/* * 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 #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, ¶ms->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, ¶ms)) != 0 || (ret = pk_use_ecparams(¶ms, 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, ¶ms, &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(¶ms, 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(¶ms, 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 */