From b4a21d51487e21052af49b755d1707d4616e2977 Mon Sep 17 00:00:00 2001 From: Frantisek Sumsal Date: Sun, 24 Dec 2023 14:49:23 +0100 Subject: [PATCH] busctl: avoid asserting on NULL message MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Avoid passing a NULL message to sd_bus_message_is_signal(), to not trip over an assertion: [ 132.869436] H testsuite-82.sh[614]: + systemctl --no-block --check-inhibitors=yes soft-reboot [ 132.967386] H systemd[1]: Created slice system-systemd\x2dcoredump.slice. [ 133.018292] H systemd[1]: Starting inhibit.service... [ 133.122610] H systemd[1]: Started systemd-coredump@0-665-0.service. [ 133.163643] H systemd[1]: Started inhibit.service. [ 133.206836] H testsuite-82.sh[614]: + exec sleep infinity [ 133.236762] H systemd-logind[611]: The system will reboot now! [ 135.891607] H systemd-coredump[667]: [🡕] Process 663 (busctl) of user 0 dumped core. Stack trace of thread 663: #0 0x00007f2ec45e6acf raise (libc.so.6 + 0x4eacf) #1 0x00007f2ec45b9ea5 abort (libc.so.6 + 0x21ea5) #2 0x00007f2ec4b5c9a6 log_assert_failed (libsystemd-shared-255.so + 0x1ff9a6) #3 0x00007f2ec4b5dca5 log_assert_failed_return (libsystemd-shared-255.so + 0x200ca5) #4 0x00007f2ec4bb3df6 sd_bus_message_is_signal (libsystemd-shared-255.so + 0x256df6) #5 0x000000000040e478 monitor (busctl + 0xe478) #6 0x000000000040e82f verb_monitor (busctl + 0xe82f) #7 0x00007f2ec4b202cb dispatch_verb (libsystemd-shared-255.so + 0x1c32cb) #8 0x00000000004074fa busctl_main (busctl + 0x74fa) #9 0x0000000000407525 run (busctl + 0x7525) #10 0x000000000040ff67 main (busctl + 0xff67) #11 0x00007f2ec45d2d85 __libc_start_main (libc.so.6 + 0x3ad85) #12 0x00000000004044be _start (busctl + 0x44be) ELF object binary architecture: AMD x86-64 [ 136.141152] H dbus-daemon[634]: [system] Monitoring connection :1.2 closed. [ 136.152233] H systemd[1]: busctl.service: Main process exited, code=dumped, status=6/ABRT [ 136.153996] H systemd[1]: busctl.service: Failed with result 'core-dump'. The asertion in question: Assertion 'm' failed at src/libsystemd/sd-bus/bus-message.c:1015, function sd_bus_message_is_signal(). Aborting. We can get a NULL message here through sd_bus_process() -> bus_process_internal() -> process_running(), so let's handle this case appropriately. --- src/busctl/busctl.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/src/busctl/busctl.c b/src/busctl/busctl.c index d233fc55adba4..b2c2bc644d763 100644 --- a/src/busctl/busctl.c +++ b/src/busctl/busctl.c @@ -1320,24 +1320,24 @@ static int monitor(int argc, char **argv, int (*dump)(sd_bus_message *m, FILE *f if (r < 0) return log_error_errno(r, "Failed to process bus: %m"); - if (!is_monitor) { - const char *name; + if (m) { + if (!is_monitor) { + const char *name; - /* wait until we lose our unique name */ - if (sd_bus_message_is_signal(m, "org.freedesktop.DBus", "NameLost") <= 0) - continue; + /* wait until we lose our unique name */ + if (sd_bus_message_is_signal(m, "org.freedesktop.DBus", "NameLost") <= 0) + continue; - r = sd_bus_message_read(m, "s", &name); - if (r < 0) - return bus_log_parse_error(r); + r = sd_bus_message_read(m, "s", &name); + if (r < 0) + return bus_log_parse_error(r); - if (streq(name, unique_name)) - is_monitor = true; + if (streq(name, unique_name)) + is_monitor = true; - continue; - } + continue; + } - if (m) { dump(m, stdout); fflush(stdout);