af97ffffa5
* Remove some unused cryptographic code * Add some notes about how Minecraft's cryptography choices have not quite survived the test of time
75 lines
2.3 KiB
C
75 lines
2.3 KiB
C
#include <CommonCrypto/CommonCryptor.h>
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#include <jni.h>
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#include <stdlib.h>
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#include <string.h>
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#include "jni_util.h"
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typedef unsigned char byte;
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JNIEXPORT jlong JNICALL
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Java_com_velocitypowered_natives_encryption_OpenSslCipherImpl_init(JNIEnv *env,
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jclass clazz,
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jbyteArray key,
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jboolean encrypt)
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{
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jsize keyLen = (*env)->GetArrayLength(env, key);
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if (keyLen != 16) {
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throwException(env, "java/lang/IllegalArgumentException", "cipher not 16 bytes");
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return 0;
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}
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// Since we know the array size is always bounded, we can just use Get<Primitive>ArrayRegion
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// and save ourselves some error-checking headaches.
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jbyte keyBytes[16];
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(*env)->GetByteArrayRegion(env, key, 0, keyLen, (jbyte*) keyBytes);
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if ((*env)->ExceptionCheck(env)) {
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return 0;
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}
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// But, you're saying, *why* are we using the key as the IV? After all, reusing the key as
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// the IV defeats the entire point - we might as well just initialize it to all zeroes.
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//
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// You can blame Mojang. For the record, we also don't consider the Minecraft protocol
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// encryption scheme to be secure, and it has reached the point where any serious cryptographic
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// protocol needs a refresh. There are multiple obvious weaknesses, and this is far from the
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// most serious.
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//
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// If you are using Minecraft in a security-sensitive application, *I don't know what to say.*
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CCCryptorRef cryptor = NULL;
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CCCryptorStatus result = CCCryptorCreateWithMode(encrypt ? kCCEncrypt : kCCDecrypt,
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kCCModeCFB8,
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kCCAlgorithmAES128,
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ccNoPadding,
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keyBytes,
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keyBytes,
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16,
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NULL,
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0,
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0,
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0,
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&cryptor);
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if (result != kCCSuccess) {
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throwException(env, "java/security/GeneralSecurityException", "openssl initialize cipher");
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return 0;
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}
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return (jlong) cryptor;
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}
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JNIEXPORT void JNICALL
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Java_com_velocitypowered_natives_encryption_OpenSslCipherImpl_free(JNIEnv *env,
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jclass clazz,
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jlong ptr)
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{
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CCCryptorRelease((CCCryptorRef) ptr);
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}
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JNIEXPORT void JNICALL
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Java_com_velocitypowered_natives_encryption_OpenSslCipherImpl_process(JNIEnv *env,
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jclass clazz,
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jlong ptr,
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jlong source,
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jint len,
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jlong dest)
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{
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CCCryptorUpdate((CCCryptorRef) ptr, (byte*) source, len, (byte*) dest, len, NULL);
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} |