static EVP_MD_CTX * setup(jose_cfg_t *cfg, const json_t *jwk, const json_t *sig, const char *alg, init_t *func) { openssl_auto(EVP_PKEY) *key = NULL; EVP_PKEY_CTX *epc = NULL; const EVP_MD *md = NULL; EVP_MD_CTX *emc = NULL; const RSA *rsa = NULL; int slen = 0; int pad = 0; switch (str2enum(alg, NAMES, NULL)) { case 0: md = EVP_sha256(); pad = RSA_PKCS1_PADDING; break; case 1: md = EVP_sha384(); pad = RSA_PKCS1_PADDING; break; case 2: md = EVP_sha512(); pad = RSA_PKCS1_PADDING; break; case 3: md = EVP_sha256(); pad = RSA_PKCS1_PSS_PADDING; slen = -1; break; case 4: md = EVP_sha384(); pad = RSA_PKCS1_PSS_PADDING; slen = -1; break; case 5: md = EVP_sha512(); pad = RSA_PKCS1_PSS_PADDING; slen = -1; break; default: return NULL; } key = jose_openssl_jwk_to_EVP_PKEY(cfg, jwk); if (!key || EVP_PKEY_base_id(key) != EVP_PKEY_RSA) return NULL; /* Don't use small keys. RFC 7518 3.3 */ rsa = EVP_PKEY_get0_RSA(key); if (!rsa) return NULL; if (RSA_size(rsa) < 2048 / 8) return NULL; emc = EVP_MD_CTX_new(); if (!emc) return NULL; if (func(emc, &epc, md, NULL, key) <= 0) goto error; if (EVP_PKEY_CTX_set_rsa_padding(epc, pad) <= 0) goto error; if (slen != 0) { if (EVP_PKEY_CTX_set_rsa_pss_saltlen(epc, slen) <= 0) goto error; } return emc; error: EVP_MD_CTX_free(emc); return NULL; }
static json_t * alg_exch_exc(const jose_hook_alg_t *alg, jose_cfg_t *cfg, const json_t *prv, const json_t *pub) { openssl_auto(EC_KEY) *lcl = NULL; openssl_auto(EC_KEY) *rem = NULL; openssl_auto(BN_CTX) *bnc = NULL; openssl_auto(EC_POINT) *p = NULL; const EC_GROUP *grp = NULL; bnc = BN_CTX_new(); if (!bnc) return NULL; lcl = jose_openssl_jwk_to_EC_KEY(cfg, prv); if (!lcl) return NULL; rem = jose_openssl_jwk_to_EC_KEY(cfg, pub); if (!rem) return NULL; grp = EC_KEY_get0_group(lcl); if (EC_GROUP_cmp(grp, EC_KEY_get0_group(rem), bnc) != 0) return NULL; p = EC_POINT_new(grp); if (!p) return NULL; if (EC_POINT_mul(grp, p, NULL, EC_KEY_get0_public_key(rem), EC_KEY_get0_private_key(lcl), bnc) <= 0) return NULL; return jose_openssl_jwk_from_EC_POINT(cfg, EC_KEY_get0_group(rem), p, NULL); }
static bool alg_wrap_wrp(const jose_hook_alg_t *alg, jose_cfg_t *cfg, json_t *jwe, json_t *rcp, const json_t *jwk, json_t *cek) { openssl_auto(EVP_PKEY_CTX) *epc = NULL; openssl_auto(EVP_PKEY) *key = NULL; const EVP_MD *md = NULL; const RSA *rsa = NULL; uint8_t *pt = NULL; uint8_t *ct = NULL; bool ret = false; size_t ptl = 0; size_t ctl = 0; int tmp = 0; int pad = 0; if (!json_object_get(cek, "k") && !jose_jwk_gen(cfg, cek)) return false; switch (str2enum(alg->name, NAMES, NULL)) { case 0: pad = RSA_PKCS1_PADDING; tmp = 11; md = EVP_sha1(); break; case 1: pad = RSA_PKCS1_OAEP_PADDING; tmp = 41; md = EVP_sha1(); break; case 2: pad = RSA_PKCS1_OAEP_PADDING; tmp = 41; md = EVP_sha256(); break; default: return false; } key = jose_openssl_jwk_to_EVP_PKEY(cfg, jwk); if (!key || EVP_PKEY_base_id(key) != EVP_PKEY_RSA) return false; ptl = jose_b64_dec(json_object_get(cek, "k"), NULL, 0); if (ptl == SIZE_MAX) return false; rsa = EVP_PKEY_get0_RSA(key); if (!rsa) return false; if ((int) ptl >= RSA_size(rsa) - tmp) return false; epc = EVP_PKEY_CTX_new(key, NULL); if (!epc) return false; if (EVP_PKEY_encrypt_init(epc) <= 0) return false; if (EVP_PKEY_CTX_set_rsa_padding(epc, pad) <= 0) return false; if (pad == RSA_PKCS1_OAEP_PADDING) { if (EVP_PKEY_CTX_set_rsa_oaep_md(epc, md) <= 0) return false; if (EVP_PKEY_CTX_set_rsa_mgf1_md(epc, md) <= 0) return false; } pt = malloc(ptl); if (!pt) return false; if (jose_b64_dec(json_object_get(cek, "k"), pt, ptl) != ptl) goto egress; if (EVP_PKEY_encrypt(epc, NULL, &ctl, pt, ptl) <= 0) goto egress; ct = malloc(ctl); if (!ct) goto egress; if (EVP_PKEY_encrypt(epc, ct, &ctl, pt, ptl) <= 0) goto egress; if (json_object_set_new(rcp, "encrypted_key", jose_b64_enc(ct, ctl)) < 0) goto egress; ret = add_entity(jwe, rcp, "recipients", "header", "encrypted_key", NULL); egress: if (pt) { OPENSSL_cleanse(pt, ptl); free(pt); } free(ct); return ret; }
static bool alg_wrap_unw(const jose_hook_alg_t *alg, jose_cfg_t *cfg, const json_t *jwe, const json_t *rcp, const json_t *jwk, json_t *cek) { openssl_auto(EVP_PKEY_CTX) *epc = NULL; openssl_auto(EVP_PKEY) *key = NULL; const uint8_t *tt = NULL; const EVP_MD *md = NULL; uint8_t *ct = NULL; uint8_t *pt = NULL; uint8_t *rt = NULL; bool ret = false; size_t ctl = 0; size_t ptl = 0; size_t rtl = 0; size_t ttl = 0; int pad = 0; switch (str2enum(alg->name, NAMES, NULL)) { case 0: pad = RSA_PKCS1_PADDING; md = EVP_sha1(); break; case 1: pad = RSA_PKCS1_OAEP_PADDING; md = EVP_sha1(); break; case 2: pad = RSA_PKCS1_OAEP_PADDING; md = EVP_sha256(); break; default: return false; } key = jose_openssl_jwk_to_EVP_PKEY(cfg, jwk); if (!key || EVP_PKEY_base_id(key) != EVP_PKEY_RSA) goto egress; ctl = jose_b64_dec(json_object_get(rcp, "encrypted_key"), NULL, 0); if (ctl == SIZE_MAX) goto egress; ct = malloc(ctl); if (!ct) goto egress; if (jose_b64_dec(json_object_get(rcp, "encrypted_key"), ct, ctl) != ctl) goto egress; ptl = ctl; pt = malloc(ptl); if (!pt) goto egress; epc = EVP_PKEY_CTX_new(key, NULL); if (!epc) goto egress; if (EVP_PKEY_decrypt_init(epc) <= 0) goto egress; if (EVP_PKEY_CTX_set_rsa_padding(epc, pad) <= 0) goto egress; if (pad == RSA_PKCS1_OAEP_PADDING) { if (EVP_PKEY_CTX_set_rsa_oaep_md(epc, md) <= 0) return false; if (EVP_PKEY_CTX_set_rsa_mgf1_md(epc, md) <= 0) goto egress; } /* Handle MMA Attack as prescribed by RFC 3218, always generate a * random buffer of appropriate length so that the same operations * are performed whether decrypt succeeds or not, in an attempt to * foil timing attacks */ rtl = ptl; rt = malloc(rtl); if (!rt) goto egress; if (RAND_bytes(rt, rtl) <= 0) goto egress; ret |= EVP_PKEY_decrypt(epc, pt, &ptl, ct, ctl) > 0; ttl = ret ? ptl : rtl; tt = ret ? pt : rt; ret |= pad == RSA_PKCS1_PADDING; if (json_object_set_new(cek, "k", jose_b64_enc(tt, ttl)) < 0) ret = false; egress: if (pt) { OPENSSL_cleanse(pt, ptl); free(pt); } if (rt) { OPENSSL_cleanse(rt, rtl); free(rt); } free(ct); return ret; }