static int ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri) { int rv = 0; X509_ALGOR *alg, *kekalg = NULL; ASN1_OCTET_STRING *ukm; const unsigned char *p; unsigned char *der = NULL; int plen, keylen; const EVP_CIPHER *kekcipher; EVP_CIPHER_CTX *kekctx; if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm)) return 0; if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm))) { ECerr(EC_F_ECDH_CMS_SET_SHARED_INFO, EC_R_KDF_PARAMETER_ERROR); return 0; } if (alg->parameter->type != V_ASN1_SEQUENCE) return 0; p = alg->parameter->value.sequence->data; plen = alg->parameter->value.sequence->length; kekalg = d2i_X509_ALGOR(NULL, &p, plen); if (!kekalg) goto err; kekctx = CMS_RecipientInfo_kari_get0_ctx(ri); if (!kekctx) goto err; kekcipher = EVP_get_cipherbyobj(kekalg->algorithm); if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE) goto err; if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL)) goto err; if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0) goto err; keylen = EVP_CIPHER_CTX_key_length(kekctx); if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0) goto err; plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen); if (!plen) goto err; if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0) goto err; der = NULL; rv = 1; err: if (kekalg) X509_ALGOR_free(kekalg); if (der) OPENSSL_free(der); return rv; }
static int ecdh_cms_encrypt(CMS_RecipientInfo *ri) { EVP_PKEY_CTX *pctx; EVP_PKEY *pkey; EVP_CIPHER_CTX *ctx; int keylen; X509_ALGOR *talg, *wrap_alg = NULL; ASN1_OBJECT *aoid; ASN1_BIT_STRING *pubkey; ASN1_STRING *wrap_str; ASN1_OCTET_STRING *ukm; unsigned char *penc = NULL; int penclen; int rv = 0; int ecdh_nid, kdf_type, kdf_nid, wrap_nid; const EVP_MD *kdf_md; pctx = CMS_RecipientInfo_get0_pkey_ctx(ri); if (!pctx) return 0; /* Get ephemeral key */ pkey = EVP_PKEY_CTX_get0_pkey(pctx); if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey, NULL, NULL, NULL)) goto err; X509_ALGOR_get0(&aoid, NULL, NULL, talg); /* Is everything uninitialised? */ if (aoid == OBJ_nid2obj(NID_undef)) { EC_KEY *eckey = pkey->pkey.ec; /* Set the key */ unsigned char *p; penclen = i2o_ECPublicKey(eckey, NULL); if (penclen <= 0) goto err; penc = OPENSSL_malloc(penclen); if (!penc) goto err; p = penc; penclen = i2o_ECPublicKey(eckey, &p); if (penclen <= 0) goto err; ASN1_STRING_set0(pubkey, penc, penclen); pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07); pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT; penc = NULL; X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), V_ASN1_UNDEF, NULL); } /* See if custom paraneters set */ kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx); if (kdf_type <= 0) goto err; if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md)) goto err; ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx); if (ecdh_nid < 0) goto err; else if (ecdh_nid == 0) ecdh_nid = NID_dh_std_kdf; else if (ecdh_nid == 1) ecdh_nid = NID_dh_cofactor_kdf; if (kdf_type == EVP_PKEY_ECDH_KDF_NONE) { kdf_type = EVP_PKEY_ECDH_KDF_X9_62; if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0) goto err; } else /* Uknown KDF */ goto err; if (kdf_md == NULL) { /* Fixme later for better MD */ kdf_md = EVP_sha1(); if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0) goto err; } if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm)) goto err; /* Lookup NID for KDF+cofactor+digest */ if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid)) goto err; /* Get wrap NID */ ctx = CMS_RecipientInfo_kari_get0_ctx(ri); wrap_nid = EVP_CIPHER_CTX_type(ctx); keylen = EVP_CIPHER_CTX_key_length(ctx); /* Package wrap algorithm in an AlgorithmIdentifier */ wrap_alg = X509_ALGOR_new(); if (!wrap_alg) goto err; wrap_alg->algorithm = OBJ_nid2obj(wrap_nid); wrap_alg->parameter = ASN1_TYPE_new(); if (!wrap_alg->parameter) goto err; if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0) goto err; if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) { ASN1_TYPE_free(wrap_alg->parameter); wrap_alg->parameter = NULL; } if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0) goto err; penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen); if (!penclen) goto err; if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, penc, penclen) <= 0) goto err; penc = NULL; /* * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter * of another AlgorithmIdentifier. */ penclen = i2d_X509_ALGOR(wrap_alg, &penc); if (!penc || !penclen) goto err; wrap_str = ASN1_STRING_new(); if (!wrap_str) goto err; ASN1_STRING_set0(wrap_str, penc, penclen); penc = NULL; X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str); rv = 1; err: OPENSSL_free(penc); X509_ALGOR_free(wrap_alg); return rv; }