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Author: ivan-hc

init.c

@@ -0,0 +1,61 @@
+// This is a bash-static initializer for Conty
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+// Replace all 0 below before compilation
+
+// The size of our statically compiled bash binary
+#define BASH_SIZE 0
+
+// The size of conty-start.sh script
+// It can be bigger than the actual size of the script
+#define SCRIPT_SIZE 0
+
+// The size of this program itself after compilation
+// It can be bigger than the actual size of the program
+#define PROGRAM_SIZE 0
+
+// Bubblewrap can handle up to 9000 arguments
+// And we reserve 1000 for internal use in Conty
+#define MAX_ARGS_NUMBER 8000
+
+int main(int argc, char* argv[])
+{
+	if (argc > MAX_ARGS_NUMBER) {
+		printf("Too many arguments");
+		return 1;
+	}
+
+	char program_path[8192] = { 0 };
+	int binary_code[BASH_SIZE + 1];
+	char bash_script[SCRIPT_SIZE + 1];
+
+	readlink("/proc/self/exe", program_path, sizeof program_path);
+	FILE *current_program = fopen(program_path, "rb");
+	int bash_binary = memfd_create("bash-static", 0);
+
+	fseek(current_program, PROGRAM_SIZE, 0);
+	fread(binary_code, BASH_SIZE, 1, current_program);
+	write(bash_binary, binary_code, BASH_SIZE);
+
+	fseek(current_program, PROGRAM_SIZE + BASH_SIZE, 0);
+	fread(bash_script, SCRIPT_SIZE, 1, current_program);
+	fclose(current_program);
+
+	char * bash_args[MAX_ARGS_NUMBER + 5] = {program_path, "-c", "--", bash_script, argv[0]};
+
+	int k = 5;
+	for (int i = 1; i < argc; i++, k++) {
+		bash_args[k] = argv[i];
+	}
+	bash_args[k] = NULL;
+
+	fexecve(bash_binary, bash_args, environ);
+	printf("Failed to execute builtin bash-static");
+
+    return 0;
+}