commit 4d70e725d16abc2f85d54b91f50e75c37c765087 Author: Nick Mathewson nickm@torproject.org Date: Wed Nov 6 11:33:23 2019 -0500

Do not try to shut down the event loop when it is not initialized.

Doing so caused us to crash in some unusual circumstances, such as using --verify-config to verify a configuration that failed during the options_act() stage.

Fixes bug 32407; bugfix on 0.3.3.1-alpha. --- changes/ticket32407 | 4 ++++ src/core/mainloop/mainloop.c | 4 ++++ src/lib/evloop/compat_libevent.c | 10 ++++++++++ src/lib/evloop/compat_libevent.h | 3 +++ 4 files changed, 21 insertions(+)

diff --git a/changes/ticket32407 b/changes/ticket32407 new file mode 100644 index 000000000..badb09abf --- /dev/null +++ b/changes/ticket32407 @@ -0,0 +1,4 @@ + o Minor bugfixes (crash): + - When running Tor with an option like --verify-config or --dump-config + that does not start the event loop, avoid crashing if we try to exit + early because of an error. Fixes bug 32407; bugfix on 0.3.3.1-alpha. diff --git a/src/core/mainloop/mainloop.c b/src/core/mainloop/mainloop.c index 6e2b300fb..64df495ba 100644 --- a/src/core/mainloop/mainloop.c +++ b/src/core/mainloop/mainloop.c @@ -774,6 +774,10 @@ tor_shutdown_event_loop_and_exit(int exitcode) main_loop_should_exit = 1; main_loop_exit_value = exitcode;

+ if (! tor_libevent_is_initialized()) { + return; /* No event loop to shut down. */ + } + /* Die with an assertion failure in ten seconds, if for some reason we don't * exit normally. */ /* XXXX We should consider this code if it's never used. */ diff --git a/src/lib/evloop/compat_libevent.c b/src/lib/evloop/compat_libevent.c index 91eacb993..939d77f85 100644 --- a/src/lib/evloop/compat_libevent.c +++ b/src/lib/evloop/compat_libevent.c @@ -181,6 +181,16 @@ tor_libevent_initialize(tor_libevent_cfg *torcfg) event_get_version(), tor_libevent_get_method()); }

+/** + * Return true iff the libevent module has been successfully initialized, + * and not subsequently shut down. + **/ +bool +tor_libevent_is_initialized(void) +{ + return the_event_base != NULL; +} + /** Return the current Libevent event base that we're set up to use. */ MOCK_IMPL(struct event_base *, tor_libevent_get_base, (void)) diff --git a/src/lib/evloop/compat_libevent.h b/src/lib/evloop/compat_libevent.h index afe887a01..92724c369 100644 --- a/src/lib/evloop/compat_libevent.h +++ b/src/lib/evloop/compat_libevent.h @@ -13,6 +13,8 @@ #include "lib/testsupport/testsupport.h" #include "lib/malloc/malloc.h"

+#include <stdbool.h> + void configure_libevent_logging(void); void suppress_libevent_log_msg(const char *msg);

@@ -68,6 +70,7 @@ typedef struct tor_libevent_cfg { } tor_libevent_cfg;

void tor_libevent_initialize(tor_libevent_cfg *cfg); +bool tor_libevent_is_initialized(void); MOCK_DECL(struct event_base *, tor_libevent_get_base, (void)); const char *tor_libevent_get_method(void); void tor_check_libevent_header_compatibility(void);