static bool
sig_done(jose_io_t *io)
{
io_t *i = containerof(io, io_t, io);
size_t len = 0;
if (EVP_DigestSignFinal(i->emc, NULL, &len) <= 0)
return false;
uint8_t buf[len];
if (EVP_DigestSignFinal(i->emc, buf, &len) <= 0)
return false;
if (json_object_set_new(i->sig, "signature",
jose_b64_enc(buf, len)) < 0)
return false;
return add_entity(i->obj, i->sig,
"signatures", "signature", "protected", "header", 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;
}
static json_t *
derive(const jose_hook_alg_t *alg, jose_cfg_t *cfg,
json_t *hdr, json_t *cek, const json_t *key)
{
const jose_hook_alg_t *halg = NULL;
const char *name = alg->name;
uint8_t pu[KEYMAX] = {};
uint8_t pv[KEYMAX] = {};
uint8_t dk[KEYMAX] = {};
uint8_t ky[KEYMAX] = {};
const char *enc = NULL;
json_t *out = NULL;
size_t dkl = 0;
size_t pul = 0;
size_t pvl = 0;
size_t kyl = 0;
halg = jose_hook_alg_find(JOSE_HOOK_ALG_KIND_HASH, "S256");
if (!halg)
goto egress;
if (json_unpack(hdr, "{s?s}", "enc", &enc) < 0)
goto egress;
if (!enc && json_unpack(cek, "{s:s}", "alg", &enc) < 0)
goto egress;
switch (str2enum(alg->name, NAMES, NULL)) {
case 0: dkl = encr_alg_keylen(cfg, enc); name = enc; break;
case 1: dkl = 16; break;
case 2: dkl = 24; break;
case 3: dkl = 32; break;
default:
goto egress;
}
if (dkl < 16 || dkl > sizeof(dk))
goto egress;
pul = decode(hdr, "apu", pu, sizeof(pu));
if (pul > sizeof(pu))
goto egress;
pvl = decode(hdr, "apv", pv, sizeof(pv));
if (pvl > sizeof(pv))
goto egress;
kyl = decode(key, "x", ky, sizeof(ky));
if (kyl > sizeof(ky))
goto egress;
if (!concatkdf(halg, cfg,
dk, dkl,
ky, kyl,
name, strlen(name),
pu, pul,
pv, pvl,
NULL))
goto egress;
out = json_pack("{s:s,s:s,s:o}", "kty", "oct", "alg", enc,
"k", jose_b64_enc(dk, dkl));
egress:
OPENSSL_cleanse(ky, sizeof(ky));
OPENSSL_cleanse(pu, sizeof(pu));
OPENSSL_cleanse(pv, sizeof(pv));
OPENSSL_cleanse(dk, sizeof(dk));
return out;
}
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)
{
const EVP_CIPHER *cph = NULL;
EVP_CIPHER_CTX *ecc = NULL;
bool ret = false;
size_t ctl = 0;
size_t ptl = 0;
int len = 0;
switch (str2enum(alg->name, NAMES, NULL)) {
case 0: cph = EVP_aes_128_wrap(); break;
case 1: cph = EVP_aes_192_wrap(); break;
case 2: cph = EVP_aes_256_wrap(); break;
default: return NULL;
}
uint8_t ky[EVP_CIPHER_key_length(cph)];
uint8_t iv[EVP_CIPHER_iv_length(cph)];
uint8_t ct[KEYMAX + EVP_CIPHER_block_size(cph) * 2];
uint8_t pt[sizeof(ct)];
memset(iv, 0xA6, sizeof(iv));
if (jose_b64_dec(json_object_get(jwk, "k"), NULL, 0) != sizeof(ky))
goto egress;
if (jose_b64_dec(json_object_get(jwk, "k"), ky, sizeof(ky)) != sizeof(ky))
goto egress;
ctl = jose_b64_dec(json_object_get(rcp, "encrypted_key"), NULL, 0);
if (ctl > sizeof(ct))
goto egress;
if (jose_b64_dec(json_object_get(rcp, "encrypted_key"), ct, ctl) != ctl)
goto egress;
ecc = EVP_CIPHER_CTX_new();
if (!ecc)
goto egress;
EVP_CIPHER_CTX_set_flags(ecc, EVP_CIPHER_CTX_FLAG_WRAP_ALLOW);
if (EVP_DecryptInit_ex(ecc, cph, NULL, ky, iv) <= 0)
goto egress;
if (EVP_DecryptUpdate(ecc, pt, &len, ct, ctl) <= 0)
goto egress;
ptl = len;
if (EVP_DecryptFinal(ecc, &pt[len], &len) <= 0)
goto egress;
ptl += len;
ret = json_object_set_new(cek, "k", jose_b64_enc(pt, ptl)) == 0;
egress:
OPENSSL_cleanse(ky, sizeof(ky));
OPENSSL_cleanse(pt, sizeof(pt));
EVP_CIPHER_CTX_free(ecc);
return ret;
}
