[PATCH xf86-input-libinput] Fix crash when using threaded input and the first device goes away
Hans de Goede
hdegoede at redhat.com
Wed Oct 5 13:31:38 UTC 2016
When the xserver uses threaded input, it keeps a pointer to the InputInfo
passed into xf86AddEnabledDevice and calls pointer->read_input on events.
But when the first enabled device goes away the pInfo we've passed into
xf86AddEnabledDevice gets freed and eventually pInfo->read_input gets
overwritten (or pInfo points to unmapped memory) leading to a segfault.
This commit fixes this by replacing the pInfo passed into
xf86AddEnabledDevice with a pointer to a global InputInfo stored inside
the driver_context struct.
Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
src/xf86libinput.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/src/xf86libinput.c b/src/xf86libinput.c
index 21f87f5..485e212 100644
--- a/src/xf86libinput.c
+++ b/src/xf86libinput.c
@@ -86,6 +86,7 @@
struct xf86libinput_driver {
struct libinput *libinput;
+ struct _InputInfoRec InputInfo;
int device_enabled_count;
};
@@ -582,7 +583,17 @@ xf86libinput_on(DeviceIntPtr dev)
if (driver_context.device_enabled_count == 0) {
#if HAVE_THREADED_INPUT
- xf86AddEnabledDevice(pInfo);
+ /*
+ * The xserver keeps a pointer to the InputInfo passed into
+ * xf86AddEnabledDevice and calls pointer->read_input on
+ * events. Thus we cannot simply pass in our current pInfo
+ * as that will be deleted when the current input device gets
+ * unplugged. Instead pass in a pointer to a global
+ * InputInfo inside the driver_context.
+ */
+ driver_context.InputInfo.fd = pInfo->fd;
+ driver_context.InputInfo.read_input = pInfo->read_input;
+ xf86AddEnabledDevice(&driver_context.InputInfo);
#else
/* Can't use xf86AddEnabledDevice on an epollfd */
AddEnabledDevice(pInfo->fd);
@@ -606,7 +617,7 @@ xf86libinput_off(DeviceIntPtr dev)
if (--driver_context.device_enabled_count == 0) {
#if HAVE_THREADED_INPUT
- xf86RemoveEnabledDevice(pInfo);
+ xf86RemoveEnabledDevice(&driver_context.InputInfo);
#else
RemoveEnabledDevice(pInfo->fd);
#endif
@@ -1923,7 +1934,7 @@ out:
}
static void
-xf86libinput_read_input(InputInfoPtr pInfo)
+xf86libinput_read_input(InputInfoPtr do_not_use)
{
struct libinput *libinput = driver_context.libinput;
int rc;
@@ -1934,9 +1945,8 @@ xf86libinput_read_input(InputInfoPtr pInfo)
return;
if (rc < 0) {
- xf86IDrvMsg(pInfo, X_ERROR,
- "Error reading events: %s\n",
- strerror(-rc));
+ xf86Msg(X_ERROR, "Error reading libinput events: %s\n",
+ strerror(-rc));
return;
}
--
2.9.3
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