From 1aec7716c1c5fccf605a46252a46ea468e684454 Mon Sep 17 00:00:00 2001 From: Shane Lontis Date: Tue, 9 Jul 2019 09:33:18 +1000 Subject: Add X9.42 KDF. Move the KDF code for CMS DH key agreement into an EVP_KDF object. There are 2 specifications for X9.42 KDF. This implementation uses DER for otherinfo which embeds the KDF loop counter inside the DER object. Reviewed-by: Tomas Mraz Reviewed-by: Matt Caswell Reviewed-by: Paul Dale (Merged from https://github.com/openssl/openssl/pull/8898) --- crypto/dh/dh_kdf.c | 160 +++++++++++------------------------------------------ 1 file changed, 31 insertions(+), 129 deletions(-) (limited to 'crypto/dh') diff --git a/crypto/dh/dh_kdf.c b/crypto/dh/dh_kdf.c index 2a01bfce46..03b1e4edd5 100644 --- a/crypto/dh/dh_kdf.c +++ b/crypto/dh/dh_kdf.c @@ -1,5 +1,5 @@ /* - * Copyright 2013-2016 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 2013-2019 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the Apache License 2.0 (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy @@ -10,141 +10,43 @@ #include "e_os.h" #ifndef OPENSSL_NO_CMS -#include -#include -#include -#include -#include - - -/* Key derivation from X9.42/RFC2631 */ -/* Uses CMS functions, hence the #ifdef wrapper. */ - -#define DH_KDF_MAX (1L << 30) - -/* Skip past an ASN1 structure: for OBJECT skip content octets too */ - -static int skip_asn1(unsigned char **pp, long *plen, int exptag) -{ - const unsigned char *q = *pp; - int i, tag, xclass; - long tmplen; - i = ASN1_get_object(&q, &tmplen, &tag, &xclass, *plen); - if (i & 0x80) - return 0; - if (tag != exptag || xclass != V_ASN1_UNIVERSAL) - return 0; - if (tag == V_ASN1_OBJECT) - q += tmplen; - *plen -= q - *pp; - *pp = (unsigned char *)q; - return 1; -} - -/* - * Encode the DH shared info structure, return an offset to the counter value - * so we can update the structure without reencoding it. - */ - -static int dh_sharedinfo_encode(unsigned char **pder, unsigned char **pctr, - ASN1_OBJECT *key_oid, size_t outlen, - const unsigned char *ukm, size_t ukmlen) -{ - unsigned char *p; - int derlen; - long tlen; - /* "magic" value to check offset is sane */ - static unsigned char ctr[4] = { 0xF3, 0x17, 0x22, 0x53 }; - X509_ALGOR atmp; - ASN1_OCTET_STRING ctr_oct, ukm_oct, *pukm_oct; - ASN1_TYPE ctr_atype; - if (ukmlen > DH_KDF_MAX || outlen > DH_KDF_MAX) - return 0; - ctr_oct.data = ctr; - ctr_oct.length = 4; - ctr_oct.flags = 0; - ctr_oct.type = V_ASN1_OCTET_STRING; - ctr_atype.type = V_ASN1_OCTET_STRING; - ctr_atype.value.octet_string = &ctr_oct; - atmp.algorithm = key_oid; - atmp.parameter = &ctr_atype; - if (ukm) { - ukm_oct.type = V_ASN1_OCTET_STRING; - ukm_oct.flags = 0; - ukm_oct.data = (unsigned char *)ukm; - ukm_oct.length = ukmlen; - pukm_oct = &ukm_oct; - } else - pukm_oct = NULL; - derlen = CMS_SharedInfo_encode(pder, &atmp, pukm_oct, outlen); - if (derlen <= 0) - return 0; - p = *pder; - tlen = derlen; - if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE)) - return 0; - if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE)) - return 0; - if (!skip_asn1(&p, &tlen, V_ASN1_OBJECT)) - return 0; - if (!skip_asn1(&p, &tlen, V_ASN1_OCTET_STRING)) - return 0; - if (CRYPTO_memcmp(p, ctr, 4)) - return 0; - *pctr = p; - return derlen; -} +# include +# include +# include +# include +# include int DH_KDF_X9_42(unsigned char *out, size_t outlen, const unsigned char *Z, size_t Zlen, ASN1_OBJECT *key_oid, const unsigned char *ukm, size_t ukmlen, const EVP_MD *md) { - EVP_MD_CTX *mctx = NULL; - int rv = 0; - unsigned int i; - size_t mdlen; - unsigned char *der = NULL, *ctr; - int derlen; - if (Zlen > DH_KDF_MAX) + int ret = 0, nid; + EVP_KDF_CTX *kctx = NULL; + const EVP_KDF *kdf = NULL; + const char *oid_sn; + + nid = OBJ_obj2nid(key_oid); + if (nid == NID_undef) return 0; - mctx = EVP_MD_CTX_new(); - if (mctx == NULL) + oid_sn = OBJ_nid2sn(nid); + if (oid_sn == NULL) return 0; - mdlen = EVP_MD_size(md); - derlen = dh_sharedinfo_encode(&der, &ctr, key_oid, outlen, ukm, ukmlen); - if (derlen == 0) + + kdf = EVP_get_kdfbyname(SN_x942kdf); + if (kdf == NULL) goto err; - for (i = 1;; i++) { - unsigned char mtmp[EVP_MAX_MD_SIZE]; - if (!EVP_DigestInit_ex(mctx, md, NULL) - || !EVP_DigestUpdate(mctx, Z, Zlen)) - goto err; - ctr[3] = i & 0xFF; - ctr[2] = (i >> 8) & 0xFF; - ctr[1] = (i >> 16) & 0xFF; - ctr[0] = (i >> 24) & 0xFF; - if (!EVP_DigestUpdate(mctx, der, derlen)) - goto err; - if (outlen >= mdlen) { - if (!EVP_DigestFinal(mctx, out, NULL)) - goto err; - outlen -= mdlen; - if (outlen == 0) - break; - out += mdlen; - } else { - if (!EVP_DigestFinal(mctx, mtmp, NULL)) - goto err; - memcpy(out, mtmp, outlen); - OPENSSL_cleanse(mtmp, mdlen); - break; - } - } - rv = 1; - err: - OPENSSL_free(der); - EVP_MD_CTX_free(mctx); - return rv; + kctx = EVP_KDF_CTX_new(kdf); + ret = + kctx != NULL + && EVP_KDF_ctrl(kctx, EVP_KDF_CTRL_SET_MD, md) > 0 + && EVP_KDF_ctrl(kctx, EVP_KDF_CTRL_SET_KEY, Z, Zlen) > 0 + && (ukm == NULL + || EVP_KDF_ctrl(kctx, EVP_KDF_CTRL_SET_UKM, ukm, ukmlen) > 0) + && EVP_KDF_ctrl(kctx, EVP_KDF_CTRL_SET_CEK_ALG, oid_sn) > 0 + && EVP_KDF_derive(kctx, out, outlen) > 0; +err: + EVP_KDF_CTX_free(kctx); + return ret; } -#endif +#endif /* OPENSSL_NO_CMS */ -- cgit v1.2.3