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Validate XDH native secret derivation #1483

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Merged
jasonkatonica merged 2 commits into from
Jun 1, 2026
Merged

Validate XDH native secret derivation #1483

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cbd78eb
Validate XDH native secret derivation
taoliult Apr 22, 2026
1fe277b
Set XEC secret buffer size explicitly on z/OS
taoliult May 22, 2026
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14 changes: 7 additions & 7 deletions src/main/java/com/ibm/crypto/plus/provider/XDHKeyAgreement.java
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Original file line number Diff line number Diff line change
Expand Up @@ -103,13 +103,13 @@ protected Key engineDoPhase(Key key, boolean lastPhase)

try {
int secrectBufferSize = 0;
String curveName = ((NamedParameterSpec) xdhPublicKeyImpl.getParams()).getName();
if (NamedParameterSpec.X25519.getName().equalsIgnoreCase(curveName)) {
secrectBufferSize = SECRET_BUFFER_SIZE_X25519; // X25519 secret buffer size
} else if (NamedParameterSpec.X448.getName().equalsIgnoreCase(curveName)) {
secrectBufferSize = SECRET_BUFFER_SIZE_X448; // X448 secret buffer size
} else {
secrectBufferSize = 0; // Let OCK decide the size
if (System.getProperty("os.name").equals("z/OS")) {
String curveName = ((NamedParameterSpec) xdhPublicKeyImpl.getParams()).getName();
if (NamedParameterSpec.X25519.getName().equalsIgnoreCase(curveName)) {
secrectBufferSize = SECRET_BUFFER_SIZE_X25519; // X25519 secret buffer size
} else if (NamedParameterSpec.X448.getName().equalsIgnoreCase(curveName)) {
secrectBufferSize = SECRET_BUFFER_SIZE_X448; // X448 secret buffer size
}
}
this.secret = XECKey.computeECDHSecret(genCtx,
ockXecKeyPub.getPKeyId(), ockXecKeyPriv.getPKeyId(), secrectBufferSize, provider);
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114 changes: 78 additions & 36 deletions src/main/native/ock/ECKey.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2233,6 +2233,7 @@ Java_com_ibm_crypto_plus_provider_ock_NativeOCKImplementation_XECKEY_1computeECD
jbyteArray secretBytes = NULL;
unsigned char *secretBytesNative = NULL;
jboolean isCopy = 0;
size_t required_len = 0;
size_t secret_key_len = 0;
int rc = 0;

Expand All @@ -2244,56 +2245,97 @@ Java_com_ibm_crypto_plus_provider_ock_NativeOCKImplementation_XECKEY_1computeECD
NULL); /* Set private key */
if (NULL == gen_ctx) {
throwOCKException(env, 0, "NULL from ICC_EVP_PKEY_CTX_new");
goto cleanup;
}

rc = ICC_EVP_PKEY_derive_init(ockCtx, gen_ctx);
if (ICC_OSSL_SUCCESS != rc) {
throwOCKException(env, 0, "ICC_EVP_PKEY_derive_init failed");
goto cleanup;
}

rc = ICC_EVP_PKEY_derive_set_peer(ockCtx, gen_ctx, ockPubXecKey); /* Set public key */
if (ICC_OSSL_SUCCESS != rc) {
throwOCKException(env, 0, "ICC_EVP_PKEY_derive_set_peer failed");
goto cleanup;
}

if (secretBufferSize > 0) {
/*
* On z/OS, querying the required secret size may not work properly.
* In that case, use the caller-provided secretBufferSize as the
* expected derived secret size.
*/
required_len = (size_t) secretBufferSize;
} else {
ICC_EVP_PKEY_derive_init(ockCtx, gen_ctx);
ICC_EVP_PKEY_derive_set_peer(ockCtx, gen_ctx,
ockPubXecKey); /* Set public key */
if (secretBufferSize > 0) {
secret_key_len = secretBufferSize;
} else {
ICC_EVP_PKEY_derive(ockCtx, gen_ctx, NULL,
&secret_key_len); /* Get secret key size */
/*
* Query the required secret size before deriving the secret.
* This avoids deriving into a buffer with an incorrect size.
*/
rc = ICC_EVP_PKEY_derive(ockCtx, gen_ctx, NULL, &required_len); /* Get secret key size */
if (ICC_OSSL_SUCCESS != rc) {
throwOCKException(env, 0,
"ICC_EVP_PKEY_derive failed to get secret size");
goto cleanup;
}
secretBytes = (*env)->NewByteArray(
env, secret_key_len); /* Create Java secret bytes array with size */
if (NULL == secretBytes) {
throwOCKException(env, 0, "NewByteArray failed");
} else {
secretBytesNative =
(unsigned char *)((*env)->GetPrimitiveArrayCritical(
env, secretBytes, &isCopy));
if (NULL == secretBytesNative) {
throwOCKException(env, 0,
"NULL from GetPrimitiveArrayCritical");
} else {
rc = ICC_EVP_PKEY_derive(ockCtx, gen_ctx, secretBytesNative,
&secret_key_len);
if (ICC_OSSL_SUCCESS != rc) {
throwOCKException(
env, 0, "ICC_EVP_PKEY_derive failed to derive a key");
}
ICC_EVP_PKEY_CTX_free(ockCtx, gen_ctx);
(*env)->ReleasePrimitiveArrayCritical(env, secretBytes,
secretBytesNative, 0);
if (debug) {
gslogFunctionExit(functionName);
}
return secretBytes;
}
if (required_len == 0) {
throwOCKException(env, 0, "Derived secret size is zero");
goto cleanup;
}
}
secret_key_len = required_len;

secretBytes = (*env)->NewByteArray(env, secret_key_len); /* Create Java secret bytes array */
if (NULL == secretBytes) {
throwOCKException(env, 0, "NewByteArray failed");
goto cleanup;
}

secretBytesNative = (unsigned char *)(*env)->GetPrimitiveArrayCritical(
env, secretBytes, &isCopy);
if (NULL == secretBytesNative) {
throwOCKException(env, 0, "NULL from GetPrimitiveArrayCritical");
goto cleanup;
}

rc = ICC_EVP_PKEY_derive(ockCtx, gen_ctx, secretBytesNative, &secret_key_len);
if (ICC_OSSL_SUCCESS != rc) {
throwOCKException(env, 0, "ICC_EVP_PKEY_derive failed to derive a key");
goto cleanup;
}

if (secret_key_len != required_len) {
throwOCKException(env, 0,
"Derived secret size does not match required size");
goto cleanup;
}

ICC_EVP_PKEY_CTX_free(ockCtx, gen_ctx);
gen_ctx = NULL;

(*env)->ReleasePrimitiveArrayCritical(env, secretBytes, secretBytesNative, 0);
secretBytesNative = NULL;

if (debug) {
gslogFunctionExit(functionName);
}

return secretBytes;

cleanup:
if (NULL != gen_ctx) {
ICC_EVP_PKEY_CTX_free(ockCtx, gen_ctx);
gen_ctx = NULL;
}

if (NULL != secretBytesNative) {
(*env)->ReleasePrimitiveArrayCritical(env, secretBytes,
secretBytesNative, 0);
(*env)->ReleasePrimitiveArrayCritical(env, secretBytes, secretBytesNative, 0);
secretBytesNative = NULL;
}

if (NULL != secretBytes) {
(*env)->DeleteLocalRef(env, secretBytes);
secretBytes = NULL;
}

if (debug) {
Expand Down
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