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Xi: fix byte-swapping of button labels 

The byte-swapping code forgot that the xXIButtonInfo is followed by a
button mask, not directly by the button labels. This resulted in client
crashes in cross-endian setups, for example in `xinput list --long`,
since the client got an invalid atom.

A new function was introduced to get the right positions for the label
and mask data.

Signed-off-by: Roman Kapl <code@rkapl.cz>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
This commit is contained in:
Roman Kapl 2018-06-07 03:31:41 +02:00 committed by Peter Hutterer
parent 9b89994110
commit cefbc6a935
1 changed files with 20 additions and 6 deletions
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26
Xi/xiquerydevice.c
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@ -237,6 +237,18 @@ SizeDeviceClasses(DeviceIntPtr dev)
return len;
}
/**
* Get pointers to button information areas holding button mask and labels.
*/
static void
ButtonInfoData(xXIButtonInfo *info, int *mask_words, unsigned char **mask,
Atom **atoms)
{
*mask_words = bytes_to_int32(bits_to_bytes(info->num_buttons));
*mask = (unsigned char*) &info[1];
*atoms = (Atom*) ((*mask) + (*mask_words) * 4);
}
/**
* Write button information into info.
* @return Number of bytes written into info.
@ -245,21 +257,20 @@ int
ListButtonInfo(DeviceIntPtr dev, xXIButtonInfo * info, Bool reportState)
{
unsigned char *bits;
Atom *labels;
int mask_len;
int i;
if (!dev || !dev->button)
return 0;
mask_len = bytes_to_int32(bits_to_bytes(dev->button->numButtons));
info->type = ButtonClass;
info->num_buttons = dev->button->numButtons;
ButtonInfoData(info, &mask_len, &bits, &labels);
info->length = bytes_to_int32(sizeof(xXIButtonInfo)) +
info->num_buttons + mask_len;
info->sourceid = dev->button->sourceid;
bits = (unsigned char *) &info[1];
memset(bits, 0, mask_len * 4);
if (reportState)
@ -267,8 +278,7 @@ ListButtonInfo(DeviceIntPtr dev, xXIButtonInfo * info, Bool reportState)
if (BitIsOn(dev->button->down, i))
SetBit(bits, i);
bits += mask_len * 4;
memcpy(bits, dev->button->labels, dev->button->numButtons * sizeof(Atom));
memcpy(labels, dev->button->labels, dev->button->numButtons * sizeof(Atom));
return info->length * 4;
}
@ -277,13 +287,17 @@ static void
SwapButtonInfo(DeviceIntPtr dev, xXIButtonInfo * info)
{
Atom *btn;
int mask_len;
unsigned char *mask;
int i;
ButtonInfoData(info, &mask_len, &mask, &btn);
swaps(&info->type);
swaps(&info->length);
swaps(&info->sourceid);
for (i = 0, btn = (Atom *) &info[1]; i < info->num_buttons; i++, btn++)
for (i = 0 ; i < info->num_buttons; i++, btn++)
swapl(btn);
swaps(&info->num_buttons);