* This function parses the PrivateKeyInfo object (PKCS#8 v1.2 = RFC 5208)
*
* PrivateKeyInfo ::= SEQUENCE {
* version Version,
* privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
* privateKey PrivateKey,
* attributes [0] IMPLICIT Attributes OPTIONAL }
*
* Version ::= INTEGER
* PrivateKeyAlgorithmIdentifier ::= AlgorithmIdentifier
* PrivateKey ::= OCTET STRING
*
* The PrivateKey OCTET STRING is a SEC1 ECPrivateKey
*/
if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
end = p + len;
if ((ret = mbedtls_asn1_get_int(&p, end, &version)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
if (version != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_VERSION, ret);
}
if ((ret = pk_get_pk_alg(&p, end, &pk_alg, &params, &ec_grp_id)) != 0) {
return ret;
}
if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
if (len < 1) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT,
MBEDTLS_ERR_ASN1_OUT_OF_DATA);
}
if ((pk_info = mbedtls_pk_info_from_type(pk_alg)) == NULL) {
return MBEDTLS_ERR_PK_UNKNOWN_PK_ALG;
}
if ((ret = mbedtls_pk_setup(pk, pk_info)) != 0) {
return ret;
}
#if defined(MBEDTLS_RSA_C)
if (pk_alg == MBEDTLS_PK_RSA) {
if ((ret = pk_parse_key_pkcs1_der(mbedtls_pk_rsa(*pk), p, len)) != 0) {
mbedtls_pk_free(pk);
return ret;
}
} else
#endif /* MBEDTLS_RSA_C */
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
if (pk_alg == MBEDTLS_PK_ECKEY || pk_alg == MBEDTLS_PK_ECKEY_DH) {
#if defined(MBEDTLS_PK_HAVE_RFC8410_CURVES)
if (MBEDTLS_PK_IS_RFC8410_GROUP_ID(ec_grp_id)) {
if ((ret =
pk_use_ecparams_rfc8410(&params, ec_grp_id, pk)) != 0 ||
(ret =
pk_parse_key_rfc8410_der(pk, p, len, end, f_rng,
p_rng)) != 0) {
mbedtls_pk_free(pk);
return ret;
}
} else
#endif
{
if ((ret = pk_use_ecparams(&params, pk)) != 0 ||
(ret = pk_parse_key_sec1_der(pk, p, len, f_rng, p_rng)) != 0) {
mbedtls_pk_free(pk);
return ret;
}
}
} else
#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
return MBEDTLS_ERR_PK_UNKNOWN_PK_ALG;
end = p + len;
if (end != (key + keylen)) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
}
return 0;
}
/*
* Parse an encrypted PKCS#8 encoded private key
*
* To save space, the decryption happens in-place on the given key buffer.
* Also, while this function may modify the keybuffer, it doesn't own it,
* and instead it is the responsibility of the caller to zeroize and properly
* free it after use.
*
*/
#if defined(MBEDTLS_PKCS12_C) || defined(MBEDTLS_PKCS5_C)
MBEDTLS_STATIC_TESTABLE int mbedtls_pk_parse_key_pkcs8_encrypted_der(
mbedtls_pk_context *pk,
unsigned char *key, size_t keylen,
const unsigned char *pwd, size_t pwdlen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
int ret, decrypted = 0;
size_t len;
unsigned char *buf;
unsigned char *p, *end;
mbedtls_asn1_buf pbe_alg_oid, pbe_params;
#if defined(MBEDTLS_PKCS12_C) && defined(MBEDTLS_CIPHER_PADDING_PKCS7)
mbedtls_cipher_type_t cipher_alg;
mbedtls_md_type_t md_alg;
#endif
size_t outlen = 0;
p = key;
end = p + keylen;
if (pwdlen == 0) {
return MBEDTLS_ERR_PK_PASSWORD_REQUIRED;
}
/*
* This function parses the EncryptedPrivateKeyInfo object (PKCS#8)
*
* EncryptedPrivateKeyInfo ::= SEQUENCE {
* encryptionAlgorithm EncryptionAlgorithmIdentifier,
* encryptedData EncryptedData
* }
*
* EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier
*
* EncryptedData ::= OCTET STRING
*
* The EncryptedData OCTET STRING is a PKCS#8 PrivateKeyInfo
*
*/
if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
end = p + len;
if ((ret = mbedtls_asn1_get_alg(&p, end, &pbe_alg_oid, &pbe_params)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING)) != 0) {
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_KEY_INVALID_FORMAT, ret);
}
buf = p;
/*
* Decrypt EncryptedData with appropriate PBE
*/
#if defined(MBEDTLS_PKCS12_C) && defined(MBEDTLS_CIPHER_PADDING_PKCS7)
if (mbedtls_oid_get_pkcs12_pbe_alg(&pbe_alg_oid, &md_alg, &cipher_alg) == 0) {
if ((ret = mbedtls_pkcs12_pbe_ext(&pbe_params, MBEDTLS_PKCS12_PBE_DECRYPT,
cipher_alg, md_alg,
pwd, pwdlen, p, len, buf, len, &outlen)) != 0) {
if (ret == MBEDTLS_ERR_PKCS12_PASSWORD_MISMATCH) {
return MBEDTLS_ERR_PK_PASSWORD_MISMATCH;
}
return ret;
}
decrypted = 1;
} else
#endif /* MBEDTLS_PKCS12_C */
#if defined(MBEDTLS_PKCS5_C) && defined(MBEDTLS_CIPHER_PADDING_PKCS7)
if (MBEDTLS_OID_CMP(MBEDTLS_OID_PKCS5_PBES2, &pbe_alg_oid) == 0) {
if ((ret = mbedtls_pkcs5_pbes2_ext(&pbe_params, MBEDTLS_PKCS5_DECRYPT, pwd, pwdlen,
p, len, buf, len, &outlen)) != 0) {
if (ret == MBEDTLS_ERR_PKCS5_PASSWORD_MISMATCH) {
return MBEDTLS_ERR_PK_PASSWORD_MISMATCH;
}
return ret;
}
decrypted = 1;
} else
#endif /* MBEDTLS_PKCS5_C */
{
((void) pwd);
}
if (decrypted == 0) {
return MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE;
}
return pk_parse_key_pkcs8_unencrypted_der(pk, buf, outlen, f_rng, p_rng);
}
#endif /* MBEDTLS_PKCS12_C || MBEDTLS_PKCS5_C */
/***********************************************************************
*
* Top-level functions, with format auto-discovery
*
**********************************************************************/
/*
* Parse a private key
*/
int mbedtls_pk_parse_key(mbedtls_pk_context *pk,
const unsigned char *key, size_t keylen,
const unsigned char *pwd, size_t pwdlen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
const mbedtls_pk_info_t *pk_info;
#if defined(MBEDTLS_PEM_PARSE_C)
size_t len;
mbedtls_pem_context pem;
#endif
if (keylen == 0) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
#if defined(MBEDTLS_PEM_PARSE_C)
mbedtls_pem_init(&pem);
#if defined(MBEDTLS_RSA_C)
/* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
if (key[keylen - 1] != '\0') {
ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
} else {
ret = mbedtls_pem_read_buffer(&pem,
"-----BEGIN RSA PRIVATE KEY-----",
"-----END RSA PRIVATE KEY-----",
key, pwd, pwdlen, &len);
}
if (ret == 0) {
pk_info = mbedtls_pk_info_from_type(MBEDTLS_PK_RSA);
if ((ret = mbedtls_pk_setup(pk, pk_info)) != 0 ||
(ret = pk_parse_key_pkcs1_der(mbedtls_pk_rsa(*pk),
pem.buf, pem.buflen)) != 0) {
mbedtls_pk_free(pk);
}
mbedtls_pem_free(&pem);
return ret;
} else if (ret == MBEDTLS_ERR_PEM_PASSWORD_MISMATCH) {
return MBEDTLS_ERR_PK_PASSWORD_MISMATCH;
} else if (ret == MBEDTLS_ERR_PEM_PASSWORD_REQUIRED) {
return MBEDTLS_ERR_PK_PASSWORD_REQUIRED;
} else if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {
return ret;
}
#endif /* MBEDTLS_RSA_C */
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
/* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
if (key[keylen - 1] != '\0') {
ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
} else {
ret = mbedtls_pem_read_buffer(&pem,
"-----BEGIN EC PRIVATE KEY-----",
"-----END EC PRIVATE KEY-----",
key, pwd, pwdlen, &len);
}
if (ret == 0) {
pk_info = mbedtls_pk_info_from_type(MBEDTLS_PK_ECKEY);
if ((ret = mbedtls_pk_setup(pk, pk_info)) != 0 ||
(ret = pk_parse_key_sec1_der(pk,
pem.buf, pem.buflen,
f_rng, p_rng)) != 0) {
mbedtls_pk_free(pk);
}
mbedtls_pem_free(&pem);
return ret;
} else if (ret == MBEDTLS_ERR_PEM_PASSWORD_MISMATCH) {
return MBEDTLS_ERR_PK_PASSWORD_MISMATCH;
} else if (ret == MBEDTLS_ERR_PEM_PASSWORD_REQUIRED) {
return MBEDTLS_ERR_PK_PASSWORD_REQUIRED;
} else if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {
return ret;
}
#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
/* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
if (key[keylen - 1] != '\0') {
ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
} else {
ret = mbedtls_pem_read_buffer(&pem,
"-----BEGIN PRIVATE KEY-----",
"-----END PRIVATE KEY-----",
key, NULL, 0, &len);
}
if (ret == 0) {
if ((ret = pk_parse_key_pkcs8_unencrypted_der(pk,
pem.buf, pem.buflen, f_rng, p_rng)) != 0) {
mbedtls_pk_free(pk);
}
mbedtls_pem_free(&pem);
return ret;
} else if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {
return ret;
}
#if defined(MBEDTLS_PKCS12_C) || defined(MBEDTLS_PKCS5_C)
/* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
if (key[keylen - 1] != '\0') {
ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
} else {
ret = mbedtls_pem_read_buffer(&pem,
"-----BEGIN ENCRYPTED PRIVATE KEY-----",
"-----END ENCRYPTED PRIVATE KEY-----",
key, NULL, 0, &len);
}
if (ret == 0) {
if ((ret = mbedtls_pk_parse_key_pkcs8_encrypted_der(pk, pem.buf, pem.buflen,
pwd, pwdlen, f_rng, p_rng)) != 0) {
mbedtls_pk_free(pk);
}
mbedtls_pem_free(&pem);
return ret;
} else if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {
return ret;
}
#endif /* MBEDTLS_PKCS12_C || MBEDTLS_PKCS5_C */
#else
((void) pwd);
((void) pwdlen);
#endif /* MBEDTLS_PEM_PARSE_C */
/*
* At this point we only know it's not a PEM formatted key. Could be any
* of the known DER encoded private key formats
*
* We try the different DER format parsers to see if one passes without
* error
*/
#if defined(MBEDTLS_PKCS12_C) || defined(MBEDTLS_PKCS5_C)
if (pwdlen != 0) {
unsigned char *key_copy;
if ((key_copy = mbedtls_calloc(1, keylen)) == NULL) {
return MBEDTLS_ERR_PK_ALLOC_FAILED;
}
memcpy(key_copy, key, keylen);
ret = mbedtls_pk_parse_key_pkcs8_encrypted_der(pk, key_copy, keylen,
pwd, pwdlen, f_rng, p_rng);
mbedtls_zeroize_and_free(key_copy, keylen);
}
if (ret == 0) {
return 0;
}
mbedtls_pk_free(pk);
mbedtls_pk_init(pk);
if (ret == MBEDTLS_ERR_PK_PASSWORD_MISMATCH) {
return ret;
}
#endif /* MBEDTLS_PKCS12_C || MBEDTLS_PKCS5_C */
ret = pk_parse_key_pkcs8_unencrypted_der(pk, key, keylen, f_rng, p_rng);
if (ret == 0) {
return 0;
}
mbedtls_pk_free(pk);
mbedtls_pk_init(pk);
#if defined(MBEDTLS_RSA_C)
pk_info = mbedtls_pk_info_from_type(MBEDTLS_PK_RSA);
if (mbedtls_pk_setup(pk, pk_info) == 0 &&
pk_parse_key_pkcs1_der(mbedtls_pk_rsa(*pk), key, keylen) == 0) {
return 0;
}
mbedtls_pk_free(pk);
mbedtls_pk_init(pk);
#endif /* MBEDTLS_RSA_C */
#if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
pk_info = mbedtls_pk_info_from_type(MBEDTLS_PK_ECKEY);
if (mbedtls_pk_setup(pk, pk_info) == 0 &&
pk_parse_key_sec1_der(pk,
key, keylen, f_rng, p_rng) == 0) {
return 0;
}
mbedtls_pk_free(pk);
#endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
/* If MBEDTLS_RSA_C is defined but MBEDTLS_PK_HAVE_ECC_KEYS isn't,
* it is ok to leave the PK context initialized but not
* freed: It is the caller's responsibility to call pk_init()
* before calling this function, and to call pk_free()
* when it fails. If MBEDTLS_PK_HAVE_ECC_KEYS is defined but MBEDTLS_RSA_C
* isn't, this leads to mbedtls_pk_free() being called
* twice, once here and once by the caller, but this is
* also ok and in line with the mbedtls_pk_free() calls
* on failed PEM parsing attempts. */
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
/*
* Parse a public key
*/
int mbedtls_pk_parse_public_key(mbedtls_pk_context *ctx,
const unsigned char *key, size_t keylen)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *p;
#if defined(MBEDTLS_RSA_C)
const mbedtls_pk_info_t *pk_info;
#endif
#if defined(MBEDTLS_PEM_PARSE_C)
size_t len;
mbedtls_pem_context pem;
#endif
if (keylen == 0) {
return MBEDTLS_ERR_PK_KEY_INVALID_FORMAT;
}
#if defined(MBEDTLS_PEM_PARSE_C)
mbedtls_pem_init(&pem);
#if defined(MBEDTLS_RSA_C)
/* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
if (key[keylen - 1] != '\0') {
ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
} else {
ret = mbedtls_pem_read_buffer(&pem,
"-----BEGIN RSA PUBLIC KEY-----",
"-----END RSA PUBLIC KEY-----",
key, NULL, 0, &len);
}
if (ret == 0) {
p = pem.buf;
if ((pk_info = mbedtls_pk_info_from_type(MBEDTLS_PK_RSA)) == NULL) {
mbedtls_pem_free(&pem);
return MBEDTLS_ERR_PK_UNKNOWN_PK_ALG;
}
if ((ret = mbedtls_pk_setup(ctx, pk_info)) != 0) {
mbedtls_pem_free(&pem);
return ret;
}
if ((ret = pk_get_rsapubkey(&p, p + pem.buflen, mbedtls_pk_rsa(*ctx))) != 0) {
mbedtls_pk_free(ctx);
}
mbedtls_pem_free(&pem);
return ret;
} else if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {
mbedtls_pem_free(&pem);
return ret;
}
#endif /* MBEDTLS_RSA_C */
/* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
if (key[keylen - 1] != '\0') {
ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
} else {
ret = mbedtls_pem_read_buffer(&pem,
"-----BEGIN PUBLIC KEY-----",
"-----END PUBLIC KEY-----",
key, NULL, 0, &len);
}
if (ret == 0) {
/*
* Was PEM encoded
*/
p = pem.buf;
ret = mbedtls_pk_parse_subpubkey(&p, p + pem.buflen, ctx);
mbedtls_pem_free(&pem);
return ret;
} else if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {
mbedtls_pem_free(&pem);
return ret;
}
mbedtls_pem_free(&pem);
#endif /* MBEDTLS_PEM_PARSE_C */
#if defined(MBEDTLS_RSA_C)
if ((pk_info = mbedtls_pk_info_from_type(MBEDTLS_PK_RSA)) == NULL) {
return MBEDTLS_ERR_PK_UNKNOWN_PK_ALG;
}
if ((ret = mbedtls_pk_setup(ctx, pk_info)) != 0) {
return ret;
}
p = (unsigned char *) key;
ret = pk_get_rsapubkey(&p, p + keylen, mbedtls_pk_rsa(*ctx));
if (ret == 0) {
return ret;
}
mbedtls_pk_free(ctx);
if (ret != (MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PK_INVALID_PUBKEY,
MBEDTLS_ERR_ASN1_UNEXPECTED_TAG))) {
return ret;
}
#endif /* MBEDTLS_RSA_C */
p = (unsigned char *) key;
ret = mbedtls_pk_parse_subpubkey(&p, p + keylen, ctx);
return ret;
}
/***********************************************************************
*
* Top-level functions, with filesystem support
*
**********************************************************************/
#if defined(MBEDTLS_FS_IO)
/*
* Load all data from a file into a given buffer.
*
* The file is expected to contain either PEM or DER encoded data.
* A terminating null byte is always appended. It is included in the announced
* length only if the data looks like it is PEM encoded.
*/
int mbedtls_pk_load_file(const char *path, unsigned char **buf, size_t *n)
{
FILE *f;
long size;
if ((f = fopen(path, "rb")) == NULL) {
return MBEDTLS_ERR_PK_FILE_IO_ERROR;
}
/* Ensure no stdio buffering of secrets, as such buffers cannot be wiped. */
mbedtls_setbuf(f, NULL);
fseek(f, 0, SEEK_END);
if ((size = ftell(f)) == -1) {
fclose(f);
return MBEDTLS_ERR_PK_FILE_IO_ERROR;
}
fseek(f, 0, SEEK_SET);
*n = (size_t) size;
if (*n + 1 == 0 ||
(*buf = mbedtls_calloc(1, *n + 1)) == NULL) {
fclose(f);
return MBEDTLS_ERR_PK_ALLOC_FAILED;
}
if (fread(*buf, 1, *n, f) != *n) {
fclose(f);
mbedtls_zeroize_and_free(*buf, *n);
return MBEDTLS_ERR_PK_FILE_IO_ERROR;
}
fclose(f);
(*buf)[*n] = '\0';
if (strstr((const char *) *buf, "-----BEGIN ") != NULL) {
++*n;
}
return 0;
}
/*
* Load and parse a private key
*/
int mbedtls_pk_parse_keyfile(mbedtls_pk_context *ctx,
const char *path, const char *pwd,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t n;
unsigned char *buf;
if ((ret = mbedtls_pk_load_file(path, &buf, &n)) != 0) {
return ret;
}
if (pwd == NULL) {
ret = mbedtls_pk_parse_key(ctx, buf, n, NULL, 0, f_rng, p_rng);
} else {
ret = mbedtls_pk_parse_key(ctx, buf, n,
(const unsigned char *) pwd, strlen(pwd), f_rng, p_rng);
}
mbedtls_zeroize_and_free(buf, n);
return ret;
}
/*
* Load and parse a public key
*/
int mbedtls_pk_parse_public_keyfile(mbedtls_pk_context *ctx, const char *path)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t n;
unsigned char *buf;
if ((ret = mbedtls_pk_load_file(path, &buf, &n)) != 0) {
return ret;
}
ret = mbedtls_pk_parse_public_key(ctx, buf, n);
mbedtls_zeroize_and_free(buf, n);
return ret;
}
#endif /* MBEDTLS_FS_IO */
#endif /* MBEDTLS_PK_PARSE_C */
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