/*
- * Copyright (c) 2009-2011 Todd C. Miller <Todd.Miller@courtesan.com>
+ * Copyright (c) 2009-2012 Todd C. Miller <Todd.Miller@courtesan.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
TQ_DECLARE(sigforward)
static struct sigforward_list sigfwd_list;
-static int handle_signals(int fd, pid_t child, int log_io,
+static int handle_signals(int sv[2], pid_t child, int log_io,
struct command_status *cstat);
static void forward_signals(int fd);
static void schedule_signal(int signo);
-
-/*
- * Like execve(2) but falls back to running through /bin/sh
- * ala execvp(3) if we get ENOEXEC.
- */
-int
-my_execve(const char *path, char *const argv[], char *const envp[])
-{
- execve(path, argv, envp);
- if (errno == ENOEXEC) {
- int argc;
- char **nargv;
-
- for (argc = 0; argv[argc] != NULL; argc++)
- continue;
- nargv = emalloc2(argc + 2, sizeof(char *));
- nargv[0] = "sh";
- nargv[1] = (char *)path;
- memcpy(nargv + 2, argv + 1, argc * sizeof(char *));
- execve(_PATH_BSHELL, nargv, envp);
- efree(nargv);
- }
- return -1;
-}
+#ifdef SA_SIGINFO
+static void handler_nofwd(int s, siginfo_t *info, void *context);
+#endif
/*
* Fork and execute a command, returns the child's pid.
struct command_status cstat;
sigaction_t sa;
pid_t child;
+ debug_decl(fork_cmnd, SUDO_DEBUG_EXEC)
zero_bytes(&sa, sizeof(sa));
sigemptyset(&sa.sa_mask);
sa.sa_handler = handler;
sigaction(SIGCONT, &sa, NULL);
- child = fork();
+ /*
+ * The policy plugin's session init must be run before we fork
+ * or certain pam modules won't be able to track their state.
+ */
+ if (policy_init_session(details) != true)
+ errorx(1, _("policy plugin failed session initialization"));
+
+ child = sudo_debug_fork();
switch (child) {
case -1:
error(1, _("unable to fork"));
close(signal_pipe[1]);
fcntl(sv[1], F_SETFD, FD_CLOEXEC);
restore_signals();
- if (exec_setup(details, NULL, -1) == TRUE) {
+ if (exec_setup(details, NULL, -1) == true) {
/* headed for execve() */
- if (details->closefrom >= 0)
- closefrom(details->closefrom);
+ sudo_debug_execve(SUDO_DEBUG_INFO, details->command,
+ details->argv, details->envp);
+ if (details->closefrom >= 0) {
+ int maxfd = details->closefrom;
+ dup2(sv[1], maxfd);
+ (void)fcntl(maxfd, F_SETFD, FD_CLOEXEC);
+ sv[1] = maxfd++;
+ if (sudo_debug_fd_set(maxfd) != -1)
+ maxfd++;
+ closefrom(maxfd);
+ }
#ifdef HAVE_SELINUX
- if (ISSET(details->flags, CD_RBAC_ENABLED))
- selinux_execve(details->command, details->argv, details->envp);
- else
+ if (ISSET(details->flags, CD_RBAC_ENABLED)) {
+ selinux_execve(details->command, details->argv, details->envp,
+ ISSET(details->flags, CD_NOEXEC));
+ } else
#endif
- my_execve(details->command, details->argv, details->envp);
+ {
+ sudo_execve(details->command, details->argv, details->envp,
+ ISSET(details->flags, CD_NOEXEC));
+ }
+ sudo_debug_printf(SUDO_DEBUG_ERROR, "unable to exec %s: %s",
+ details->command, strerror(errno));
}
cstat.type = CMD_ERRNO;
cstat.val = errno;
send(sv[1], &cstat, sizeof(cstat), 0);
+ sudo_debug_exit_int(__func__, __FILE__, __LINE__, sudo_debug_subsys, 1);
_exit(1);
}
- return child;
+ debug_return_int(child);
}
static struct signal_state {
save_signals(void)
{
struct signal_state *ss;
+ debug_decl(save_signals, SUDO_DEBUG_EXEC)
for (ss = saved_signals; ss->signo != -1; ss++)
sigaction(ss->signo, NULL, &ss->sa);
+
+ debug_return;
}
/*
restore_signals(void)
{
struct signal_state *ss;
+ debug_decl(restore_signals, SUDO_DEBUG_EXEC)
for (ss = saved_signals; ss->signo != -1; ss++)
sigaction(ss->signo, &ss->sa, NULL);
+
+ debug_return;
}
/*
* we fact that we have two different controlling terminals to deal with.
*/
int
-sudo_execve(struct command_details *details, struct command_status *cstat)
+sudo_execute(struct command_details *details, struct command_status *cstat)
{
- int maxfd, n, nready, sv[2], log_io = FALSE;
+ int maxfd, n, nready, sv[2];
const char *utmp_user = NULL;
+ bool log_io = false;
fd_set *fdsr, *fdsw;
sigaction_t sa;
pid_t child;
+ debug_decl(sudo_execute, SUDO_DEBUG_EXEC)
/* If running in background mode, fork and exit. */
if (ISSET(details->flags, CD_BACKGROUND)) {
- switch (fork()) {
+ switch (sudo_debug_fork()) {
case -1:
cstat->type = CMD_ERRNO;
cstat->val = errno;
- return -1;
+ debug_return_int(-1);
case 0:
/* child continues without controlling terminal */
(void)setpgid(0, 0);
break;
default:
/* parent exits (but does not flush buffers) */
+ sudo_debug_exit_int(__func__, __FILE__, __LINE__,
+ sudo_debug_subsys, 0);
_exit(0);
}
}
* as the io plugin tailqueue will be empty and no I/O logging will occur.
*/
if (!tq_empty(&io_plugins) || ISSET(details->flags, CD_USE_PTY)) {
- log_io = TRUE;
+ log_io = true;
if (ISSET(details->flags, CD_SET_UTMP))
utmp_user = details->utmp_user ? details->utmp_user : user_details.username;
- sudo_debug(8, "allocate pty for I/O logging");
+ sudo_debug_printf(SUDO_DEBUG_INFO, "allocate pty for I/O logging");
pty_setup(details->euid, user_details.tty, utmp_user);
}
sigemptyset(&sa.sa_mask);
/*
- * Signals for forward to the child process (excluding SIGALRM and SIGCHLD).
+ * Signals to forward to the child process (excluding SIGALRM and SIGCHLD).
* Note: HP-UX select() will not be interrupted if SA_RESTART set.
*/
sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */
sa.sa_handler = handler;
sigaction(SIGALRM, &sa, NULL);
sigaction(SIGCHLD, &sa, NULL);
- sigaction(SIGHUP, &sa, NULL);
- sigaction(SIGINT, &sa, NULL);
sigaction(SIGPIPE, &sa, NULL);
- sigaction(SIGQUIT, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
sigaction(SIGUSR1, &sa, NULL);
sigaction(SIGUSR2, &sa, NULL);
+ /*
+ * When not running the command in a pty, we do not want to
+ * forward signals generated by the kernel that the child will
+ * already have received either by virtue of being in the
+ * controlling tty's process group (SIGINT, SIGQUIT) or because
+ * the session is terminating (SIGHUP).
+ */
+#ifdef SA_SIGINFO
+ if (!log_io) {
+ sa.sa_flags |= SA_SIGINFO;
+ sa.sa_sigaction = handler_nofwd;
+ }
+#endif
+ sigaction(SIGHUP, &sa, NULL);
+ sigaction(SIGINT, &sa, NULL);
+ sigaction(SIGQUIT, &sa, NULL);
+
/* Max fd we will be selecting on. */
maxfd = MAX(sv[0], signal_pipe[0]);
* In the event loop we pass input from user tty to master
* and pass output from master to stdout and IO plugin.
*/
- fdsr = (fd_set *)emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
- fdsw = (fd_set *)emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
+ fdsr = emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
+ fdsw = emalloc2(howmany(maxfd + 1, NFDBITS), sizeof(fd_mask));
for (;;) {
- zero_bytes(fdsw, howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask));
- zero_bytes(fdsr, howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask));
+ memset(fdsw, 0, howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask));
+ memset(fdsr, 0, howmany(maxfd + 1, NFDBITS) * sizeof(fd_mask));
FD_SET(signal_pipe[0], fdsr);
FD_SET(sv[0], fdsr);
if (log_io)
fd_set_iobs(fdsr, fdsw); /* XXX - better name */
nready = select(maxfd + 1, fdsr, fdsw, NULL, NULL);
+ sudo_debug_printf(SUDO_DEBUG_DEBUG, "select returns %d", nready);
if (nready == -1) {
- if (errno == EINTR)
+ if (errno == EINTR || errno == ENOMEM)
continue;
- error(1, _("select failed"));
+ if (errno == EBADF || errno == EIO) {
+ /* One of the ttys must have gone away. */
+ goto do_tty_io;
+ }
+ warning(_("select failed"));
+ sudo_debug_printf(SUDO_DEBUG_ERROR,
+ "select failure, terminating child");
+ schedule_signal(SIGKILL);
+ forward_signals(sv[0]);
+ break;
}
if (FD_ISSET(sv[0], fdsw)) {
forward_signals(sv[0]);
}
if (FD_ISSET(signal_pipe[0], fdsr)) {
- n = handle_signals(signal_pipe[0], child, log_io, cstat);
+ n = handle_signals(sv, child, log_io, cstat);
if (n == 0) {
/* Child has exited, cstat is set, we are done. */
- goto done;
+ break;
}
if (n == -1) {
/* Error reading signal_pipe[0], should not happen. */
if (FD_ISSET(sv[0], fdsr)) {
/* read child status */
n = recv(sv[0], cstat, sizeof(*cstat), 0);
- if (n == -1) {
- if (errno == EINTR)
- continue;
- /*
- * If not logging I/O we will receive ECONNRESET when
- * the command is executed. It is safe to ignore this.
- */
- if (log_io && errno != EAGAIN) {
- cstat->type = CMD_ERRNO;
- cstat->val = errno;
+ if (n != sizeof(*cstat)) {
+ if (n == -1) {
+ if (errno == EINTR)
+ continue;
+ /*
+ * If not logging I/O we may receive ECONNRESET when
+ * the command is executed and sv is closed.
+ * It is safe to ignore this.
+ */
+ if (log_io && errno != EAGAIN) {
+ cstat->type = CMD_ERRNO;
+ cstat->val = errno;
+ break;
+ }
+ sudo_debug_printf(SUDO_DEBUG_ERROR,
+ "failed to read child status: %s", strerror(errno));
+ } else {
+ /* Short read or EOF. */
+ sudo_debug_printf(SUDO_DEBUG_ERROR,
+ "failed to read child status: %s",
+ n ? "short read" : "EOF");
+ /* XXX - should set cstat */
break;
}
}
if (cstat->type == CMD_WSTATUS) {
if (WIFSTOPPED(cstat->val)) {
/* Suspend parent and tell child how to resume on return. */
- sudo_debug(8, "child stopped, suspending parent");
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "child stopped, suspending parent");
n = suspend_parent(WSTOPSIG(cstat->val));
schedule_signal(n);
continue;
} else {
/* Child exited or was killed, either way we are done. */
+ sudo_debug_printf(SUDO_DEBUG_INFO, "child exited or was killed");
break;
}
} else if (cstat->type == CMD_ERRNO) {
/* Child was unable to execute command or broken pipe. */
+ sudo_debug_printf(SUDO_DEBUG_INFO, "errno from child: %s",
+ strerror(cstat->val));
break;
}
}
-
+do_tty_io:
if (perform_io(fdsr, fdsw, cstat) != 0) {
/* I/O error, kill child if still alive and finish. */
+ sudo_debug_printf(SUDO_DEBUG_ERROR, "I/O error, terminating child");
schedule_signal(SIGKILL);
forward_signals(sv[0]);
break;
}
#endif
-done:
efree(fdsr);
efree(fdsw);
while (!tq_empty(&sigfwd_list)) {
efree(sigfwd);
}
- return cstat->type == CMD_ERRNO ? -1 : 0;
+ debug_return_int(cstat->type == CMD_ERRNO ? -1 : 0);
}
/*
* Returns -1 on error, 0 on child exit, else 1.
*/
static int
-handle_signals(int fd, pid_t child, int log_io, struct command_status *cstat)
+handle_signals(int sv[2], pid_t child, int log_io, struct command_status *cstat)
{
unsigned char signo;
ssize_t nread;
int status;
pid_t pid;
+ debug_decl(handle_signals, SUDO_DEBUG_EXEC)
for (;;) {
/* read signal pipe */
/* If pipe is empty, we are done. */
if (errno == EAGAIN)
break;
- sudo_debug(9, "error reading signal pipe %s", strerror(errno));
+ sudo_debug_printf(SUDO_DEBUG_ERROR, "error reading signal pipe %s",
+ strerror(errno));
cstat->type = CMD_ERRNO;
cstat->val = errno;
- return -1;
+ debug_return_int(-1);
}
- sudo_debug(9, "received signal %d", signo);
+ sudo_debug_printf(SUDO_DEBUG_DIAG, "received signal %d", signo);
if (signo == SIGCHLD) {
/*
* If logging I/O, child is the intermediate process,
pid = waitpid(child, &status, WUNTRACED|WNOHANG);
} while (pid == -1 && errno == EINTR);
if (pid == child) {
- /* If not logging I/O and child has exited we are done. */
- if (!log_io) {
+ if (log_io) {
+ /*
+ * On BSD we get ECONNRESET on sv[0] if monitor dies
+ * and select() will return with sv[0] readable.
+ * On Linux that doesn't appear to happen so if the
+ * monitor dies, shut down the socketpair to force a
+ * select() notification.
+ */
+ (void) shutdown(sv[0], SHUT_WR);
+ } else {
if (WIFSTOPPED(status)) {
/*
* Save the controlling terminal's process group
int fd = open(_PATH_TTY, O_RDWR|O_NOCTTY, 0);
if (fd != -1)
saved_pgrp = tcgetpgrp(fd);
- if (kill(getpid(), WSTOPSIG(status)) != 0)
- warning("kill(%d, %d)", getpid(), WSTOPSIG(status));
+ if (kill(getpid(), WSTOPSIG(status)) != 0) {
+ warning("kill(%d, %d)", (int)getpid(),
+ WSTOPSIG(status));
+ }
if (fd != -1) {
if (saved_pgrp != (pid_t)-1)
(void)tcsetpgrp(fd, saved_pgrp);
/* Child has exited, we are done. */
cstat->type = CMD_WSTATUS;
cstat->val = status;
- return 0;
+ debug_return_int(0);
}
}
- /* Else we get ECONNRESET on sv[0] if child dies. */
}
} else {
if (log_io) {
} else {
/* Nothing listening on sv[0], send directly. */
if (signo == SIGALRM)
- terminate_child(child, FALSE);
+ terminate_child(child, false);
else if (kill(child, signo) != 0)
- warning("kill(%d, %d)", child, signo);
+ warning("kill(%d, %d)", (int)child, signo);
}
}
}
- return 1;
+ debug_return_int(1);
}
/*
struct sigforward *sigfwd;
struct command_status cstat;
ssize_t nsent;
+ debug_decl(forward_signals, SUDO_DEBUG_EXEC)
while (!tq_empty(&sigfwd_list)) {
sigfwd = tq_first(&sigfwd_list);
- sudo_debug(9, "sending signal %d to child over backchannel",
- sigfwd->signo);
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "sending signal %d to child over backchannel", sigfwd->signo);
cstat.type = CMD_SIGNO;
cstat.val = sigfwd->signo;
do {
efree(sigfwd);
if (nsent != sizeof(cstat)) {
if (errno == EPIPE) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR,
+ "broken pipe writing to child over backchannel");
/* Other end of socket gone, empty out sigfwd_list. */
while (!tq_empty(&sigfwd_list)) {
sigfwd = tq_first(&sigfwd_list);
tq_remove(&sigfwd_list, sigfwd);
efree(sigfwd);
}
+ /* XXX - child (monitor) is dead, we should exit too? */
}
break;
}
}
+ debug_return;
}
/*
schedule_signal(int signo)
{
struct sigforward *sigfwd;
+ debug_decl(schedule_signal, SUDO_DEBUG_EXEC)
- sigfwd = emalloc(sizeof(*sigfwd));
+ sudo_debug_printf(SUDO_DEBUG_DIAG, "forwarding signal %d to child", signo);
+
+ sigfwd = ecalloc(1, sizeof(*sigfwd));
sigfwd->prev = sigfwd;
- sigfwd->next = NULL;
+ /* sigfwd->next = NULL; */
sigfwd->signo = signo;
tq_append(&sigfwd_list, sigfwd);
+
+ debug_return;
}
/*
* The pipe is non-blocking, if we overflow the kernel's pipe
* buffer we drop the signal. This is not a problem in practice.
*/
- if (write(signal_pipe[1], &signo, sizeof(signo)) == -1)
- /* shut up glibc */;
+ ignore_result(write(signal_pipe[1], &signo, sizeof(signo)));
+}
+
+#ifdef SA_SIGINFO
+/*
+ * Generic handler for signals passed from parent -> child.
+ * The other end of signal_pipe is checked in the main event loop.
+ * This version is for the non-pty case and does not forward
+ * signals that are generated by the kernel.
+ */
+static void
+handler_nofwd(int s, siginfo_t *info, void *context)
+{
+ unsigned char signo = (unsigned char)s;
+
+ /* Only forward user-generated signals. */
+ if (info == NULL || info->si_code <= 0) {
+ /*
+ * The pipe is non-blocking, if we overflow the kernel's pipe
+ * buffer we drop the signal. This is not a problem in practice.
+ */
+ ignore_result(write(signal_pipe[1], &signo, sizeof(signo)));
+ }
}
+#endif /* SA_SIGINFO */
/*
* Open a pipe and make both ends non-blocking.
pipe_nonblock(int fds[2])
{
int flags, rval;
+ debug_decl(pipe_nonblock, SUDO_DEBUG_EXEC)
rval = pipe(fds);
if (rval != -1) {
}
}
- return rval;
+ debug_return_int(rval);
}
projects / debian / sudo / blobdiff