[PATCH wayland v4 11/11] tests: Check for wrong fd delivery with zombie objects
Daniel Stone
daniels at collabora.com
Thu Dec 28 19:53:57 UTC 2017
From: Derek Foreman <derekf at osg.samsung.com>
Until recently, if an event attempting to deliver an fd to a zombie
object was demarshalled after the object was made into a zombie, we
leaked the fd and left it in the buffer.
If another event attempting to deliver an fd to a live object was in that
same buffer, the zombie's fd would be delivered instead.
This test recreates that situation.
While this is a ridiculously contrived way to force this race - delivering
an event from a destruction handler - I do have reports of this race
being hit in real world code.
Signed-off-by: Derek Foreman <derekf at osg.samsung.com>
Acked-by: Daniel Stone <daniels at collabora.com>
Signed-off-by: Daniel Stone <daniels at collabora.com>
---
protocol/tests.xml | 11 +++-
tests/display-test.c | 153 ++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 160 insertions(+), 4 deletions(-)
diff --git a/protocol/tests.xml b/protocol/tests.xml
index 77f6e243..ea56ae49 100644
--- a/protocol/tests.xml
+++ b/protocol/tests.xml
@@ -26,7 +26,7 @@
SOFTWARE.
</copyright>
- <interface name="fd_passer" version="1">
+ <interface name="fd_passer" version="2">
<description summary="Sends an event with an fd">
A trivial interface for fd passing tests.
</description>
@@ -39,5 +39,14 @@
<description summary="passes a file descriptor"/>
<arg name="fd" type="fd" summary="file descriptor"/>
</event>
+
+ <!-- Version 2 additions -->
+ <request name="conjoin" since="2">
+ <description summary="register another fd passer with this one">
+ Tells this fd passer object about another one to send events
+ to for more complicated fd leak tests.
+ </description>
+ <arg name="passer" type="object" interface="fd_passer"/>
+ </request>
</interface>
</protocol>
diff --git a/tests/display-test.c b/tests/display-test.c
index 06231585..9b49a0ec 100644
--- a/tests/display-test.c
+++ b/tests/display-test.c
@@ -1128,27 +1128,83 @@ zombie_client(void *data)
client_disconnect_nocheck(c);
}
+struct passer_data {
+ struct wl_resource *conjoined_passer;
+};
+
+static void
+feed_pipe(int fd, char tosend)
+{
+ int count;
+
+ do {
+ count = write(fd, &tosend, 1);
+ } while (count != 1 && errno == EAGAIN);
+ assert(count == 1);
+ close(fd);
+}
+
static void
fd_passer_clobber(struct wl_client *client, struct wl_resource *res)
{
+ struct passer_data *pdata = wl_resource_get_user_data(res);
+ int pipes1[2], pipes2[2], ret;
+
+ if (pdata->conjoined_passer) {
+ ret = pipe(pipes1);
+ assert(ret == 0);
+ ret = pipe(pipes2);
+ assert(ret == 0);
+
+ wl_resource_queue_event(res, FD_PASSER_FD, pipes1[0]);
+ fd_passer_send_fd(pdata->conjoined_passer, pipes2[0]);
+ feed_pipe(pipes1[1], '1');
+ feed_pipe(pipes2[1], '2');
+ close(pipes1[0]);
+ close(pipes2[0]);
+ }
wl_resource_destroy(res);
}
+static void
+fd_passer_twin(struct wl_client *client, struct wl_resource *res, struct wl_resource *passer)
+{
+ struct passer_data *pdata = wl_resource_get_user_data(res);
+
+ pdata->conjoined_passer = passer;
+}
+
static const struct fd_passer_interface fdp_interface = {
fd_passer_clobber,
+ fd_passer_twin
};
+static void
+pdata_destroy(struct wl_resource *res)
+{
+ struct passer_data *pdata = wl_resource_get_user_data(res);
+
+ free(pdata);
+}
+
static void
bind_fd_passer(struct wl_client *client, void *data,
uint32_t vers, uint32_t id)
{
struct wl_resource *res;
+ struct passer_data *pdata;
+
+ pdata = malloc(sizeof(*pdata));
+ assert(pdata);
+ pdata->conjoined_passer = NULL;
res = wl_resource_create(client, &fd_passer_interface, vers, id);
- wl_resource_set_implementation(res, &fdp_interface, NULL, NULL);
+ wl_resource_set_implementation(res, &fdp_interface, pdata, pdata_destroy);
assert(res);
- fd_passer_send_pre_fd(res);
- fd_passer_send_fd(res, fileno(stdin));
+ if (vers == 1) {
+ fd_passer_send_pre_fd(res);
+ fd_passer_send_fd(res, fileno(stdin));
+ }
}
TEST(zombie_fd)
@@ -1168,3 +1224,94 @@ TEST(zombie_fd)
display_destroy(d);
}
+
+
+static void
+double_pre_fd(void *data, struct fd_passer *fdp)
+{
+ assert(false);
+}
+
+static void
+double_fd(void *data, struct fd_passer *fdp, int32_t fd)
+{
+ char buf;
+ int count;
+
+ do {
+ count = read(fd, &buf, 1);
+ } while (count != 1 && errno == EAGAIN);
+ assert(count == 1);
+
+ close(fd);
+ fd_passer_destroy(fdp);
+ assert(buf == '2');
+}
+
+struct fd_passer_listener double_fd_passer_listener = {
+ double_pre_fd,
+ double_fd,
+};
+
+
+static void
+double_zombie_fd_handle_globals(void *data, struct wl_registry *registry,
+ uint32_t id, const char *intf, uint32_t ver)
+{
+ struct fd_passer *fdp1, *fdp2;
+
+ if (!strcmp(intf, "fd_passer")) {
+ fdp1 = wl_registry_bind(registry, id, &fd_passer_interface, 2);
+ fd_passer_add_listener(fdp1, &double_fd_passer_listener, NULL);
+ fdp2 = wl_registry_bind(registry, id, &fd_passer_interface, 2);
+ fd_passer_add_listener(fdp2, &double_fd_passer_listener, NULL);
+ fd_passer_conjoin(fdp1, fdp2);
+ fd_passer_destroy(fdp1);
+ }
+}
+
+static const struct wl_registry_listener double_zombie_fd_registry_listener = {
+ double_zombie_fd_handle_globals,
+ NULL
+};
+
+static void
+double_zombie_client(void *data)
+{
+ struct client *c = client_connect();
+ struct wl_registry *registry;
+
+ registry = wl_display_get_registry(c->wl_display);
+ wl_registry_add_listener(registry, &double_zombie_fd_registry_listener, NULL);
+
+ /* Gets the registry */
+ wl_display_roundtrip(c->wl_display);
+
+ /* One more so server can respond to conjoin+destroy */
+ wl_display_roundtrip(c->wl_display);
+
+ /* And finally push out our last fd_passer.destroy */
+ wl_display_roundtrip(c->wl_display);
+
+ wl_registry_destroy(registry);
+
+ client_disconnect_nocheck(c);
+}
+
+TEST(zombie_fd_errant_consumption)
+{
+ struct display *d;
+ struct wl_global *g;
+
+ d = display_create();
+
+ g = wl_global_create(d->wl_display, &fd_passer_interface,
+ 2, d, bind_fd_passer);
+
+ client_create_noarg(d, double_zombie_client);
+ display_run(d);
+
+ wl_global_destroy(g);
+
+ display_destroy(d);
+}
--
2.14.3
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