summaryrefslogtreecommitdiff
path: root/xserver/Xext/xace.c
blob: 14a5e7963ddcbc40b5e31b99d6cc6860852861e6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
/************************************************************

Author: Eamon Walsh <ewalsh@epoch.ncsc.mil>

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
this permission notice appear in supporting documentation.  This permission
notice shall be included in all copies or substantial portions of the
Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

********************************************************/

#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#include <stdarg.h>
#include "windowstr.h"
#include "scrnintstr.h"
#include "gcstruct.h"
#include "xacestr.h"
#include "modinit.h"

CallbackListPtr XaceHooks[XACE_NUM_HOOKS] = {0};

/* Proc vectors for untrusted clients, swapped and unswapped versions.
 * These are the same as the normal proc vectors except that extensions
 * that haven't declared themselves secure will have ProcBadRequest plugged
 * in for their major opcode dispatcher.  This prevents untrusted clients
 * from guessing extension major opcodes and using the extension even though
 * the extension can't be listed or queried.
 */
int (*UntrustedProcVector[256])(
    ClientPtr /*client*/
);
int (*SwappedUntrustedProcVector[256])(
    ClientPtr /*client*/
);

/* Entry point for hook functions.  Called by Xserver.
 */
int XaceHook(int hook, ...)
{
    pointer calldata;	/* data passed to callback */
    int *prv = NULL;	/* points to return value from callback */
    va_list ap;		/* argument list */
    va_start(ap, hook);

    /* Marshal arguments for passing to callback.
     * Each callback has its own case, which sets up a structure to hold
     * the arguments and integer return parameter, or in some cases just
     * sets calldata directly to a single argument (with no return result)
     */
    switch (hook)
    {
	case XACE_CORE_DISPATCH: {
	    XaceCoreDispatchRec rec = {
		va_arg(ap, ClientPtr),
		TRUE	/* default allow */
	    };
	    calldata = &rec;
	    prv = &rec.rval;
	    break;
	}
	case XACE_RESOURCE_ACCESS: {
	    XaceResourceAccessRec rec = {
		va_arg(ap, ClientPtr),
		va_arg(ap, XID),
		va_arg(ap, RESTYPE),
		va_arg(ap, Mask),
		va_arg(ap, pointer),
		TRUE	/* default allow */
	    };
	    calldata = &rec;
	    prv = &rec.rval;
	    break;
	}
	case XACE_DEVICE_ACCESS: {
	    XaceDeviceAccessRec rec = {
		va_arg(ap, ClientPtr),
		va_arg(ap, DeviceIntPtr),
		va_arg(ap, Bool),
		TRUE	/* default allow */
	    };
	    calldata = &rec;
	    prv = &rec.rval;
	    break;
	}
	case XACE_PROPERTY_ACCESS: {
	    XacePropertyAccessRec rec = {
		va_arg(ap, ClientPtr),
		va_arg(ap, WindowPtr),
		va_arg(ap, Atom),
		va_arg(ap, Mask),
		SecurityAllowOperation   /* default allow */
	    };
	    calldata = &rec;
	    prv = &rec.rval;
	    break;
	}
	case XACE_DRAWABLE_ACCESS: {
	    XaceDrawableAccessRec rec = {
		va_arg(ap, ClientPtr),
		va_arg(ap, DrawablePtr),
		TRUE	/* default allow */
	    };
	    calldata = &rec;
	    prv = &rec.rval;
	    break;
	}
	case XACE_MAP_ACCESS:
	case XACE_BACKGRND_ACCESS: {
	    XaceMapAccessRec rec = {
		va_arg(ap, ClientPtr),
		va_arg(ap, WindowPtr),
		TRUE	/* default allow */
	    };
	    calldata = &rec;
	    prv = &rec.rval;
	    break;
	}
	case XACE_EXT_DISPATCH:
	case XACE_EXT_ACCESS: {
	    XaceExtAccessRec rec = {
		va_arg(ap, ClientPtr),
		va_arg(ap, ExtensionEntry*),
		TRUE	/* default allow */
	    };
	    calldata = &rec;
	    prv = &rec.rval;
	    break;
	}
	case XACE_HOSTLIST_ACCESS: {
	    XaceHostlistAccessRec rec = {
		va_arg(ap, ClientPtr),
		va_arg(ap, Mask),
		TRUE	/* default allow */
	    };
	    calldata = &rec;
	    prv = &rec.rval;
	    break;
	}
	case XACE_SITE_POLICY: {
	    XaceSitePolicyRec rec = {
		va_arg(ap, char*),
		va_arg(ap, int),
		FALSE	/* default unrecognized */
	    };
	    calldata = &rec;
	    prv = &rec.rval;
	    break;
	}
	case XACE_DECLARE_EXT_SECURE: {
	    XaceDeclareExtSecureRec rec = {
		va_arg(ap, ExtensionEntry*),
		va_arg(ap, Bool)
	    };
	    calldata = &rec;
	    break;
	}
	case XACE_AUTH_AVAIL: {
	    XaceAuthAvailRec rec = {
		va_arg(ap, ClientPtr),
		va_arg(ap, XID)
	    };
	    calldata = &rec;
	    break;
	}
	case XACE_KEY_AVAIL: {
	    XaceKeyAvailRec rec = {
		va_arg(ap, xEventPtr),
		va_arg(ap, DeviceIntPtr),
		va_arg(ap, int)
	    };
	    calldata = &rec;
	    break;
	}
	case XACE_WINDOW_INIT: {
	    XaceWindowRec rec = {
		va_arg(ap, ClientPtr),
		va_arg(ap, WindowPtr)
	    };
	    calldata = &rec;
	    break;
	}
	case XACE_AUDIT_BEGIN: {
	    XaceAuditRec rec = {
		va_arg(ap, ClientPtr),
		0
	    };
	    calldata = &rec;
	    break;
	}
	case XACE_AUDIT_END: {
	    XaceAuditRec rec = {
		va_arg(ap, ClientPtr),
		va_arg(ap, int)
	    };
	    calldata = &rec;
	    break;
	}
	default: {
	    va_end(ap);
	    return 0;	/* unimplemented hook number */
	}
    }
    va_end(ap);
 
    /* call callbacks and return result, if any. */
    CallCallbacks(&XaceHooks[hook], calldata);
    return prv ? *prv : 0;
}

static int
ProcXaceDispatch(ClientPtr client)
{
    REQUEST(xReq);

    switch (stuff->data)
    {
	default:
	    return BadRequest;
    }
} /* ProcXaceDispatch */

static int
SProcXaceDispatch(ClientPtr client)
{
    REQUEST(xReq);

    switch (stuff->data)
    {
	default:
	    return BadRequest;
    }
} /* SProcXaceDispatch */


/* XaceResetProc
 *
 * Arguments:
 *	extEntry is the extension information for the XACE extension.
 *
 * Returns: nothing.
 *
 * Side Effects:
 *	Performs any cleanup needed by XACE at server shutdown time.
 */
static void
XaceResetProc(ExtensionEntry *extEntry)
{
    int i;

    for (i=0; i<XACE_NUM_HOOKS; i++)
    {
	DeleteCallbackList(&XaceHooks[i]);
	XaceHooks[i] = NULL;
    }
} /* XaceResetProc */


static int
XaceCatchDispatchProc(ClientPtr client)
{
    REQUEST(xReq);
    int major = stuff->reqType;

    if (!ProcVector[major])
	return (BadRequest);

    if (!XaceHook(XACE_CORE_DISPATCH, client))
	return (BadAccess);

    return client->swapped ? 
	(* SwappedProcVector[major])(client) :
	(* ProcVector[major])(client);
}

static int
XaceCatchExtProc(ClientPtr client)
{
    REQUEST(xReq);
    int major = stuff->reqType;
    ExtensionEntry *ext = GetExtensionEntry(major);

    if (!ext || !ProcVector[major])
	return (BadRequest);

    if (!XaceHook(XACE_EXT_DISPATCH, client, ext))
	return (BadRequest); /* pretend extension doesn't exist */

    return client->swapped ?
	(* SwappedProcVector[major])(client) :
	(* ProcVector[major])(client);
}

	
/* SecurityClientStateCallback
 *
 * Arguments:
 *	pcbl is &ClientStateCallback.
 *	nullata is NULL.
 *	calldata is a pointer to a NewClientInfoRec (include/dixstruct.h)
 *	which contains information about client state changes.
 *
 * Returns: nothing.
 *
 * Side Effects:
 * 
 * If a new client is connecting, its authorization ID is copied to
 * client->authID.  If this is a generated authorization, its reference
 * count is bumped, its timer is cancelled if it was running, and its
 * trustlevel is copied to TRUSTLEVEL(client).
 * 
 * If a client is disconnecting and the client was using a generated
 * authorization, the authorization's reference count is decremented, and
 * if it is now zero, the timer for this authorization is started.
 */

static void
XaceClientStateCallback(
    CallbackListPtr *pcbl,
    pointer nulldata,
    pointer calldata)
{
    NewClientInfoRec *pci = (NewClientInfoRec *)calldata;
    ClientPtr client = pci->client;

    switch (client->clientState)
    {
	case ClientStateRunning:
	{ 
	    client->requestVector = client->swapped ?
		SwappedUntrustedProcVector : UntrustedProcVector;
	    break;
	}
	default: break; 
    }
} /* XaceClientStateCallback */

/* XaceExtensionInit
 *
 * Initialize the XACE Extension
 */
void XaceExtensionInit(INITARGS)
{
    ExtensionEntry	*extEntry;
    int i;

    if (!AddCallback(&ClientStateCallback, XaceClientStateCallback, NULL))
	return;

    extEntry = AddExtension(XACE_EXTENSION_NAME,
			    XaceNumberEvents, XaceNumberErrors,
			    ProcXaceDispatch, SProcXaceDispatch,
			    XaceResetProc, StandardMinorOpcode);

    /* initialize dispatching intercept functions */
    for (i = 0; i < 128; i++)
    {
	UntrustedProcVector[i] = XaceCatchDispatchProc;
	SwappedUntrustedProcVector[i] = XaceCatchDispatchProc;
    }
    for (i = 128; i < 256; i++)
    {
	UntrustedProcVector[i] = XaceCatchExtProc;
	SwappedUntrustedProcVector[i] = XaceCatchExtProc;
    }
}

/* XaceCensorImage
 *
 * Called after pScreen->GetImage to prevent pieces or trusted windows from
 * being returned in image data from an untrusted window.
 *
 * Arguments:
 *	client is the client doing the GetImage.
 *      pVisibleRegion is the visible region of the window.
 *	widthBytesLine is the width in bytes of one horizontal line in pBuf.
 *	pDraw is the source window.
 *	x, y, w, h is the rectangle of image data from pDraw in pBuf.
 *	format is the format of the image data in pBuf: ZPixmap or XYPixmap.
 *	pBuf is the image data.
 *
 * Returns: nothing.
 *
 * Side Effects:
 *	Any part of the rectangle (x, y, w, h) that is outside the visible
 *	region of the window will be destroyed (overwritten) in pBuf.
 */
void
XaceCensorImage(client, pVisibleRegion, widthBytesLine, pDraw, x, y, w, h,
		format, pBuf)
    ClientPtr client;
    RegionPtr pVisibleRegion;
    long widthBytesLine;
    DrawablePtr pDraw;
    int x, y, w, h;
    unsigned int format;
    char * pBuf;
{
    ScreenPtr pScreen = pDraw->pScreen;
    RegionRec imageRegion;  /* region representing x,y,w,h */
    RegionRec censorRegion; /* region to obliterate */
    BoxRec imageBox;
    int nRects;

    imageBox.x1 = x;
    imageBox.y1 = y;
    imageBox.x2 = x + w;
    imageBox.y2 = y + h;
    REGION_INIT(pScreen, &imageRegion, &imageBox, 1);
    REGION_NULL(pScreen, &censorRegion);

    /* censorRegion = imageRegion - visibleRegion */
    REGION_SUBTRACT(pScreen, &censorRegion, &imageRegion, pVisibleRegion);
    nRects = REGION_NUM_RECTS(&censorRegion);
    if (nRects > 0)
    { /* we have something to censor */
	GCPtr pScratchGC = NULL;
	PixmapPtr pPix = NULL;
	xRectangle *pRects = NULL;
	Bool failed = FALSE;
	int depth = 1;
	int bitsPerPixel = 1;
	int i;
	BoxPtr pBox;

	/* convert region to list-of-rectangles for PolyFillRect */

	pRects = (xRectangle *)ALLOCATE_LOCAL(nRects * sizeof(xRectangle *));
	if (!pRects)
	{
	    failed = TRUE;
	    goto failSafe;
	}
	for (pBox = REGION_RECTS(&censorRegion), i = 0;
	     i < nRects;
	     i++, pBox++)
	{
	    pRects[i].x = pBox->x1;
	    pRects[i].y = pBox->y1 - imageBox.y1;
	    pRects[i].width  = pBox->x2 - pBox->x1;
	    pRects[i].height = pBox->y2 - pBox->y1;
	}

	/* use pBuf as a fake pixmap */

	if (format == ZPixmap)
	{
	    depth = pDraw->depth;
	    bitsPerPixel = pDraw->bitsPerPixel;
	}

	pPix = GetScratchPixmapHeader(pDraw->pScreen, w, h,
		    depth, bitsPerPixel,
		    widthBytesLine, (pointer)pBuf);
	if (!pPix)
	{
	    failed = TRUE;
	    goto failSafe;
	}

	pScratchGC = GetScratchGC(depth, pPix->drawable.pScreen);
	if (!pScratchGC)
	{
	    failed = TRUE;
	    goto failSafe;
	}

	ValidateGC(&pPix->drawable, pScratchGC);
	(* pScratchGC->ops->PolyFillRect)(&pPix->drawable,
			    pScratchGC, nRects, pRects);

    failSafe:
	if (failed)
	{
	    /* Censoring was not completed above.  To be safe, wipe out
	     * all the image data so that nothing trusted gets out.
	     */
	    bzero(pBuf, (int)(widthBytesLine * h));
	}
	if (pRects)     DEALLOCATE_LOCAL(pRects);
	if (pScratchGC) FreeScratchGC(pScratchGC);
	if (pPix)       FreeScratchPixmapHeader(pPix);
    }
    REGION_UNINIT(pScreen, &imageRegion);
    REGION_UNINIT(pScreen, &censorRegion);
} /* XaceCensorImage */