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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 02:23:56 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 02:23:56 +0000
commit9620f76a210d9d8c1aaff25e99d6dc513f87e6e9 (patch)
treeceecc90fb95780872c35da764c5163f38e4727c4 /src/exec_pty.c
parentInitial commit. (diff)
downloadsudo-9620f76a210d9d8c1aaff25e99d6dc513f87e6e9.tar.xz
sudo-9620f76a210d9d8c1aaff25e99d6dc513f87e6e9.zip
Adding upstream version 1.8.27.upstream/1.8.27upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/exec_pty.c')
-rw-r--r--src/exec_pty.c1813
1 files changed, 1813 insertions, 0 deletions
diff --git a/src/exec_pty.c b/src/exec_pty.c
new file mode 100644
index 0000000..c1ccd4b
--- /dev/null
+++ b/src/exec_pty.c
@@ -0,0 +1,1813 @@
+/*
+ * Copyright (c) 2009-2019 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <sys/ioctl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif /* HAVE_STRING_H */
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif /* HAVE_STRINGS_H */
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <termios.h> /* for struct winsize on HP-UX */
+
+#include "sudo.h"
+#include "sudo_event.h"
+#include "sudo_exec.h"
+#include "sudo_plugin.h"
+#include "sudo_plugin_int.h"
+
+/* Evaluates to true if the event has /dev/tty as its fd. */
+#define USERTTY_EVENT(_ev) (sudo_ev_get_fd((_ev)) == io_fds[SFD_USERTTY])
+
+#define TERM_COOKED 0
+#define TERM_RAW 1
+
+/* Tail queue of messages to send to the monitor. */
+struct monitor_message {
+ TAILQ_ENTRY(monitor_message) entries;
+ struct command_status cstat;
+};
+TAILQ_HEAD(monitor_message_list, monitor_message);
+
+struct exec_closure_pty {
+ pid_t monitor_pid;
+ pid_t cmnd_pid;
+ pid_t ppgrp;
+ short rows;
+ short cols;
+ struct command_status *cstat;
+ struct command_details *details;
+ struct sudo_event_base *evbase;
+ struct sudo_event *backchannel_event;
+ struct sudo_event *fwdchannel_event;
+ struct sudo_event *sigint_event;
+ struct sudo_event *sigquit_event;
+ struct sudo_event *sigtstp_event;
+ struct sudo_event *sigterm_event;
+ struct sudo_event *sighup_event;
+ struct sudo_event *sigalrm_event;
+ struct sudo_event *sigusr1_event;
+ struct sudo_event *sigusr2_event;
+ struct sudo_event *sigchld_event;
+ struct sudo_event *sigwinch_event;
+ struct monitor_message_list monitor_messages;
+};
+
+/*
+ * I/O buffer with associated read/write events and a logging action.
+ * Used to, e.g. pass data from the pty to the user's terminal
+ * and any I/O logging plugins.
+ */
+struct io_buffer;
+typedef bool (*sudo_io_action_t)(const char *, unsigned int, struct io_buffer *);
+struct io_buffer {
+ SLIST_ENTRY(io_buffer) entries;
+ struct exec_closure_pty *ec;
+ struct sudo_event *revent;
+ struct sudo_event *wevent;
+ sudo_io_action_t action;
+ int len; /* buffer length (how much produced) */
+ int off; /* write position (how much already consumed) */
+ char buf[64 * 1024];
+};
+SLIST_HEAD(io_buffer_list, io_buffer);
+
+static char slavename[PATH_MAX];
+int io_fds[6] = { -1, -1, -1, -1, -1, -1};
+static bool foreground, pipeline;
+static int ttymode = TERM_COOKED;
+static sigset_t ttyblock;
+static struct io_buffer_list iobufs;
+static const char *utmp_user;
+
+static void del_io_events(bool nonblocking);
+static void sync_ttysize(struct exec_closure_pty *ec);
+static int safe_close(int fd);
+static void ev_free_by_fd(struct sudo_event_base *evbase, int fd);
+static void check_foreground(struct exec_closure_pty *ec);
+static void add_io_events(struct sudo_event_base *evbase);
+static void schedule_signal(struct exec_closure_pty *ec, int signo);
+
+/*
+ * Cleanup hook for sudo_fatal()/sudo_fatalx()
+ */
+void
+pty_cleanup(void)
+{
+ debug_decl(cleanup, SUDO_DEBUG_EXEC);
+
+ if (io_fds[SFD_USERTTY] != -1)
+ sudo_term_restore(io_fds[SFD_USERTTY], false);
+ if (utmp_user != NULL)
+ utmp_logout(slavename, 0);
+
+ debug_return;
+}
+
+/*
+ * Allocate a pty if /dev/tty is a tty.
+ * Fills in io_fds[SFD_USERTTY], io_fds[SFD_MASTER], io_fds[SFD_SLAVE]
+ * and slavename globals.
+ */
+static bool
+pty_setup(struct command_details *details, const char *tty)
+{
+ debug_decl(pty_setup, SUDO_DEBUG_EXEC);
+
+ io_fds[SFD_USERTTY] = open(_PATH_TTY, O_RDWR);
+ if (io_fds[SFD_USERTTY] == -1) {
+ sudo_debug_printf(SUDO_DEBUG_INFO, "%s: no %s, not allocating a pty",
+ __func__, _PATH_TTY);
+ debug_return_bool(false);
+ }
+
+ if (!get_pty(&io_fds[SFD_MASTER], &io_fds[SFD_SLAVE],
+ slavename, sizeof(slavename), details->euid))
+ sudo_fatal(U_("unable to allocate pty"));
+
+ /* Add entry to utmp/utmpx? */
+ if (ISSET(details->flags, CD_SET_UTMP)) {
+ utmp_user =
+ details->utmp_user ? details->utmp_user : user_details.username;
+ utmp_login(tty, slavename, io_fds[SFD_SLAVE], utmp_user);
+ }
+
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "%s: %s fd %d, pty master fd %d, pty slave fd %d",
+ __func__, _PATH_TTY, io_fds[SFD_USERTTY], io_fds[SFD_MASTER],
+ io_fds[SFD_SLAVE]);
+
+ debug_return_bool(true);
+}
+
+/*
+ * Make the tty slave the controlling tty.
+ * This is only used by the monitor but slavename[] is static.
+ */
+int
+pty_make_controlling(void)
+{
+ if (io_fds[SFD_SLAVE] != -1) {
+#ifdef TIOCSCTTY
+ if (ioctl(io_fds[SFD_SLAVE], TIOCSCTTY, NULL) != 0)
+ return -1;
+#else
+ /* Set controlling tty by reopening slave. */
+ int fd = open(slavename, O_RDWR);
+ if (fd == -1)
+ return -1;
+ close(fd);
+#endif
+ }
+ return 0;
+}
+
+/* Call I/O plugin tty input log method. */
+static bool
+log_ttyin(const char *buf, unsigned int n, struct io_buffer *iob)
+{
+ struct plugin_container *plugin;
+ sigset_t omask;
+ bool ret = true;
+ debug_decl(log_ttyin, SUDO_DEBUG_EXEC);
+
+ sigprocmask(SIG_BLOCK, &ttyblock, &omask);
+ TAILQ_FOREACH(plugin, &io_plugins, entries) {
+ if (plugin->u.io->log_ttyin) {
+ int rc;
+
+ sudo_debug_set_active_instance(plugin->debug_instance);
+ rc = plugin->u.io->log_ttyin(buf, n);
+ if (rc <= 0) {
+ if (rc < 0) {
+ /* Error: disable plugin's I/O function. */
+ plugin->u.io->log_ttyin = NULL;
+ }
+ ret = false;
+ break;
+ }
+ }
+ }
+ sudo_debug_set_active_instance(sudo_debug_instance);
+ sigprocmask(SIG_SETMASK, &omask, NULL);
+
+ debug_return_bool(ret);
+}
+
+/* Call I/O plugin stdin log method. */
+static bool
+log_stdin(const char *buf, unsigned int n, struct io_buffer *iob)
+{
+ struct plugin_container *plugin;
+ sigset_t omask;
+ bool ret = true;
+ debug_decl(log_stdin, SUDO_DEBUG_EXEC);
+
+ sigprocmask(SIG_BLOCK, &ttyblock, &omask);
+ TAILQ_FOREACH(plugin, &io_plugins, entries) {
+ if (plugin->u.io->log_stdin) {
+ int rc;
+
+ sudo_debug_set_active_instance(plugin->debug_instance);
+ rc = plugin->u.io->log_stdin(buf, n);
+ if (rc <= 0) {
+ if (rc < 0) {
+ /* Error: disable plugin's I/O function. */
+ plugin->u.io->log_stdin = NULL;
+ }
+ ret = false;
+ break;
+ }
+ }
+ }
+ sudo_debug_set_active_instance(sudo_debug_instance);
+ sigprocmask(SIG_SETMASK, &omask, NULL);
+
+ debug_return_bool(ret);
+}
+
+/* Call I/O plugin tty output log method. */
+static bool
+log_ttyout(const char *buf, unsigned int n, struct io_buffer *iob)
+{
+ struct plugin_container *plugin;
+ sigset_t omask;
+ bool ret = true;
+ debug_decl(log_ttyout, SUDO_DEBUG_EXEC);
+
+ sigprocmask(SIG_BLOCK, &ttyblock, &omask);
+ TAILQ_FOREACH(plugin, &io_plugins, entries) {
+ if (plugin->u.io->log_ttyout) {
+ int rc;
+
+ sudo_debug_set_active_instance(plugin->debug_instance);
+ rc = plugin->u.io->log_ttyout(buf, n);
+ if (rc <= 0) {
+ if (rc < 0) {
+ /* Error: disable plugin's I/O function. */
+ plugin->u.io->log_ttyout = NULL;
+ }
+ ret = false;
+ break;
+ }
+ }
+ }
+ sudo_debug_set_active_instance(sudo_debug_instance);
+ if (!ret) {
+ /*
+ * I/O plugin rejected the output, delete the write event
+ * (user's tty) so we do not display the rejected output.
+ */
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "%s: deleting and freeing devtty wevent %p", __func__, iob->wevent);
+ sudo_ev_free(iob->wevent);
+ iob->wevent = NULL;
+ iob->off = iob->len = 0;
+ }
+ sigprocmask(SIG_SETMASK, &omask, NULL);
+
+ debug_return_bool(ret);
+}
+
+/* Call I/O plugin stdout log method. */
+static bool
+log_stdout(const char *buf, unsigned int n, struct io_buffer *iob)
+{
+ struct plugin_container *plugin;
+ sigset_t omask;
+ bool ret = true;
+ debug_decl(log_stdout, SUDO_DEBUG_EXEC);
+
+ sigprocmask(SIG_BLOCK, &ttyblock, &omask);
+ TAILQ_FOREACH(plugin, &io_plugins, entries) {
+ if (plugin->u.io->log_stdout) {
+ int rc;
+
+ sudo_debug_set_active_instance(plugin->debug_instance);
+ rc = plugin->u.io->log_stdout(buf, n);
+ if (rc <= 0) {
+ if (rc < 0) {
+ /* Error: disable plugin's I/O function. */
+ plugin->u.io->log_stdout = NULL;
+ }
+ ret = false;
+ break;
+ }
+ }
+ }
+ sudo_debug_set_active_instance(sudo_debug_instance);
+ if (!ret) {
+ /*
+ * I/O plugin rejected the output, delete the write event
+ * (user's stdout) so we do not display the rejected output.
+ */
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "%s: deleting and freeing stdout wevent %p", __func__, iob->wevent);
+ sudo_ev_free(iob->wevent);
+ iob->wevent = NULL;
+ iob->off = iob->len = 0;
+ }
+ sigprocmask(SIG_SETMASK, &omask, NULL);
+
+ debug_return_bool(ret);
+}
+
+/* Call I/O plugin stderr log method. */
+static bool
+log_stderr(const char *buf, unsigned int n, struct io_buffer *iob)
+{
+ struct plugin_container *plugin;
+ sigset_t omask;
+ bool ret = true;
+ debug_decl(log_stderr, SUDO_DEBUG_EXEC);
+
+ sigprocmask(SIG_BLOCK, &ttyblock, &omask);
+ TAILQ_FOREACH(plugin, &io_plugins, entries) {
+ if (plugin->u.io->log_stderr) {
+ int rc;
+
+ sudo_debug_set_active_instance(plugin->debug_instance);
+ rc = plugin->u.io->log_stderr(buf, n);
+ if (rc <= 0) {
+ if (rc < 0) {
+ /* Error: disable plugin's I/O function. */
+ plugin->u.io->log_stderr = NULL;
+ }
+ ret = false;
+ break;
+ }
+ }
+ }
+ sudo_debug_set_active_instance(sudo_debug_instance);
+ if (!ret) {
+ /*
+ * I/O plugin rejected the output, delete the write event
+ * (user's stderr) so we do not display the rejected output.
+ */
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "%s: deleting and freeing stderr wevent %p", __func__, iob->wevent);
+ sudo_ev_free(iob->wevent);
+ iob->wevent = NULL;
+ iob->off = iob->len = 0;
+ }
+ sigprocmask(SIG_SETMASK, &omask, NULL);
+
+ debug_return_bool(ret);
+}
+
+/* Call I/O plugin suspend log method. */
+static void
+log_suspend(int signo)
+{
+ struct plugin_container *plugin;
+ sigset_t omask;
+ debug_decl(log_suspend, SUDO_DEBUG_EXEC);
+
+ sigprocmask(SIG_BLOCK, &ttyblock, &omask);
+ TAILQ_FOREACH(plugin, &io_plugins, entries) {
+ if (plugin->u.io->version < SUDO_API_MKVERSION(1, 13))
+ continue;
+ if (plugin->u.io->log_suspend) {
+ int rc;
+
+ sudo_debug_set_active_instance(plugin->debug_instance);
+ rc = plugin->u.io->log_suspend(signo);
+ if (rc <= 0) {
+ if (rc < 0) {
+ /* Error: disable plugin's I/O function. */
+ plugin->u.io->log_suspend = NULL;
+ }
+ break;
+ }
+ }
+ }
+ sudo_debug_set_active_instance(sudo_debug_instance);
+ sigprocmask(SIG_SETMASK, &omask, NULL);
+
+ debug_return;
+}
+
+/* Call I/O plugin window change log method. */
+static void
+log_winchange(unsigned int rows, unsigned int cols)
+{
+ struct plugin_container *plugin;
+ sigset_t omask;
+ debug_decl(log_winchange, SUDO_DEBUG_EXEC);
+
+ sigprocmask(SIG_BLOCK, &ttyblock, &omask);
+ TAILQ_FOREACH(plugin, &io_plugins, entries) {
+ if (plugin->u.io->version < SUDO_API_MKVERSION(1, 12))
+ continue;
+ if (plugin->u.io->change_winsize) {
+ int rc;
+
+ sudo_debug_set_active_instance(plugin->debug_instance);
+ rc = plugin->u.io->change_winsize(rows, cols);
+ if (rc <= 0) {
+ if (rc < 0) {
+ /* Error: disable plugin's I/O function. */
+ plugin->u.io->change_winsize = NULL;
+ }
+ break;
+ }
+ }
+ }
+ sudo_debug_set_active_instance(sudo_debug_instance);
+ sigprocmask(SIG_SETMASK, &omask, NULL);
+
+ debug_return;
+}
+
+/*
+ * Check whether we are running in the foregroup.
+ * Updates the foreground global and does lazy init of the
+ * the pty slave as needed.
+ */
+static void
+check_foreground(struct exec_closure_pty *ec)
+{
+ debug_decl(check_foreground, SUDO_DEBUG_EXEC);
+
+ if (io_fds[SFD_USERTTY] != -1) {
+ foreground = tcgetpgrp(io_fds[SFD_USERTTY]) == ec->ppgrp;
+
+ /* Also check for window size changes. */
+ sync_ttysize(ec);
+ }
+
+ debug_return;
+}
+
+/*
+ * Suspend sudo if the underlying command is suspended.
+ * Returns SIGCONT_FG if the command should be resumed in the
+ * foreground or SIGCONT_BG if it is a background process.
+ */
+static int
+suspend_sudo(struct exec_closure_pty *ec, int signo)
+{
+ char signame[SIG2STR_MAX];
+ struct sigaction sa, osa;
+ int ret = 0;
+ debug_decl(suspend_sudo, SUDO_DEBUG_EXEC);
+
+ switch (signo) {
+ case SIGTTOU:
+ case SIGTTIN:
+ /*
+ * If sudo is already the foreground process, just resume the command
+ * in the foreground. If not, we'll suspend sudo and resume later.
+ */
+ if (!foreground)
+ check_foreground(ec);
+ if (foreground) {
+ if (ttymode != TERM_RAW) {
+ if (sudo_term_raw(io_fds[SFD_USERTTY], 0))
+ ttymode = TERM_RAW;
+ }
+ ret = SIGCONT_FG; /* resume command in foreground */
+ break;
+ }
+ /* FALLTHROUGH */
+ case SIGSTOP:
+ case SIGTSTP:
+ /* Flush any remaining output and deschedule I/O events. */
+ del_io_events(true);
+
+ /* Restore original tty mode before suspending. */
+ if (ttymode != TERM_COOKED)
+ sudo_term_restore(io_fds[SFD_USERTTY], false);
+
+ /* Log the suspend event. */
+ log_suspend(signo);
+
+ if (sig2str(signo, signame) == -1)
+ snprintf(signame, sizeof(signame), "%d", signo);
+
+ /* Suspend self and continue command when we resume. */
+ if (signo != SIGSTOP) {
+ memset(&sa, 0, sizeof(sa));
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = SA_RESTART;
+ sa.sa_handler = SIG_DFL;
+ if (sudo_sigaction(signo, &sa, &osa) != 0)
+ sudo_warn(U_("unable to set handler for signal %d"), signo);
+ }
+ sudo_debug_printf(SUDO_DEBUG_INFO, "kill parent SIG%s", signame);
+ if (killpg(ec->ppgrp, signo) != 0)
+ sudo_warn("killpg(%d, SIG%s)", (int)ec->ppgrp, signame);
+
+ /* Log the resume event. */
+ log_suspend(SIGCONT);
+
+ /* Check foreground/background status on resume. */
+ check_foreground(ec);
+
+ /*
+ * We always resume the command in the foreground if sudo itself
+ * is the foreground process. This helps work around poorly behaved
+ * programs that catch SIGTTOU/SIGTTIN but suspend themselves with
+ * SIGSTOP. At worst, sudo will go into the background but upon
+ * resume the command will be runnable. Otherwise, we can get into
+ * a situation where the command will immediately suspend itself.
+ */
+ sudo_debug_printf(SUDO_DEBUG_INFO, "parent is in %s, ttymode %d -> %d",
+ foreground ? "foreground" : "background", ttymode,
+ foreground ? TERM_RAW : TERM_COOKED);
+
+ if (foreground) {
+ /* Foreground process, set tty to raw mode. */
+ if (sudo_term_raw(io_fds[SFD_USERTTY], 0))
+ ttymode = TERM_RAW;
+ } else {
+ /* Background process, no access to tty. */
+ ttymode = TERM_COOKED;
+ }
+
+ if (signo != SIGSTOP) {
+ if (sudo_sigaction(signo, &osa, NULL) != 0)
+ sudo_warn(U_("unable to restore handler for signal %d"), signo);
+ }
+
+ ret = ttymode == TERM_RAW ? SIGCONT_FG : SIGCONT_BG;
+ break;
+ }
+
+ debug_return_int(ret);
+}
+
+/*
+ * SIGTTIN signal handler for read_callback that just sets a flag.
+ */
+static volatile sig_atomic_t got_sigttin;
+
+static void
+sigttin(int signo)
+{
+ got_sigttin = 1;
+}
+
+/*
+ * Read an iobuf that is ready.
+ */
+static void
+read_callback(int fd, int what, void *v)
+{
+ struct io_buffer *iob = v;
+ struct sudo_event_base *evbase = sudo_ev_get_base(iob->revent);
+ struct sigaction sa, osa;
+ int saved_errno;
+ ssize_t n;
+ debug_decl(read_callback, SUDO_DEBUG_EXEC);
+
+ /*
+ * We ignore SIGTTIN by default but we need to handle it when reading
+ * from the terminal. A signal event won't work here because the
+ * read() would be restarted, preventing the callback from running.
+ */
+ memset(&sa, 0, sizeof(sa));
+ sigemptyset(&sa.sa_mask);
+ sa.sa_handler = sigttin;
+ got_sigttin = 0;
+ sigaction(SIGTTIN, &sa, &osa);
+ n = read(fd, iob->buf + iob->len, sizeof(iob->buf) - iob->len);
+ saved_errno = errno;
+ sigaction(SIGTTIN, &osa, NULL);
+ errno = saved_errno;
+
+ switch (n) {
+ case -1:
+ if (got_sigttin) {
+ /* Schedule SIGTTIN to be forwared to the command. */
+ schedule_signal(iob->ec, SIGTTIN);
+ }
+ if (errno == EAGAIN || errno == EINTR)
+ break;
+ /* treat read error as fatal and close the fd */
+ sudo_debug_printf(SUDO_DEBUG_ERROR,
+ "error reading fd %d: %s", fd, strerror(errno));
+ /* FALLTHROUGH */
+ case 0:
+ /* got EOF or pty has gone away */
+ if (n == 0) {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "read EOF from fd %d", fd);
+ }
+ safe_close(fd);
+ ev_free_by_fd(evbase, fd);
+ /* If writer already consumed the buffer, close it too. */
+ if (iob->wevent != NULL && iob->off == iob->len) {
+ safe_close(sudo_ev_get_fd(iob->wevent));
+ ev_free_by_fd(evbase, sudo_ev_get_fd(iob->wevent));
+ iob->off = iob->len = 0;
+ }
+ break;
+ default:
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "read %zd bytes from fd %d", n, fd);
+ if (!iob->action(iob->buf + iob->len, n, iob)) {
+ terminate_command(iob->ec->cmnd_pid, true);
+ iob->ec->cmnd_pid = -1;
+ }
+ iob->len += n;
+ /* Enable writer now that there is data in the buffer. */
+ if (iob->wevent != NULL) {
+ if (sudo_ev_add(evbase, iob->wevent, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+ }
+ /* Re-enable reader if buffer is not full. */
+ if (iob->len != sizeof(iob->buf)) {
+ if (sudo_ev_add(evbase, iob->revent, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+ }
+ break;
+ }
+}
+
+/*
+ * SIGTTOU signal handler for write_callback that just sets a flag.
+ */
+static volatile sig_atomic_t got_sigttou;
+
+static void
+sigttou(int signo)
+{
+ got_sigttou = 1;
+}
+
+/*
+ * Write an iobuf that is ready.
+ */
+static void
+write_callback(int fd, int what, void *v)
+{
+ struct io_buffer *iob = v;
+ struct sudo_event_base *evbase = sudo_ev_get_base(iob->wevent);
+ struct sigaction sa, osa;
+ int saved_errno;
+ ssize_t n;
+ debug_decl(write_callback, SUDO_DEBUG_EXEC);
+
+ /*
+ * We ignore SIGTTOU by default but we need to handle it when writing
+ * to the terminal. A signal event won't work here because the
+ * write() would be restarted, preventing the callback from running.
+ */
+ memset(&sa, 0, sizeof(sa));
+ sigemptyset(&sa.sa_mask);
+ sa.sa_handler = sigttou;
+ got_sigttou = 0;
+ sigaction(SIGTTOU, &sa, &osa);
+ n = write(fd, iob->buf + iob->off, iob->len - iob->off);
+ saved_errno = errno;
+ sigaction(SIGTTOU, &osa, NULL);
+ errno = saved_errno;
+
+ if (n == -1) {
+ switch (errno) {
+ case EPIPE:
+ case ENXIO:
+ case EIO:
+ case EBADF:
+ /* other end of pipe closed or pty revoked */
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "unable to write %d bytes to fd %d",
+ iob->len - iob->off, fd);
+ /* Close reader if there is one. */
+ if (iob->revent != NULL) {
+ safe_close(sudo_ev_get_fd(iob->revent));
+ ev_free_by_fd(evbase, sudo_ev_get_fd(iob->revent));
+ }
+ safe_close(fd);
+ ev_free_by_fd(evbase, fd);
+ break;
+ case EINTR:
+ if (got_sigttou) {
+ /* Schedule SIGTTOU to be forwared to the command. */
+ schedule_signal(iob->ec, SIGTTOU);
+ }
+ /* FALLTHROUGH */
+ case EAGAIN:
+ /* not an error */
+ break;
+ default:
+ /* XXX - need a way to distinguish non-exec error. */
+ iob->ec->cstat->type = CMD_ERRNO;
+ iob->ec->cstat->val = errno;
+ sudo_debug_printf(SUDO_DEBUG_ERROR,
+ "error writing fd %d: %s", fd, strerror(errno));
+ sudo_ev_loopbreak(evbase);
+ break;
+ }
+ } else {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "wrote %zd bytes to fd %d", n, fd);
+ iob->off += n;
+ /* Reset buffer if fully consumed. */
+ if (iob->off == iob->len) {
+ iob->off = iob->len = 0;
+ /* Forward the EOF from reader to writer. */
+ if (iob->revent == NULL) {
+ safe_close(fd);
+ ev_free_by_fd(evbase, fd);
+ }
+ }
+ /* Re-enable writer if buffer is not empty. */
+ if (iob->len > iob->off) {
+ if (sudo_ev_add(evbase, iob->wevent, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+ }
+ /* Enable reader if buffer is not full. */
+ if (iob->revent != NULL &&
+ (ttymode == TERM_RAW || !USERTTY_EVENT(iob->revent))) {
+ if (iob->len != sizeof(iob->buf)) {
+ if (sudo_ev_add(evbase, iob->revent, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+ }
+ }
+ }
+}
+
+static void
+io_buf_new(int rfd, int wfd,
+ bool (*action)(const char *, unsigned int, struct io_buffer *),
+ struct exec_closure_pty *ec, struct io_buffer_list *head)
+{
+ int n;
+ struct io_buffer *iob;
+ debug_decl(io_buf_new, SUDO_DEBUG_EXEC);
+
+ /* Set non-blocking mode. */
+ n = fcntl(rfd, F_GETFL, 0);
+ if (n != -1 && !ISSET(n, O_NONBLOCK))
+ (void) fcntl(rfd, F_SETFL, n | O_NONBLOCK);
+ n = fcntl(wfd, F_GETFL, 0);
+ if (n != -1 && !ISSET(n, O_NONBLOCK))
+ (void) fcntl(wfd, F_SETFL, n | O_NONBLOCK);
+
+ /* Allocate and add to head of list. */
+ if ((iob = malloc(sizeof(*iob))) == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ iob->ec = ec;
+ iob->revent = sudo_ev_alloc(rfd, SUDO_EV_READ, read_callback, iob);
+ iob->wevent = sudo_ev_alloc(wfd, SUDO_EV_WRITE, write_callback, iob);
+ iob->len = 0;
+ iob->off = 0;
+ iob->action = action;
+ iob->buf[0] = '\0';
+ if (iob->revent == NULL || iob->wevent == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ SLIST_INSERT_HEAD(head, iob, entries);
+
+ debug_return;
+}
+
+/*
+ * We already closed the slave pty so reads from the master will not block.
+ */
+static void
+pty_finish(struct command_status *cstat)
+{
+ struct io_buffer *iob;
+ int n;
+ debug_decl(pty_finish, SUDO_DEBUG_EXEC);
+
+ /* Flush any remaining output (the plugin already got it). */
+ if (io_fds[SFD_USERTTY] != -1) {
+ n = fcntl(io_fds[SFD_USERTTY], F_GETFL, 0);
+ if (n != -1 && ISSET(n, O_NONBLOCK)) {
+ CLR(n, O_NONBLOCK);
+ (void) fcntl(io_fds[SFD_USERTTY], F_SETFL, n);
+ }
+ }
+ del_io_events(false);
+
+ /* Free I/O buffers. */
+ while ((iob = SLIST_FIRST(&iobufs)) != NULL) {
+ SLIST_REMOVE_HEAD(&iobufs, entries);
+ if (iob->revent != NULL)
+ sudo_ev_free(iob->revent);
+ if (iob->wevent != NULL)
+ sudo_ev_free(iob->wevent);
+ free(iob);
+ }
+
+ /* Restore terminal settings. */
+ if (io_fds[SFD_USERTTY] != -1)
+ sudo_term_restore(io_fds[SFD_USERTTY], false);
+
+ /* Update utmp */
+ if (utmp_user != NULL)
+ utmp_logout(slavename, cstat->type == CMD_WSTATUS ? cstat->val : 0);
+
+ debug_return;
+}
+
+/*
+ * Send command status to the monitor (signal or window size change).
+ */
+static void
+send_command_status(struct exec_closure_pty *ec, int type, int val)
+{
+ struct monitor_message *msg;
+ debug_decl(send_command, SUDO_DEBUG_EXEC)
+
+ if ((msg = calloc(1, sizeof(*msg))) == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ msg->cstat.type = type;
+ msg->cstat.val = val;
+ TAILQ_INSERT_TAIL(&ec->monitor_messages, msg, entries);
+
+ if (sudo_ev_add(ec->evbase, ec->fwdchannel_event, NULL, true) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ /* Restart event loop to send the command immediately. */
+ sudo_ev_loopcontinue(ec->evbase);
+
+ debug_return;
+}
+
+/*
+ * Schedule a signal to be forwarded.
+ */
+static void
+schedule_signal(struct exec_closure_pty *ec, int signo)
+{
+ char signame[SIG2STR_MAX];
+ debug_decl(schedule_signal, SUDO_DEBUG_EXEC)
+
+ 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);
+ sudo_debug_printf(SUDO_DEBUG_DIAG, "scheduled SIG%s for command", signame);
+
+ send_command_status(ec, CMD_SIGNO, signo);
+
+ debug_return;
+}
+
+static void
+backchannel_cb(int fd, int what, void *v)
+{
+ struct exec_closure_pty *ec = v;
+ struct command_status cstat;
+ ssize_t nread;
+ debug_decl(backchannel_cb, SUDO_DEBUG_EXEC)
+
+ /*
+ * Read command status from the monitor.
+ * Note that the backchannel is a *blocking* socket.
+ */
+ nread = recv(fd, &cstat, sizeof(cstat), MSG_WAITALL);
+ switch (nread) {
+ case -1:
+ switch (errno) {
+ case EINTR:
+ case EAGAIN:
+ /* Nothing ready. */
+ break;
+ default:
+ if (ec->cstat->val == CMD_INVALID) {
+ ec->cstat->type = CMD_ERRNO;
+ ec->cstat->val = errno;
+ sudo_debug_printf(SUDO_DEBUG_ERROR,
+ "%s: failed to read command status: %s",
+ __func__, strerror(errno));
+ sudo_ev_loopbreak(ec->evbase);
+ }
+ break;
+ }
+ break;
+ case 0:
+ /* EOF, monitor exited or was killed. */
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "EOF on backchannel, monitor dead?");
+ if (ec->cstat->type == CMD_INVALID) {
+ /* XXX - need new CMD_ type for monitor errors. */
+ ec->cstat->type = CMD_ERRNO;
+ ec->cstat->val = ECONNRESET;
+ }
+ sudo_ev_loopexit(ec->evbase);
+ break;
+ case sizeof(cstat):
+ /* Check command status. */
+ switch (cstat.type) {
+ case CMD_PID:
+ ec->cmnd_pid = cstat.val;
+ sudo_debug_printf(SUDO_DEBUG_INFO, "executed %s, pid %d",
+ ec->details->command, (int)ec->cmnd_pid);
+ break;
+ case CMD_WSTATUS:
+ if (WIFSTOPPED(cstat.val)) {
+ int signo;
+
+ /* Suspend parent and tell monitor how to resume on return. */
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "command stopped, suspending parent");
+ signo = suspend_sudo(ec, WSTOPSIG(cstat.val));
+ schedule_signal(ec, signo);
+ /* Re-enable I/O events */
+ add_io_events(ec->evbase);
+ } else {
+ /* Command exited or was killed, either way we are done. */
+ sudo_debug_printf(SUDO_DEBUG_INFO, "command exited or was killed");
+ sudo_ev_loopexit(ec->evbase);
+ }
+ *ec->cstat = cstat;
+ break;
+ case CMD_ERRNO:
+ /* Monitor was unable to execute command or broken pipe. */
+ sudo_debug_printf(SUDO_DEBUG_INFO, "errno from monitor: %s",
+ strerror(cstat.val));
+ sudo_ev_loopbreak(ec->evbase);
+ *ec->cstat = cstat;
+ break;
+ }
+ /* Keep reading command status messages until EAGAIN or EOF. */
+ break;
+ default:
+ /* Short read, should not happen. */
+ if (ec->cstat->val == CMD_INVALID) {
+ ec->cstat->type = CMD_ERRNO;
+ ec->cstat->val = EIO;
+ sudo_debug_printf(SUDO_DEBUG_ERROR,
+ "%s: failed to read command status: short read", __func__);
+ sudo_ev_loopbreak(ec->evbase);
+ }
+ break;
+ }
+ debug_return;
+}
+
+/*
+ * Handle changes to the monitors's status (SIGCHLD).
+ */
+static void
+handle_sigchld_pty(struct exec_closure_pty *ec)
+{
+ int n, status;
+ pid_t pid;
+ debug_decl(handle_sigchld_pty, SUDO_DEBUG_EXEC)
+
+ /*
+ * Monitor process was signaled; wait for it as needed.
+ */
+ do {
+ pid = waitpid(ec->monitor_pid, &status, WUNTRACED|WNOHANG);
+ } while (pid == -1 && errno == EINTR);
+ switch (pid) {
+ case 0:
+ errno = ECHILD;
+ /* FALLTHROUGH */
+ case -1:
+ sudo_warn(U_("%s: %s"), __func__, "waitpid");
+ debug_return;
+ }
+
+ /*
+ * If the monitor dies we get notified via backchannel_cb().
+ * If it was stopped, we should stop too (the command keeps
+ * running in its pty) and continue it when we come back.
+ */
+ if (WIFSTOPPED(status)) {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "monitor stopped, suspending sudo");
+ n = suspend_sudo(ec, WSTOPSIG(status));
+ kill(pid, SIGCONT);
+ schedule_signal(ec, n);
+ /* Re-enable I/O events */
+ add_io_events(ec->evbase);
+ } else if (WIFSIGNALED(status)) {
+ char signame[SIG2STR_MAX];
+ if (sig2str(WTERMSIG(status), signame) == -1)
+ snprintf(signame, sizeof(signame), "%d", WTERMSIG(status));
+ sudo_debug_printf(SUDO_DEBUG_INFO, "%s: monitor (%d) killed, SIG%s",
+ __func__, (int)ec->monitor_pid, signame);
+ ec->monitor_pid = -1;
+ } else {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "%s: monitor exited, status %d", __func__, WEXITSTATUS(status));
+ ec->monitor_pid = -1;
+ }
+ debug_return;
+}
+
+/* Signal callback */
+static void
+signal_cb_pty(int signo, int what, void *v)
+{
+ struct sudo_ev_siginfo_container *sc = v;
+ struct exec_closure_pty *ec = sc->closure;
+ char signame[SIG2STR_MAX];
+ debug_decl(signal_cb_pty, SUDO_DEBUG_EXEC)
+
+ if (ec->monitor_pid == -1)
+ debug_return;
+
+ if (sig2str(signo, signame) == -1)
+ snprintf(signame, sizeof(signame), "%d", signo);
+ sudo_debug_printf(SUDO_DEBUG_DIAG,
+ "%s: evbase %p, monitor: %d, signo %s(%d), cstat %p", __func__,
+ ec->evbase, (int)ec->monitor_pid, signame, signo, ec->cstat);
+
+ switch (signo) {
+ case SIGCHLD:
+ handle_sigchld_pty(ec);
+ break;
+ case SIGWINCH:
+ sync_ttysize(ec);
+ break;
+ default:
+ /*
+ * Do not forward signals sent by a process in the command's process
+ * group, as we don't want the command to indirectly kill itself.
+ * For example, this can happen with some versions of reboot that
+ * call kill(-1, SIGTERM) to kill all other processes.
+ */
+ if (USER_SIGNALED(sc->siginfo) && sc->siginfo->si_pid != 0) {
+ pid_t si_pgrp = getpgid(sc->siginfo->si_pid);
+ if (si_pgrp != -1) {
+ if (si_pgrp == ec->ppgrp || si_pgrp == ec->cmnd_pid)
+ debug_return;
+ } else if (sc->siginfo->si_pid == ec->cmnd_pid) {
+ debug_return;
+ }
+ }
+ /* Schedule signal to be forwared to the command. */
+ schedule_signal(ec, signo);
+ break;
+ }
+
+ debug_return;
+}
+
+/*
+ * Forward signals in monitor_messages to the monitor so it can
+ * deliver them to the command.
+ */
+static void
+fwdchannel_cb(int sock, int what, void *v)
+{
+ struct exec_closure_pty *ec = v;
+ char signame[SIG2STR_MAX];
+ struct monitor_message *msg;
+ ssize_t nsent;
+ debug_decl(fwdchannel_cb, SUDO_DEBUG_EXEC)
+
+ while ((msg = TAILQ_FIRST(&ec->monitor_messages)) != NULL) {
+ switch (msg->cstat.type) {
+ case CMD_SIGNO:
+ if (msg->cstat.val == SIGCONT_FG)
+ strlcpy(signame, "CONT_FG", sizeof(signame));
+ else if (msg->cstat.val == SIGCONT_BG)
+ strlcpy(signame, "CONT_BG", sizeof(signame));
+ else if (sig2str(msg->cstat.val, signame) == -1)
+ snprintf(signame, sizeof(signame), "%d", msg->cstat.val);
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "sending SIG%s to monitor over backchannel", signame);
+ break;
+ case CMD_TTYWINCH:
+ sudo_debug_printf(SUDO_DEBUG_INFO, "sending window size change "
+ "to monitor over backchannelL %d x %d",
+ msg->cstat.val & 0xffff, (msg->cstat.val >> 16) & 0xffff);
+ break;
+ default:
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "sending cstat type %d, value %d to monitor over backchannel",
+ msg->cstat.type, msg->cstat.val);
+ break;
+ }
+ TAILQ_REMOVE(&ec->monitor_messages, msg, entries);
+ nsent = send(sock, &msg->cstat, sizeof(msg->cstat), 0);
+ if (nsent != sizeof(msg->cstat)) {
+ if (errno == EPIPE) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR,
+ "broken pipe writing to monitor over backchannel");
+ /* Other end of socket gone, empty out monitor_messages. */
+ free(msg);
+ while ((msg = TAILQ_FIRST(&ec->monitor_messages)) != NULL) {
+ TAILQ_REMOVE(&ec->monitor_messages, msg, entries);
+ free(msg);
+ }
+ /* XXX - need new CMD_ type for monitor errors. */
+ ec->cstat->type = CMD_ERRNO;
+ ec->cstat->val = errno;
+ sudo_ev_loopbreak(ec->evbase);
+ }
+ break;
+ }
+ free(msg);
+ }
+}
+
+/*
+ * Fill in the exec closure and setup initial exec events.
+ * Allocates events for the signal pipe and backchannel.
+ * Forwarded signals on the backchannel are enabled on demand.
+ */
+static void
+fill_exec_closure_pty(struct exec_closure_pty *ec, struct command_status *cstat,
+ struct command_details *details, pid_t ppgrp, int backchannel)
+{
+ debug_decl(fill_exec_closure_pty, SUDO_DEBUG_EXEC)
+
+ /* Fill in the non-event part of the closure. */
+ ec->cmnd_pid = -1;
+ ec->ppgrp = ppgrp;
+ ec->cstat = cstat;
+ ec->details = details;
+ ec->rows = user_details.ts_rows;
+ ec->cols = user_details.ts_cols;
+ TAILQ_INIT(&ec->monitor_messages);
+
+ /* Setup event base and events. */
+ ec->evbase = sudo_ev_base_alloc();
+ if (ec->evbase == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+
+ /* Event for command status via backchannel. */
+ ec->backchannel_event = sudo_ev_alloc(backchannel,
+ SUDO_EV_READ|SUDO_EV_PERSIST, backchannel_cb, ec);
+ if (ec->backchannel_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->backchannel_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+ sudo_debug_printf(SUDO_DEBUG_INFO, "backchannel fd %d\n", backchannel);
+
+ /* Events for local signals. */
+ ec->sigint_event = sudo_ev_alloc(SIGINT,
+ SUDO_EV_SIGINFO, signal_cb_pty, ec);
+ if (ec->sigint_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->sigint_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ ec->sigquit_event = sudo_ev_alloc(SIGQUIT,
+ SUDO_EV_SIGINFO, signal_cb_pty, ec);
+ if (ec->sigquit_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->sigquit_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ ec->sigtstp_event = sudo_ev_alloc(SIGTSTP,
+ SUDO_EV_SIGINFO, signal_cb_pty, ec);
+ if (ec->sigtstp_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->sigtstp_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ ec->sigterm_event = sudo_ev_alloc(SIGTERM,
+ SUDO_EV_SIGINFO, signal_cb_pty, ec);
+ if (ec->sigterm_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->sigterm_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ ec->sighup_event = sudo_ev_alloc(SIGHUP,
+ SUDO_EV_SIGINFO, signal_cb_pty, ec);
+ if (ec->sighup_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->sighup_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ ec->sigalrm_event = sudo_ev_alloc(SIGALRM,
+ SUDO_EV_SIGINFO, signal_cb_pty, ec);
+ if (ec->sigalrm_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->sigalrm_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ ec->sigusr1_event = sudo_ev_alloc(SIGUSR1,
+ SUDO_EV_SIGINFO, signal_cb_pty, ec);
+ if (ec->sigusr1_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->sigusr1_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ ec->sigusr2_event = sudo_ev_alloc(SIGUSR2,
+ SUDO_EV_SIGINFO, signal_cb_pty, ec);
+ if (ec->sigusr2_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->sigusr2_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ ec->sigchld_event = sudo_ev_alloc(SIGCHLD,
+ SUDO_EV_SIGINFO, signal_cb_pty, ec);
+ if (ec->sigchld_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->sigchld_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ ec->sigwinch_event = sudo_ev_alloc(SIGWINCH,
+ SUDO_EV_SIGINFO, signal_cb_pty, ec);
+ if (ec->sigwinch_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+ if (sudo_ev_add(ec->evbase, ec->sigwinch_event, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+
+ /* The signal forwarding event gets added on demand. */
+ ec->fwdchannel_event = sudo_ev_alloc(backchannel,
+ SUDO_EV_WRITE, fwdchannel_cb, ec);
+ if (ec->fwdchannel_event == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+
+ /* Set the default event base. */
+ sudo_ev_base_setdef(ec->evbase);
+
+ debug_return;
+}
+
+/*
+ * Free the dynamically-allocated contents of the exec closure.
+ */
+static void
+free_exec_closure_pty(struct exec_closure_pty *ec)
+{
+ struct monitor_message *msg;
+ debug_decl(free_exec_closure_pty, SUDO_DEBUG_EXEC)
+
+ sudo_ev_base_free(ec->evbase);
+ sudo_ev_free(ec->backchannel_event);
+ sudo_ev_free(ec->fwdchannel_event);
+ sudo_ev_free(ec->sigint_event);
+ sudo_ev_free(ec->sigquit_event);
+ sudo_ev_free(ec->sigtstp_event);
+ sudo_ev_free(ec->sigterm_event);
+ sudo_ev_free(ec->sighup_event);
+ sudo_ev_free(ec->sigalrm_event);
+ sudo_ev_free(ec->sigusr1_event);
+ sudo_ev_free(ec->sigusr2_event);
+ sudo_ev_free(ec->sigchld_event);
+ sudo_ev_free(ec->sigwinch_event);
+
+ while ((msg = TAILQ_FIRST(&ec->monitor_messages)) != NULL) {
+ TAILQ_REMOVE(&ec->monitor_messages, msg, entries);
+ free(msg);
+ }
+
+ debug_return;
+}
+
+/*
+ * Execute a command in a pty, potentially with I/O loggging, and
+ * wait for it to finish.
+ * 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.
+ */
+bool
+exec_pty(struct command_details *details, struct command_status *cstat)
+{
+ int io_pipe[3][2] = { { -1, -1 }, { -1, -1 }, { -1, -1 } };
+ bool interpose[3] = { false, false, false };
+ struct exec_closure_pty ec = { 0 };
+ struct plugin_container *plugin;
+ sigset_t set, oset;
+ struct sigaction sa;
+ struct stat sb;
+ pid_t ppgrp;
+ int sv[2];
+ debug_decl(exec_pty, SUDO_DEBUG_EXEC)
+
+ /*
+ * Allocate a pty.
+ */
+ if (!pty_setup(details, user_details.tty)) {
+ if (TAILQ_EMPTY(&io_plugins)) {
+ /* Not logging I/O and didn't allocate a pty. */
+ debug_return_bool(false);
+ }
+ }
+
+ /*
+ * We communicate with the monitor over a bi-directional pair of sockets.
+ * Parent sends signal info to monitor and monitor sends back wait status.
+ */
+ if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) == -1)
+ sudo_fatal(U_("unable to create sockets"));
+
+ /*
+ * We don't want to receive SIGTTIN/SIGTTOU.
+ * XXX - this affects tcsetattr() and tcsetpgrp() too.
+ */
+ memset(&sa, 0, sizeof(sa));
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = SA_RESTART;
+ sa.sa_handler = SIG_IGN;
+ if (sudo_sigaction(SIGTTIN, &sa, NULL) != 0)
+ sudo_warn(U_("unable to set handler for signal %d"), SIGTTIN);
+ if (sudo_sigaction(SIGTTOU, &sa, NULL) != 0)
+ sudo_warn(U_("unable to set handler for signal %d"), SIGTTOU);
+
+ /*
+ * 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)
+ sudo_fatalx(U_("policy plugin failed session initialization"));
+
+ /*
+ * Child will run the command in the pty, parent will pass data
+ * to and from pty.
+ */
+
+ /* So we can block tty-generated signals */
+ sigemptyset(&ttyblock);
+ sigaddset(&ttyblock, SIGINT);
+ sigaddset(&ttyblock, SIGQUIT);
+ sigaddset(&ttyblock, SIGTSTP);
+ sigaddset(&ttyblock, SIGTTIN);
+ sigaddset(&ttyblock, SIGTTOU);
+
+ ppgrp = getpgrp(); /* parent's pgrp, so child can signal us */
+
+ /* Determine whether any of std{in,out,err} should be logged. */
+ TAILQ_FOREACH(plugin, &io_plugins, entries) {
+ if (plugin->u.io->log_stdin)
+ interpose[STDIN_FILENO] = true;
+ if (plugin->u.io->log_stdout)
+ interpose[STDOUT_FILENO] = true;
+ if (plugin->u.io->log_stderr)
+ interpose[STDERR_FILENO] = true;
+ }
+
+ /*
+ * Setup stdin/stdout/stderr for command, to be duped after forking.
+ * In background mode there is no stdin.
+ */
+ if (!ISSET(details->flags, CD_BACKGROUND))
+ io_fds[SFD_STDIN] = io_fds[SFD_SLAVE];
+ io_fds[SFD_STDOUT] = io_fds[SFD_SLAVE];
+ io_fds[SFD_STDERR] = io_fds[SFD_SLAVE];
+
+ if (io_fds[SFD_USERTTY] != -1) {
+ /* Read from /dev/tty, write to pty master */
+ if (!ISSET(details->flags, CD_BACKGROUND)) {
+ io_buf_new(io_fds[SFD_USERTTY], io_fds[SFD_MASTER],
+ log_ttyin, &ec, &iobufs);
+ }
+
+ /* Read from pty master, write to /dev/tty */
+ io_buf_new(io_fds[SFD_MASTER], io_fds[SFD_USERTTY],
+ log_ttyout, &ec, &iobufs);
+
+ /* Are we the foreground process? */
+ foreground = tcgetpgrp(io_fds[SFD_USERTTY]) == ppgrp;
+ }
+
+ /*
+ * If stdin, stdout or stderr is not a tty and logging is enabled,
+ * use a pipe to interpose ourselves instead of using the pty fd.
+ */
+ if (io_fds[SFD_STDIN] == -1 || !isatty(STDIN_FILENO)) {
+ if (!interpose[STDIN_FILENO]) {
+ /* Not logging stdin, do not interpose. */
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "stdin not a tty, not logging");
+ if (fstat(STDIN_FILENO, &sb) == 0 && S_ISFIFO(sb.st_mode))
+ pipeline = true;
+ io_fds[SFD_STDIN] = dup(STDIN_FILENO);
+ if (io_fds[SFD_STDIN] == -1)
+ sudo_fatal("dup");
+ } else {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "stdin not a tty, creating a pipe");
+ pipeline = true;
+ if (pipe(io_pipe[STDIN_FILENO]) != 0)
+ sudo_fatal(U_("unable to create pipe"));
+ io_buf_new(STDIN_FILENO, io_pipe[STDIN_FILENO][1],
+ log_stdin, &ec, &iobufs);
+ io_fds[SFD_STDIN] = io_pipe[STDIN_FILENO][0];
+ }
+ }
+ if (io_fds[SFD_STDOUT] == -1 || !isatty(STDOUT_FILENO)) {
+ if (!interpose[STDOUT_FILENO]) {
+ /* Not logging stdout, do not interpose. */
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "stdout not a tty, not logging");
+ if (fstat(STDOUT_FILENO, &sb) == 0 && S_ISFIFO(sb.st_mode))
+ pipeline = true;
+ io_fds[SFD_STDOUT] = dup(STDOUT_FILENO);
+ if (io_fds[SFD_STDOUT] == -1)
+ sudo_fatal("dup");
+ } else {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "stdout not a tty, creating a pipe");
+ pipeline = true;
+ if (pipe(io_pipe[STDOUT_FILENO]) != 0)
+ sudo_fatal(U_("unable to create pipe"));
+ io_buf_new(io_pipe[STDOUT_FILENO][0], STDOUT_FILENO,
+ log_stdout, &ec, &iobufs);
+ io_fds[SFD_STDOUT] = io_pipe[STDOUT_FILENO][1];
+ }
+ }
+ if (io_fds[SFD_STDERR] == -1 || !isatty(STDERR_FILENO)) {
+ if (!interpose[STDERR_FILENO]) {
+ /* Not logging stderr, do not interpose. */
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "stderr not a tty, not logging");
+ if (fstat(STDERR_FILENO, &sb) == 0 && S_ISFIFO(sb.st_mode))
+ pipeline = true;
+ io_fds[SFD_STDERR] = dup(STDERR_FILENO);
+ if (io_fds[SFD_STDERR] == -1)
+ sudo_fatal("dup");
+ } else {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "stderr not a tty, creating a pipe");
+ if (pipe(io_pipe[STDERR_FILENO]) != 0)
+ sudo_fatal(U_("unable to create pipe"));
+ io_buf_new(io_pipe[STDERR_FILENO][0], STDERR_FILENO,
+ log_stderr, &ec, &iobufs);
+ io_fds[SFD_STDERR] = io_pipe[STDERR_FILENO][1];
+ }
+ }
+
+ if (foreground) {
+ /* Copy terminal attrs from user tty -> pty slave. */
+ if (!sudo_term_copy(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE])) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO,
+ "%s: unable to copy terminal settings to pty", __func__);
+ foreground = false;
+ } else {
+ /* Start in raw mode unless part of a pipeline or backgrounded. */
+ if (!pipeline && !ISSET(details->flags, CD_EXEC_BG)) {
+ if (sudo_term_raw(io_fds[SFD_USERTTY], 0))
+ ttymode = TERM_RAW;
+ }
+ }
+ }
+
+ /*
+ * Block signals until we have our handlers setup in the parent so
+ * we don't miss SIGCHLD if the command exits immediately.
+ */
+ sigfillset(&set);
+ sigprocmask(SIG_BLOCK, &set, &oset);
+
+ /* Check for early termination or suspend signals before we fork. */
+ if (sudo_terminated(cstat)) {
+ sigprocmask(SIG_SETMASK, &oset, NULL);
+ debug_return_int(true);
+ }
+
+ ec.monitor_pid = sudo_debug_fork();
+ switch (ec.monitor_pid) {
+ case -1:
+ sudo_fatal(U_("unable to fork"));
+ break;
+ case 0:
+ /* child */
+ close(sv[0]);
+ (void)fcntl(sv[1], F_SETFD, FD_CLOEXEC);
+ /* Close the other end of the stdin/stdout/stderr pipes and exec. */
+ if (io_pipe[STDIN_FILENO][1] != -1)
+ close(io_pipe[STDIN_FILENO][1]);
+ if (io_pipe[STDOUT_FILENO][0] != -1)
+ close(io_pipe[STDOUT_FILENO][0]);
+ if (io_pipe[STDERR_FILENO][0] != -1)
+ close(io_pipe[STDERR_FILENO][0]);
+ /*
+ * If stdin/stdout is not a tty, start command in the background
+ * since it might be part of a pipeline that reads from /dev/tty.
+ * In this case, we rely on the command receiving SIGTTOU or SIGTTIN
+ * when it needs access to the controlling tty.
+ */
+ exec_monitor(details, &oset, foreground && !pipeline, sv[1]);
+ cstat->type = CMD_ERRNO;
+ cstat->val = errno;
+ if (send(sv[1], cstat, sizeof(*cstat), 0) == -1) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO,
+ "%s: unable to send status to parent", __func__);
+ }
+ _exit(1);
+ }
+
+ /*
+ * We close the pty slave so only the monitor and command have a
+ * reference to it. This ensures that we can don't block reading
+ * from the master when the command and monitor have exited.
+ */
+ if (io_fds[SFD_SLAVE] != -1) {
+ close(io_fds[SFD_SLAVE]);
+ io_fds[SFD_SLAVE] = -1;
+ }
+
+ /* Tell the monitor to continue now that the slave is closed. */
+ cstat->type = CMD_SIGNO;
+ cstat->val = 0;
+ while (send(sv[0], cstat, sizeof(*cstat), 0) == -1) {
+ if (errno != EINTR && errno != EAGAIN)
+ sudo_fatal(U_("unable to send message to monitor process"));
+ }
+
+ /* Close the other end of the stdin/stdout/stderr pipes and socketpair. */
+ if (io_pipe[STDIN_FILENO][0] != -1)
+ close(io_pipe[STDIN_FILENO][0]);
+ if (io_pipe[STDOUT_FILENO][1] != -1)
+ close(io_pipe[STDOUT_FILENO][1]);
+ if (io_pipe[STDERR_FILENO][1] != -1)
+ close(io_pipe[STDERR_FILENO][1]);
+ close(sv[1]);
+
+ /* No longer need execfd. */
+ if (details->execfd != -1) {
+ close(details->execfd);
+ details->execfd = -1;
+ }
+
+ /* Set command timeout if specified. */
+ if (ISSET(details->flags, CD_SET_TIMEOUT))
+ alarm(details->timeout);
+
+ /*
+ * Fill in exec closure, allocate event base, signal events and
+ * the backchannel event.
+ */
+ fill_exec_closure_pty(&ec, cstat, details, ppgrp, sv[0]);
+
+ /* Restore signal mask now that signal handlers are setup. */
+ sigprocmask(SIG_SETMASK, &oset, NULL);
+
+ /*
+ * I/O logging must be in the C locale for floating point numbers
+ * to be logged consistently.
+ */
+ setlocale(LC_ALL, "C");
+
+ /*
+ * In the event loop we pass input from user tty to master
+ * and pass output from master to stdout and IO plugin.
+ */
+ add_io_events(ec.evbase);
+ if (sudo_ev_dispatch(ec.evbase) == -1)
+ sudo_warn(U_("error in event loop"));
+ if (sudo_ev_got_break(ec.evbase)) {
+ /* error from callback or monitor died */
+ sudo_debug_printf(SUDO_DEBUG_ERROR, "event loop exited prematurely");
+ /* XXX - may need to terminate command if cmnd_pid != -1 */
+ }
+
+ /* Flush any remaining output, free I/O bufs and events, do logout. */
+ pty_finish(cstat);
+
+ /* Free things up. */
+ free_exec_closure_pty(&ec);
+
+ debug_return_bool(true);
+}
+
+/*
+ * Schedule I/O events before starting the main event loop or
+ * resuming from suspend.
+ */
+static void
+add_io_events(struct sudo_event_base *evbase)
+{
+ struct io_buffer *iob;
+ debug_decl(add_io_events, SUDO_DEBUG_EXEC);
+
+ /*
+ * Schedule all readers as long as the buffer is not full.
+ * Schedule writers that contain buffered data.
+ * Normally, write buffers are added on demand when data is read.
+ */
+ SLIST_FOREACH(iob, &iobufs, entries) {
+ /* Don't read from /dev/tty if we are not in the foreground. */
+ if (iob->revent != NULL &&
+ (ttymode == TERM_RAW || !USERTTY_EVENT(iob->revent))) {
+ if (iob->len != sizeof(iob->buf)) {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "added I/O revent %p, fd %d, events %d",
+ iob->revent, iob->revent->fd, iob->revent->events);
+ if (sudo_ev_add(evbase, iob->revent, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+ }
+ }
+ if (iob->wevent != NULL) {
+ /* Enable writer if buffer is not empty. */
+ if (iob->len > iob->off) {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "added I/O wevent %p, fd %d, events %d",
+ iob->wevent, iob->wevent->fd, iob->wevent->events);
+ if (sudo_ev_add(evbase, iob->wevent, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+ }
+ }
+ }
+ debug_return;
+}
+
+/*
+ * Flush any output buffered in iobufs or readable from fds other
+ * than /dev/tty. Removes I/O events from the event base when done.
+ */
+static void
+del_io_events(bool nonblocking)
+{
+ struct io_buffer *iob;
+ struct sudo_event_base *evbase;
+ debug_decl(del_io_events, SUDO_DEBUG_EXEC);
+
+ /* Remove iobufs from existing event base. */
+ SLIST_FOREACH(iob, &iobufs, entries) {
+ if (iob->revent != NULL) {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "deleted I/O revent %p, fd %d, events %d",
+ iob->revent, iob->revent->fd, iob->revent->events);
+ sudo_ev_del(NULL, iob->revent);
+ }
+ if (iob->wevent != NULL) {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "deleted I/O wevent %p, fd %d, events %d",
+ iob->wevent, iob->wevent->fd, iob->wevent->events);
+ sudo_ev_del(NULL, iob->wevent);
+ }
+ }
+
+ /* Create temporary event base for flushing. */
+ evbase = sudo_ev_base_alloc();
+ if (evbase == NULL)
+ sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+
+ /* Avoid reading from /dev/tty, just flush existing data. */
+ SLIST_FOREACH(iob, &iobufs, entries) {
+ /* Don't read from /dev/tty while flushing. */
+ if (iob->revent != NULL && !USERTTY_EVENT(iob->revent)) {
+ if (iob->len != sizeof(iob->buf)) {
+ if (sudo_ev_add(evbase, iob->revent, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+ }
+ }
+ /* Flush any write buffers with data in them. */
+ if (iob->wevent != NULL) {
+ if (iob->len > iob->off) {
+ if (sudo_ev_add(evbase, iob->wevent, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+ }
+ }
+ }
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "%s: flushing remaining I/O buffers (nonblocking)", __func__);
+ (void) sudo_ev_loop(evbase, SUDO_EVLOOP_NONBLOCK);
+
+ /*
+ * If not in non-blocking mode, make sure we flush write buffers.
+ * We don't want to read from the pty or stdin since that might block
+ * and the command is no longer running anyway.
+ */
+ if (!nonblocking) {
+ /* Clear out iobufs from event base. */
+ SLIST_FOREACH(iob, &iobufs, entries) {
+ if (iob->revent != NULL && !USERTTY_EVENT(iob->revent))
+ sudo_ev_del(evbase, iob->revent);
+ if (iob->wevent != NULL)
+ sudo_ev_del(evbase, iob->wevent);
+ }
+
+ SLIST_FOREACH(iob, &iobufs, entries) {
+ /* Flush any write buffers with data in them. */
+ if (iob->wevent != NULL) {
+ if (iob->len > iob->off) {
+ if (sudo_ev_add(evbase, iob->wevent, NULL, false) == -1)
+ sudo_fatal(U_("unable to add event to queue"));
+ }
+ }
+ }
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "%s: flushing remaining write buffers (blocking)", __func__);
+ (void) sudo_ev_dispatch(evbase);
+
+ /* We should now have flushed all write buffers. */
+ SLIST_FOREACH(iob, &iobufs, entries) {
+ if (iob->wevent != NULL) {
+ if (iob->len > iob->off) {
+ sudo_debug_printf(SUDO_DEBUG_ERROR,
+ "unflushed data: wevent %p, fd %d, events %d",
+ iob->wevent, iob->wevent->fd, iob->wevent->events);
+ }
+ }
+ }
+ }
+
+ /* Free temporary event base, removing its events. */
+ sudo_ev_base_free(evbase);
+
+ debug_return;
+}
+
+/*
+ * Check for tty size changes.
+ * Passes the new window size to the I/O plugin and to the monitor.
+ */
+static void
+sync_ttysize(struct exec_closure_pty *ec)
+{
+ struct winsize wsize;
+ debug_decl(sync_ttysize, SUDO_DEBUG_EXEC);
+
+ if (ioctl(io_fds[SFD_USERTTY], TIOCGWINSZ, &wsize) == 0) {
+ if (wsize.ws_row != ec->rows || wsize.ws_col != ec->cols) {
+ const unsigned int wsize_packed = (wsize.ws_row & 0xffff) |
+ ((wsize.ws_col & 0xffff) << 16);
+
+ /* Log window change event. */
+ log_winchange(wsize.ws_row, wsize.ws_col);
+
+ /* Send window change event to monitor process. */
+ send_command_status(ec, CMD_TTYWINCH, wsize_packed);
+
+ /* Update rows/cols. */
+ ec->rows = wsize.ws_row;
+ ec->cols = wsize.ws_col;
+ }
+ }
+
+ debug_return;
+}
+
+/*
+ * Remove and free any events associated with the specified
+ * file descriptor present in the I/O buffers list.
+ */
+static void
+ev_free_by_fd(struct sudo_event_base *evbase, int fd)
+{
+ struct io_buffer *iob;
+ debug_decl(ev_free_by_fd, SUDO_DEBUG_EXEC);
+
+ /* Deschedule any users of the fd and free up the events. */
+ SLIST_FOREACH(iob, &iobufs, entries) {
+ if (iob->revent != NULL) {
+ if (sudo_ev_get_fd(iob->revent) == fd) {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "%s: deleting and freeing revent %p with fd %d",
+ __func__, iob->revent, fd);
+ sudo_ev_free(iob->revent);
+ iob->revent = NULL;
+ }
+ }
+ if (iob->wevent != NULL) {
+ if (sudo_ev_get_fd(iob->wevent) == fd) {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "%s: deleting and freeing wevent %p with fd %d",
+ __func__, iob->wevent, fd);
+ sudo_ev_free(iob->wevent);
+ iob->wevent = NULL;
+ }
+ }
+ }
+ debug_return;
+}
+
+/*
+ * Only close the fd if it is not /dev/tty or std{in,out,err}.
+ * Return value is the same as close(2).
+ */
+static int
+safe_close(int fd)
+{
+ debug_decl(safe_close, SUDO_DEBUG_EXEC);
+
+ /* Avoid closing /dev/tty or std{in,out,err}. */
+ if (fd < 3 || fd == io_fds[SFD_USERTTY]) {
+ sudo_debug_printf(SUDO_DEBUG_INFO,
+ "%s: not closing fd %d (%s)", __func__, fd, _PATH_TTY);
+ errno = EINVAL;
+ debug_return_int(-1);
+ }
+ sudo_debug_printf(SUDO_DEBUG_INFO, "%s: closing fd %d", __func__, fd);
+ debug_return_int(close(fd));
+}