[PATCH 05/15] xkb: Check for unsuported comibnation of action for XkbSetMap

[Pauli Nieminen]

On Wed, Jul 28, 2010 at 1:58 AM, Peter Hutterer
<peter.hutterer at who-t.net> wrote:
> On Tue, Jul 27, 2010 at 03:09:46PM +0300, Pauli Nieminen wrote:
>> This prevents validation code from using uninitialized values.
>>
Fixes:
uninit_use_in_call: Using uninitialized element of array "symsPerKey"
in call to function "CheckKeyActions"

>> Signed-off-by: Pauli Nieminen <ext-pauli.nieminen at nokia.com>
>> ---
>>  xkb/xkb.c |    8 ++++++++
>>  1 files changed, 8 insertions(+), 0 deletions(-)
>>
>> diff --git a/xkb/xkb.c b/xkb/xkb.c
>> index 935f5ea..9a5d5b3 100644
>> --- a/xkb/xkb.c
>> +++ b/xkb/xkb.c
>> @@ -2366,6 +2366,14 @@ _XkbSetMapChecks(ClientPtr client, DeviceIntPtr dev, xkbSetMapReq *req, char* va
>>       }
>>      }
>>
>> +    if ((!(req->present & XkbKeySymsMask) &&
>> +         (req->present & XkbKeyActionsMask)) ||
>> +     (!(req->present & XkbKeyTypesMask) &&
>> +         (req->present & XkbKeySymsMask))) {
>> +     client->errorValue = req->present;
>> +     return BadMatch;
>> +    }
>> +
>>      if ((req->present & XkbKeyTypesMask) &&
>>       (!CheckKeyTypes(client,xkb,req,(xkbKeyTypeWireDesc **)&values,
>>                                               &nTypes,mapWidths))) {
>> --
>> 1.6.3.3
>
> What was the error message that triggered this patch? It's not really
> obvious from the patch or from the current code.
>

Problem is that CheckKeySyms initializes symsPerKey which is then read
in CheckKeyActions. If XkbKeyActionsMask is set without XkbKeySymsMask
that would cause validation to use uninitialized values from the
array.

Same dependency also applies for CheckKeyTypes and CheckKeySyms.

> Cheers,
>  Peter