embedaddon/sudo/src/exec.c - diff

Return to exec.c CVS log

Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / sudo / src

Diff for /embedaddon/sudo/src/exec.c between versions 1.1.1.3 and 1.1.1.4

version 1.1.1.3, 2012/10/09 09:29:52	version 1.1.1.4, 2013/07/22 10:46:13
Line 1	Line 1
/*	/*
* Copyright (c) 2009-2012 Todd C. Miller <Todd.Miller@courtesan.com>	* Copyright (c) 2009-2013 Todd C. Miller <Todd.Miller@courtesan.com>
*	*
* Permission to use, copy, modify, and distribute this software for any	* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above	* purpose with or without fee is hereby granted, provided that the above
Line 17	Line 17
#include <config.h>	#include <config.h>

#include <sys/types.h>	#include <sys/types.h>
#include <sys/param.h>
#ifdef HAVE_SYS_SYSMACROS_H	#ifdef HAVE_SYS_SYSMACROS_H
# include <sys/sysmacros.h>	# include <sys/sysmacros.h>
#endif	#endif
Line 50	Line 49
#if TIME_WITH_SYS_TIME	#if TIME_WITH_SYS_TIME
# include <time.h>	# include <time.h>
#endif	#endif
#ifdef HAVE_SETLOCALE
# include <locale.h>
#endif
#include <errno.h>	#include <errno.h>
#include <fcntl.h>	#include <fcntl.h>
#include <signal.h>	#include <signal.h>
Line 63	Line 59
#include "sudo_plugin.h"	#include "sudo_plugin.h"
#include "sudo_plugin_int.h"	#include "sudo_plugin_int.h"

/* Shared with exec_pty.c for use with handler(). */
int signal_pipe[2];

/* We keep a tailq of signals to forward to child. */	/* We keep a tailq of signals to forward to child. */
struct sigforward {	struct sigforward {
struct sigforward prev, next;	struct sigforward prev, next;
Line 77 static pid_t ppgrp = -1;	Line 70 static pid_t ppgrp = -1;

volatile pid_t cmnd_pid = -1;	volatile pid_t cmnd_pid = -1;

static int handle_signals(int sv[2], pid_t child, int log_io,	static int dispatch_signals(int sv[2], pid_t child, int log_io,
struct command_status *cstat);	struct command_status *cstat);
	static int dispatch_pending_signals(struct command_status *cstat);
static void forward_signals(int fd);	static void forward_signals(int fd);
static void schedule_signal(int signo);	static void schedule_signal(int signo);
#ifdef SA_SIGINFO	#ifdef SA_SIGINFO
Line 110 static int fork_cmnd(struct command_details *details,	Line 104 static int fork_cmnd(struct command_details *details,
* XXX - currently we send SIGCONT upon resume in some cases where	* XXX - currently we send SIGCONT upon resume in some cases where
* we don't need to (e.g. command pgrp == parent pgrp).	* we don't need to (e.g. command pgrp == parent pgrp).
*/	*/
zero_bytes(&sa, sizeof(sa));	memset(&sa, 0, sizeof(sa));
sigemptyset(&sa.sa_mask);	sigfillset(&sa.sa_mask);
sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */	sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */
#ifdef SA_SIGINFO	#ifdef SA_SIGINFO
sa.sa_flags \|= SA_SIGINFO;	sa.sa_flags \|= SA_SIGINFO;
Line 119 static int fork_cmnd(struct command_details *details,	Line 113 static int fork_cmnd(struct command_details *details,
#else	#else
sa.sa_handler = handler;	sa.sa_handler = handler;
#endif	#endif
sigaction(SIGCONT, &sa, NULL);	sudo_sigaction(SIGCONT, &sa, NULL);
#ifdef SA_SIGINFO	#ifdef SA_SIGINFO
sa.sa_sigaction = handler_user_only;	sa.sa_sigaction = handler_user_only;
#endif	#endif
sigaction(SIGTSTP, &sa, NULL);	sudo_sigaction(SIGTSTP, &sa, NULL);

/*	/*
* The policy plugin's session init must be run before we 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.	* or certain pam modules won't be able to track their state.
*/	*/
if (policy_init_session(details) != true)	if (policy_init_session(details) != true)
errorx(1, _("policy plugin failed session initialization"));	fatalx(_("policy plugin failed session initialization"));

cmnd_pid = sudo_debug_fork();	cmnd_pid = sudo_debug_fork();
switch (cmnd_pid) {	switch (cmnd_pid) {
case -1:	case -1:
error(1, _("unable to fork"));	fatal(_("unable to fork"));
break;	break;
case 0:	case 0:
/* child */	/* child */
Line 143 static int fork_cmnd(struct command_details *details,	Line 137 static int fork_cmnd(struct command_details *details,
close(signal_pipe[0]);	close(signal_pipe[0]);
close(signal_pipe[1]);	close(signal_pipe[1]);
fcntl(sv[1], F_SETFD, FD_CLOEXEC);	fcntl(sv[1], F_SETFD, FD_CLOEXEC);
restore_signals();	exec_cmnd(details, &cstat, &sv[1]);
if (exec_setup(details, NULL, -1) == true) {
/* headed for execve() */
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,
ISSET(details->flags, CD_NOEXEC));
} else
#endif
{
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);	send(sv[1], &cstat, sizeof(cstat), 0);
sudo_debug_exit_int(__func__, __FILE__, __LINE__, sudo_debug_subsys, 1);	sudo_debug_exit_int(__func__, __FILE__, __LINE__, sudo_debug_subsys, 1);
_exit(1);	_exit(1);
Line 181 static int fork_cmnd(struct command_details *details,	Line 147 static int fork_cmnd(struct command_details *details,
debug_return_int(cmnd_pid);	debug_return_int(cmnd_pid);
}	}

static struct signal_state {
int signo;
sigaction_t sa;
} saved_signals[] = {
{ SIGALRM },
{ SIGCHLD },
{ SIGCONT },
{ SIGHUP },
{ SIGINT },
{ SIGPIPE },
{ SIGQUIT },
{ SIGTERM },
{ SIGTSTP },
{ SIGTTIN },
{ SIGTTOU },
{ SIGUSR1 },
{ SIGUSR2 },
{ -1 }
};

/*	/*
* Save signal handler state so it can be restored before exec.	* Setup the execution environment and execute the command.
	* If SELinux is enabled, run the command via sesh, otherwise
	* execute it directly.
	* If the exec fails, cstat is filled in with the value of errno.
*/	*/
void	void
save_signals(void)	exec_cmnd(struct command_details details, struct command_status cstat,
	int *errfd)
{	{
struct signal_state *ss;	debug_decl(exec_cmnd, SUDO_DEBUG_EXEC)
debug_decl(save_signals, SUDO_DEBUG_EXEC)

for (ss = saved_signals; ss->signo != -1; ss++)	restore_signals();
sigaction(ss->signo, NULL, &ss->sa);	if (exec_setup(details, NULL, -1) == true) {
	/* headed for execve() */
	sudo_debug_execve(SUDO_DEBUG_INFO, details->command,
	details->argv, details->envp);
	if (details->closefrom >= 0) {
	int maxfd = details->closefrom;
	/* Preserve back channel if present. */
	if (errfd != NULL) {
	dup2(*errfd, maxfd);
	(void)fcntl(maxfd, F_SETFD, FD_CLOEXEC);
	*errfd = 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,
	ISSET(details->flags, CD_NOEXEC));
	} else
	#endif
	{
	sudo_execve(details->command, details->argv, details->envp,
	ISSET(details->flags, CD_NOEXEC));
	}
	cstat->type = CMD_ERRNO;
	cstat->val = errno;
	sudo_debug_printf(SUDO_DEBUG_ERROR, "unable to exec %s: %s",
	details->command, strerror(errno));
	}
debug_return;	debug_return;
}	}

/*	/*
* Restore signal handlers to initial state.	* Execute a command, potentially in a pty with I/O loggging, and
*/	* wait for it to finish.
void
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;
}

/*
* Execute a command, potentially in a pty with I/O loggging.
* This is a little bit tricky due to how POSIX job control works and	* This is a little bit tricky due to how POSIX job control works and
* we fact that we have two different controlling terminals to deal with.	* we fact that we have two different controlling terminals to deal with.
*/	*/
Line 248 sudo_execute(struct command_details *details, struct c	Line 212 sudo_execute(struct command_details *details, struct c
pid_t child;	pid_t child;
debug_decl(sudo_execute, SUDO_DEBUG_EXEC)	debug_decl(sudo_execute, SUDO_DEBUG_EXEC)

	dispatch_pending_signals(cstat);

/* If running in background mode, fork and exit. */	/* If running in background mode, fork and exit. */
if (ISSET(details->flags, CD_BACKGROUND)) {	if (ISSET(details->flags, CD_BACKGROUND)) {
switch (sudo_debug_fork()) {	switch (sudo_debug_fork()) {
Line 278 sudo_execute(struct command_details *details, struct c	Line 244 sudo_execute(struct command_details *details, struct c
utmp_user = details->utmp_user ? details->utmp_user : user_details.username;	utmp_user = details->utmp_user ? details->utmp_user : user_details.username;
sudo_debug_printf(SUDO_DEBUG_INFO, "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);	pty_setup(details->euid, user_details.tty, utmp_user);
	} else if (!ISSET(details->flags, CD_SET_TIMEOUT) &&
	policy_plugin.u.policy->close == NULL) {
	/* If no I/O logging, timeout or policy close we can exec directly. */
	exec_cmnd(details, cstat, NULL);
	goto done;
}	}

/*	/*
Line 285 sudo_execute(struct command_details *details, struct c	Line 256 sudo_execute(struct command_details *details, struct c
* Parent sends signal info to child and child sends back wait status.	* Parent sends signal info to child and child sends back wait status.
*/	*/
if (socketpair(PF_UNIX, SOCK_DGRAM, 0, sv) == -1)	if (socketpair(PF_UNIX, SOCK_DGRAM, 0, sv) == -1)
error(1, _("unable to create sockets"));	fatal(_("unable to create sockets"));

/*	/*
* We use a pipe to atomically handle signal notification within
* the select() loop.
*/
if (pipe_nonblock(signal_pipe) != 0)
error(1, _("unable to create pipe"));

zero_bytes(&sa, sizeof(sa));
sigemptyset(&sa.sa_mask);

/*
* Signals to forward to the child process (excluding SIGALRM and SIGCHLD).	* Signals to forward to the child process (excluding SIGALRM and SIGCHLD).
	* We block all other signals while running the signal handler.
* Note: HP-UX select() will not be interrupted if SA_RESTART set.	* Note: HP-UX select() will not be interrupted if SA_RESTART set.
*/	*/
	memset(&sa, 0, sizeof(sa));
	sigfillset(&sa.sa_mask);
sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */	sa.sa_flags = SA_INTERRUPT; /* do not restart syscalls */
#ifdef SA_SIGINFO	#ifdef SA_SIGINFO
sa.sa_flags \|= SA_SIGINFO;	sa.sa_flags \|= SA_SIGINFO;
Line 308 sudo_execute(struct command_details *details, struct c	Line 272 sudo_execute(struct command_details *details, struct c
#else	#else
sa.sa_handler = handler;	sa.sa_handler = handler;
#endif	#endif
sigaction(SIGALRM, &sa, NULL);	sudo_sigaction(SIGTERM, &sa, NULL);
sigaction(SIGCHLD, &sa, NULL);	sudo_sigaction(SIGALRM, &sa, NULL); /* XXX - only if there is a timeout */
sigaction(SIGPIPE, &sa, NULL);	sudo_sigaction(SIGCHLD, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);	sudo_sigaction(SIGPIPE, &sa, NULL);
sigaction(SIGUSR1, &sa, NULL);	sudo_sigaction(SIGUSR1, &sa, NULL);
sigaction(SIGUSR2, &sa, NULL);	sudo_sigaction(SIGUSR2, &sa, NULL);

/*	/*
* When not running the command in a pty, we do not want to	* When not running the command in a pty, we do not want to
Line 328 sudo_execute(struct command_details *details, struct c	Line 292 sudo_execute(struct command_details *details, struct c
sa.sa_sigaction = handler_user_only;	sa.sa_sigaction = handler_user_only;
}	}
#endif	#endif
sigaction(SIGHUP, &sa, NULL);	sudo_sigaction(SIGHUP, &sa, NULL);
sigaction(SIGINT, &sa, NULL);	sudo_sigaction(SIGINT, &sa, NULL);
sigaction(SIGQUIT, &sa, NULL);	sudo_sigaction(SIGQUIT, &sa, NULL);

/* Max fd we will be selecting on. */	/* Max fd we will be selecting on. */
maxfd = MAX(sv[0], signal_pipe[0]);	maxfd = MAX(sv[0], signal_pipe[0]);
Line 349 sudo_execute(struct command_details *details, struct c	Line 313 sudo_execute(struct command_details *details, struct c
if (ISSET(details->flags, CD_SET_TIMEOUT))	if (ISSET(details->flags, CD_SET_TIMEOUT))
alarm(details->timeout);	alarm(details->timeout);

#ifdef HAVE_SETLOCALE
/*	/*
* I/O logging must be in the C locale for floating point numbers	* I/O logging must be in the C locale for floating point numbers
* to be logged consistently.	* to be logged consistently.
*/	*/
setlocale(LC_ALL, "C");	setlocale(LC_ALL, "C");
#endif

/*	/*
* In the event loop we pass input from user tty to master	* In the event loop we pass input from user tty to master
Line 393 sudo_execute(struct command_details *details, struct c	Line 355 sudo_execute(struct command_details *details, struct c
forward_signals(sv[0]);	forward_signals(sv[0]);
}	}
if (FD_ISSET(signal_pipe[0], fdsr)) {	if (FD_ISSET(signal_pipe[0], fdsr)) {
n = handle_signals(sv, child, log_io, cstat);	n = dispatch_signals(sv, child, log_io, cstat);
if (n == 0) {	if (n == 0) {
/* Child has exited, cstat is set, we are done. */	/* Child has exited, cstat is set, we are done. */
break;	break;
Line 495 do_tty_io:	Line 457 do_tty_io:
tq_remove(&sigfwd_list, sigfwd);	tq_remove(&sigfwd_list, sigfwd);
efree(sigfwd);	efree(sigfwd);
}	}
	done:
debug_return_int(cstat->type == CMD_ERRNO ? -1 : 0);	debug_return_int(cstat->type == CMD_ERRNO ? -1 : 0);
}	}

/*	/*
* Read signals on fd written to by handler().	* Read signals on signal_pipe written by handler().
* Returns -1 on error, 0 on child exit, else 1.	* Returns -1 on error, 0 on child exit, else 1.
*/	*/
static int	static int
handle_signals(int sv[2], pid_t child, int log_io, struct command_status *cstat)	dispatch_signals(int sv[2], pid_t child, int log_io, struct command_status *cstat)
{	{
char signame[SIG2STR_MAX];	char signame[SIG2STR_MAX];
unsigned char signo;	unsigned char signo;
ssize_t nread;	ssize_t nread;
int status;	int status;
pid_t pid;	pid_t pid;
debug_decl(handle_signals, SUDO_DEBUG_EXEC)	debug_decl(dispatch_signals, SUDO_DEBUG_EXEC)

for (;;) {	for (;;) {
/* read signal pipe */	/* read signal pipe */
Line 573 handle_signals(int sv[2], pid_t child, int log_io, str	Line 535 handle_signals(int sv[2], pid_t child, int log_io, str
saved_pgrp = -1;	saved_pgrp = -1;
}	}
if (signo == SIGTSTP) {	if (signo == SIGTSTP) {
zero_bytes(&sa, sizeof(sa));	memset(&sa, 0, sizeof(sa));
sigemptyset(&sa.sa_mask);	sigemptyset(&sa.sa_mask);
	sa.sa_flags = SA_RESTART;
sa.sa_handler = SIG_DFL;	sa.sa_handler = SIG_DFL;
sigaction(SIGTSTP, &sa, &osa);	sudo_sigaction(SIGTSTP, &sa, &osa);
}	}
if (kill(getpid(), signo) != 0)	if (kill(getpid(), signo) != 0)
warning("kill(%d, SIG%s)", (int)getpid(), signame);	warning("kill(%d, SIG%s)", (int)getpid(), signame);
if (signo == SIGTSTP)	if (signo == SIGTSTP)
sigaction(SIGTSTP, &osa, NULL);	sudo_sigaction(SIGTSTP, &osa, NULL);
if (fd != -1) {	if (fd != -1) {
/*	/*
* Restore command's process group if different.	* Restore command's process group if different.
Line 616 handle_signals(int sv[2], pid_t child, int log_io, str	Line 579 handle_signals(int sv[2], pid_t child, int log_io, str
}	}

/*	/*
	* Drain pending signals from signale_pipe written by sudo_handler().
	* Handles the case where the signal was sent to us before
	* we have executed the command.
	* Returns 1 if we should terminate, else 0.
	*/
	static int
	dispatch_pending_signals(struct command_status *cstat)
	{
	ssize_t nread;
	struct sigaction sa;
	unsigned char signo = 0;
	int rval = 0;
	debug_decl(dispatch_pending_signals, SUDO_DEBUG_EXEC)

	for (;;) {
	nread = read(signal_pipe[0], &signo, sizeof(signo));
	if (nread <= 0) {
	/* It should not be possible to get EOF but just in case. */
	if (nread == 0)
	errno = ECONNRESET;
	/* Restart if interrupted by signal so the pipe doesn't fill. */
	if (errno == EINTR)
	continue;
	/* If pipe is empty, we are done. */
	if (errno == EAGAIN)
	break;
	sudo_debug_printf(SUDO_DEBUG_ERROR, "error reading signal pipe %s",
	strerror(errno));
	cstat->type = CMD_ERRNO;
	cstat->val = errno;
	rval = 1;
	break;
	}
	/* Take the first terminal signal. */
	if (signo == SIGINT \|\| signo == SIGQUIT) {
	cstat->type = CMD_WSTATUS;
	cstat->val = signo + 128;
	rval = 1;
	break;
	}
	}
	/* Only stop if we haven't already been terminated. */
	if (signo == SIGTSTP)
	{
	memset(&sa, 0, sizeof(sa));
	sigemptyset(&sa.sa_mask);
	sa.sa_flags = SA_RESTART;
	sa.sa_handler = SIG_DFL;
	sudo_sigaction(SIGTSTP, &sa, NULL);
	if (kill(getpid(), SIGTSTP) != 0)
	warning("kill(%d, SIGTSTP)", (int)getpid());
	/* No need to reinstall SIGTSTP handler. */
	}
	debug_return_int(rval);
	}

	/*
* Forward signals in sigfwd_list to child listening on fd.	* Forward signals in sigfwd_list to child listening on fd.
*/	*/
static void	static void
Line 629 forward_signals(int sock)	Line 649 forward_signals(int sock)

while (!tq_empty(&sigfwd_list)) {	while (!tq_empty(&sigfwd_list)) {
sigfwd = tq_first(&sigfwd_list);	sigfwd = tq_first(&sigfwd_list);
if (sig2str(sigfwd->signo, signame) == -1)	if (sigfwd->signo == SIGCONT_FG)
	strlcpy(signame, "CONT_FG", sizeof(signame));
	else if (sigfwd->signo == SIGCONT_BG)
	strlcpy(signame, "CONT_BG", sizeof(signame));
	else if (sig2str(sigfwd->signo, signame) == -1)
snprintf(signame, sizeof(signame), "%d", sigfwd->signo);	snprintf(signame, sizeof(signame), "%d", sigfwd->signo);
sudo_debug_printf(SUDO_DEBUG_INFO,	sudo_debug_printf(SUDO_DEBUG_INFO,
"sending SIG%s to child over backchannel", signame);	"sending SIG%s to child over backchannel", signame);
Line 668 schedule_signal(int signo)	Line 692 schedule_signal(int signo)
char signame[SIG2STR_MAX];	char signame[SIG2STR_MAX];
debug_decl(schedule_signal, SUDO_DEBUG_EXEC)	debug_decl(schedule_signal, SUDO_DEBUG_EXEC)

if (sig2str(signo, signame) == -1)	if (signo == SIGCONT_FG)
	strlcpy(signame, "CONT_FG", sizeof(signame));
	else if (signo == SIGCONT_BG)
	strlcpy(signame, "CONT_BG", sizeof(signame));
	else if (sig2str(signo, signame) == -1)
snprintf(signame, sizeof(signame), "%d", signo);	snprintf(signame, sizeof(signame), "%d", signo);
sudo_debug_printf(SUDO_DEBUG_DIAG, "forwarding SIG%s to child", signame);	sudo_debug_printf(SUDO_DEBUG_DIAG, "scheduled SIG%s for child", signame);

sigfwd = ecalloc(1, sizeof(*sigfwd));	sigfwd = ecalloc(1, sizeof(*sigfwd));
sigfwd->prev = sigfwd;	sigfwd->prev = sigfwd;

FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>

Removed from v.1.1.1.3
changed lines
	Added in v.1.1.1.4