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authorChris Wilson <chris@chris-wilson.co.uk>2010-08-10 19:30:20 +0100
committerJulien Cristau <jcristau@debian.org>2010-08-21 20:08:10 +0100
commit845f0bb1b941e770d88c40afe029e2fedd8655d9 (patch)
treee223cca46fa18a88737339e7a6efc9eac4c2b4f8
parentf07fc1461d38c8228d1bacf3d19932cac7bacddd (diff)
xace: Invalid reference to out-of-scope data.
The callback data passed by reference to the hook was allocated on stack within the scope of the case statement. The compiler is free to reuse any of that stack space whilst making the function call so we may end up passing garbage into the callback. References: Bug 18451 - Xorg server 1.5.2 SEGV during XFixesGetCursorImage() https://bugs.freedesktop.org/show_bug.cgi?id=18451 v2: Drop the unrelated hunk that snuck in when ammending the commit message. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Alan Coopersmith <alan.coopersmith@oracle.com> Signed-off-by: Keith Packard <keithp@keithp.com> (cherry picked from commit 6dae7f3792611aace1df0cca63bf50c50d93de43)
-rw-r--r--Xext/xace.c170
1 files changed, 75 insertions, 95 deletions
diff --git a/Xext/xace.c b/Xext/xace.c
index bf0e98fb0..414eb4aa2 100644
--- a/Xext/xace.c
+++ b/Xext/xace.c
@@ -87,7 +87,18 @@ void XaceHookAuditEnd(ClientPtr ptr, int result)
*/
int XaceHook(int hook, ...)
{
- pointer calldata; /* data passed to callback */
+ union {
+ XaceResourceAccessRec res;
+ XaceDeviceAccessRec dev;
+ XaceSendAccessRec send;
+ XaceReceiveAccessRec recv;
+ XaceClientAccessRec client;
+ XaceExtAccessRec ext;
+ XaceServerAccessRec server;
+ XaceScreenAccessRec screen;
+ XaceAuthAvailRec auth;
+ XaceKeyAvailRec key;
+ } u;
int *prv = NULL; /* points to return value from callback */
va_list ap; /* argument list */
va_start(ap, hook);
@@ -99,117 +110,86 @@ int XaceHook(int hook, ...)
*/
switch (hook)
{
- case XACE_RESOURCE_ACCESS: {
- XaceResourceAccessRec rec;
- rec.client = va_arg(ap, ClientPtr);
- rec.id = va_arg(ap, XID);
- rec.rtype = va_arg(ap, RESTYPE);
- rec.res = va_arg(ap, pointer);
- rec.ptype = va_arg(ap, RESTYPE);
- rec.parent = va_arg(ap, pointer);
- rec.access_mode = va_arg(ap, Mask);
- rec.status = Success; /* default allow */
- calldata = &rec;
- prv = &rec.status;
+ case XACE_RESOURCE_ACCESS:
+ u.res.client = va_arg(ap, ClientPtr);
+ u.res.id = va_arg(ap, XID);
+ u.res.rtype = va_arg(ap, RESTYPE);
+ u.res.res = va_arg(ap, pointer);
+ u.res.ptype = va_arg(ap, RESTYPE);
+ u.res.parent = va_arg(ap, pointer);
+ u.res.access_mode = va_arg(ap, Mask);
+ u.res.status = Success; /* default allow */
+ prv = &u.res.status;
break;
- }
- case XACE_DEVICE_ACCESS: {
- XaceDeviceAccessRec rec;
- rec.client = va_arg(ap, ClientPtr);
- rec.dev = va_arg(ap, DeviceIntPtr);
- rec.access_mode = va_arg(ap, Mask);
- rec.status = Success; /* default allow */
- calldata = &rec;
- prv = &rec.status;
+ case XACE_DEVICE_ACCESS:
+ u.dev.client = va_arg(ap, ClientPtr);
+ u.dev.dev = va_arg(ap, DeviceIntPtr);
+ u.dev.access_mode = va_arg(ap, Mask);
+ u.dev.status = Success; /* default allow */
+ prv = &u.dev.status;
break;
- }
- case XACE_SEND_ACCESS: {
- XaceSendAccessRec rec;
- rec.client = va_arg(ap, ClientPtr);
- rec.dev = va_arg(ap, DeviceIntPtr);
- rec.pWin = va_arg(ap, WindowPtr);
- rec.events = va_arg(ap, xEventPtr);
- rec.count = va_arg(ap, int);
- rec.status = Success; /* default allow */
- calldata = &rec;
- prv = &rec.status;
+ case XACE_SEND_ACCESS:
+ u.send.client = va_arg(ap, ClientPtr);
+ u.send.dev = va_arg(ap, DeviceIntPtr);
+ u.send.pWin = va_arg(ap, WindowPtr);
+ u.send.events = va_arg(ap, xEventPtr);
+ u.send.count = va_arg(ap, int);
+ u.send.status = Success; /* default allow */
+ prv = &u.send.status;
break;
- }
- case XACE_RECEIVE_ACCESS: {
- XaceReceiveAccessRec rec;
- rec.client = va_arg(ap, ClientPtr);
- rec.pWin = va_arg(ap, WindowPtr);
- rec.events = va_arg(ap, xEventPtr);
- rec.count = va_arg(ap, int);
- rec.status = Success; /* default allow */
- calldata = &rec;
- prv = &rec.status;
+ case XACE_RECEIVE_ACCESS:
+ u.recv.client = va_arg(ap, ClientPtr);
+ u.recv.pWin = va_arg(ap, WindowPtr);
+ u.recv.events = va_arg(ap, xEventPtr);
+ u.recv.count = va_arg(ap, int);
+ u.recv.status = Success; /* default allow */
+ prv = &u.recv.status;
break;
- }
- case XACE_CLIENT_ACCESS: {
- XaceClientAccessRec rec;
- rec.client = va_arg(ap, ClientPtr);
- rec.target = va_arg(ap, ClientPtr);
- rec.access_mode = va_arg(ap, Mask);
- rec.status = Success; /* default allow */
- calldata = &rec;
- prv = &rec.status;
+ case XACE_CLIENT_ACCESS:
+ u.client.client = va_arg(ap, ClientPtr);
+ u.client.target = va_arg(ap, ClientPtr);
+ u.client.access_mode = va_arg(ap, Mask);
+ u.client.status = Success; /* default allow */
+ prv = &u.client.status;
break;
- }
- case XACE_EXT_ACCESS: {
- XaceExtAccessRec rec;
- rec.client = va_arg(ap, ClientPtr);
- rec.ext = va_arg(ap, ExtensionEntry*);
- rec.access_mode = DixGetAttrAccess;
- rec.status = Success; /* default allow */
- calldata = &rec;
- prv = &rec.status;
+ case XACE_EXT_ACCESS:
+ u.ext.client = va_arg(ap, ClientPtr);
+ u.ext.ext = va_arg(ap, ExtensionEntry*);
+ u.ext.access_mode = DixGetAttrAccess;
+ u.ext.status = Success; /* default allow */
+ prv = &u.ext.status;
break;
- }
- case XACE_SERVER_ACCESS: {
- XaceServerAccessRec rec;
- rec.client = va_arg(ap, ClientPtr);
- rec.access_mode = va_arg(ap, Mask);
- rec.status = Success; /* default allow */
- calldata = &rec;
- prv = &rec.status;
+ case XACE_SERVER_ACCESS:
+ u.server.client = va_arg(ap, ClientPtr);
+ u.server.access_mode = va_arg(ap, Mask);
+ u.server.status = Success; /* default allow */
+ prv = &u.server.status;
break;
- }
case XACE_SCREEN_ACCESS:
- case XACE_SCREENSAVER_ACCESS: {
- XaceScreenAccessRec rec;
- rec.client = va_arg(ap, ClientPtr);
- rec.screen = va_arg(ap, ScreenPtr);
- rec.access_mode = va_arg(ap, Mask);
- rec.status = Success; /* default allow */
- calldata = &rec;
- prv = &rec.status;
+ case XACE_SCREENSAVER_ACCESS:
+ u.screen.client = va_arg(ap, ClientPtr);
+ u.screen.screen = va_arg(ap, ScreenPtr);
+ u.screen.access_mode = va_arg(ap, Mask);
+ u.screen.status = Success; /* default allow */
+ prv = &u.screen.status;
break;
- }
- case XACE_AUTH_AVAIL: {
- XaceAuthAvailRec rec;
- rec.client = va_arg(ap, ClientPtr);
- rec.authId = va_arg(ap, XID);
- calldata = &rec;
+ case XACE_AUTH_AVAIL:
+ u.auth.client = va_arg(ap, ClientPtr);
+ u.auth.authId = va_arg(ap, XID);
break;
- }
- case XACE_KEY_AVAIL: {
- XaceKeyAvailRec rec;
- rec.event = va_arg(ap, xEventPtr);
- rec.keybd = va_arg(ap, DeviceIntPtr);
- rec.count = va_arg(ap, int);
- calldata = &rec;
+ case XACE_KEY_AVAIL:
+ u.key.event = va_arg(ap, xEventPtr);
+ u.key.keybd = va_arg(ap, DeviceIntPtr);
+ u.key.count = va_arg(ap, int);
break;
- }
- default: {
+ default:
va_end(ap);
return 0; /* unimplemented hook number */
- }
}
va_end(ap);
/* call callbacks and return result, if any. */
- CallCallbacks(&XaceHooks[hook], calldata);
+ CallCallbacks(&XaceHooks[hook], &u);
return prv ? *prv : Success;
}