diff options
Diffstat (limited to 'asn1.c')
| -rw-r--r-- | asn1.c | 183 |
1 files changed, 183 insertions, 0 deletions
@@ -60,12 +60,36 @@ * Algorithm OIDs used in SPKI and PKCS #8. */ +/* + * From RFC 5480 New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX) + * + * rsaEncryption OBJECT IDENTIFIER ::= { + * iso(1) member-body(2) US(840) rsadsi(113549) pkcs(1) + * pkcs-1(1) 1 } + */ const uint8_t hal_asn1_oid_rsaEncryption[] = { 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01 }; const size_t hal_asn1_oid_rsaEncryption_len = sizeof(hal_asn1_oid_rsaEncryption); +/* + * From RFC 5480 Elliptic Curve Cryptography Subject Public Key Information + * + * id-ecPublicKey OBJECT IDENTIFIER ::= { + * iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 } + */ const uint8_t hal_asn1_oid_ecPublicKey[] = { 0x2A, 0x86, 0x48, 0xCE, 0x3D, 0x02, 0x01 }; const size_t hal_asn1_oid_ecPublicKey_len = sizeof(hal_asn1_oid_ecPublicKey); +/* + * From RFC 5649 Advanced Encryption Standard (AES) Key Wrap with Padding Algorithm + * + * aes OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) + * us(840) organization(1) gov(101) csor(3) + * nistAlgorithm(4) 1 } + * + * id-aes128-wrap-pad OBJECT IDENTIFIER ::= { aes 8 } + * + * id-aes256-wrap-pad OBJECT IDENTIFIER ::= { aes 48 } + */ #if KEK_LENGTH == (bitsToBytes(128)) const uint8_t hal_asn1_oid_aesKeyWrap[] = { 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x01, 0x08 }; const size_t hal_asn1_oid_aesKeyWrap_len = sizeof(hal_asn1_oid_aesKeyWrap); @@ -77,6 +101,15 @@ const size_t hal_asn1_oid_aesKeyWrap_len = sizeof(hal_asn1_oid_aesKeyWrap); #endif /* + * From draft-housley-cms-mts-hash-sig Use of the Hash-based Merkle Tree Signature (MTS) Algorithm in the Cryptographic Message Syntax (CMS) + * + * id-alg-mts-hashsig OBJECT IDENTIFIER ::= { iso(1) member-body(2) + * us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) alg(3) 17 } + */ +const uint8_t hal_asn1_oid_mts_hashsig[] = { 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x09, 0x10, 0x03, 0x11 }; +const size_t hal_asn1_oid_mts_hashsig_len = sizeof(hal_asn1_oid_mts_hashsig); + +/* * Encode tag and length fields of an ASN.1 object. * * Sets *der_len to the size of of the ASN.1 header (tag and length @@ -174,6 +207,88 @@ hal_error_t hal_asn1_encode_integer(const fp_int * const bn, } /* + * Encode an unsigned ASN.1 INTEGER from a uint32_t. If der is + * NULL, just return the length of what we would have encoded. + */ + +hal_error_t hal_asn1_encode_uint32(const uint32_t n, + uint8_t *der, size_t *der_len, const size_t der_max) +{ + /* + * We only handle unsigned INTEGERs, so we need to pad data with a + * leading zero if the most significant bit is set, to avoid + * flipping the ASN.1 sign bit. + */ + + size_t vlen; + hal_error_t err; + size_t hlen; + + /* DER says to use the minimum number of octets */ + if (n < 0x80) vlen = 1; + else if (n < 0x8000) vlen = 2; + else if (n < 0x800000) vlen = 3; + else if (n < 0x80000000) vlen = 4; + else vlen = 5; + + err = hal_asn1_encode_header(ASN1_INTEGER, vlen, der, &hlen, der_max); + + if (der_len != NULL) + *der_len = hlen + vlen; + + if (der == NULL || err != HAL_OK) + return err; + + hal_assert(hlen + vlen <= der_max); + + der += hlen; + + uint32_t m = n; + for (size_t i = vlen; i > 0; --i) { + der[i - 1] = m & 0xff; + m >>= 8; + } + + return HAL_OK; +} + +/* + * Encode an ASN.1 OCTET STRING. If der is NULL, just return the length + * of what we would have encoded. + */ + +hal_error_t hal_asn1_encode_octet_string(const uint8_t * const data, const size_t data_len, + uint8_t *der, size_t *der_len, const size_t der_max) +{ + if (data_len == 0 || (der != NULL && data == NULL)) + return HAL_ERROR_BAD_ARGUMENTS; + + size_t hlen; + hal_error_t err; + + if ((err = hal_asn1_encode_header(ASN1_OCTET_STRING, data_len, NULL, &hlen, 0)) != HAL_OK) + return err; + + if (der_len != NULL) + *der_len = hlen + data_len; + + if (der == NULL) + return HAL_OK; + + hal_assert(hlen + data_len <= der_max); + + /* + * Handle data early, in case it was staged into our output buffer. + */ + memmove(der + hlen, data, data_len); + + if ((err = hal_asn1_encode_header(ASN1_OCTET_STRING, data_len, der, &hlen, der_max)) != HAL_OK) + return err; + + return HAL_OK; +} + +/* * Encode a public key into a X.509 SubjectPublicKeyInfo (RFC 5280). */ @@ -483,6 +598,68 @@ hal_error_t hal_asn1_decode_integer(fp_int *bn, } /* + * Decode an ASN.1 INTEGER into a uint32_t. Since we only + * support (or need to support, or expect to see) unsigned integers, + * we return failure if the sign bit is set in the ASN.1 INTEGER. + */ + +hal_error_t hal_asn1_decode_uint32(uint32_t *np, + const uint8_t * const der, size_t *der_len, const size_t der_max) +{ + if (np == NULL || der == NULL) + return HAL_ERROR_BAD_ARGUMENTS; + + hal_error_t err; + size_t hlen, vlen; + + if ((err = hal_asn1_decode_header(ASN1_INTEGER, der, der_max, &hlen, &vlen)) != HAL_OK) + return err; + + if (der_len != NULL) + *der_len = hlen + vlen; + + if (vlen < 1 || vlen > 5 || (der[hlen] & 0x80) != 0x00 || (vlen == 5 && der[hlen] != 0)) + return HAL_ERROR_ASN1_PARSE_FAILED; + + uint32_t n = 0; + for (size_t i = 0; i < vlen; ++i) { + n <<= 8; // slightly inefficient for the first octet + n += der[hlen + i]; + } + *np = n; + + return HAL_OK; +} + +/* + * Decode an ASN.1 OCTET STRING. + */ + +hal_error_t hal_asn1_decode_octet_string(uint8_t *data, const size_t data_len, + const uint8_t * const der, size_t *der_len, const size_t der_max) +{ + if (der == NULL) + return HAL_ERROR_BAD_ARGUMENTS; + + size_t hlen, vlen; + hal_error_t err; + + if ((err = hal_asn1_decode_header(ASN1_OCTET_STRING, der, der_max, &hlen, &vlen)) != HAL_OK) + return err; + + if (der_len != NULL) + *der_len = hlen + vlen; + + if (data != NULL) { + if (data_len != vlen) + return HAL_ERROR_ASN1_PARSE_FAILED; + memmove(data, der + hlen, vlen); + } + + return HAL_OK; +} + +/* * Decode a public key from a X.509 SubjectPublicKeyInfo (RFC 5280). */ @@ -787,6 +964,12 @@ hal_error_t hal_asn1_guess_key_type(hal_key_type_t *type, return err; } + if (alg_oid_len == hal_asn1_oid_mts_hashsig_len && memcmp(alg_oid, hal_asn1_oid_mts_hashsig, alg_oid_len) == 0) { + *type = public ? HAL_KEY_TYPE_HASHSIG_PUBLIC : HAL_KEY_TYPE_HASHSIG_PRIVATE; + *curve = HAL_CURVE_NONE; + return HAL_OK; + } + *type = HAL_KEY_TYPE_NONE; *curve = HAL_CURVE_NONE; return HAL_ERROR_UNSUPPORTED_KEY; |