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Xi: get device changed data from DeviceChangedEvents, not the device (#23100)

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If a new device posts an event while the DCE is in the queue, getting the
data from the device may result in invalid memory access.

X.Org Bug 23100 <http://bugs.freedesktop.org/show_bug.cgi?id=23100>
This commit is contained in:
Peter Hutterer 2009-08-03 16:46:11 +10:00
parent 8ce4fde76f
commit 55e1ea08d0
1 changed files with 66 additions and 3 deletions
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69
Xi/exevents.c
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@ -674,6 +674,69 @@ DeepCopyDeviceClasses(DeviceIntPtr from, DeviceIntPtr to, DeviceChangedEvent *dc
}
static int
AppendKeyInfo(DeviceChangedEvent *dce, xXIKeyInfo* info)
{
uint32_t *kc;
int i;
info->type = KeyClass;
info->num_keycodes = dce->keys.max_keycode - dce->keys.min_keycode + 1;
info->length = sizeof(xXIKeyInfo)/4 + info->num_keycodes;
info->sourceid = dce->deviceid;
kc = (uint32_t*)&info[1];
for (i = 0; i < info->num_keycodes; i++)
*kc++ = i + dce->keys.min_keycode;
return info->length * 4;
}
static int
AppendButtonInfo(DeviceChangedEvent *dce, xXIButtonInfo *info)
{
unsigned char *bits;
int mask_len;
mask_len = bytes_to_int32(bits_to_bytes(dce->buttons.num_buttons));
info->type = ButtonClass;
info->num_buttons = dce->buttons.num_buttons;
info->length = bytes_to_int32(sizeof(xXIButtonInfo)) +
info->num_buttons + mask_len;
info->sourceid = dce->deviceid;
bits = (unsigned char*)&info[1];
memset(bits, 0, mask_len * 4);
/* FIXME: is_down? */
bits += mask_len * 4;
memcpy(bits, dce->buttons.names, dce->buttons.num_buttons * sizeof(Atom));
return info->length * 4;
}
static int
AppendValuatorInfo(DeviceChangedEvent *dce, xXIValuatorInfo *info, int axisnumber)
{
info->type = ValuatorClass;
info->length = sizeof(xXIValuatorInfo)/4;
info->label = dce->valuators[axisnumber].name;
info->min.integral = dce->valuators[axisnumber].min;
info->min.frac = 0;
info->max.integral = dce->valuators[axisnumber].max;
info->max.frac = 0;
/* FIXME: value */
info->value.integral = 0;
info->value.frac = 0;
info->resolution = dce->valuators[axisnumber].resolution;
info->number = axisnumber;
info->mode = dce->valuators[axisnumber].mode; /* Server doesn't have per-axis mode yet */
info->sourceid = dce->deviceid;
return info->length * 4;
}
/**
* Send an XI2 DeviceChangedEvent to all interested clients.
*/
@ -723,13 +786,13 @@ XISendDeviceChangedEvent(DeviceIntPtr device, DeviceIntPtr master, DeviceChanged
if (dce->buttons.num_buttons)
{
dcce->num_classes++;
ptr += ListButtonInfo(device, (xXIButtonInfo*)ptr);
ptr += AppendButtonInfo(dce, (xXIButtonInfo*)ptr);
}
if (nkeys)
{
dcce->num_classes++;
ptr += ListKeyInfo(device, (xXIKeyInfo*)ptr);
ptr += AppendKeyInfo(dce, (xXIKeyInfo*)ptr);
}
if (dce->num_valuators)
@ -738,7 +801,7 @@ XISendDeviceChangedEvent(DeviceIntPtr device, DeviceIntPtr master, DeviceChanged
dcce->num_classes += dce->num_valuators;
for (i = 0; i < dce->num_valuators; i++)
ptr += ListValuatorInfo(device, (xXIValuatorInfo*)ptr, i);
ptr += AppendValuatorInfo(dce, (xXIValuatorInfo*)ptr, i);
}
/* we don't actually swap if there's a NullClient, swapping is done