diff options
Diffstat (limited to 'src/suspend_nopty.c')
| -rw-r--r-- | src/suspend_nopty.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/src/suspend_nopty.c b/src/suspend_nopty.c new file mode 100644 index 0000000..1cfe0c2 --- /dev/null +++ b/src/suspend_nopty.c @@ -0,0 +1,119 @@ +/* + * SPDX-License-Identifier: ISC + * + * Copyright (c) 2009-2022 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 <stdio.h> +#include <string.h> +#include <unistd.h> +#include <errno.h> +#include <fcntl.h> +#include <signal.h> + +#include "sudo.h" +#include "sudo_exec.h" + +void +suspend_sudo_nopty(struct exec_closure *ec, int signo, pid_t my_pid, + pid_t my_pgrp, pid_t cmnd_pid) +{ + struct sigaction sa, osa; + pid_t saved_pgrp = -1; + int fd; + debug_decl(suspend_sudo_nopty, SUDO_DEBUG_EXEC); + + /* + * Save the controlling terminal's process group so we can restore + * it after we resume, if needed. Most well-behaved shells change + * the pgrp back to its original value before suspending so we must + * not try to restore in that case, lest we race with the command + * upon resume, potentially stopping sudo with SIGTTOU while the + * command continues to run. + */ + fd = open(_PATH_TTY, O_RDWR); + if (fd != -1) { + saved_pgrp = tcgetpgrp(fd); + if (saved_pgrp == -1) { + close(fd); + fd = -1; + } + } + + if (saved_pgrp != -1) { + /* + * Command was stopped trying to access the controlling + * terminal. If the command has a different pgrp and we + * own the controlling terminal, give it to the command's + * pgrp and let it continue. + */ + if (signo == SIGTTOU || signo == SIGTTIN) { + if (saved_pgrp == my_pgrp) { + pid_t cmnd_pgrp = getpgid(cmnd_pid); + if (cmnd_pgrp != my_pgrp) { + if (tcsetpgrp_nobg(fd, cmnd_pgrp) == 0) { + if (killpg(cmnd_pgrp, SIGCONT) != 0) + sudo_warn("kill(%d, SIGCONT)", (int)cmnd_pgrp); + close(fd); + debug_return; + } + } + } + } + } + + /* Log the suspend event. */ + log_suspend(ec, signo); + + if (signo == SIGTSTP) { + memset(&sa, 0, sizeof(sa)); + sigemptyset(&sa.sa_mask); + sa.sa_flags = SA_RESTART; + sa.sa_handler = SIG_DFL; + if (sudo_sigaction(SIGTSTP, &sa, &osa) != 0) + sudo_warn(U_("unable to set handler for signal %d"), SIGTSTP); + } + if (kill(my_pid, signo) != 0) + sudo_warn("kill(%d, %d)", (int)my_pid, signo); + if (signo == SIGTSTP) { + if (sudo_sigaction(SIGTSTP, &osa, NULL) != 0) + sudo_warn(U_("unable to restore handler for signal %d"), SIGTSTP); + } + + /* Log the resume event. */ + log_suspend(ec, SIGCONT); + + if (saved_pgrp != -1) { + /* + * On resume, restore foreground process group, if different. + * Otherwise, we cannot resume some shells (pdksh). + * + * It is possible that we are no longer the foreground process, + * use tcsetpgrp_nobg() to prevent sudo from receiving SIGTTOU. + */ + if (saved_pgrp != my_pgrp) + tcsetpgrp_nobg(fd, saved_pgrp); + close(fd); + } + + debug_return; +} |