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randr: add BUG_* checks for possible NULL pointer issue 

The ‘RRCrtcNotify() and RRCrtcSet() functions are exported, so there's chance
that a buggy driver could call them with NULL parameter, leading to segfault.
Those are hard to trace, so it's better having a BUG_* check here.

| ../randr/rrcrtc.c: In function ‘RRCrtcNotify’:
| ../randr/rrcrtc.c:187:5: warning: use of NULL ‘outputs’ where non-null expected [CWE-476] [-Wanalyzer-null-argument]
|   187 |     memcpy(crtc->outputs, outputs, numOutputs * sizeof(RROutputPtr));
|       |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

| ../randr/rrcrtc.c: In function ‘RRCrtcSet’:
| ../randr/rrcrtc.c:742:20: warning: dereference of NULL ‘outputs’ [CWE-476] [-Wanalyzer-null-dereference]
|   742 |         if (outputs[o]) {
|       |             ~~~~~~~^~~

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
This commit is contained in:
Enrico Weigelt, metux IT consult 2025-05-06 16:39:28 +02:00
parent 90cd5c38ee
commit 5193f57aae
1 changed files with 8 additions and 1 deletions
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9
randr/rrcrtc.c
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@ -22,13 +22,15 @@
*/ */
#include <dix-config.h> #include <dix-config.h>
#include <X11/Xatom.h>
#include "randr/randrstr_priv.h" #include "randr/randrstr_priv.h"
#include "randr/rrdispatch_priv.h" #include "randr/rrdispatch_priv.h"
#include "os/bug_priv.h"
#include "swaprep.h" #include "swaprep.h"
#include "mipointer.h" #include "mipointer.h"
#include <X11/Xatom.h>
RESTYPE RRCrtcType = 0; RESTYPE RRCrtcType = 0;
@ -184,10 +186,13 @@ RRCrtcNotify(RRCrtcPtr crtc,
crtc->outputs = newoutputs; crtc->outputs = newoutputs;
crtc->numOutputs = numOutputs; crtc->numOutputs = numOutputs;
} }
/* /*
* Copy the new list of outputs into the crtc * Copy the new list of outputs into the crtc
*/ */
BUG_RETURN_VAL(outputs == NULL, FALSE);
memcpy(crtc->outputs, outputs, numOutputs * sizeof(RROutputPtr)); memcpy(crtc->outputs, outputs, numOutputs * sizeof(RROutputPtr));
/* /*
* Update remaining crtc fields * Update remaining crtc fields
*/ */
@ -749,6 +754,8 @@ RRCrtcSet(RRCrtcPtr crtc,
Bool crtcChanged; Bool crtcChanged;
int o; int o;
BUG_RETURN_VAL(outputs == NULL, FALSE);
rrScrPriv(pScreen); rrScrPriv(pScreen);
crtcChanged = FALSE; crtcChanged = FALSE;