sandbox/src/sandbox.c

#include <sys/ptrace.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/reg.h>
#include <sys/uio.h>
#include <strings.h>
#include <string.h>
#include <elf.h>
#include "sandbox.h"

static inline void get_args(struct s_sandboxenv *env)
{
}

int waitForSyscall(const int pid, int _status)
{
	int status;
	static int current_status = SANDBOX_SYS_EXIT;

	if (current_status == _status || (_status != SANDBOX_SYS_ENTER && _status != SANDBOX_SYS_EXIT))
		return 0;
	ptrace(PTRACE_SYSCALL, pid, NULL, 0);
	current_status = _status;
	if (waitpid(pid, &status, 0) == -1)
		return -1;
	return 0;
}

int manageSyscall(struct s_sandboxenv *env)
{
	t_syscall_fnc ovr_fnc;

	if (env->syscall_no.syscall_no >= NR_syscalls ||
			!(ovr_fnc = env->functions[env->syscall_no.syscall_no]))
	{
		/* Unrecognized syscall */
		return 0;
	}
	return (ovr_fnc)(env);
}

void read_registers(struct s_sandboxenv *env)
{
	struct iovec iov = { &(env->registers), sizeof(env->registers) };

	ptrace(PTRACE_GETREGSET, env->child_pid, NT_PRSTATUS, &iov);
#ifdef __x86_64__
	env->syscall_no.syscall_no = (unsigned int) env->registers.orig_rax;
	env->syscall_no.syscall_return = (unsigned int) env->registers.rax;
	REGISTER_TYPE result[] = { env->registers.rdi, env->registers.rsi,
			env->registers.rdx, env->registers.r10,
			env->registers.r8, env->registers.r9 };
#else
	env->syscall_no.syscall_no = (unsigned int) env->registers.orig_eax;
	env->syscall_no.syscall_return = (unsigned int) env->registers.eax;
	REGISTER_TYPE result[] = { env->registers.ebx, env->registers.ecx,
			env->registers.edx, env->registers.esi,
			env->registers.edi, env->registers.ebp };
#endif
	memcpy(env->syscall_args, result, sizeof(REGISTER_TYPE) * 6);
}

void doTrace(int pid, const t_param *params)
{
	int status;
	struct s_sandboxenv sandbox_env;

	ptrace(PTRACE_ATTACH, pid, 0, 0);
	kill(pid, SIGTRAP);
	waitpid(pid, &status, 0);
	sandbox_env.params = params;
	sandbox_env.child_pid = pid;
    //TODO get error output from command-line
    sandbox_env.errorOutput = stderr;
	sandbox_env.filetable = sllist_create();
	init_syscalls(&sandbox_env);

	while (1)
	{
		if (waitForSyscall(pid, SANDBOX_SYS_ENTER))
			break;
		read_registers(&sandbox_env);
		if (manageSyscall(&sandbox_env))
			ptrace(PTRACE_SETREGS, pid, 0, &(sandbox_env.registers));
		if (waitForSyscall(pid, SANDBOX_SYS_EXIT))
			break;
	}

	prompt_sandbox(&sandbox_env);
	sllist_destroy(sandbox_env.filetable);
}

int launch_program(const t_param *params)
{
	int child = fork();

	if (child == -1)
		return -1;
	else if (child == 0)
		doExec(getpid(), params);
	else
		doTrace(child, params);
	return 0;
}