include $(s)/sherlock/Makefile
endif
-# Programs we want to compile
-#PROGS+=$(o)/test
-#$(o)/test: $(o)/test.o $(LIBUCW) $(LIBLANG) $(LIBCHARSET) $(LIBIMAGES)
+include $(s)/box/Makefile
# And finally the default rules of the build system
include $(s)/build/Makebottom
--- /dev/null
+# Makefile for MO-Eval sandbox
+# (c) 2008 Martin Mares <mj@ucw.cz>
+
+DIRS+=box
+PROGS+=$(o)/box/box
+
+$(o)/box/box: $(o)/box/box.o
+$(o)/box/box.o: $(o)/box/syscall-table.h
+
+$(o)/box/syscall-table.h: $(s)/box/mk-syscall-table
+ sh $^ >$@
--- /dev/null
+/*
+ * A Simple Sandbox for MO-Eval
+ *
+ * (c) 2001--2008 Martin Mares <mj@ucw.cz>
+ */
+
+#define _LARGEFILE64_SOURCE
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <time.h>
+#include <sys/wait.h>
+#include <sys/user.h>
+#include <sys/time.h>
+#include <sys/ptrace.h>
+#include <sys/signal.h>
+#include <sys/sysinfo.h>
+#include <sys/syscall.h>
+#include <sys/resource.h>
+
+#define NONRET __attribute__((noreturn))
+#define UNUSED __attribute__((unused))
+#define ARRAY_SIZE(a) (int)(sizeof(a)/sizeof(a[0]))
+
+static int filter_syscalls; /* 0=off, 1=liberal, 2=totalitarian */
+static int timeout; /* milliseconds */
+static int wall_timeout;
+static int pass_environ;
+static int file_access;
+static int verbose;
+static int memory_limit;
+static char *redir_stdin, *redir_stdout, *redir_stderr;
+static char *set_cwd;
+
+static pid_t box_pid;
+static int is_ptraced;
+static volatile int timer_tick;
+static struct timeval start_time;
+static int ticks_per_sec;
+static int exec_seen;
+static int partial_line;
+
+#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ > 0
+/* glibc 2.1 or newer -> has lseek64 */
+#define long_seek(f,o,w) lseek64(f,o,w)
+#else
+/* Touching clandestine places in glibc */
+extern loff_t llseek(int fd, loff_t pos, int whence);
+#define long_seek(f,o,w) llseek(f,o,w)
+#endif
+
+static void NONRET
+box_exit(void)
+{
+ if (box_pid > 0)
+ {
+ if (is_ptraced)
+ ptrace(PTRACE_KILL, box_pid);
+ kill(-box_pid, SIGKILL);
+ kill(box_pid, SIGKILL);
+ }
+ exit(1);
+}
+
+static void
+flush_line(void)
+{
+ if (partial_line)
+ fputc('\n', stderr);
+ partial_line = 0;
+}
+
+static void NONRET __attribute__((format(printf,1,2)))
+die(char *msg, ...)
+{
+ va_list args;
+ va_start(args, msg);
+ flush_line();
+ vfprintf(stderr, msg, args);
+ fputc('\n', stderr);
+ box_exit();
+}
+
+static void __attribute__((format(printf,1,2)))
+msg(char *msg, ...)
+{
+ va_list args;
+ va_start(args, msg);
+ if (verbose)
+ {
+ int len = strlen(msg);
+ if (len > 0)
+ partial_line = (msg[len-1] != '\n');
+ vfprintf(stderr, msg, args);
+ fflush(stderr);
+ }
+ va_end(args);
+}
+
+static void *
+xmalloc(size_t size)
+{
+ void *p = malloc(size);
+ if (!p)
+ die("Out of memory");
+ return p;
+}
+
+/*** Syscall rules ***/
+
+static const char * const syscall_names[] = {
+#include "box/syscall-table.h"
+};
+#define NUM_SYSCALLS ARRAY_SIZE(syscall_names)
+#define NUM_ACTIONS (NUM_SYSCALLS+64)
+
+enum action {
+ A_DEFAULT, // Use the default action
+ A_NO, // Always forbid
+ A_YES, // Always permit
+ A_FILENAME, // Permit if arg1 is a known filename
+ A_LIBERAL = 128, // Valid only in liberal mode
+};
+
+static unsigned char syscall_action[NUM_ACTIONS] = {
+#define S(x) [__NR_##x]
+
+ // Syscalls permitted for specific file names
+ S(open) = A_FILENAME,
+ S(creat) = A_FILENAME,
+ S(unlink) = A_FILENAME,
+ S(oldstat) = A_FILENAME,
+ S(access) = A_FILENAME,
+ S(oldlstat) = A_FILENAME,
+ S(truncate) = A_FILENAME,
+ S(stat) = A_FILENAME,
+ S(lstat) = A_FILENAME,
+ S(truncate64) = A_FILENAME,
+ S(stat64) = A_FILENAME,
+ S(lstat64) = A_FILENAME,
+ S(readlink) = A_FILENAME,
+
+ // Syscalls permitted always
+ S(exit) = A_YES,
+ S(read) = A_YES,
+ S(write) = A_YES,
+ S(close) = A_YES,
+ S(lseek) = A_YES,
+ S(getpid) = A_YES,
+ S(getuid) = A_YES,
+ S(oldfstat) = A_YES,
+ S(dup) = A_YES,
+ S(brk) = A_YES,
+ S(getgid) = A_YES,
+ S(geteuid) = A_YES,
+ S(getegid) = A_YES,
+ S(dup2) = A_YES,
+ S(ftruncate) = A_YES,
+ S(fstat) = A_YES,
+ S(personality) = A_YES,
+ S(_llseek) = A_YES,
+ S(readv) = A_YES,
+ S(writev) = A_YES,
+ S(getresuid) = A_YES,
+#ifdef __NR_pread64
+ S(pread64) = A_YES,
+ S(pwrite64) = A_YES,
+#else
+ S(pread) = A_YES,
+ S(pwrite) = A_YES,
+#endif
+ S(ftruncate64) = A_YES,
+ S(fstat64) = A_YES,
+ S(fcntl) = A_YES,
+ S(fcntl64) = A_YES,
+ S(mmap) = A_YES,
+ S(munmap) = A_YES,
+ S(ioctl) = A_YES,
+ S(uname) = A_YES,
+ S(gettid) = A_YES,
+ S(set_thread_area) = A_YES,
+ S(get_thread_area) = A_YES,
+ S(exit_group) = A_YES,
+
+ // Syscalls permitted only in liberal mode
+ S(time) = A_YES | A_LIBERAL,
+ S(alarm) = A_YES | A_LIBERAL,
+ S(pause) = A_YES | A_LIBERAL,
+ S(signal) = A_YES | A_LIBERAL,
+ S(fchmod) = A_YES | A_LIBERAL,
+ S(sigaction) = A_YES | A_LIBERAL,
+ S(sgetmask) = A_YES | A_LIBERAL,
+ S(ssetmask) = A_YES | A_LIBERAL,
+ S(sigsuspend) = A_YES | A_LIBERAL,
+ S(sigpending) = A_YES | A_LIBERAL,
+ S(getrlimit) = A_YES | A_LIBERAL,
+ S(getrusage) = A_YES | A_LIBERAL,
+ S(ugetrlimit) = A_YES | A_LIBERAL,
+ S(gettimeofday) = A_YES | A_LIBERAL,
+ S(select) = A_YES | A_LIBERAL,
+ S(readdir) = A_YES | A_LIBERAL,
+ S(setitimer) = A_YES | A_LIBERAL,
+ S(getitimer) = A_YES | A_LIBERAL,
+ S(sigreturn) = A_YES | A_LIBERAL,
+ S(mprotect) = A_YES | A_LIBERAL,
+ S(sigprocmask) = A_YES | A_LIBERAL,
+ S(getdents) = A_YES | A_LIBERAL,
+ S(getdents64) = A_YES | A_LIBERAL,
+ S(_newselect) = A_YES | A_LIBERAL,
+ S(fdatasync) = A_YES | A_LIBERAL,
+ S(mremap) = A_YES | A_LIBERAL,
+ S(poll) = A_YES | A_LIBERAL,
+ S(getcwd) = A_YES | A_LIBERAL,
+ S(nanosleep) = A_YES | A_LIBERAL,
+ S(rt_sigreturn) = A_YES | A_LIBERAL,
+ S(rt_sigaction) = A_YES | A_LIBERAL,
+ S(rt_sigprocmask) = A_YES | A_LIBERAL,
+ S(rt_sigpending) = A_YES | A_LIBERAL,
+ S(rt_sigtimedwait) = A_YES | A_LIBERAL,
+ S(rt_sigqueueinfo) = A_YES | A_LIBERAL,
+ S(rt_sigsuspend) = A_YES | A_LIBERAL,
+ S(mmap2) = A_YES | A_LIBERAL,
+ S(_sysctl) = A_YES | A_LIBERAL,
+#undef S
+};
+
+static const char *
+syscall_name(unsigned int id, char *buf)
+{
+ if (id < NUM_SYSCALLS && syscall_names[id])
+ return syscall_names[id];
+ else
+ {
+ sprintf(buf, "#%d", id);
+ return buf;
+ }
+}
+
+static int
+syscall_by_name(char *name)
+{
+ for (unsigned int i=0; i<NUM_SYSCALLS; i++)
+ if (syscall_names[i] && !strcmp(syscall_names[i], name))
+ return i;
+ if (name[0] == '#')
+ name++;
+ if (!*name)
+ return -1;
+ char *ep;
+ unsigned long l = strtoul(name, &ep, 0);
+ if (*ep)
+ return -1;
+ if (l >= NUM_ACTIONS)
+ return NUM_ACTIONS;
+ return l;
+}
+
+static int
+set_syscall_action(char *a)
+{
+ char *sep = strchr(a, '=');
+ enum action act = A_YES;
+ if (sep)
+ {
+ *sep++ = 0;
+ if (!strcmp(sep, "yes"))
+ act = A_YES;
+ else if (!strcmp(sep, "no"))
+ act = A_NO;
+ else if (!strcmp(sep, "file"))
+ act = A_FILENAME;
+ else
+ return 0;
+ }
+
+ int sys = syscall_by_name(a);
+ if (sys < 0)
+ die("Unknown syscall `%s'", a);
+ if (sys >= NUM_ACTIONS)
+ die("Syscall `%s' out of range", a);
+ syscall_action[sys] = act;
+ return 1;
+}
+
+/*** Path rules ***/
+
+struct path_rule {
+ char *path;
+ enum action action;
+ struct path_rule *next;
+};
+
+static struct path_rule default_path_rules[] = {
+ { "/etc/", A_YES },
+ { "/lib/", A_YES },
+ { "/usr/lib/", A_YES },
+ { "/opt/lib/", A_YES },
+ { "/usr/share/zoneinfo/", A_YES },
+ { "/usr/share/locale/", A_YES },
+ { "/dev/null", A_YES },
+ { "/dev/zero", A_YES },
+ { "/proc/meminfo", A_YES },
+ { "/proc/self/stat", A_YES },
+ { "/proc/self/exe", A_YES }, // Needed by FPC 2.0.x runtime
+};
+
+static struct path_rule *user_path_rules;
+static struct path_rule **last_path_rule = &user_path_rules;
+
+static int
+set_path_action(char *a)
+{
+ char *sep = strchr(a, '=');
+ enum action act = A_YES;
+ if (sep)
+ {
+ *sep++ = 0;
+ if (!strcmp(sep, "yes"))
+ act = A_YES;
+ else if (!strcmp(sep, "no"))
+ act = A_NO;
+ else
+ return 0;
+ }
+
+ struct path_rule *r = xmalloc(sizeof(*r) + strlen(a) + 1);
+ r->path = (char *)(r+1);
+ strcpy(r->path, a);
+ r->action = act;
+ r->next = NULL;
+ *last_path_rule = r;
+ last_path_rule = &r->next;
+ return 1;
+}
+
+static enum action
+match_path_rule(struct path_rule *r, char *path)
+{
+ char *rr = r->path;
+ while (*rr)
+ if (*rr++ != *path++)
+ {
+ if (rr[-1] == '/' && !path[-1])
+ break;
+ return A_DEFAULT;
+ }
+ if (rr > r->path && rr[-1] != '/' && *path)
+ return A_DEFAULT;
+ return r->action;
+}
+
+/*** Environment rules ***/
+
+struct env_rule {
+ char *var; // Variable to match
+ char *val; // ""=clear, NULL=inherit
+ int var_len;
+ struct env_rule *next;
+};
+
+static struct env_rule *first_env_rule;
+static struct env_rule **last_env_rule = &first_env_rule;
+
+static struct env_rule default_env_rules[] = {
+ { "LIBC_FATAL_STDERR_", "1" }
+};
+
+static int
+set_env_action(char *a0)
+{
+ struct env_rule *r = xmalloc(sizeof(*r) + strlen(a0) + 1);
+ char *a = (char *)(r+1);
+ strcpy(a, a0);
+
+ char *sep = strchr(a, '=');
+ if (sep == a)
+ return 0;
+ r->var = a;
+ if (sep)
+ {
+ *sep++ = 0;
+ r->val = sep;
+ }
+ else
+ r->val = NULL;
+ *last_env_rule = r;
+ last_env_rule = &r->next;
+ r->next = NULL;
+ return 1;
+}
+
+static int
+match_env_var(char *env_entry, struct env_rule *r)
+{
+ if (strncmp(env_entry, r->var, r->var_len))
+ return 0;
+ return (env_entry[r->var_len] == '=');
+}
+
+static void
+apply_env_rule(char **env, int *env_sizep, struct env_rule *r)
+{
+ // First remove the variable if already set
+ int pos = 0;
+ while (pos < *env_sizep && !match_env_var(env[pos], r))
+ pos++;
+ if (pos < *env_sizep)
+ {
+ (*env_sizep)--;
+ env[pos] = env[*env_sizep];
+ env[*env_sizep] = NULL;
+ }
+
+ // What is the new value?
+ char *new;
+ if (r->val)
+ {
+ if (!r->val[0])
+ return;
+ new = xmalloc(r->var_len + 1 + strlen(r->val) + 1);
+ sprintf(new, "%s=%s", r->var, r->val);
+ }
+ else
+ {
+ pos = 0;
+ while (environ[pos] && !match_env_var(environ[pos], r))
+ pos++;
+ if (!(new = environ[pos]))
+ return;
+ }
+
+ // Add it at the end of the array
+ env[(*env_sizep)++] = new;
+ env[*env_sizep] = NULL;
+}
+
+static char **
+setup_environment(void)
+{
+ // Link built-in rules with user rules
+ for (int i=ARRAY_SIZE(default_env_rules)-1; i >= 0; i--)
+ {
+ default_env_rules[i].next = first_env_rule;
+ first_env_rule = &default_env_rules[i];
+ }
+
+ // Scan the original environment
+ char **orig_env = environ;
+ int orig_size = 0;
+ while (orig_env[orig_size])
+ orig_size++;
+
+ // For each rule, reserve one more slot and calculate length
+ int num_rules = 0;
+ for (struct env_rule *r = first_env_rule; r; r=r->next)
+ {
+ num_rules++;
+ r->var_len = strlen(r->var);
+ }
+
+ // Create a new environment
+ char **env = xmalloc((orig_size + num_rules + 1) * sizeof(char *));
+ int size;
+ if (pass_environ)
+ {
+ memcpy(env, environ, orig_size * sizeof(char *));
+ size = orig_size;
+ }
+ else
+ size = 0;
+ env[size] = NULL;
+
+ // Apply the rules one by one
+ for (struct env_rule *r = first_env_rule; r; r=r->next)
+ apply_env_rule(env, &size, r);
+
+ // Return the new env and pass some gossip
+ if (verbose > 1)
+ {
+ fprintf(stderr, "Passing environment:\n");
+ for (int i=0; env[i]; i++)
+ fprintf(stderr, "\t%s\n", env[i]);
+ }
+ return env;
+}
+
+/*** Syscall checks ***/
+
+static void
+valid_filename(unsigned long addr)
+{
+ char namebuf[4096], *p, *end;
+ static int mem_fd;
+
+ if (!file_access)
+ die("File access forbidden");
+ if (file_access >= 9)
+ return;
+
+ if (!mem_fd)
+ {
+ sprintf(namebuf, "/proc/%d/mem", (int) box_pid);
+ mem_fd = open(namebuf, O_RDONLY);
+ if (mem_fd < 0)
+ die("open(%s): %m", namebuf);
+ }
+ p = end = namebuf;
+ do
+ {
+ if (p >= end)
+ {
+ int remains = PAGE_SIZE - (addr & (PAGE_SIZE-1));
+ int l = namebuf + sizeof(namebuf) - end;
+ if (l > remains)
+ l = remains;
+ if (!l)
+ die("Access to file with name too long");
+ if (long_seek(mem_fd, addr, SEEK_SET) < 0)
+ die("long_seek(mem): %m");
+ remains = read(mem_fd, end, l);
+ if (remains < 0)
+ die("read(mem): %m");
+ if (!remains)
+ die("Access to file with name out of memory");
+ end += l;
+ addr += l;
+ }
+ }
+ while (*p++);
+
+ msg("[%s] ", namebuf);
+ if (file_access >= 3)
+ return;
+
+ // Everything in current directory is permitted
+ if (!strchr(namebuf, '/') && strcmp(namebuf, ".."))
+ return;
+
+ // ".." anywhere in the path is forbidden
+ enum action act = A_DEFAULT;
+ if (strstr(namebuf, ".."))
+ act = A_NO;
+
+ // Scan user rules
+ for (struct path_rule *r = user_path_rules; r && !act; r=r->next)
+ act = match_path_rule(r, namebuf);
+
+ // Scan built-in rules
+ if (file_access >= 2)
+ for (int i=0; i<ARRAY_SIZE(default_path_rules) && !act; i++)
+ act = match_path_rule(&default_path_rules[i], namebuf);
+
+ if (act != A_YES)
+ die("Forbidden access to file `%s'", namebuf);
+}
+
+static int
+valid_syscall(struct user *u)
+{
+ unsigned int sys = u->regs.orig_eax;
+ enum action act = (sys < NUM_ACTIONS) ? syscall_action[sys] : A_DEFAULT;
+
+ if (act & A_LIBERAL)
+ {
+ if (filter_syscalls == 1)
+ act &= ~A_LIBERAL;
+ else
+ act = A_DEFAULT;
+ }
+ switch (act)
+ {
+ case A_YES:
+ return 1;
+ case A_NO:
+ return 0;
+ case A_FILENAME:
+ valid_filename(u->regs.ebx);
+ return 1;
+ default: ;
+ }
+
+ switch (sys)
+ {
+ case __NR_kill:
+ if (u->regs.ebx == box_pid)
+ die("Committed suicide by signal %d", (int)u->regs.ecx);
+ return 0;
+ case __NR_tgkill:
+ if (u->regs.ebx == box_pid && u->regs.ecx == box_pid)
+ die("Committed suicide by signal %d", (int)u->regs.edx);
+ return 0;
+ default:
+ return 0;
+ }
+}
+
+static void
+signal_alarm(int unused UNUSED)
+{
+ /* Time limit checks are synchronous, so we only schedule them there. */
+ timer_tick = 1;
+ alarm(1);
+}
+
+static void
+signal_int(int unused UNUSED)
+{
+ /* Interrupts are fatal, so no synchronization requirements. */
+ die("Interrupted");
+}
+
+static void
+check_timeout(void)
+{
+ if (wall_timeout)
+ {
+ struct timeval now, wall;
+ int wall_ms;
+ gettimeofday(&now, NULL);
+ timersub(&now, &start_time, &wall);
+ wall_ms = wall.tv_sec*1000 + wall.tv_usec/1000;
+ if (wall_ms > wall_timeout)
+ die("Time limit exceeded (wall clock)");
+ if (verbose > 1)
+ fprintf(stderr, "[wall time check: %d msec]\n", wall_ms);
+ }
+ if (timeout)
+ {
+ char buf[4096], *x;
+ int c, utime, stime, ms;
+ static int proc_status_fd;
+ if (!proc_status_fd)
+ {
+ sprintf(buf, "/proc/%d/stat", (int) box_pid);
+ proc_status_fd = open(buf, O_RDONLY);
+ if (proc_status_fd < 0)
+ die("open(%s): %m", buf);
+ }
+ lseek(proc_status_fd, 0, SEEK_SET);
+ if ((c = read(proc_status_fd, buf, sizeof(buf)-1)) < 0)
+ die("read on /proc/$pid/stat: %m");
+ if (c >= (int) sizeof(buf) - 1)
+ die("/proc/$pid/stat too long");
+ buf[c] = 0;
+ x = buf;
+ while (*x && *x != ' ')
+ x++;
+ while (*x == ' ')
+ x++;
+ if (*x++ != '(')
+ die("proc syntax error 1");
+ while (*x && (*x != ')' || x[1] != ' '))
+ x++;
+ while (*x == ')' || *x == ' ')
+ x++;
+ if (sscanf(x, "%*c %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %d %d", &utime, &stime) != 2)
+ die("proc syntax error 2");
+ ms = (utime + stime) * 1000 / ticks_per_sec;
+ if (verbose > 1)
+ fprintf(stderr, "[time check: %d msec]\n", ms);
+ if (ms > timeout)
+ die("Time limit exceeded");
+ }
+}
+
+static void
+boxkeeper(void)
+{
+ int syscall_count = 0;
+ struct sigaction sa;
+
+ is_ptraced = 1;
+ bzero(&sa, sizeof(sa));
+ sa.sa_handler = signal_int;
+ sigaction(SIGINT, &sa, NULL);
+ gettimeofday(&start_time, NULL);
+ ticks_per_sec = sysconf(_SC_CLK_TCK);
+ if (ticks_per_sec <= 0)
+ die("Invalid ticks_per_sec!");
+ if (timeout || wall_timeout)
+ {
+ sa.sa_handler = signal_alarm;
+ sigaction(SIGALRM, &sa, NULL);
+ alarm(1);
+ }
+ for(;;)
+ {
+ struct rusage rus;
+ int stat;
+ pid_t p;
+ if (timer_tick)
+ {
+ check_timeout();
+ timer_tick = 0;
+ }
+ p = wait4(box_pid, &stat, WUNTRACED, &rus);
+ if (p < 0)
+ {
+ if (errno == EINTR)
+ continue;
+ die("wait4: %m");
+ }
+ if (p != box_pid)
+ die("wait4: unknown pid %d exited!", p);
+ if (WIFEXITED(stat))
+ {
+ struct timeval total, now, wall;
+ int total_ms, wall_ms;
+ box_pid = 0;
+ if (WEXITSTATUS(stat))
+ die("Exited with error status %d", WEXITSTATUS(stat));
+ timeradd(&rus.ru_utime, &rus.ru_stime, &total);
+ total_ms = total.tv_sec*1000 + total.tv_usec/1000;
+ gettimeofday(&now, NULL);
+ timersub(&now, &start_time, &wall);
+ wall_ms = wall.tv_sec*1000 + wall.tv_usec/1000;
+ if (timeout && total_ms > timeout)
+ die("Time limit exceeded");
+ if (wall_timeout && wall_ms > wall_timeout)
+ die("Time limit exceeded (wall clock)");
+ flush_line();
+ fprintf(stderr, "OK (%d.%03d sec real, %d.%03d sec wall, %d syscalls)\n",
+ (int) total.tv_sec, (int) total.tv_usec/1000,
+ (int) wall.tv_sec, (int) wall.tv_usec/1000,
+ syscall_count);
+ exit(0);
+ }
+ if (WIFSIGNALED(stat))
+ {
+ box_pid = 0;
+ die("Caught fatal signal %d%s", WTERMSIG(stat), (syscall_count ? "" : " during startup"));
+ }
+ if (WIFSTOPPED(stat))
+ {
+ int sig = WSTOPSIG(stat);
+ if (sig == SIGTRAP)
+ {
+ struct user u;
+ static int stop_count = -1;
+ if (ptrace(PTRACE_GETREGS, box_pid, NULL, &u) < 0)
+ die("ptrace(PTRACE_GETREGS): %m");
+ stop_count++;
+ if (!stop_count) /* Traceme request */
+ msg(">> Traceme request caught\n");
+ else if (stop_count & 1) /* Syscall entry */
+ {
+ char namebuf[32];
+ msg(">> Syscall %-12s (%08lx,%08lx,%08lx) ", syscall_name(u.regs.orig_eax, namebuf), u.regs.ebx, u.regs.ecx, u.regs.edx);
+ if (!exec_seen)
+ {
+ msg("[master] ");
+ if (u.regs.orig_eax == __NR_execve)
+ exec_seen = 1;
+ }
+ else if (valid_syscall(&u))
+ syscall_count++;
+ else
+ {
+ /*
+ * Unfortunately, PTRACE_KILL kills _after_ the syscall completes,
+ * so we have to change it to something harmless (e.g., an undefined
+ * syscall) and make the program continue.
+ */
+ unsigned int sys = u.regs.orig_eax;
+ u.regs.orig_eax = 0xffffffff;
+ if (ptrace(PTRACE_SETREGS, box_pid, NULL, &u) < 0)
+ die("ptrace(PTRACE_SETREGS): %m");
+ die("Forbidden syscall %s", syscall_name(sys, namebuf));
+ }
+ }
+ else /* Syscall return */
+ msg("= %ld\n", u.regs.eax);
+ ptrace(PTRACE_SYSCALL, box_pid, 0, 0);
+ }
+ else if (sig != SIGSTOP && sig != SIGXCPU && sig != SIGXFSZ)
+ {
+ msg(">> Signal %d\n", sig);
+ ptrace(PTRACE_SYSCALL, box_pid, 0, sig);
+ }
+ else
+ die("Received signal %d", sig);
+ }
+ else
+ die("wait4: unknown status %x, giving up!", stat);
+ }
+}
+
+static void
+box_inside(int argc, char **argv)
+{
+ struct rlimit rl;
+ char *args[argc+1];
+
+ memcpy(args, argv, argc * sizeof(char *));
+ args[argc] = NULL;
+ if (set_cwd && chdir(set_cwd))
+ die("chdir: %m");
+ if (redir_stdin)
+ {
+ close(0);
+ if (open(redir_stdin, O_RDONLY) != 0)
+ die("open(\"%s\"): %m", redir_stdin);
+ }
+ if (redir_stdout)
+ {
+ close(1);
+ if (open(redir_stdout, O_WRONLY | O_CREAT | O_TRUNC, 0666) != 1)
+ die("open(\"%s\"): %m", redir_stdout);
+ }
+ if (redir_stderr)
+ {
+ close(2);
+ if (open(redir_stderr, O_WRONLY | O_CREAT | O_TRUNC, 0666) != 2)
+ die("open(\"%s\"): %m", redir_stderr);
+ }
+ else
+ dup2(1, 2);
+ setpgrp();
+ if (memory_limit)
+ {
+ rl.rlim_cur = rl.rlim_max = memory_limit * 1024;
+ if (setrlimit(RLIMIT_AS, &rl) < 0)
+ die("setrlimit: %m");
+ }
+ rl.rlim_cur = rl.rlim_max = 64;
+ if (setrlimit(RLIMIT_NOFILE, &rl) < 0)
+ die("setrlimit: %m");
+ if (filter_syscalls)
+ {
+ if (ptrace(PTRACE_TRACEME) < 0)
+ die("ptrace(PTRACE_TRACEME): %m");
+ /* Trick: Make sure that we are stopped until the boxkeeper wakes up. */
+ signal(SIGCHLD, SIG_IGN);
+ raise(SIGCHLD);
+ }
+ execve(args[0], args, setup_environment());
+ die("execve(\"%s\"): %m", args[0]);
+}
+
+static void
+usage(void)
+{
+ fprintf(stderr, "Invalid arguments!\n");
+ printf("\
+Usage: box [<options>] -- <command> <arguments>\n\
+\n\
+Options:\n\
+-a <level>\tSet file access level (0=none, 1=cwd, 2=/etc,/lib,..., 3=whole fs, 9=no checks; needs -f)\n\
+-c <dir>\tChange directory to <dir> first\n\
+-e\t\tInherit full environment of the parent process\n\
+-E <var>\tInherit the environment variable <var> from the parent process\n\
+-E <var>=<val>\tSet the environment variable <var> to <val>; unset it if <var> is empty\n\
+-f\t\tFilter system calls (-ff=very restricted)\n\
+-i <file>\tRedirect stdin from <file>\n\
+-m <size>\tLimit address space to <size> KB\n\
+-o <file>\tRedirect stdout to <file>\n\
+-p <path>\tPermit access to the specified path (or subtree if it ends with a `/')\n\
+-p <path>=<act>\tDefine action for the specified path (<act>=yes/no)\n\
+-r <file>\tRedirect stderr to <file>\n\
+-s <sys>\tPermit the specified syscall (be careful)\n\
+-s <sys>=<act>\tDefine action for the specified syscall (<act>=yes/no/file)\n\
+-t <time>\tSet run time limit (seconds, fractions allowed)\n\
+-T\t\tAllow syscalls for measuring run time\n\
+-v\t\tBe verbose (use multiple times for even more verbosity)\n\
+-w <time>\tSet wall clock time limit (seconds, fractions allowed)\n\
+");
+ exit(1);
+}
+
+int
+main(int argc, char **argv)
+{
+ int c;
+ uid_t uid;
+
+ while ((c = getopt(argc, argv, "a:c:eE:fi:m:o:p:r:s:t:Tvw:")) >= 0)
+ switch (c)
+ {
+ case 'a':
+ file_access = atol(optarg);
+ break;
+ case 'c':
+ set_cwd = optarg;
+ break;
+ case 'e':
+ pass_environ = 1;
+ break;
+ case 'E':
+ if (!set_env_action(optarg))
+ usage();
+ break;
+ case 'f':
+ filter_syscalls++;
+ break;
+ case 'i':
+ redir_stdin = optarg;
+ break;
+ case 'm':
+ memory_limit = atol(optarg);
+ break;
+ case 'o':
+ redir_stdout = optarg;
+ break;
+ case 'p':
+ if (!set_path_action(optarg))
+ usage();
+ break;
+ case 'r':
+ redir_stderr = optarg;
+ break;
+ case 's':
+ if (!set_syscall_action(optarg))
+ usage();
+ break;
+ case 't':
+ timeout = 1000*atof(optarg);
+ break;
+ case 'T':
+ syscall_action[__NR_times] = A_YES;
+ break;
+ case 'v':
+ verbose++;
+ break;
+ case 'w':
+ wall_timeout = 1000*atof(optarg);
+ break;
+ default:
+ usage();
+ }
+ if (optind >= argc)
+ usage();
+
+ uid = geteuid();
+ if (setreuid(uid, uid) < 0)
+ die("setreuid: %m");
+ box_pid = fork();
+ if (box_pid < 0)
+ die("fork: %m");
+ if (!box_pid)
+ box_inside(argc-optind, argv+optind);
+ else
+ boxkeeper();
+ die("Internal error: fell over edge of the world");
+}
--- /dev/null
+#!/bin/sh
+set -e
+(
+echo '/* Syscall table automatically generated by mk-syscall-table */'
+echo
+echo '#include <asm/unistd.h>' |
+ gcc -E -dM - |
+ sed 's/^#define __NR_\([^ ]\+\).*/[ __NR_\1 ] = "\1",/;t;d'
+)
+++ /dev/null
-/*
- * A Simple Sandbox for MO-Eval
- *
- * (c) 2001--2008 Martin Mares <mj@ucw.cz>
- */
-
-#define _LARGEFILE64_SOURCE
-#define _GNU_SOURCE
-
-#include <errno.h>
-#include <stdio.h>
-#include <fcntl.h>
-#include <stdlib.h>
-#include <string.h>
-#include <stdarg.h>
-#include <unistd.h>
-#include <getopt.h>
-#include <time.h>
-#include <sys/wait.h>
-#include <sys/user.h>
-#include <sys/time.h>
-#include <sys/ptrace.h>
-#include <sys/signal.h>
-#include <sys/sysinfo.h>
-#include <sys/syscall.h>
-#include <sys/resource.h>
-
-#define NONRET __attribute__((noreturn))
-#define UNUSED __attribute__((unused))
-#define ARRAY_SIZE(a) (int)(sizeof(a)/sizeof(a[0]))
-
-static int filter_syscalls; /* 0=off, 1=liberal, 2=totalitarian */
-static int timeout; /* milliseconds */
-static int wall_timeout;
-static int pass_environ;
-static int file_access;
-static int verbose;
-static int memory_limit;
-static char *redir_stdin, *redir_stdout, *redir_stderr;
-static char *set_cwd;
-
-static pid_t box_pid;
-static int is_ptraced;
-static volatile int timer_tick;
-static struct timeval start_time;
-static int ticks_per_sec;
-static int exec_seen;
-static int partial_line;
-
-#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ > 0
-/* glibc 2.1 or newer -> has lseek64 */
-#define long_seek(f,o,w) lseek64(f,o,w)
-#else
-/* Touching clandestine places in glibc */
-extern loff_t llseek(int fd, loff_t pos, int whence);
-#define long_seek(f,o,w) llseek(f,o,w)
-#endif
-
-static void NONRET
-box_exit(void)
-{
- if (box_pid > 0)
- {
- if (is_ptraced)
- ptrace(PTRACE_KILL, box_pid);
- kill(-box_pid, SIGKILL);
- kill(box_pid, SIGKILL);
- }
- exit(1);
-}
-
-static void
-flush_line(void)
-{
- if (partial_line)
- fputc('\n', stderr);
- partial_line = 0;
-}
-
-static void NONRET __attribute__((format(printf,1,2)))
-die(char *msg, ...)
-{
- va_list args;
- va_start(args, msg);
- flush_line();
- vfprintf(stderr, msg, args);
- fputc('\n', stderr);
- box_exit();
-}
-
-static void __attribute__((format(printf,1,2)))
-msg(char *msg, ...)
-{
- va_list args;
- va_start(args, msg);
- if (verbose)
- {
- int len = strlen(msg);
- if (len > 0)
- partial_line = (msg[len-1] != '\n');
- vfprintf(stderr, msg, args);
- fflush(stderr);
- }
- va_end(args);
-}
-
-static void *
-xmalloc(size_t size)
-{
- void *p = malloc(size);
- if (!p)
- die("Out of memory");
- return p;
-}
-
-/*** Syscall rules ***/
-
-static const char * const syscall_names[] = {
-#include "syscall-table.h"
-};
-#define NUM_SYSCALLS ARRAY_SIZE(syscall_names)
-#define NUM_ACTIONS (NUM_SYSCALLS+64)
-
-enum action {
- A_DEFAULT, // Use the default action
- A_NO, // Always forbid
- A_YES, // Always permit
- A_FILENAME, // Permit if arg1 is a known filename
- A_LIBERAL = 128, // Valid only in liberal mode
-};
-
-static unsigned char syscall_action[NUM_ACTIONS] = {
-#define S(x) [__NR_##x]
-
- // Syscalls permitted for specific file names
- S(open) = A_FILENAME,
- S(creat) = A_FILENAME,
- S(unlink) = A_FILENAME,
- S(oldstat) = A_FILENAME,
- S(access) = A_FILENAME,
- S(oldlstat) = A_FILENAME,
- S(truncate) = A_FILENAME,
- S(stat) = A_FILENAME,
- S(lstat) = A_FILENAME,
- S(truncate64) = A_FILENAME,
- S(stat64) = A_FILENAME,
- S(lstat64) = A_FILENAME,
- S(readlink) = A_FILENAME,
-
- // Syscalls permitted always
- S(exit) = A_YES,
- S(read) = A_YES,
- S(write) = A_YES,
- S(close) = A_YES,
- S(lseek) = A_YES,
- S(getpid) = A_YES,
- S(getuid) = A_YES,
- S(oldfstat) = A_YES,
- S(dup) = A_YES,
- S(brk) = A_YES,
- S(getgid) = A_YES,
- S(geteuid) = A_YES,
- S(getegid) = A_YES,
- S(dup2) = A_YES,
- S(ftruncate) = A_YES,
- S(fstat) = A_YES,
- S(personality) = A_YES,
- S(_llseek) = A_YES,
- S(readv) = A_YES,
- S(writev) = A_YES,
- S(getresuid) = A_YES,
-#ifdef __NR_pread64
- S(pread64) = A_YES,
- S(pwrite64) = A_YES,
-#else
- S(pread) = A_YES,
- S(pwrite) = A_YES,
-#endif
- S(ftruncate64) = A_YES,
- S(fstat64) = A_YES,
- S(fcntl) = A_YES,
- S(fcntl64) = A_YES,
- S(mmap) = A_YES,
- S(munmap) = A_YES,
- S(ioctl) = A_YES,
- S(uname) = A_YES,
- S(gettid) = A_YES,
- S(set_thread_area) = A_YES,
- S(get_thread_area) = A_YES,
- S(exit_group) = A_YES,
-
- // Syscalls permitted only in liberal mode
- S(time) = A_YES | A_LIBERAL,
- S(alarm) = A_YES | A_LIBERAL,
- S(pause) = A_YES | A_LIBERAL,
- S(signal) = A_YES | A_LIBERAL,
- S(fchmod) = A_YES | A_LIBERAL,
- S(sigaction) = A_YES | A_LIBERAL,
- S(sgetmask) = A_YES | A_LIBERAL,
- S(ssetmask) = A_YES | A_LIBERAL,
- S(sigsuspend) = A_YES | A_LIBERAL,
- S(sigpending) = A_YES | A_LIBERAL,
- S(getrlimit) = A_YES | A_LIBERAL,
- S(getrusage) = A_YES | A_LIBERAL,
- S(ugetrlimit) = A_YES | A_LIBERAL,
- S(gettimeofday) = A_YES | A_LIBERAL,
- S(select) = A_YES | A_LIBERAL,
- S(readdir) = A_YES | A_LIBERAL,
- S(setitimer) = A_YES | A_LIBERAL,
- S(getitimer) = A_YES | A_LIBERAL,
- S(sigreturn) = A_YES | A_LIBERAL,
- S(mprotect) = A_YES | A_LIBERAL,
- S(sigprocmask) = A_YES | A_LIBERAL,
- S(getdents) = A_YES | A_LIBERAL,
- S(getdents64) = A_YES | A_LIBERAL,
- S(_newselect) = A_YES | A_LIBERAL,
- S(fdatasync) = A_YES | A_LIBERAL,
- S(mremap) = A_YES | A_LIBERAL,
- S(poll) = A_YES | A_LIBERAL,
- S(getcwd) = A_YES | A_LIBERAL,
- S(nanosleep) = A_YES | A_LIBERAL,
- S(rt_sigreturn) = A_YES | A_LIBERAL,
- S(rt_sigaction) = A_YES | A_LIBERAL,
- S(rt_sigprocmask) = A_YES | A_LIBERAL,
- S(rt_sigpending) = A_YES | A_LIBERAL,
- S(rt_sigtimedwait) = A_YES | A_LIBERAL,
- S(rt_sigqueueinfo) = A_YES | A_LIBERAL,
- S(rt_sigsuspend) = A_YES | A_LIBERAL,
- S(mmap2) = A_YES | A_LIBERAL,
- S(_sysctl) = A_YES | A_LIBERAL,
-#undef S
-};
-
-static const char *
-syscall_name(unsigned int id, char *buf)
-{
- if (id < NUM_SYSCALLS && syscall_names[id])
- return syscall_names[id];
- else
- {
- sprintf(buf, "#%d", id);
- return buf;
- }
-}
-
-static int
-syscall_by_name(char *name)
-{
- for (unsigned int i=0; i<NUM_SYSCALLS; i++)
- if (syscall_names[i] && !strcmp(syscall_names[i], name))
- return i;
- if (name[0] == '#')
- name++;
- if (!*name)
- return -1;
- char *ep;
- unsigned long l = strtoul(name, &ep, 0);
- if (*ep)
- return -1;
- if (l >= NUM_ACTIONS)
- return NUM_ACTIONS;
- return l;
-}
-
-static int
-set_syscall_action(char *a)
-{
- char *sep = strchr(a, '=');
- enum action act = A_YES;
- if (sep)
- {
- *sep++ = 0;
- if (!strcmp(sep, "yes"))
- act = A_YES;
- else if (!strcmp(sep, "no"))
- act = A_NO;
- else if (!strcmp(sep, "file"))
- act = A_FILENAME;
- else
- return 0;
- }
-
- int sys = syscall_by_name(a);
- if (sys < 0)
- die("Unknown syscall `%s'", a);
- if (sys >= NUM_ACTIONS)
- die("Syscall `%s' out of range", a);
- syscall_action[sys] = act;
- return 1;
-}
-
-/*** Path rules ***/
-
-struct path_rule {
- char *path;
- enum action action;
- struct path_rule *next;
-};
-
-static struct path_rule default_path_rules[] = {
- { "/etc/", A_YES },
- { "/lib/", A_YES },
- { "/usr/lib/", A_YES },
- { "/opt/lib/", A_YES },
- { "/usr/share/zoneinfo/", A_YES },
- { "/usr/share/locale/", A_YES },
- { "/dev/null", A_YES },
- { "/dev/zero", A_YES },
- { "/proc/meminfo", A_YES },
- { "/proc/self/stat", A_YES },
- { "/proc/self/exe", A_YES }, // Needed by FPC 2.0.x runtime
-};
-
-static struct path_rule *user_path_rules;
-static struct path_rule **last_path_rule = &user_path_rules;
-
-static int
-set_path_action(char *a)
-{
- char *sep = strchr(a, '=');
- enum action act = A_YES;
- if (sep)
- {
- *sep++ = 0;
- if (!strcmp(sep, "yes"))
- act = A_YES;
- else if (!strcmp(sep, "no"))
- act = A_NO;
- else
- return 0;
- }
-
- struct path_rule *r = xmalloc(sizeof(*r) + strlen(a) + 1);
- r->path = (char *)(r+1);
- strcpy(r->path, a);
- r->action = act;
- r->next = NULL;
- *last_path_rule = r;
- last_path_rule = &r->next;
- return 1;
-}
-
-static enum action
-match_path_rule(struct path_rule *r, char *path)
-{
- char *rr = r->path;
- while (*rr)
- if (*rr++ != *path++)
- {
- if (rr[-1] == '/' && !path[-1])
- break;
- return A_DEFAULT;
- }
- if (rr > r->path && rr[-1] != '/' && *path)
- return A_DEFAULT;
- return r->action;
-}
-
-/*** Environment rules ***/
-
-struct env_rule {
- char *var; // Variable to match
- char *val; // ""=clear, NULL=inherit
- int var_len;
- struct env_rule *next;
-};
-
-static struct env_rule *first_env_rule;
-static struct env_rule **last_env_rule = &first_env_rule;
-
-static struct env_rule default_env_rules[] = {
- { "LIBC_FATAL_STDERR_", "1" }
-};
-
-static int
-set_env_action(char *a0)
-{
- struct env_rule *r = xmalloc(sizeof(*r) + strlen(a0) + 1);
- char *a = (char *)(r+1);
- strcpy(a, a0);
-
- char *sep = strchr(a, '=');
- if (sep == a)
- return 0;
- r->var = a;
- if (sep)
- {
- *sep++ = 0;
- r->val = sep;
- }
- else
- r->val = NULL;
- *last_env_rule = r;
- last_env_rule = &r->next;
- r->next = NULL;
- return 1;
-}
-
-static int
-match_env_var(char *env_entry, struct env_rule *r)
-{
- if (strncmp(env_entry, r->var, r->var_len))
- return 0;
- return (env_entry[r->var_len] == '=');
-}
-
-static void
-apply_env_rule(char **env, int *env_sizep, struct env_rule *r)
-{
- // First remove the variable if already set
- int pos = 0;
- while (pos < *env_sizep && !match_env_var(env[pos], r))
- pos++;
- if (pos < *env_sizep)
- {
- (*env_sizep)--;
- env[pos] = env[*env_sizep];
- env[*env_sizep] = NULL;
- }
-
- // What is the new value?
- char *new;
- if (r->val)
- {
- if (!r->val[0])
- return;
- new = xmalloc(r->var_len + 1 + strlen(r->val) + 1);
- sprintf(new, "%s=%s", r->var, r->val);
- }
- else
- {
- pos = 0;
- while (environ[pos] && !match_env_var(environ[pos], r))
- pos++;
- if (!(new = environ[pos]))
- return;
- }
-
- // Add it at the end of the array
- env[(*env_sizep)++] = new;
- env[*env_sizep] = NULL;
-}
-
-static char **
-setup_environment(void)
-{
- // Link built-in rules with user rules
- for (int i=ARRAY_SIZE(default_env_rules)-1; i >= 0; i--)
- {
- default_env_rules[i].next = first_env_rule;
- first_env_rule = &default_env_rules[i];
- }
-
- // Scan the original environment
- char **orig_env = environ;
- int orig_size = 0;
- while (orig_env[orig_size])
- orig_size++;
-
- // For each rule, reserve one more slot and calculate length
- int num_rules = 0;
- for (struct env_rule *r = first_env_rule; r; r=r->next)
- {
- num_rules++;
- r->var_len = strlen(r->var);
- }
-
- // Create a new environment
- char **env = xmalloc((orig_size + num_rules + 1) * sizeof(char *));
- int size;
- if (pass_environ)
- {
- memcpy(env, environ, orig_size * sizeof(char *));
- size = orig_size;
- }
- else
- size = 0;
- env[size] = NULL;
-
- // Apply the rules one by one
- for (struct env_rule *r = first_env_rule; r; r=r->next)
- apply_env_rule(env, &size, r);
-
- // Return the new env and pass some gossip
- if (verbose > 1)
- {
- fprintf(stderr, "Passing environment:\n");
- for (int i=0; env[i]; i++)
- fprintf(stderr, "\t%s\n", env[i]);
- }
- return env;
-}
-
-/*** Syscall checks ***/
-
-static void
-valid_filename(unsigned long addr)
-{
- char namebuf[4096], *p, *end;
- static int mem_fd;
-
- if (!file_access)
- die("File access forbidden");
- if (file_access >= 9)
- return;
-
- if (!mem_fd)
- {
- sprintf(namebuf, "/proc/%d/mem", (int) box_pid);
- mem_fd = open(namebuf, O_RDONLY);
- if (mem_fd < 0)
- die("open(%s): %m", namebuf);
- }
- p = end = namebuf;
- do
- {
- if (p >= end)
- {
- int remains = PAGE_SIZE - (addr & (PAGE_SIZE-1));
- int l = namebuf + sizeof(namebuf) - end;
- if (l > remains)
- l = remains;
- if (!l)
- die("Access to file with name too long");
- if (long_seek(mem_fd, addr, SEEK_SET) < 0)
- die("long_seek(mem): %m");
- remains = read(mem_fd, end, l);
- if (remains < 0)
- die("read(mem): %m");
- if (!remains)
- die("Access to file with name out of memory");
- end += l;
- addr += l;
- }
- }
- while (*p++);
-
- msg("[%s] ", namebuf);
- if (file_access >= 3)
- return;
-
- // Everything in current directory is permitted
- if (!strchr(namebuf, '/') && strcmp(namebuf, ".."))
- return;
-
- // ".." anywhere in the path is forbidden
- enum action act = A_DEFAULT;
- if (strstr(namebuf, ".."))
- act = A_NO;
-
- // Scan user rules
- for (struct path_rule *r = user_path_rules; r && !act; r=r->next)
- act = match_path_rule(r, namebuf);
-
- // Scan built-in rules
- if (file_access >= 2)
- for (int i=0; i<ARRAY_SIZE(default_path_rules) && !act; i++)
- act = match_path_rule(&default_path_rules[i], namebuf);
-
- if (act != A_YES)
- die("Forbidden access to file `%s'", namebuf);
-}
-
-static int
-valid_syscall(struct user *u)
-{
- unsigned int sys = u->regs.orig_eax;
- enum action act = (sys < NUM_ACTIONS) ? syscall_action[sys] : A_DEFAULT;
-
- if (act & A_LIBERAL)
- {
- if (filter_syscalls == 1)
- act &= ~A_LIBERAL;
- else
- act = A_DEFAULT;
- }
- switch (act)
- {
- case A_YES:
- return 1;
- case A_NO:
- return 0;
- case A_FILENAME:
- valid_filename(u->regs.ebx);
- return 1;
- default: ;
- }
-
- switch (sys)
- {
- case __NR_kill:
- if (u->regs.ebx == box_pid)
- die("Committed suicide by signal %d", (int)u->regs.ecx);
- return 0;
- case __NR_tgkill:
- if (u->regs.ebx == box_pid && u->regs.ecx == box_pid)
- die("Committed suicide by signal %d", (int)u->regs.edx);
- return 0;
- default:
- return 0;
- }
-}
-
-static void
-signal_alarm(int unused UNUSED)
-{
- /* Time limit checks are synchronous, so we only schedule them there. */
- timer_tick = 1;
- alarm(1);
-}
-
-static void
-signal_int(int unused UNUSED)
-{
- /* Interrupts are fatal, so no synchronization requirements. */
- die("Interrupted");
-}
-
-static void
-check_timeout(void)
-{
- if (wall_timeout)
- {
- struct timeval now, wall;
- int wall_ms;
- gettimeofday(&now, NULL);
- timersub(&now, &start_time, &wall);
- wall_ms = wall.tv_sec*1000 + wall.tv_usec/1000;
- if (wall_ms > wall_timeout)
- die("Time limit exceeded (wall clock)");
- if (verbose > 1)
- fprintf(stderr, "[wall time check: %d msec]\n", wall_ms);
- }
- if (timeout)
- {
- char buf[4096], *x;
- int c, utime, stime, ms;
- static int proc_status_fd;
- if (!proc_status_fd)
- {
- sprintf(buf, "/proc/%d/stat", (int) box_pid);
- proc_status_fd = open(buf, O_RDONLY);
- if (proc_status_fd < 0)
- die("open(%s): %m", buf);
- }
- lseek(proc_status_fd, 0, SEEK_SET);
- if ((c = read(proc_status_fd, buf, sizeof(buf)-1)) < 0)
- die("read on /proc/$pid/stat: %m");
- if (c >= (int) sizeof(buf) - 1)
- die("/proc/$pid/stat too long");
- buf[c] = 0;
- x = buf;
- while (*x && *x != ' ')
- x++;
- while (*x == ' ')
- x++;
- if (*x++ != '(')
- die("proc syntax error 1");
- while (*x && (*x != ')' || x[1] != ' '))
- x++;
- while (*x == ')' || *x == ' ')
- x++;
- if (sscanf(x, "%*c %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %d %d", &utime, &stime) != 2)
- die("proc syntax error 2");
- ms = (utime + stime) * 1000 / ticks_per_sec;
- if (verbose > 1)
- fprintf(stderr, "[time check: %d msec]\n", ms);
- if (ms > timeout)
- die("Time limit exceeded");
- }
-}
-
-static void
-boxkeeper(void)
-{
- int syscall_count = 0;
- struct sigaction sa;
-
- is_ptraced = 1;
- bzero(&sa, sizeof(sa));
- sa.sa_handler = signal_int;
- sigaction(SIGINT, &sa, NULL);
- gettimeofday(&start_time, NULL);
- ticks_per_sec = sysconf(_SC_CLK_TCK);
- if (ticks_per_sec <= 0)
- die("Invalid ticks_per_sec!");
- if (timeout || wall_timeout)
- {
- sa.sa_handler = signal_alarm;
- sigaction(SIGALRM, &sa, NULL);
- alarm(1);
- }
- for(;;)
- {
- struct rusage rus;
- int stat;
- pid_t p;
- if (timer_tick)
- {
- check_timeout();
- timer_tick = 0;
- }
- p = wait4(box_pid, &stat, WUNTRACED, &rus);
- if (p < 0)
- {
- if (errno == EINTR)
- continue;
- die("wait4: %m");
- }
- if (p != box_pid)
- die("wait4: unknown pid %d exited!", p);
- if (WIFEXITED(stat))
- {
- struct timeval total, now, wall;
- int total_ms, wall_ms;
- box_pid = 0;
- if (WEXITSTATUS(stat))
- die("Exited with error status %d", WEXITSTATUS(stat));
- timeradd(&rus.ru_utime, &rus.ru_stime, &total);
- total_ms = total.tv_sec*1000 + total.tv_usec/1000;
- gettimeofday(&now, NULL);
- timersub(&now, &start_time, &wall);
- wall_ms = wall.tv_sec*1000 + wall.tv_usec/1000;
- if (timeout && total_ms > timeout)
- die("Time limit exceeded");
- if (wall_timeout && wall_ms > wall_timeout)
- die("Time limit exceeded (wall clock)");
- flush_line();
- fprintf(stderr, "OK (%d.%03d sec real, %d.%03d sec wall, %d syscalls)\n",
- (int) total.tv_sec, (int) total.tv_usec/1000,
- (int) wall.tv_sec, (int) wall.tv_usec/1000,
- syscall_count);
- exit(0);
- }
- if (WIFSIGNALED(stat))
- {
- box_pid = 0;
- die("Caught fatal signal %d%s", WTERMSIG(stat), (syscall_count ? "" : " during startup"));
- }
- if (WIFSTOPPED(stat))
- {
- int sig = WSTOPSIG(stat);
- if (sig == SIGTRAP)
- {
- struct user u;
- static int stop_count = -1;
- if (ptrace(PTRACE_GETREGS, box_pid, NULL, &u) < 0)
- die("ptrace(PTRACE_GETREGS): %m");
- stop_count++;
- if (!stop_count) /* Traceme request */
- msg(">> Traceme request caught\n");
- else if (stop_count & 1) /* Syscall entry */
- {
- char namebuf[32];
- msg(">> Syscall %-12s (%08lx,%08lx,%08lx) ", syscall_name(u.regs.orig_eax, namebuf), u.regs.ebx, u.regs.ecx, u.regs.edx);
- if (!exec_seen)
- {
- msg("[master] ");
- if (u.regs.orig_eax == __NR_execve)
- exec_seen = 1;
- }
- else if (valid_syscall(&u))
- syscall_count++;
- else
- {
- /*
- * Unfortunately, PTRACE_KILL kills _after_ the syscall completes,
- * so we have to change it to something harmless (e.g., an undefined
- * syscall) and make the program continue.
- */
- unsigned int sys = u.regs.orig_eax;
- u.regs.orig_eax = 0xffffffff;
- if (ptrace(PTRACE_SETREGS, box_pid, NULL, &u) < 0)
- die("ptrace(PTRACE_SETREGS): %m");
- die("Forbidden syscall %s", syscall_name(sys, namebuf));
- }
- }
- else /* Syscall return */
- msg("= %ld\n", u.regs.eax);
- ptrace(PTRACE_SYSCALL, box_pid, 0, 0);
- }
- else if (sig != SIGSTOP && sig != SIGXCPU && sig != SIGXFSZ)
- {
- msg(">> Signal %d\n", sig);
- ptrace(PTRACE_SYSCALL, box_pid, 0, sig);
- }
- else
- die("Received signal %d", sig);
- }
- else
- die("wait4: unknown status %x, giving up!", stat);
- }
-}
-
-static void
-box_inside(int argc, char **argv)
-{
- struct rlimit rl;
- char *args[argc+1];
-
- memcpy(args, argv, argc * sizeof(char *));
- args[argc] = NULL;
- if (set_cwd && chdir(set_cwd))
- die("chdir: %m");
- if (redir_stdin)
- {
- close(0);
- if (open(redir_stdin, O_RDONLY) != 0)
- die("open(\"%s\"): %m", redir_stdin);
- }
- if (redir_stdout)
- {
- close(1);
- if (open(redir_stdout, O_WRONLY | O_CREAT | O_TRUNC, 0666) != 1)
- die("open(\"%s\"): %m", redir_stdout);
- }
- if (redir_stderr)
- {
- close(2);
- if (open(redir_stderr, O_WRONLY | O_CREAT | O_TRUNC, 0666) != 2)
- die("open(\"%s\"): %m", redir_stderr);
- }
- else
- dup2(1, 2);
- setpgrp();
- if (memory_limit)
- {
- rl.rlim_cur = rl.rlim_max = memory_limit * 1024;
- if (setrlimit(RLIMIT_AS, &rl) < 0)
- die("setrlimit: %m");
- }
- rl.rlim_cur = rl.rlim_max = 64;
- if (setrlimit(RLIMIT_NOFILE, &rl) < 0)
- die("setrlimit: %m");
- if (filter_syscalls)
- {
- if (ptrace(PTRACE_TRACEME) < 0)
- die("ptrace(PTRACE_TRACEME): %m");
- /* Trick: Make sure that we are stopped until the boxkeeper wakes up. */
- signal(SIGCHLD, SIG_IGN);
- raise(SIGCHLD);
- }
- execve(args[0], args, setup_environment());
- die("execve(\"%s\"): %m", args[0]);
-}
-
-static void
-usage(void)
-{
- fprintf(stderr, "Invalid arguments!\n");
- printf("\
-Usage: box [<options>] -- <command> <arguments>\n\
-\n\
-Options:\n\
--a <level>\tSet file access level (0=none, 1=cwd, 2=/etc,/lib,..., 3=whole fs, 9=no checks; needs -f)\n\
--c <dir>\tChange directory to <dir> first\n\
--e\t\tInherit full environment of the parent process\n\
--E <var>\tInherit the environment variable <var> from the parent process\n\
--E <var>=<val>\tSet the environment variable <var> to <val>; unset it if <var> is empty\n\
--f\t\tFilter system calls (-ff=very restricted)\n\
--i <file>\tRedirect stdin from <file>\n\
--m <size>\tLimit address space to <size> KB\n\
--o <file>\tRedirect stdout to <file>\n\
--p <path>\tPermit access to the specified path (or subtree if it ends with a `/')\n\
--p <path>=<act>\tDefine action for the specified path (<act>=yes/no)\n\
--r <file>\tRedirect stderr to <file>\n\
--s <sys>\tPermit the specified syscall (be careful)\n\
--s <sys>=<act>\tDefine action for the specified syscall (<act>=yes/no/file)\n\
--t <time>\tSet run time limit (seconds, fractions allowed)\n\
--T\t\tAllow syscalls for measuring run time\n\
--v\t\tBe verbose (use multiple times for even more verbosity)\n\
--w <time>\tSet wall clock time limit (seconds, fractions allowed)\n\
-");
- exit(1);
-}
-
-int
-main(int argc, char **argv)
-{
- int c;
- uid_t uid;
-
- while ((c = getopt(argc, argv, "a:c:eE:fi:m:o:p:r:s:t:Tvw:")) >= 0)
- switch (c)
- {
- case 'a':
- file_access = atol(optarg);
- break;
- case 'c':
- set_cwd = optarg;
- break;
- case 'e':
- pass_environ = 1;
- break;
- case 'E':
- if (!set_env_action(optarg))
- usage();
- break;
- case 'f':
- filter_syscalls++;
- break;
- case 'i':
- redir_stdin = optarg;
- break;
- case 'm':
- memory_limit = atol(optarg);
- break;
- case 'o':
- redir_stdout = optarg;
- break;
- case 'p':
- if (!set_path_action(optarg))
- usage();
- break;
- case 'r':
- redir_stderr = optarg;
- break;
- case 's':
- if (!set_syscall_action(optarg))
- usage();
- break;
- case 't':
- timeout = 1000*atof(optarg);
- break;
- case 'T':
- syscall_action[__NR_times] = A_YES;
- break;
- case 'v':
- verbose++;
- break;
- case 'w':
- wall_timeout = 1000*atof(optarg);
- break;
- default:
- usage();
- }
- if (optind >= argc)
- usage();
-
- uid = geteuid();
- if (setreuid(uid, uid) < 0)
- die("setreuid: %m");
- box_pid = fork();
- if (box_pid < 0)
- die("fork: %m");
- if (!box_pid)
- box_inside(argc-optind, argv+optind);
- else
- boxkeeper();
- die("Internal error: fell over edge of the world");
-}
+++ /dev/null
-#!/bin/sh
-set -e
-(
-echo '/* Syscall table automatically generated by mk-syscall-table */'
-echo
-echo '#include <asm/unistd.h>' |
- gcc -E -dM - |
- sed 's/^#define __NR_\([^ ]\+\).*/[ __NR_\1 ] = "\1",/;t;d'
-) >src/syscall-table.h
projects / moe.git / commitdiff