| Message ID | 20181003074238.15648-1-andrew.gregory.8@gmail.com |
|---|---|
| State | Accepted, archived |
| Headers | show |
On 3/10/18 5:42 pm, Andrew Gregory wrote: > Front-ends or libraries may set signals to be ignored, which gets > inherited across fork and exec. This can cause scripts to malfunction > if they expect the signal. To make matters worse, scripts written in > bash can't reset signals that were ignored when bash was started. > > Fixes FS#56756 > > Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com> > --- > > Hopefully nobody ignores or depends on signals outside of the POSIX > list. As far as I can tell, the only way to reset all signal handlers > is to iterate over the entire range of positive integers. I know of no other way either. Patch looks fine. A > > lib/libalpm/util.c | 20 ++++++++++++++++++++ > test/pacman/tests/TESTS | 1 + > test/pacman/tests/scriptlet-signal-reset.py | 11 +++++++++++ > 3 files changed, 32 insertions(+) > create mode 100644 test/pacman/tests/scriptlet-signal-reset.py > > diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c > index a06f5bfd..eaf85e93 100644 > --- a/lib/libalpm/util.c > +++ b/lib/libalpm/util.c > @@ -548,6 +548,25 @@ static int _alpm_chroot_read_from_child(alpm_handle_t *handle, int fd, > return 0; > } > > +static void _alpm_reset_signals(void) > +{ > + /* reset POSIX defined signals (see signal.h) */ > + /* there are likely more but there is no easy way > + * to get the full list of valid signals */ > + int *i, signals[] = { > + SIGABRT, SIGALRM, SIGBUS, SIGCHLD, SIGCONT, SIGFPE, SIGHUP, SIGILL, > + SIGINT, SIGKILL, SIGPIPE, SIGQUIT, SIGSEGV, SIGSTOP, SIGTERM, SIGTSTP, > + SIGTTIN, SIGTTOU, SIGUSR1, SIGUSR2, SIGPOLL, SIGPROF, SIGSYS, SIGTRAP, > + SIGURG, SIGVTALRM, SIGXCPU, SIGXFSZ, > + 0 > + }; > + struct sigaction def; > + def.sa_handler = SIG_DFL; > + for(i = signals; *i; i++) { > + sigaction(*i, &def, NULL); > + } > +} > + > /** Execute a command with arguments in a chroot. > * @param handle the context handle > * @param cmd command to execute > @@ -633,6 +652,7 @@ int _alpm_run_chroot(alpm_handle_t *handle, const char *cmd, char *const argv[], > exit(1); > } > umask(0022); > + _alpm_reset_signals(); > execv(cmd, argv); > /* execv only returns if there was an error */ > fprintf(stderr, _("call to execv failed (%s)\n"), strerror(errno)); > diff --git a/test/pacman/tests/TESTS b/test/pacman/tests/TESTS > index b11cb511..5deb93c4 100644 > --- a/test/pacman/tests/TESTS > +++ b/test/pacman/tests/TESTS > @@ -150,6 +150,7 @@ TESTS += test/pacman/tests/replace102.py > TESTS += test/pacman/tests/replace103.py > TESTS += test/pacman/tests/replace104.py > TESTS += test/pacman/tests/replace110.py > +TESTS += test/pacman/tests/scriptlet-signal-reset.py > TESTS += test/pacman/tests/scriptlet001.py > TESTS += test/pacman/tests/scriptlet002.py > TESTS += test/pacman/tests/sign001.py > diff --git a/test/pacman/tests/scriptlet-signal-reset.py b/test/pacman/tests/scriptlet-signal-reset.py > new file mode 100644 > index 00000000..27246d12 > --- /dev/null > +++ b/test/pacman/tests/scriptlet-signal-reset.py > @@ -0,0 +1,11 @@ > +self.description = "Reset signals before running scriptlets/hooks" > + > +p1 = pmpkg("dummy") > +# check if SIGPIPE is ignored, it should be fatal, but GPGME ignores it > +p1.install['post_install'] = "kill -PIPE $$; echo fail > sigpipe_was_ignored" > +self.addpkg(p1) > + > +self.args = "-U %s" % p1.filename() > + > +self.addrule("PACMAN_RETCODE=0") > +self.addrule("!FILE_EXIST=sigpipe_was_ignored") >
diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c index a06f5bfd..eaf85e93 100644 --- a/lib/libalpm/util.c +++ b/lib/libalpm/util.c @@ -548,6 +548,25 @@ static int _alpm_chroot_read_from_child(alpm_handle_t *handle, int fd, return 0; } +static void _alpm_reset_signals(void) +{ + /* reset POSIX defined signals (see signal.h) */ + /* there are likely more but there is no easy way + * to get the full list of valid signals */ + int *i, signals[] = { + SIGABRT, SIGALRM, SIGBUS, SIGCHLD, SIGCONT, SIGFPE, SIGHUP, SIGILL, + SIGINT, SIGKILL, SIGPIPE, SIGQUIT, SIGSEGV, SIGSTOP, SIGTERM, SIGTSTP, + SIGTTIN, SIGTTOU, SIGUSR1, SIGUSR2, SIGPOLL, SIGPROF, SIGSYS, SIGTRAP, + SIGURG, SIGVTALRM, SIGXCPU, SIGXFSZ, + 0 + }; + struct sigaction def; + def.sa_handler = SIG_DFL; + for(i = signals; *i; i++) { + sigaction(*i, &def, NULL); + } +} + /** Execute a command with arguments in a chroot. * @param handle the context handle * @param cmd command to execute @@ -633,6 +652,7 @@ int _alpm_run_chroot(alpm_handle_t *handle, const char *cmd, char *const argv[], exit(1); } umask(0022); + _alpm_reset_signals(); execv(cmd, argv); /* execv only returns if there was an error */ fprintf(stderr, _("call to execv failed (%s)\n"), strerror(errno)); diff --git a/test/pacman/tests/TESTS b/test/pacman/tests/TESTS index b11cb511..5deb93c4 100644 --- a/test/pacman/tests/TESTS +++ b/test/pacman/tests/TESTS @@ -150,6 +150,7 @@ TESTS += test/pacman/tests/replace102.py TESTS += test/pacman/tests/replace103.py TESTS += test/pacman/tests/replace104.py TESTS += test/pacman/tests/replace110.py +TESTS += test/pacman/tests/scriptlet-signal-reset.py TESTS += test/pacman/tests/scriptlet001.py TESTS += test/pacman/tests/scriptlet002.py TESTS += test/pacman/tests/sign001.py diff --git a/test/pacman/tests/scriptlet-signal-reset.py b/test/pacman/tests/scriptlet-signal-reset.py new file mode 100644 index 00000000..27246d12 --- /dev/null +++ b/test/pacman/tests/scriptlet-signal-reset.py @@ -0,0 +1,11 @@ +self.description = "Reset signals before running scriptlets/hooks" + +p1 = pmpkg("dummy") +# check if SIGPIPE is ignored, it should be fatal, but GPGME ignores it +p1.install['post_install'] = "kill -PIPE $$; echo fail > sigpipe_was_ignored" +self.addpkg(p1) + +self.args = "-U %s" % p1.filename() + +self.addrule("PACMAN_RETCODE=0") +self.addrule("!FILE_EXIST=sigpipe_was_ignored")
Front-ends or libraries may set signals to be ignored, which gets inherited across fork and exec. This can cause scripts to malfunction if they expect the signal. To make matters worse, scripts written in bash can't reset signals that were ignored when bash was started. Fixes FS#56756 Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com> --- Hopefully nobody ignores or depends on signals outside of the POSIX list. As far as I can tell, the only way to reset all signal handlers is to iterate over the entire range of positive integers. lib/libalpm/util.c | 20 ++++++++++++++++++++ test/pacman/tests/TESTS | 1 + test/pacman/tests/scriptlet-signal-reset.py | 11 +++++++++++ 3 files changed, 32 insertions(+) create mode 100644 test/pacman/tests/scriptlet-signal-reset.py