/*
- * A Simple Testing Sandbox
+ * A Simple Sandbox for MO-Eval
*
- * (c) 2001--2007 Martin Mares <mj@ucw.cz>
+ * (c) 2001--2008 Martin Mares <mj@ucw.cz>
*/
#define _LARGEFILE64_SOURCE
#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 file_access;
static int verbose;
static int memory_limit;
-static int allow_times;
static char *redir_stdin, *redir_stdout;
static char *set_cwd;
static volatile int timer_tick;
static struct timeval start_time;
static int ticks_per_sec;
+static int exec_seen;
#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ > 0
/* glibc 2.1 or newer -> has lseek64 */
va_end(args);
}
+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 {
+ SC_DEFAULT, // Use the default action
+ SC_NO, // Always forbid
+ SC_YES, // Always permit
+ SC_FILENAME, // Permit if arg1 is a known filename
+ SC_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) = SC_FILENAME,
+ S(creat) = SC_FILENAME,
+ S(unlink) = SC_FILENAME,
+ S(oldstat) = SC_FILENAME,
+ S(access) = SC_FILENAME,
+ S(oldlstat) = SC_FILENAME,
+ S(truncate) = SC_FILENAME,
+ S(stat) = SC_FILENAME,
+ S(lstat) = SC_FILENAME,
+ S(truncate64) = SC_FILENAME,
+ S(stat64) = SC_FILENAME,
+ S(lstat64) = SC_FILENAME,
+ S(readlink) = SC_FILENAME,
+
+ // Syscalls permitted always
+ S(exit) = SC_YES,
+ S(read) = SC_YES,
+ S(write) = SC_YES,
+ S(close) = SC_YES,
+ S(lseek) = SC_YES,
+ S(getpid) = SC_YES,
+ S(getuid) = SC_YES,
+ S(oldfstat) = SC_YES,
+ S(dup) = SC_YES,
+ S(brk) = SC_YES,
+ S(getgid) = SC_YES,
+ S(geteuid) = SC_YES,
+ S(getegid) = SC_YES,
+ S(dup2) = SC_YES,
+ S(ftruncate) = SC_YES,
+ S(fstat) = SC_YES,
+ S(personality) = SC_YES,
+ S(_llseek) = SC_YES,
+ S(readv) = SC_YES,
+ S(writev) = SC_YES,
+ S(getresuid) = SC_YES,
+#ifdef __NR_pread64
+ S(pread64) = SC_YES,
+ S(pwrite64) = SC_YES,
+#else
+ S(pread) = SC_YES,
+ S(pwrite) = SC_YES,
+#endif
+ S(ftruncate64) = SC_YES,
+ S(fstat64) = SC_YES,
+ S(fcntl) = SC_YES,
+ S(fcntl64) = SC_YES,
+ S(mmap) = SC_YES,
+ S(munmap) = SC_YES,
+ S(ioctl) = SC_YES,
+ S(uname) = SC_YES,
+ S(gettid) = SC_YES,
+ S(set_thread_area) = SC_YES,
+ S(get_thread_area) = SC_YES,
+ S(exit_group) = SC_YES,
+
+ // Syscalls permitted only in liberal mode
+ S(time) = SC_YES | SC_LIBERAL,
+ S(alarm) = SC_YES | SC_LIBERAL,
+ S(pause) = SC_YES | SC_LIBERAL,
+ S(signal) = SC_YES | SC_LIBERAL,
+ S(fchmod) = SC_YES | SC_LIBERAL,
+ S(sigaction) = SC_YES | SC_LIBERAL,
+ S(sgetmask) = SC_YES | SC_LIBERAL,
+ S(ssetmask) = SC_YES | SC_LIBERAL,
+ S(sigsuspend) = SC_YES | SC_LIBERAL,
+ S(sigpending) = SC_YES | SC_LIBERAL,
+ S(getrlimit) = SC_YES | SC_LIBERAL,
+ S(getrusage) = SC_YES | SC_LIBERAL,
+ S(ugetrlimit) = SC_YES | SC_LIBERAL,
+ S(gettimeofday) = SC_YES | SC_LIBERAL,
+ S(select) = SC_YES | SC_LIBERAL,
+ S(readdir) = SC_YES | SC_LIBERAL,
+ S(setitimer) = SC_YES | SC_LIBERAL,
+ S(getitimer) = SC_YES | SC_LIBERAL,
+ S(sigreturn) = SC_YES | SC_LIBERAL,
+ S(mprotect) = SC_YES | SC_LIBERAL,
+ S(sigprocmask) = SC_YES | SC_LIBERAL,
+ S(getdents) = SC_YES | SC_LIBERAL,
+ S(getdents64) = SC_YES | SC_LIBERAL,
+ S(_newselect) = SC_YES | SC_LIBERAL,
+ S(fdatasync) = SC_YES | SC_LIBERAL,
+ S(mremap) = SC_YES | SC_LIBERAL,
+ S(poll) = SC_YES | SC_LIBERAL,
+ S(getcwd) = SC_YES | SC_LIBERAL,
+ S(nanosleep) = SC_YES | SC_LIBERAL,
+ S(rt_sigreturn) = SC_YES | SC_LIBERAL,
+ S(rt_sigaction) = SC_YES | SC_LIBERAL,
+ S(rt_sigprocmask) = SC_YES | SC_LIBERAL,
+ S(rt_sigpending) = SC_YES | SC_LIBERAL,
+ S(rt_sigtimedwait) = SC_YES | SC_LIBERAL,
+ S(rt_sigqueueinfo) = SC_YES | SC_LIBERAL,
+ S(rt_sigsuspend) = SC_YES | SC_LIBERAL,
+ S(mmap2) = SC_YES | SC_LIBERAL,
+ S(_sysctl) = SC_YES | SC_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_action(char *a)
+{
+ char *sep = strchr(a, '=');
+ enum action act = SC_YES;
+ if (sep)
+ {
+ *sep++ = 0;
+ if (!strcmp(sep, "yes"))
+ act = SC_YES;
+ else if (!strcmp(sep, "no"))
+ act = SC_NO;
+ else if (!strcmp(sep, "file"))
+ act = SC_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;
+}
+
+struct path_rule {
+ char *path;
+ enum action action;
+ struct path_rule *next;
+};
+
+static struct path_rule default_path_rules[] = {
+ { "/etc/", SC_YES },
+ { "/lib/", SC_YES },
+ { "/usr/lib/", SC_YES },
+ { "/opt/lib/", SC_YES },
+ { "/usr/share/zoneinfo/", SC_YES },
+ { "/usr/share/locale/", SC_YES },
+ { "/dev/null", SC_YES },
+ { "/dev/zero", SC_YES },
+ { "/proc/meminfo", SC_YES },
+ { "/proc/self/stat", SC_YES },
+ { "/proc/self/exe", SC_YES }, // Needed by FPC 2.0.x runtime
+};
+
+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 SC_DEFAULT;
+ }
+ if (rr > r->path && rr[-1] != '/' && *path)
+ return SC_DEFAULT;
+ return r->action;
+}
+
static void
valid_filename(unsigned long addr)
{
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 = SC_DEFAULT;
+ if (strstr(namebuf, ".."))
+ act = SC_NO;
+
+ // Scan built-in rules
if (file_access >= 2)
- {
- if ((!strncmp(namebuf, "/etc/", 5) ||
- !strncmp(namebuf, "/lib/", 5) ||
- !strncmp(namebuf, "/usr/lib/", 9) ||
- !strncmp(namebuf, "/opt/lib/", 9))
- && !strstr(namebuf, ".."))
- return;
- if (!strcmp(namebuf, "/dev/null") ||
- !strcmp(namebuf, "/dev/zero") ||
- !strcmp(namebuf, "/proc/meminfo") ||
- !strcmp(namebuf, "/proc/self/stat") ||
- !strcmp(namebuf, "/proc/self/exe") || /* Needed by FPC 2.0.x runtime */
- !strncmp(namebuf, "/usr/share/zoneinfo/", 20))
- return;
- }
- die("Forbidden access to file `%s'", namebuf);
+ for (int i=0; i<ARRAY_SIZE(default_path_rules) && !act; i++)
+ act = match_path_rule(&default_path_rules[i], namebuf);
+
+ if (act != SC_YES)
+ die("Forbidden access to file `%s'", namebuf);
}
static int
valid_syscall(struct user *u)
{
- switch (u->regs.orig_eax)
+ unsigned int sys = u->regs.orig_eax;
+ enum action act = (sys < NUM_ACTIONS) ? syscall_action[sys] : SC_DEFAULT;
+
+ if (act & SC_LIBERAL)
{
- case __NR_execve:
- {
- static int exec_counter;
- return !exec_counter++;
- }
- case __NR_open:
- case __NR_creat:
- case __NR_unlink:
- case __NR_oldstat:
- case __NR_access:
- case __NR_oldlstat:
- case __NR_truncate:
- case __NR_stat:
- case __NR_lstat:
- case __NR_truncate64:
- case __NR_stat64:
- case __NR_lstat64:
- case __NR_readlink:
- valid_filename(u->regs.ebx);
+ if (filter_syscalls == 1)
+ act &= ~SC_LIBERAL;
+ else
+ act = SC_DEFAULT;
+ }
+ switch (act)
+ {
+ case SC_YES:
return 1;
- case __NR_exit:
- case __NR_read:
- case __NR_write:
- case __NR_close:
- case __NR_lseek:
- case __NR_getpid:
- case __NR_getuid:
- case __NR_oldfstat:
- case __NR_dup:
- case __NR_brk:
- case __NR_getgid:
- case __NR_geteuid:
- case __NR_getegid:
- case __NR_dup2:
- case __NR_ftruncate:
- case __NR_fstat:
- case __NR_personality:
- case __NR__llseek:
- case __NR_readv:
- case __NR_writev:
- case __NR_getresuid:
-#ifdef __NR_pread64
- case __NR_pread64:
- case __NR_pwrite64:
-#else
- case __NR_pread:
- case __NR_pwrite:
-#endif
- case __NR_ftruncate64:
- case __NR_fstat64:
- case __NR_fcntl:
- case __NR_fcntl64:
- case __NR_mmap:
- case __NR_munmap:
- case __NR_ioctl:
- case __NR_uname:
- case __NR_gettid:
- case __NR_set_thread_area:
- case __NR_get_thread_area:
- case __NR_exit_group:
+ case SC_NO:
+ return 0;
+ case SC_FILENAME:
+ valid_filename(u->regs.ebx);
return 1;
- case __NR_time:
- case __NR_alarm:
- case __NR_pause:
- case __NR_signal:
- case __NR_fchmod:
- case __NR_sigaction:
- case __NR_sgetmask:
- case __NR_ssetmask:
- case __NR_sigsuspend:
- case __NR_sigpending:
- case __NR_getrlimit:
- case __NR_getrusage:
- case __NR_gettimeofday:
- case __NR_select:
- case __NR_readdir:
- case __NR_setitimer:
- case __NR_getitimer:
- case __NR_sigreturn:
- case __NR_mprotect:
- case __NR_sigprocmask:
- case __NR_getdents:
- case __NR_getdents64:
- case __NR__newselect:
- case __NR_fdatasync:
- case __NR_mremap:
- case __NR_poll:
- case __NR_getcwd:
- case __NR_nanosleep:
- case __NR_rt_sigreturn:
- case __NR_rt_sigaction:
- case __NR_rt_sigprocmask:
- case __NR_rt_sigpending:
- case __NR_rt_sigtimedwait:
- case __NR_rt_sigqueueinfo:
- case __NR_rt_sigsuspend:
- case __NR_mmap2:
- case __NR__sysctl:
- return (filter_syscalls == 1);
- case __NR_times:
- return allow_times;
+ default: ;
+ }
+
+ switch (sys)
+ {
case __NR_kill:
if (u->regs.ebx == box_pid)
- die("Commited suicide by signal %d", (int)u->regs.ecx);
+ 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("Commited suicide by signal %d", (int)u->regs.edx);
+ die("Committed suicide by signal %d", (int)u->regs.edx);
return 0;
default:
return 0;
if (WIFSIGNALED(stat))
{
box_pid = 0;
- die("Caught fatal signal %d", WTERMSIG(stat));
+ die("Caught fatal signal %d%s", WTERMSIG(stat), (syscall_count ? "" : " during startup"));
}
if (WIFSTOPPED(stat))
{
msg(">> Traceme request caught\n");
else if (stop_count & 1) /* Syscall entry */
{
- msg(">> Syscall %3ld (%08lx,%08lx,%08lx) ", u.regs.orig_eax, u.regs.ebx, u.regs.ecx, u.regs.edx);
- syscall_count++;
- if (!valid_syscall(&u))
+ 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,
u.regs.orig_eax = 0xffffffff;
if (ptrace(PTRACE_SETREGS, box_pid, NULL, &u) < 0)
die("ptrace(PTRACE_SETREGS): %m");
- die("Forbidden syscall %d", sys);
+ die("Forbidden syscall %s", syscall_name(sys, namebuf));
}
}
else /* Syscall return */
rl.rlim_cur = rl.rlim_max = 64;
if (setrlimit(RLIMIT_NOFILE, &rl) < 0)
die("setrlimit: %m");
- if (filter_syscalls && ptrace(PTRACE_TRACEME) < 0)
- die("ptrace(PTRACE_TRACEME): %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, (pass_environ ? environ : env));
die("execve(\"%s\"): %m", args[0]);
}
-i <file>\tRedirect stdin from <file>\n\
-m <size>\tLimit address space to <size> KB\n\
-o <file>\tRedirect stdout 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\n\
int c;
uid_t uid;
- while ((c = getopt(argc, argv, "a:c:efi:m:o:t:Tvw:")) >= 0)
+ while ((c = getopt(argc, argv, "a:c:efi:m:o:s:t:Tvw:")) >= 0)
switch (c)
{
case 'a':
case 'o':
redir_stdout = optarg;
break;
+ case 's':
+ if (!set_action(optarg))
+ usage();
+ break;
case 't':
timeout = 1000*atof(optarg);
break;
case 'T':
- allow_times++;
+ syscall_action[__NR_times] = SC_YES;
break;
case 'v':
verbose++;
projects / moe.git / blobdiff