Added RNG based encryption to the code to extract binary from define value

1 files changed, 70 insertions, 0 deletions

diff --git a/extract_decoded_executable/encrypter.c b/extract_decoded_executable/encrypter.c
new file mode 100644
index 0000000..34732cb
--- /dev/null
+++ b/extract_decoded_executable/encrypter.c
@@ -0,0 +1,70 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <math.h>
+#include <sys/stat.h>
+#include "rng.h"
+
+void encrypt_test_binary(){
+	init_rng();
+	unsigned char enc_key[256];
+	memset( (void*)&enc_key, 0, sizeof(enc_key) );
+	size_t k_size = 0;
+	for ( ; k_size < 256; k_size++ )
+		enc_key[k_size] = (unsigned char)get_random_int( 1, 255 );
+	struct stat test_bin_info;
+	memset( (void*)&test_bin_info, 0, sizeof(struct stat) );
+	if ( stat("./test_binary", &test_bin_info) == -1 ){
+		fprintf( stderr, "Failed to stat: %s\n", strerror(errno) );
+		return;
+	}
+	if ( !((test_bin_info.st_mode & S_IFMT) == S_IFREG) ){
+		fputs( "Error: test binary is not regular file\n", stderr );
+		return;
+	}
+	unsigned char *test_bin_bytes = (unsigned char*)calloc( (size_t)test_bin_info.st_size, sizeof(unsigned char) );
+	if ( test_bin_bytes == NULL ){
+		fprintf( stderr, "Error: failed to allocate memory for reading test binary: %s\n", strerror(errno) );
+		return;
+	}
+	int test_bin_fd = open( "./test_binary", O_RDONLY, 0755 );
+	if ( test_bin_fd == -1 ){
+		fprintf( stderr, "Error: failed to open test binary for encryption: %s\n", strerror(errno) );
+		free( test_bin_bytes );
+		return;
+	}
+	if ( read(test_bin_fd, (void*)test_bin_bytes, (size_t)test_bin_info.st_size) == -1 ){
+		fprintf( stderr, "Error: failed to read test binary bytes: %s\n", strerror(errno) );
+		close( test_bin_fd );
+		free( test_bin_bytes );
+		return;
+	}
+	close( test_bin_fd );
+	size_t encrypted_bytes = 0;
+	for ( ; encrypted_bytes < (size_t)test_bin_info.st_size; encrypted_bytes++ )
+		test_bin_bytes[encrypted_bytes] = test_bin_bytes[encrypted_bytes] ^ enc_key[(size_t)test_bin_info.st_size % 255];
+	test_bin_fd = open( "./test_binary", O_RDWR | O_CREAT | O_TRUNC );
+	if ( test_bin_fd == -1 ){
+		fprintf( stderr, "Error: failed to open test binary for writing: %s\n", strerror(errno) );
+		free( test_bin_bytes );
+		return;
+	}
+	if ( write(test_bin_fd, (const void*)test_bin_bytes, (size_t)test_bin_info.st_size) == -1 ){
+		fprintf( stderr, "Error: failed to write encrypted test binary: %s\n", strerror(errno) );
+		close( test_bin_fd );
+		free( test_bin_bytes );
+		return;
+	}
+	close( test_bin_fd );
+	free( test_bin_bytes );
+	return;
+}
+
+int main( int argc, char *const *args ){
+	encrypt_test_binary();
+	return 0;
+}