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Refactor encrypted_try_key() for better parameter handling and no ext…
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…ra pgp_fingerprint() call.
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@ni4
ni4 committed Jun 24, 2024
1 parent 657b188 commit 09df05b
Showing 1 changed file with 42 additions and 50 deletions.
92 changes: 42 additions & 50 deletions src/librepgp/stream-parse.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1568,17 +1568,17 @@ do_enforce_aes_v3pkesk(pgp_pubkey_alg_t alg)

static bool
encrypted_try_key(pgp_source_encrypted_param_t *param,
pgp_pk_sesskey_t * sesskey,
pgp_key_pkt_t * seckey,
pgp_pk_sesskey_t & sesskey,
pgp_key_t & seckey,
rnp::SecurityContext & ctx)
{
pgp_encrypted_material_t encmaterial;
try {
if (!sesskey->parse_material(encmaterial)) {
if (!sesskey.parse_material(encmaterial)) {
return false;
}
seckey->material.validate(ctx, false);
if (!seckey->material.valid()) {
seckey.material().validate(ctx, false);
if (!seckey.material().valid()) {
RNP_LOG("Attempt to decrypt using the key with invalid material.");
return false;
}
Expand All @@ -1594,17 +1594,17 @@ encrypted_try_key(pgp_source_encrypted_param_t *param,
- The payload following any v6 PKESK or v6 SKESK packet MUST be a v2 SEIPD.
- implementations MUST NOT precede a v2 SEIPD payload with either v3 PKESK or v4
SKESK packets. */
if ((param->is_v2_seipd() && (sesskey->version != PGP_PKSK_V6)) ||
(param->auth_type == rnp::AuthType::MDC && (sesskey->version != PGP_PKSK_V3))) {
if ((param->is_v2_seipd() && (sesskey.version != PGP_PKSK_V6)) ||
(param->auth_type == rnp::AuthType::MDC && (sesskey.version != PGP_PKSK_V3))) {
RNP_LOG("Attempt to mix SEIPD v1 with PKESK v6 or SEIPD v2 with PKESK v3");
return false;
}
#endif

#if defined(ENABLE_CRYPTO_REFRESH) || defined(ENABLE_PQC)
/* check that AES is used when mandated by the standard */
if (do_enforce_aes_v3pkesk(sesskey->alg) && sesskey->version == PGP_PKSK_V3) {
switch (sesskey->salg) {
if (do_enforce_aes_v3pkesk(sesskey.alg) && sesskey.version == PGP_PKSK_V3) {
switch (sesskey.salg) {
case PGP_SA_AES_128:
case PGP_SA_AES_192:
case PGP_SA_AES_256:
Expand All @@ -1619,15 +1619,15 @@ encrypted_try_key(pgp_source_encrypted_param_t *param,

rnp::secure_array<uint8_t, PGP_MPINT_SIZE> decbuf;
/* Decrypting session key value */
rnp_result_t err;
bool res = false;
pgp_key_material_t *keymaterial = &seckey->material;
size_t declen = 0;
switch (sesskey->alg) {
rnp_result_t err;
bool res = false;
auto & keymaterial = seckey.material();
size_t declen = 0;
switch (sesskey.alg) {
case PGP_PKA_RSA:
case PGP_PKA_RSA_ENCRYPT_ONLY:
err = rsa_decrypt_pkcs1(
&ctx.rng, decbuf.data(), &declen, &encmaterial.rsa, &keymaterial->rsa);
&ctx.rng, decbuf.data(), &declen, &encmaterial.rsa, &keymaterial.rsa);
if (err) {
RNP_LOG("RSA decryption failure");
return false;
Expand All @@ -1636,7 +1636,7 @@ encrypted_try_key(pgp_source_encrypted_param_t *param,
case PGP_PKA_SM2:
#if defined(ENABLE_SM2)
declen = decbuf.size();
err = sm2_decrypt(decbuf.data(), &declen, &encmaterial.sm2, &keymaterial->ec);
err = sm2_decrypt(decbuf.data(), &declen, &encmaterial.sm2, &keymaterial.ec);

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if (err != RNP_SUCCESS) {
RNP_LOG("SM2 decryption failure, error %x", (int) err);
return false;
Expand All @@ -1649,32 +1649,25 @@ encrypted_try_key(pgp_source_encrypted_param_t *param,
case PGP_PKA_ELGAMAL:
case PGP_PKA_ELGAMAL_ENCRYPT_OR_SIGN: {
const rnp_result_t ret = elgamal_decrypt_pkcs1(
&ctx.rng, decbuf.data(), &declen, &encmaterial.eg, &keymaterial->eg);
&ctx.rng, decbuf.data(), &declen, &encmaterial.eg, &keymaterial.eg);
if (ret) {
RNP_LOG("ElGamal decryption failure [%X]", ret);
return false;
}
break;
}
case PGP_PKA_ECDH: {
if (!curve_supported(keymaterial->ec.curve)) {
RNP_LOG("ECDH decrypt: curve %d is not supported.", (int) keymaterial->ec.curve);
if (!curve_supported(keymaterial.ec.curve)) {
RNP_LOG("ECDH decrypt: curve %d is not supported.", (int) keymaterial.ec.curve);

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return false;
}
pgp_fingerprint_t fingerprint;
if (pgp_fingerprint(fingerprint, *seckey)) {
/* LCOV_EXCL_START */
RNP_LOG("ECDH fingerprint calculation failed");
return false;
/* LCOV_EXCL_END */
}
if ((keymaterial->ec.curve == PGP_CURVE_25519) &&
!x25519_bits_tweaked(keymaterial->ec)) {
if ((keymaterial.ec.curve == PGP_CURVE_25519) &&
!x25519_bits_tweaked(keymaterial.ec)) {
RNP_LOG("Warning: bits of 25519 secret key are not tweaked.");
}
declen = decbuf.size();
err = ecdh_decrypt_pkcs5(
decbuf.data(), &declen, &encmaterial.ecdh, &keymaterial->ec, fingerprint);
decbuf.data(), &declen, &encmaterial.ecdh, &keymaterial.ec, seckey.fp());
if (err) {
RNP_LOG("ECDH decryption error %u", err);
return false;
Expand All @@ -1685,8 +1678,8 @@ encrypted_try_key(pgp_source_encrypted_param_t *param,
case PGP_PKA_X25519:
declen = decbuf.size();
err = x25519_native_decrypt(
&ctx.rng, keymaterial->x25519, &encmaterial.x25519, decbuf.data(), &declen);
if (err != RNP_SUCCESS) {
&ctx.rng, keymaterial.x25519, &encmaterial.x25519, decbuf.data(), &declen);
if (err) {
RNP_LOG("X25519 decryption error %u", err);
return false;
}
Expand All @@ -1703,41 +1696,40 @@ encrypted_try_key(pgp_source_encrypted_param_t *param,
case PGP_PKA_KYBER768_BP256:
FALLTHROUGH_STATEMENT;
case PGP_PKA_KYBER1024_BP384: {
pgp_key_t key(*seckey, true); /* make public-key `pgp_key_t` object from seckey */
declen = decbuf.size();
err = keymaterial->kyber_ecdh.priv.decrypt(
err = keymaterial.kyber_ecdh.priv.decrypt(
&ctx.rng, decbuf.data(), &declen, &encmaterial.kyber_ecdh);
if (err != RNP_SUCCESS) {
if (err) {
RNP_LOG("ML-KEM + ECC decryption failure");
return false;
}
break;
}
#endif
default:
RNP_LOG("unsupported public key algorithm %d\n", seckey->alg);
RNP_LOG("unsupported public key algorithm %d\n", seckey.alg());

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return false;
}

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PGP_PKA_ECDH (49 lines)
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uint8_t *decbuf_sesskey = decbuf.data();
size_t decbuf_sesskey_len = declen;
#if defined(ENABLE_CRYPTO_REFRESH) || defined(ENABLE_PQC)
if (do_encrypt_pkesk_v3_alg_id(sesskey->alg))
if (do_encrypt_pkesk_v3_alg_id(sesskey.alg))
#endif
{
sesskey->salg = static_cast<pgp_symm_alg_t>(decbuf[0]);
sesskey.salg = static_cast<pgp_symm_alg_t>(decbuf[0]);
}
size_t keylen = pgp_key_size(sesskey->salg);
if (sesskey->version == PGP_PKSK_V3) {
size_t keylen = pgp_key_size(sesskey.salg);
if (sesskey.version == PGP_PKSK_V3) {
/* Check algorithm and key length */
if (!pgp_is_sa_supported(sesskey->salg)) {
RNP_LOG("Unsupported symmetric algorithm %d", (int) sesskey->salg);
if (!pgp_is_sa_supported(sesskey.salg)) {
RNP_LOG("Unsupported symmetric algorithm %d", (int) sesskey.salg);
return false;
}

#if defined(ENABLE_CRYPTO_REFRESH) || defined(ENABLE_PQC)
size_t alg_id_bytes = do_encrypt_pkesk_v3_alg_id(sesskey->alg) ? 1 : 0;
size_t checksum_bytes = have_pkesk_checksum(sesskey->alg) ? 2 : 0;
size_t alg_id_bytes = do_encrypt_pkesk_v3_alg_id(sesskey.alg) ? 1 : 0;
size_t checksum_bytes = have_pkesk_checksum(sesskey.alg) ? 2 : 0;
#else
size_t alg_id_bytes = 1;
size_t checksum_bytes = 2;
Expand All @@ -1755,7 +1747,7 @@ encrypted_try_key(pgp_source_encrypted_param_t *param,
else { // V6 PKESK
/* compute the expected key length from the decbuf_sesskey_len and check */
keylen =
have_pkesk_checksum(sesskey->alg) ? decbuf_sesskey_len - 2 : decbuf_sesskey_len;
have_pkesk_checksum(sesskey.alg) ? decbuf_sesskey_len - 2 : decbuf_sesskey_len;
if (pgp_key_size(param->aead_hdr.ealg) != keylen) {
RNP_LOG("invalid symmetric key length");
return false;
Expand All @@ -1769,7 +1761,7 @@ encrypted_try_key(pgp_source_encrypted_param_t *param,
#endif

#if defined(ENABLE_CRYPTO_REFRESH) || defined(ENABLE_PQC)
if (have_pkesk_checksum(sesskey->alg))
if (have_pkesk_checksum(sesskey.alg))
#endif
{
/* Validate checksum */
Expand All @@ -1786,18 +1778,18 @@ encrypted_try_key(pgp_source_encrypted_param_t *param,
}

#if defined(ENABLE_CRYPTO_REFRESH) || defined(ENABLE_PQC)
if (sesskey->version == PGP_PKSK_V3)
if (sesskey.version == PGP_PKSK_V3)
#endif
{
if (param->use_cfb()) {
/* Decrypt header */
res = encrypted_decrypt_cfb_header(param, sesskey->salg, decbuf_sesskey);
res = encrypted_decrypt_cfb_header(param, sesskey.salg, decbuf_sesskey);
} else {
/* Start AEAD decrypting, assuming we have correct key */
res = encrypted_start_aead(param, sesskey->salg, decbuf_sesskey);
res = encrypted_start_aead(param, sesskey.salg, decbuf_sesskey);
}
if (res) {
param->salg = sesskey->salg;
param->salg = sesskey.salg;
}
return res;
}
Expand Down Expand Up @@ -2495,7 +2487,7 @@ init_encrypted_src(pgp_parse_handler_t *handler, pgp_source_t *src, pgp_source_t

/* Try to initialize the decryption */
rnp::LogStop logstop(hidden);
if (encrypted_try_key(param, &pubenc, &seckey->pkt(), *handler->ctx->ctx)) {
if (encrypted_try_key(param, pubenc, *seckey, *handler->ctx->ctx)) {
have_key = true;
/* inform handler that we used this pubenc */
if (handler->on_decryption_start) {
Expand Down

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