| Message ID | 20201107000458.8754-2-geoff@hostfission.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v9,1/1] audio/jack: fix use after free segfault | expand |
On Samstag, 7. November 2020 01:04:58 CET Geoffrey McRae wrote: > This change registers a bottom handler to close the JACK client > connection when a server shutdown signal is recieved. Without this > libjack2 attempts to "clean up" old clients and causes a use after free > segfault. > > Signed-off-by: Geoffrey McRae <geoff@hostfission.com> > --- > audio/jackaudio.c | 50 +++++++++++++++++++++++++++++++++++------------ > 1 file changed, 37 insertions(+), 13 deletions(-) > > diff --git a/audio/jackaudio.c b/audio/jackaudio.c > index 1e714b30bc..e00e19061a 100644 > --- a/audio/jackaudio.c > +++ b/audio/jackaudio.c > @@ -25,6 +25,7 @@ > #include "qemu/osdep.h" > #include "qemu/module.h" > #include "qemu/atomic.h" > +#include "qemu/main-loop.h" > #include "qemu-common.h" > #include "audio.h" > > @@ -63,6 +64,7 @@ typedef struct QJackClient { > QJackState state; > jack_client_t *client; > jack_nframes_t freq; > + QEMUBH *shutdown_bh; > > struct QJack *j; > int nchannels; > @@ -87,6 +89,7 @@ QJackIn; > static int qjack_client_init(QJackClient *c); > static void qjack_client_connect_ports(QJackClient *c); > static void qjack_client_fini(QJackClient *c); > +QemuMutex qjack_shutdown_lock; > I think this should be: static QemuMutex qjack_shutdown_lock; as this mutex is only accessed from within this unit. Except of that: Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> BTW it is common practice to add local functions for initializing, destroying, locking and unlocking a specific mutex use case to avoid issues when code evolves. But so far the use of this mutex is trivial, so it is Ok for now from my PoV. > static void qjack_buffer_create(QJackBuffer *buffer, int channels, int > frames) { > @@ -306,21 +309,27 @@ static int qjack_xrun(void *arg) > return 0; > } > > +static void qjack_shutdown_bh(void *opaque) > +{ > + QJackClient *c = (QJackClient *)opaque; > + qjack_client_fini(c); > +} > + > static void qjack_shutdown(void *arg) > { > QJackClient *c = (QJackClient *)arg; > c->state = QJACK_STATE_SHUTDOWN; > + qemu_bh_schedule(c->shutdown_bh); > } > > static void qjack_client_recover(QJackClient *c) > { > - if (c->state == QJACK_STATE_SHUTDOWN) { > - qjack_client_fini(c); > + if (c->state != QJACK_STATE_DISCONNECTED) { > + return; > } > > /* packets is used simply to throttle this */ > - if (c->state == QJACK_STATE_DISCONNECTED && > - c->packets % 100 == 0) { > + if (c->packets % 100 == 0) { > > /* if enabled then attempt to recover */ > if (c->enabled) { > @@ -489,15 +498,16 @@ static int qjack_init_out(HWVoiceOut *hw, struct > audsettings *as, QJackOut *jo = (QJackOut *)hw; > Audiodev *dev = (Audiodev *)drv_opaque; > > - qjack_client_fini(&jo->c); > - > jo->c.out = true; > jo->c.enabled = false; > jo->c.nchannels = as->nchannels; > jo->c.opt = dev->u.jack.out; > > + jo->c.shutdown_bh = qemu_bh_new(qjack_shutdown_bh, &jo->c); > + > int ret = qjack_client_init(&jo->c); > if (ret != 0) { > + qemu_bh_delete(jo->c.shutdown_bh); > return ret; > } > > @@ -525,15 +535,16 @@ static int qjack_init_in(HWVoiceIn *hw, struct > audsettings *as, QJackIn *ji = (QJackIn *)hw; > Audiodev *dev = (Audiodev *)drv_opaque; > > - qjack_client_fini(&ji->c); > - > ji->c.out = false; > ji->c.enabled = false; > ji->c.nchannels = as->nchannels; > ji->c.opt = dev->u.jack.in; > > + ji->c.shutdown_bh = qemu_bh_new(qjack_shutdown_bh, &ji->c); > + > int ret = qjack_client_init(&ji->c); > if (ret != 0) { > + qemu_bh_delete(ji->c.shutdown_bh); > return ret; > } > > @@ -555,7 +566,7 @@ static int qjack_init_in(HWVoiceIn *hw, struct > audsettings *as, return 0; > } > > -static void qjack_client_fini(QJackClient *c) > +static void qjack_client_fini_locked(QJackClient *c) > { > switch (c->state) { > case QJACK_STATE_RUNNING: > @@ -564,28 +575,40 @@ static void qjack_client_fini(QJackClient *c) > > case QJACK_STATE_SHUTDOWN: > jack_client_close(c->client); > + c->client = NULL; > + > + qjack_buffer_free(&c->fifo); > + g_free(c->port); > + > + c->state = QJACK_STATE_DISCONNECTED; > /* fallthrough */ > > case QJACK_STATE_DISCONNECTED: > break; > } > +} > > - qjack_buffer_free(&c->fifo); > - g_free(c->port); > - > - c->state = QJACK_STATE_DISCONNECTED; > +static void qjack_client_fini(QJackClient *c) > +{ > + qemu_mutex_lock(&qjack_shutdown_lock); > + qjack_client_fini_locked(c); > + qemu_mutex_unlock(&qjack_shutdown_lock); > } > > static void qjack_fini_out(HWVoiceOut *hw) > { > QJackOut *jo = (QJackOut *)hw; > qjack_client_fini(&jo->c); > + > + qemu_bh_delete(jo->c.shutdown_bh); > } > > static void qjack_fini_in(HWVoiceIn *hw) > { > QJackIn *ji = (QJackIn *)hw; > qjack_client_fini(&ji->c); > + > + qemu_bh_delete(ji->c.shutdown_bh); > } > > static void qjack_enable_out(HWVoiceOut *hw, bool enable) > @@ -662,6 +685,7 @@ static void qjack_info(const char *msg) > > static void register_audio_jack(void) > { > + qemu_mutex_init(&qjack_shutdown_lock); > audio_driver_register(&jack_driver); > jack_set_thread_creator(qjack_thread_creator); > jack_set_error_function(qjack_error); Best regards, Christian Schoenebeck
On Samstag, 7. November 2020 10:58:10 CET Christian Schoenebeck wrote: > On Samstag, 7. November 2020 01:04:58 CET Geoffrey McRae wrote: > > This change registers a bottom handler to close the JACK client > > connection when a server shutdown signal is recieved. Without this One last minor thing, typo here: "received". > > libjack2 attempts to "clean up" old clients and causes a use after free > > segfault. > > > > Signed-off-by: Geoffrey McRae <geoff@hostfission.com> > > --- > > > > audio/jackaudio.c | 50 +++++++++++++++++++++++++++++++++++------------ > > 1 file changed, 37 insertions(+), 13 deletions(-) > > > > diff --git a/audio/jackaudio.c b/audio/jackaudio.c > > index 1e714b30bc..e00e19061a 100644 > > --- a/audio/jackaudio.c > > +++ b/audio/jackaudio.c > > @@ -25,6 +25,7 @@ > > > > #include "qemu/osdep.h" > > #include "qemu/module.h" > > #include "qemu/atomic.h" > > > > +#include "qemu/main-loop.h" > > > > #include "qemu-common.h" > > #include "audio.h" > > > > @@ -63,6 +64,7 @@ typedef struct QJackClient { > > > > QJackState state; > > jack_client_t *client; > > jack_nframes_t freq; > > > > + QEMUBH *shutdown_bh; > > > > struct QJack *j; > > int nchannels; > > > > @@ -87,6 +89,7 @@ QJackIn; > > > > static int qjack_client_init(QJackClient *c); > > static void qjack_client_connect_ports(QJackClient *c); > > static void qjack_client_fini(QJackClient *c); > > > > +QemuMutex qjack_shutdown_lock; > > I think this should be: > > static QemuMutex qjack_shutdown_lock; > > as this mutex is only accessed from within this unit. Except of that: > > Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> > > BTW it is common practice to add local functions for initializing, > destroying, locking and unlocking a specific mutex use case to avoid issues > when code evolves. But so far the use of this mutex is trivial, so it is Ok > for now from my PoV. > > > static void qjack_buffer_create(QJackBuffer *buffer, int channels, int > > > > frames) { > > @@ -306,21 +309,27 @@ static int qjack_xrun(void *arg) > > > > return 0; > > > > } > > > > +static void qjack_shutdown_bh(void *opaque) > > +{ > > + QJackClient *c = (QJackClient *)opaque; > > + qjack_client_fini(c); > > +} > > + > > > > static void qjack_shutdown(void *arg) > > { > > > > QJackClient *c = (QJackClient *)arg; > > c->state = QJACK_STATE_SHUTDOWN; > > > > + qemu_bh_schedule(c->shutdown_bh); > > > > } > > > > static void qjack_client_recover(QJackClient *c) > > { > > > > - if (c->state == QJACK_STATE_SHUTDOWN) { > > - qjack_client_fini(c); > > + if (c->state != QJACK_STATE_DISCONNECTED) { > > + return; > > > > } > > > > /* packets is used simply to throttle this */ > > > > - if (c->state == QJACK_STATE_DISCONNECTED && > > - c->packets % 100 == 0) { > > + if (c->packets % 100 == 0) { > > > > /* if enabled then attempt to recover */ > > if (c->enabled) { > > > > @@ -489,15 +498,16 @@ static int qjack_init_out(HWVoiceOut *hw, struct > > audsettings *as, QJackOut *jo = (QJackOut *)hw; > > > > Audiodev *dev = (Audiodev *)drv_opaque; > > > > - qjack_client_fini(&jo->c); > > - > > > > jo->c.out = true; > > jo->c.enabled = false; > > jo->c.nchannels = as->nchannels; > > jo->c.opt = dev->u.jack.out; > > > > + jo->c.shutdown_bh = qemu_bh_new(qjack_shutdown_bh, &jo->c); > > + > > > > int ret = qjack_client_init(&jo->c); > > if (ret != 0) { > > > > + qemu_bh_delete(jo->c.shutdown_bh); > > > > return ret; > > > > } > > > > @@ -525,15 +535,16 @@ static int qjack_init_in(HWVoiceIn *hw, struct > > audsettings *as, QJackIn *ji = (QJackIn *)hw; > > > > Audiodev *dev = (Audiodev *)drv_opaque; > > > > - qjack_client_fini(&ji->c); > > - > > > > ji->c.out = false; > > ji->c.enabled = false; > > ji->c.nchannels = as->nchannels; > > ji->c.opt = dev->u.jack.in; > > > > + ji->c.shutdown_bh = qemu_bh_new(qjack_shutdown_bh, &ji->c); > > + > > > > int ret = qjack_client_init(&ji->c); > > if (ret != 0) { > > > > + qemu_bh_delete(ji->c.shutdown_bh); > > > > return ret; > > > > } > > > > @@ -555,7 +566,7 @@ static int qjack_init_in(HWVoiceIn *hw, struct > > audsettings *as, return 0; > > > > } > > > > -static void qjack_client_fini(QJackClient *c) > > +static void qjack_client_fini_locked(QJackClient *c) > > > > { > > > > switch (c->state) { > > > > case QJACK_STATE_RUNNING: > > @@ -564,28 +575,40 @@ static void qjack_client_fini(QJackClient *c) > > > > case QJACK_STATE_SHUTDOWN: > > jack_client_close(c->client); > > > > + c->client = NULL; > > + > > + qjack_buffer_free(&c->fifo); > > + g_free(c->port); > > + > > + c->state = QJACK_STATE_DISCONNECTED; > > > > /* fallthrough */ > > > > case QJACK_STATE_DISCONNECTED: > > break; > > > > } > > > > +} > > > > - qjack_buffer_free(&c->fifo); > > - g_free(c->port); > > - > > - c->state = QJACK_STATE_DISCONNECTED; > > +static void qjack_client_fini(QJackClient *c) > > +{ > > + qemu_mutex_lock(&qjack_shutdown_lock); > > + qjack_client_fini_locked(c); > > + qemu_mutex_unlock(&qjack_shutdown_lock); > > > > } > > > > static void qjack_fini_out(HWVoiceOut *hw) > > { > > > > QJackOut *jo = (QJackOut *)hw; > > qjack_client_fini(&jo->c); > > > > + > > + qemu_bh_delete(jo->c.shutdown_bh); > > > > } > > > > static void qjack_fini_in(HWVoiceIn *hw) > > { > > > > QJackIn *ji = (QJackIn *)hw; > > qjack_client_fini(&ji->c); > > > > + > > + qemu_bh_delete(ji->c.shutdown_bh); > > > > } > > > > static void qjack_enable_out(HWVoiceOut *hw, bool enable) > > > > @@ -662,6 +685,7 @@ static void qjack_info(const char *msg) > > > > static void register_audio_jack(void) > > { > > > > + qemu_mutex_init(&qjack_shutdown_lock); > > > > audio_driver_register(&jack_driver); > > jack_set_thread_creator(qjack_thread_creator); > > jack_set_error_function(qjack_error); > > Best regards, > Christian Schoenebeck
diff --git a/audio/jackaudio.c b/audio/jackaudio.c index 1e714b30bc..e00e19061a 100644 --- a/audio/jackaudio.c +++ b/audio/jackaudio.c @@ -25,6 +25,7 @@ #include "qemu/osdep.h" #include "qemu/module.h" #include "qemu/atomic.h" +#include "qemu/main-loop.h" #include "qemu-common.h" #include "audio.h" @@ -63,6 +64,7 @@ typedef struct QJackClient { QJackState state; jack_client_t *client; jack_nframes_t freq; + QEMUBH *shutdown_bh; struct QJack *j; int nchannels; @@ -87,6 +89,7 @@ QJackIn; static int qjack_client_init(QJackClient *c); static void qjack_client_connect_ports(QJackClient *c); static void qjack_client_fini(QJackClient *c); +QemuMutex qjack_shutdown_lock; static void qjack_buffer_create(QJackBuffer *buffer, int channels, int frames) { @@ -306,21 +309,27 @@ static int qjack_xrun(void *arg) return 0; } +static void qjack_shutdown_bh(void *opaque) +{ + QJackClient *c = (QJackClient *)opaque; + qjack_client_fini(c); +} + static void qjack_shutdown(void *arg) { QJackClient *c = (QJackClient *)arg; c->state = QJACK_STATE_SHUTDOWN; + qemu_bh_schedule(c->shutdown_bh); } static void qjack_client_recover(QJackClient *c) { - if (c->state == QJACK_STATE_SHUTDOWN) { - qjack_client_fini(c); + if (c->state != QJACK_STATE_DISCONNECTED) { + return; } /* packets is used simply to throttle this */ - if (c->state == QJACK_STATE_DISCONNECTED && - c->packets % 100 == 0) { + if (c->packets % 100 == 0) { /* if enabled then attempt to recover */ if (c->enabled) { @@ -489,15 +498,16 @@ static int qjack_init_out(HWVoiceOut *hw, struct audsettings *as, QJackOut *jo = (QJackOut *)hw; Audiodev *dev = (Audiodev *)drv_opaque; - qjack_client_fini(&jo->c); - jo->c.out = true; jo->c.enabled = false; jo->c.nchannels = as->nchannels; jo->c.opt = dev->u.jack.out; + jo->c.shutdown_bh = qemu_bh_new(qjack_shutdown_bh, &jo->c); + int ret = qjack_client_init(&jo->c); if (ret != 0) { + qemu_bh_delete(jo->c.shutdown_bh); return ret; } @@ -525,15 +535,16 @@ static int qjack_init_in(HWVoiceIn *hw, struct audsettings *as, QJackIn *ji = (QJackIn *)hw; Audiodev *dev = (Audiodev *)drv_opaque; - qjack_client_fini(&ji->c); - ji->c.out = false; ji->c.enabled = false; ji->c.nchannels = as->nchannels; ji->c.opt = dev->u.jack.in; + ji->c.shutdown_bh = qemu_bh_new(qjack_shutdown_bh, &ji->c); + int ret = qjack_client_init(&ji->c); if (ret != 0) { + qemu_bh_delete(ji->c.shutdown_bh); return ret; } @@ -555,7 +566,7 @@ static int qjack_init_in(HWVoiceIn *hw, struct audsettings *as, return 0; } -static void qjack_client_fini(QJackClient *c) +static void qjack_client_fini_locked(QJackClient *c) { switch (c->state) { case QJACK_STATE_RUNNING: @@ -564,28 +575,40 @@ static void qjack_client_fini(QJackClient *c) case QJACK_STATE_SHUTDOWN: jack_client_close(c->client); + c->client = NULL; + + qjack_buffer_free(&c->fifo); + g_free(c->port); + + c->state = QJACK_STATE_DISCONNECTED; /* fallthrough */ case QJACK_STATE_DISCONNECTED: break; } +} - qjack_buffer_free(&c->fifo); - g_free(c->port); - - c->state = QJACK_STATE_DISCONNECTED; +static void qjack_client_fini(QJackClient *c) +{ + qemu_mutex_lock(&qjack_shutdown_lock); + qjack_client_fini_locked(c); + qemu_mutex_unlock(&qjack_shutdown_lock); } static void qjack_fini_out(HWVoiceOut *hw) { QJackOut *jo = (QJackOut *)hw; qjack_client_fini(&jo->c); + + qemu_bh_delete(jo->c.shutdown_bh); } static void qjack_fini_in(HWVoiceIn *hw) { QJackIn *ji = (QJackIn *)hw; qjack_client_fini(&ji->c); + + qemu_bh_delete(ji->c.shutdown_bh); } static void qjack_enable_out(HWVoiceOut *hw, bool enable) @@ -662,6 +685,7 @@ static void qjack_info(const char *msg) static void register_audio_jack(void) { + qemu_mutex_init(&qjack_shutdown_lock); audio_driver_register(&jack_driver); jack_set_thread_creator(qjack_thread_creator); jack_set_error_function(qjack_error);
This change registers a bottom handler to close the JACK client connection when a server shutdown signal is recieved. Without this libjack2 attempts to "clean up" old clients and causes a use after free segfault. Signed-off-by: Geoffrey McRae <geoff@hostfission.com> --- audio/jackaudio.c | 50 +++++++++++++++++++++++++++++++++++------------ 1 file changed, 37 insertions(+), 13 deletions(-)