If no match is found within the 'while' loop, the value of 'ndevices'
will be -1 at the point we reach 'if (!ndevices)' since we use the
post-decrement operator. In addition to never producing the expected
error message, this also results in a NULL dereference immediately
afterwards.
Signed-off-by: Jason Gerecke <killert...@gmail.com>
---
Changes in v2:
* Changed from a pre-decrement 'while' to a 'for' loop. The former
wouldn't work right with ndevices == 0 and would have required a
second 'Unable to locate device' error message.
tools/xsetwacom.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/tools/xsetwacom.c b/tools/xsetwacom.c
index 276f7dd..beb4f25 100644
--- a/tools/xsetwacom.c
+++ b/tools/xsetwacom.c
@@ -1758,14 +1758,15 @@ static void get_mode(Display *dpy, XDevice *dev,
param_t* param, int argc, char
XValuatorInfoPtr v;
info = XListInputDevices(dpy, &ndevices);
- while(ndevices--)
+
+ for (i = 0; i < ndevices; i++)
{
- d = &info[ndevices];
+ d = &info[i];
if (d->id == dev->device_id)
break;
}
- if (!ndevices) /* device id 0 is reserved and can't be our device */
+ if (i >= ndevices)
{
fprintf(stderr, "Unable to locate device.\n");
return;
--
2.1.0
------------------------------------------------------------------------------
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