X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=box%2Fbox.c;h=323e07e77e9d270dc85d43f0092a346deba41ed1;hb=0964fde49f014747a8252c6e02a1373d3763b44a;hp=2aaec6ae92a6621e7207998e1f0b38d5437fe3a3;hpb=785436fb49da899e77a3a977f61f564a6a71f831;p=eval.git diff --git a/box/box.c b/box/box.c index 2aaec6a..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; @@ -211,7 +213,11 @@ enum action { A_NO, // Always forbid 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 }; static unsigned char syscall_action[NUM_ACTIONS] = { @@ -233,7 +239,7 @@ static unsigned char syscall_action[NUM_ACTIONS] = { S(readlink) = A_FILENAME, // Syscalls permitted always - S(exit) = A_YES, + S(exit) = A_YES | A_SAMPLE_MEM, S(read) = A_YES, S(write) = A_YES, S(close) = A_YES, @@ -274,7 +280,7 @@ static unsigned char syscall_action[NUM_ACTIONS] = { S(set_thread_area) = A_YES, S(get_thread_area) = A_YES, S(set_tid_address) = A_YES, - S(exit_group) = A_YES, + S(exit_group) = A_YES | A_SAMPLE_MEM, // Syscalls permitted only in liberal mode S(time) = A_YES | A_LIBERAL, @@ -295,7 +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, @@ -306,7 +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, @@ -647,28 +653,28 @@ valid_filename(unsigned long addr) err("FA: Forbidden access to file `%s'", namebuf); } +// Check syscall. If invalid, return -1, otherwise return the action mask. 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; + unsigned int act = (sys < NUM_ACTIONS) ? syscall_action[sys] : A_DEFAULT; if (act & A_LIBERAL) { - if (filter_syscalls == 1) - act &= ~A_LIBERAL; - else + if (filter_syscalls != 1) act = A_DEFAULT; } - switch (act) + + switch (act & A_ACTION_MASK) { case A_YES: - return 1; + return act; case A_NO: - return 0; + return -1; case A_FILENAME: valid_filename(u->regs.ebx); - return 1; + return act; default: ; } @@ -680,16 +686,16 @@ valid_syscall(struct user *u) meta_printf("exitsig:%d\n", (int)u->regs.ecx); err("SG: Committed suicide by signal %d", (int)u->regs.ecx); } - return 0; + return -1; case __NR_tgkill: if (u->regs.ebx == box_pid && u->regs.ecx == box_pid) { meta_printf("exitsig:%d\n", (int)u->regs.edx); err("SG: Committed suicide by signal %d", (int)u->regs.edx); } - return 0; + return -1; default: - return 0; + return -1; } } @@ -767,7 +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"); } } @@ -897,25 +903,42 @@ 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"); - 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]; - msg(">> Syscall %-12s (%08lx,%08lx,%08lx) ", syscall_name(u.regs.orig_eax, namebuf), u.regs.ebx, u.regs.ecx, u.regs.edx); + int act; + 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 (valid_syscall(&u)) - syscall_count++; + else if ((act = valid_syscall(&u)) >= 0) + { + last_act = act; + syscall_count++; + if (act & A_SAMPLE_MEM) + sample_mem_peak(); + } else { /* @@ -923,19 +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); - sample_mem_peak(); + { + 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 */ @@ -992,15 +1037,15 @@ box_inside(int argc, char **argv) rl.rlim_cur = rl.rlim_max = 64; if (setrlimit(RLIMIT_NOFILE, &rl) < 0) die("setrlimit: %m"); + char **env = setup_environment(); 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); + raise(SIGSTOP); } - execve(args[0], args, setup_environment()); + execve(args[0], args, env); die("execve(\"%s\"): %m", args[0]); } @@ -1031,6 +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