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Ignore signals sent by the command's process group, not just the

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command itself.  If we cannot determine the process group ID of the
sender (as it may no longer exist), just check the process ID.
This commit is contained in:
Todd C. Miller
2014-05-28 09:50:14 -06:00
parent b121da2e21
commit 826e190f31
2 changed files with 49 additions and 26 deletions
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54
src/exec.c
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@@ -865,13 +865,20 @@ handler(int s, siginfo_t *info, void *context)
unsigned char signo = (unsigned char)s;
/*
* If the signal came from the command we ran, just ignore
* it since we don't want the child to indirectly kill itself.
* This can happen with, e.g. BSD-derived versions of reboot
* that call kill(-1, SIGTERM) to kill all other processes.
* Do not forward signals sent by a process in the command's process
* group, do not forward it as we don't want the child 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 (info != NULL && info->si_code == SI_USER && info->si_pid == cmnd_pid)
return;
if (info != NULL && info->si_code == SI_USER) {
pid_t si_pgrp = getpgid(info->si_pid);
if (si_pgrp != (pid_t)-1) {
if (si_pgrp == ppgrp || si_pgrp == cmnd_pid)
return;
} else if (info->si_pid == cmnd_pid) {
return;
}
}
/*
* The pipe is non-blocking, if we overflow the kernel's pipe
@@ -910,22 +917,31 @@ static void
handler_user_only(int s, siginfo_t *info, void *context)
{
unsigned char signo = (unsigned char)s;
pid_t si_pgrp;
/*
* Only forward user-generated signals not sent by the command.
* Signals sent by the kernel may include SIGTSTP when the user
* presses ^Z. Curses programs often trap ^Z and send SIGTSTP
* to their pgrp, so we don't want to send an extra 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.
*/
if (info != NULL && info->si_code == SI_USER && info->si_pid != cmnd_pid) {
/*
* The pipe is non-blocking, if we overflow the kernel's pipe
* buffer we drop the signal. This is not a problem in practice.
*/
while (write(signal_pipe[1], &signo, sizeof(signo)) == -1) {
if (errno != EINTR)
break;
}
if (info == NULL || info->si_code != SI_USER)
return;
if ((si_pgrp = getpgid(info->si_pid)) != (pid_t)-1) {
if (si_pgrp == ppgrp || si_pgrp == cmnd_pid)
return;
} else if (info->si_pid == cmnd_pid) {
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.
*/
while (write(signal_pipe[1], &signo, sizeof(signo)) == -1) {
if (errno != EINTR)
break;
}
}
#endif /* SA_SIGINFO */