X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=box%2Fbox.c;h=323e07e77e9d270dc85d43f0092a346deba41ed1;hb=0964fde49f014747a8252c6e02a1373d3763b44a;hp=da7dfc1b83ca4e3cfbb7c34d734037db2973e47a;hpb=a263d633483e41b64c7fdc4bc09f0c8bbf18a308;p=eval.git diff --git a/box/box.c b/box/box.c index da7dfc1..323e07e 100644 --- a/box/box.c +++ b/box/box.c @@ -32,6 +32,7 @@ static int filter_syscalls; /* 0=off, 1=liberal, 2=totalitarian */ static int timeout; /* milliseconds */ static int wall_timeout; +static int extra_timeout; static int pass_environ; static int file_access; static int verbose; @@ -116,6 +117,7 @@ box_exit(int rc) ptrace(PTRACE_KILL, box_pid); kill(-box_pid, SIGKILL); kill(box_pid, SIGKILL); + meta_printf("killed:1\n"); struct rusage rus; int stat; @@ -212,6 +214,7 @@ enum action { A_YES, // Always permit A_FILENAME, // Permit if arg1 is a known filename A_ACTION_MASK = 15, + A_NO_RETVAL = 32, // Does not return a value A_SAMPLE_MEM = 64, // Sample memory usage before the syscall A_LIBERAL = 128, // Valid only in liberal mode // Must fit in a unsigned char @@ -298,7 +301,7 @@ static unsigned char syscall_action[NUM_ACTIONS] = { 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(sigreturn) = A_YES | A_LIBERAL | A_NO_RETVAL, S(mprotect) = A_YES | A_LIBERAL, S(sigprocmask) = A_YES | A_LIBERAL, S(getdents) = A_YES | A_LIBERAL, @@ -309,7 +312,7 @@ static unsigned char syscall_action[NUM_ACTIONS] = { 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_sigreturn) = A_YES | A_LIBERAL | A_NO_RETVAL, S(rt_sigaction) = A_YES | A_LIBERAL, S(rt_sigprocmask) = A_YES | A_LIBERAL, S(rt_sigpending) = A_YES | A_LIBERAL, @@ -770,7 +773,7 @@ check_timeout(void) ms = (utime + stime) * 1000 / ticks_per_sec; if (verbose > 1) fprintf(stderr, "[time check: %d msec]\n", ms); - if (ms > timeout) + if (ms > timeout && ms > extra_timeout) err("TO: Time limit exceeded"); } } @@ -900,28 +903,38 @@ boxkeeper(void) int sig = WSTOPSIG(stat); if (sig == SIGTRAP) { + if (verbose > 2) + msg("[ptrace status %08x] ", stat); + static int stop_count; + if (!stop_count++) /* Traceme request */ + msg(">> Traceme request caught\n"); + else + err("SG: Breakpoint"); + ptrace(PTRACE_SYSCALL, box_pid, 0, 0); + } + else if (sig == (SIGTRAP | 0x80)) + { + if (verbose > 2) + msg("[ptrace status %08x] ", stat); struct user u; - static int stop_count = -1; + static unsigned int sys_tick, last_sys, last_act; if (ptrace(PTRACE_GETREGS, box_pid, NULL, &u) < 0) die("ptrace(PTRACE_GETREGS): %m"); - if (u.regs.orig_eax < 0) /* Process issued a breakpoint instruction */ - err("SG: Breakpoint"); - stop_count++; - if (!stop_count) /* Traceme request */ - msg(">> Traceme request caught\n"); - else if (stop_count & 1) /* Syscall entry */ + unsigned int sys = u.regs.orig_eax; + if (++sys_tick & 1) /* Syscall entry */ { char namebuf[32]; int act; - msg(">> Syscall %-12s (%08lx,%08lx,%08lx) ", syscall_name(u.regs.orig_eax, namebuf), u.regs.ebx, u.regs.ecx, u.regs.edx); + msg(">> Syscall %-12s (%08lx,%08lx,%08lx) ", syscall_name(sys, namebuf), u.regs.ebx, u.regs.ecx, u.regs.edx); if (!exec_seen) { msg("[master] "); - if (u.regs.orig_eax == __NR_execve) + if (sys == __NR_execve) exec_seen = 1; } else if ((act = valid_syscall(&u)) >= 0) { + last_act = act; syscall_count++; if (act & A_SAMPLE_MEM) sample_mem_peak(); @@ -933,18 +946,41 @@ boxkeeper(void) * 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"); err("FO: Forbidden syscall %s", syscall_name(sys, namebuf)); } + last_sys = sys; } else /* Syscall return */ - msg("= %ld\n", u.regs.eax); + { + if (sys == 0xffffffff) + { + /* Some syscalls (sigreturn et al.) do not return a value */ + if (!(last_act & A_NO_RETVAL)) + err("XX: Syscall does not return, but it should"); + } + else + { + if (sys != last_sys) + err("XX: Mismatched syscall entry/exit"); + } + if (last_act & A_NO_RETVAL) + msg("= ?\n"); + else + msg("= %ld\n", u.regs.eax); + } ptrace(PTRACE_SYSCALL, box_pid, 0, 0); } - else if (sig != SIGSTOP && sig != SIGXCPU && sig != SIGXFSZ) + else if (sig == SIGSTOP) + { + msg(">> SIGSTOP\n"); + if (ptrace(PTRACE_SETOPTIONS, box_pid, NULL, (void *) PTRACE_O_TRACESYSGOOD) < 0) + die("ptrace(PTRACE_SETOPTIONS): %m"); + ptrace(PTRACE_SYSCALL, box_pid, 0, 0); + } + else if (sig != SIGXCPU && sig != SIGXFSZ) { msg(">> Signal %d\n", sig); sample_mem_peak(); /* Signal might be fatal, so update mem-peak */ @@ -1007,8 +1043,7 @@ box_inside(int argc, char **argv) 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); + raise(SIGSTOP); } execve(args[0], args, env); die("execve(\"%s\"): %m", args[0]); @@ -1041,6 +1076,8 @@ Options:\n\ -T\t\tAllow syscalls for measuring run time\n\ -v\t\tBe verbose (use multiple times for even more verbosity)\n\ -w