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Fix handling of signal forwarding when running commands in a script.

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We need to forward signals from a process in the same pgrp if the
pgrp leader is not either sudo or the command itself.
This commit is contained in:
Todd C. Miller
2022-11-07 14:51:41 -07:00
parent c7071f6da0
commit 36742deec3
4 changed files with 43 additions and 32 deletions
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8
src/exec_monitor.c
View File

@@ -282,12 +282,14 @@ mon_signal_cb(int signo, int what, void *v)
* 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);
pid_t si_pgrp;
if (sc->siginfo->si_pid == mc->cmnd_pid)
debug_return;
si_pgrp = getpgid(sc->siginfo->si_pid);
if (si_pgrp != -1) {
if (si_pgrp == mc->cmnd_pgrp)
debug_return;
} else if (sc->siginfo->si_pid == mc->cmnd_pid) {
debug_return;
}
}
deliver_signal(mc, signo, false);

42
src/exec_nopty.c
View File

@@ -122,6 +122,7 @@ signal_cb_nopty(int signo, int what, void *v)
struct sudo_ev_siginfo_container *sc = v;
struct exec_closure *ec = sc->closure;
char signame[SIG2STR_MAX];
pid_t si_pgrp;
debug_decl(signal_cb_nopty, SUDO_DEBUG_EXEC);
if (ec->cmnd_pid == -1)
@@ -151,38 +152,40 @@ signal_cb_nopty(int signo, int what, void *v)
case SIGQUIT:
case SIGTSTP:
/*
* Only forward user-generated signals not sent by a process in
* the command's own process group. Signals sent by the kernel
* may include SIGTSTP when the user presses ^Z. Curses programs
* often trap ^Z and send SIGTSTP to their own pgrp, so we don't
* want to send an extra SIGTSTP.
* Only forward user-generated signals not sent by a process other than
* the command itself or a member of the command's process group (but
* only when either sudo or the command is the process group leader).
* Signals sent by the kernel may include SIGTSTP when the user presses
* ^Z. Curses programs often trap ^Z and send SIGTSTP to their own
* process group, so we don't want to send an extra SIGTSTP.
*/
if (!USER_SIGNALED(sc->siginfo))
debug_return;
if (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) {
if (sc->siginfo->si_pid == ec->cmnd_pid)
debug_return;
si_pgrp = getpgid(sc->siginfo->si_pid);
if (si_pgrp != -1) {
if (si_pgrp == ec->cmnd_pid || si_pgrp == ec->sudo_pid)
debug_return;
}
}
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.
* Do not forward signals sent by the command itself or a member of the
* command's process group (but only when either sudo or the command is
* the process group leader). 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) {
if (sc->siginfo->si_pid == ec->cmnd_pid)
debug_return;
si_pgrp = getpgid(sc->siginfo->si_pid);
if (si_pgrp != -1) {
if (si_pgrp == ec->cmnd_pid || si_pgrp == ec->sudo_pid)
debug_return;
}
}
break;
@@ -210,6 +213,7 @@ fill_exec_closure(struct exec_closure *ec,
debug_decl(fill_exec_closure, SUDO_DEBUG_EXEC);
/* Fill in the non-event part of the closure. */
ec->sudo_pid = getpid();
ec->ppgrp = getpgrp();
ec->cstat = cstat;
ec->details = details;

24
src/exec_pty.c
View File

@@ -761,18 +761,21 @@ signal_cb_pty(int signo, int what, void *v)
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.
* Do not forward signals sent by the command itself or a member of the
* command's process group (but only when either sudo or the command is
* the process group leader). 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) {
pid_t si_pgrp;
if (sc->siginfo->si_pid == ec->cmnd_pid)
debug_return;
si_pgrp = getpgid(sc->siginfo->si_pid);
if (si_pgrp != -1) {
if (si_pgrp == ec->cmnd_pid || si_pgrp == ec->sudo_pid)
debug_return;
}
}
/* Schedule signal to be forwarded to the command. */
@@ -851,8 +854,9 @@ fill_exec_closure(struct exec_closure *ec, struct command_status *cstat,
debug_decl(fill_exec_closure, SUDO_DEBUG_EXEC);
/* Fill in the non-event part of the closure. */
ec->cmnd_pid = -1;
ec->sudo_pid = getpid();
ec->ppgrp = ppgrp;
ec->cmnd_pid = -1;
ec->cstat = cstat;
ec->details = details;
ec->rows = user_details.ts_rows;

1
src/sudo_exec.h
View File

@@ -74,6 +74,7 @@ struct exec_closure {
struct sudo_event *sigwinch_event;
struct command_status *cstat;
void *intercept;
pid_t sudo_pid;
pid_t monitor_pid;
pid_t cmnd_pid;
pid_t ppgrp;