memsafer-r3.cpp@ 78403

Last change on this file since 78403 was 78337, checked in by vboxsync, 6 years ago
IPRT/memsafer: Added RTMemSaferGetSize.
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1	/* $Id: memsafer-r3.cpp 78337 2019-04-26 20:30:19Z vboxsync $ */
2	/** @file
3	* IPRT - Memory Allocate for Sensitive Data, generic heap-based implementation.
4	*/
5
6	/*
7	* Copyright (C) 2006-2019 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*/
26
27
28	/*********************************************************************************************************************************
29	* Header Files *
30	*********************************************************************************************************************************/
31	#include "internal/iprt.h"
32	#include <iprt/memsafer.h>
33
34	#include <iprt/asm.h>
35	#include <iprt/assert.h>
36	#include <iprt/avl.h>
37	#include <iprt/critsect.h>
38	#include <iprt/err.h>
39	#include <iprt/mem.h>
40	#include <iprt/once.h>
41	#include <iprt/rand.h>
42	#include <iprt/param.h>
43	#include <iprt/string.h>
44	#ifdef IN_SUP_R3
45	# include <VBox/sup.h>
46	#endif
47
48
49	/*********************************************************************************************************************************
50	* Defined Constants And Macros *
51	*********************************************************************************************************************************/
52	/** Allocation size alignment (power of two). */
53	#define RTMEMSAFER_ALIGN 16
54
55
56	/*********************************************************************************************************************************
57	* Structures and Typedefs *
58	*********************************************************************************************************************************/
59	/**
60	* Allocators.
61	*/
62	typedef enum RTMEMSAFERALLOCATOR
63	{
64	/** Invalid method. */
65	RTMEMSAFERALLOCATOR_INVALID = 0,
66	/** RTMemPageAlloc. */
67	RTMEMSAFERALLOCATOR_RTMEMPAGE,
68	/** SUPR3PageAllocEx. */
69	RTMEMSAFERALLOCATOR_SUPR3
70	} RTMEMSAFERALLOCATOR;
71
72	/**
73	* Tracking node (lives on normal heap).
74	*/
75	typedef struct RTMEMSAFERNODE
76	{
77	/** Node core.
78	* The core key is a scrambled pointer the user memory. */
79	AVLPVNODECORE Core;
80	/** The allocation flags. */
81	uint32_t fFlags;
82	/** The offset into the allocation of the user memory. */
83	uint32_t offUser;
84	/** The requested allocation size. */
85	size_t cbUser;
86	/** The allocation size in pages, this includes the two guard pages. */
87	uint32_t cPages;
88	/** The allocator used for this node. */
89	RTMEMSAFERALLOCATOR enmAllocator;
90	/** XOR scrambler value for memory. */
91	uintptr_t uScramblerXor;
92	} RTMEMSAFERNODE;
93	/** Pointer to an allocation tracking node. */
94	typedef RTMEMSAFERNODE *PRTMEMSAFERNODE;
95
96
97	/*********************************************************************************************************************************
98	* Global Variables *
99	*********************************************************************************************************************************/
100	/** Init once structure for this module. */
101	static RTONCE g_MemSaferOnce = RTONCE_INITIALIZER;
102	/** Critical section protecting the allocation tree. */
103	static RTCRITSECTRW g_MemSaferCritSect;
104	/** Tree of allocation nodes. */
105	static AVLPVTREE g_pMemSaferTree;
106	/** XOR scrambler value pointers. */
107	static uintptr_t g_uMemSaferPtrScramblerXor;
108	/** Pointer rotate shift count.*/
109	static uintptr_t g_cMemSaferPtrScramblerRotate;
110
111
112	/**
113	* @callback_method_impl{FNRTONCE, Inits globals.}
114	*/
115	static DECLCALLBACK(int32_t) rtMemSaferOnceInit(void *pvUserIgnore)
116	{
117	RT_NOREF_PV(pvUserIgnore);
118
119	g_uMemSaferPtrScramblerXor = (uintptr_t)RTRandU64();
120	g_cMemSaferPtrScramblerRotate = RTRandU32Ex(0, ARCH_BITS - 1);
121	return RTCritSectRwInit(&g_MemSaferCritSect);
122	}
123
124
125	/**
126	* @callback_method_impl{PFNRTONCECLEANUP, Cleans up globals.}
127	*/
128	static DECLCALLBACK(void) rtMemSaferOnceTerm(void *pvUser, bool fLazyCleanUpOk)
129	{
130	RT_NOREF_PV(pvUser);
131
132	if (!fLazyCleanUpOk)
133	{
134	RTCritSectRwDelete(&g_MemSaferCritSect);
135	Assert(!g_pMemSaferTree);
136	}
137	}
138
139
140
141	DECLINLINE(void ) rtMemSaferScramblePointer(void pvUser)
142	{
143	uintptr_t uPtr = (uintptr_t)pvUser;
144	uPtr ^= g_uMemSaferPtrScramblerXor;
145	#if ARCH_BITS == 64
146	uPtr = ASMRotateRightU64(uPtr, g_cMemSaferPtrScramblerRotate);
147	#elif ARCH_BITS == 32
148	uPtr = ASMRotateRightU32(uPtr, g_cMemSaferPtrScramblerRotate);
149	#else
150	# error "Unsupported/missing ARCH_BITS."
151	#endif
152	return (void *)uPtr;
153	}
154
155
156	/**
157	* Inserts a tracking node into the tree.
158	*
159	* @param pThis The allocation tracking node to insert.
160	*/
161	static void rtMemSaferNodeInsert(PRTMEMSAFERNODE pThis)
162	{
163	RTCritSectRwEnterExcl(&g_MemSaferCritSect);
164	pThis->Core.Key = rtMemSaferScramblePointer(pThis->Core.Key);
165	bool fRc = RTAvlPVInsert(&g_pMemSaferTree, &pThis->Core);
166	RTCritSectRwLeaveExcl(&g_MemSaferCritSect);
167	Assert(fRc); NOREF(fRc);
168	}
169
170
171	/**
172	* Finds a tracking node into the tree.
173	*
174	* @returns The allocation tracking node for @a pvUser. NULL if not found.
175	* @param pvUser The user pointer to the allocation.
176	*/
177	static PRTMEMSAFERNODE rtMemSaferNodeLookup(void *pvUser)
178	{
179	void *pvKey = rtMemSaferScramblePointer(pvUser);
180	RTCritSectRwEnterShared(&g_MemSaferCritSect);
181	PRTMEMSAFERNODE pThis = (PRTMEMSAFERNODE)RTAvlPVGet(&g_pMemSaferTree, pvKey);
182	RTCritSectRwLeaveShared(&g_MemSaferCritSect);
183	return pThis;
184	}
185
186
187	/**
188	* Removes a tracking node from the tree.
189	*
190	* @returns The allocation tracking node for @a pvUser. NULL if not found.
191	* @param pvUser The user pointer to the allocation.
192	*/
193	static PRTMEMSAFERNODE rtMemSaferNodeRemove(void *pvUser)
194	{
195	void *pvKey = rtMemSaferScramblePointer(pvUser);
196	RTCritSectRwEnterExcl(&g_MemSaferCritSect);
197	PRTMEMSAFERNODE pThis = (PRTMEMSAFERNODE)RTAvlPVRemove(&g_pMemSaferTree, pvKey);
198	RTCritSectRwLeaveExcl(&g_MemSaferCritSect);
199	return pThis;
200	}
201
202
203	RTDECL(int) RTMemSaferScramble(void *pv, size_t cb)
204	{
205	PRTMEMSAFERNODE pThis = rtMemSaferNodeLookup(pv);
206	AssertReturn(pThis, VERR_INVALID_POINTER);
207	AssertMsgReturn(cb == pThis->cbUser, ("cb=%#zx != %#zx\n", cb, pThis->cbUser), VERR_INVALID_PARAMETER);
208
209	/* First time we get a new xor value. */
210	if (!pThis->uScramblerXor)
211	pThis->uScramblerXor = (uintptr_t)RTRandU64();
212
213	/* Note! This isn't supposed to be safe, just less obvious. */
214	uintptr_t pu = (uintptr_t )pv;
215	cb = RT_ALIGN_Z(cb, RTMEMSAFER_ALIGN);
216	while (cb > 0)
217	{
218	*pu ^= pThis->uScramblerXor;
219	pu++;
220	cb -= sizeof(*pu);
221	}
222
223	return VINF_SUCCESS;
224	}
225	RT_EXPORT_SYMBOL(RTMemSaferScramble);
226
227
228	RTDECL(int) RTMemSaferUnscramble(void *pv, size_t cb)
229	{
230	PRTMEMSAFERNODE pThis = rtMemSaferNodeLookup(pv);
231	AssertReturn(pThis, VERR_INVALID_POINTER);
232	AssertMsgReturn(cb == pThis->cbUser, ("cb=%#zx != %#zx\n", cb, pThis->cbUser), VERR_INVALID_PARAMETER);
233
234	/* Note! This isn't supposed to be safe, just less obvious. */
235	uintptr_t pu = (uintptr_t )pv;
236	cb = RT_ALIGN_Z(cb, RTMEMSAFER_ALIGN);
237	while (cb > 0)
238	{
239	*pu ^= pThis->uScramblerXor;
240	pu++;
241	cb -= sizeof(*pu);
242	}
243
244	return VINF_SUCCESS;
245	}
246	RT_EXPORT_SYMBOL(RTMemSaferUnscramble);
247
248
249	/**
250	* Initializes the pages.
251	*
252	* Fills the memory with random bytes in order to make it less obvious where the
253	* secret data starts and ends. We also zero the user memory in case the
254	* allocator does not do this.
255	*
256	* @param pThis The allocation tracer node. The Core.Key member
257	* will be set.
258	* @param pvPages The pages to initialize.
259	*/
260	static void rtMemSaferInitializePages(PRTMEMSAFERNODE pThis, void *pvPages)
261	{
262	RTRandBytes(pvPages, PAGE_SIZE + pThis->offUser);
263
264	uint8_t pbUser = (uint8_t )pvPages + PAGE_SIZE + pThis->offUser;
265	pThis->Core.Key = pbUser;
266	RT_BZERO(pbUser, pThis->cbUser); /* paranoia */
267
268	RTRandBytes(pbUser + pThis->cbUser, (size_t)pThis->cPages * PAGE_SIZE - PAGE_SIZE - pThis->offUser - pThis->cbUser);
269	}
270
271
272	/**
273	* Allocates and initializes pages from the support driver and initializes it.
274	*
275	* @returns VBox status code.
276	* @param pThis The allocator node. Core.Key will be set on successful
277	* return (unscrambled).
278	*/
279	static int rtMemSaferSupR3AllocPages(PRTMEMSAFERNODE pThis)
280	{
281	#ifdef IN_SUP_R3
282	/*
283	* Try allocate the memory.
284	*/
285	void *pvPages;
286	int rc = SUPR3PageAllocEx(pThis->cPages, 0 /* fFlags /, &pvPages, NULL / pR0Ptr /, NULL / paPages */);
287	if (RT_SUCCESS(rc))
288	{
289	rtMemSaferInitializePages(pThis, pvPages);
290
291	/*
292	* On darwin we cannot allocate pages without an R0 mapping and
293	* SUPR3PageAllocEx falls back to another method which is incompatible with
294	* the way SUPR3PageProtect works. Ignore changing the protection of the guard
295	* pages.
296	*/
297	#ifdef RT_OS_DARWIN
298	return VINF_SUCCESS;
299	#else
300	/*
301	* Configure the guard pages.
302	* SUPR3PageProtect isn't supported on all hosts, we ignore that.
303	*/
304	rc = SUPR3PageProtect(pvPages, NIL_RTR0PTR, 0, PAGE_SIZE, RTMEM_PROT_NONE);
305	if (RT_SUCCESS(rc))
306	{
307	rc = SUPR3PageProtect(pvPages, NIL_RTR0PTR, (pThis->cPages - 1) * PAGE_SIZE, PAGE_SIZE, RTMEM_PROT_NONE);
308	if (RT_SUCCESS(rc))
309	return VINF_SUCCESS;
310	SUPR3PageProtect(pvPages, NIL_RTR0PTR, 0, PAGE_SIZE, RTMEM_PROT_READ \| RTMEM_PROT_WRITE);
311	}
312	else if (rc == VERR_NOT_SUPPORTED)
313	return VINF_SUCCESS;
314
315	/* failed. */
316	int rc2 = SUPR3PageFreeEx(pvPages, pThis->cPages); AssertRC(rc2);
317	#endif
318	}
319	return rc;
320
321	#else /* !IN_SUP_R3 */
322	RT_NOREF_PV(pThis);
323	return VERR_NOT_SUPPORTED;
324	#endif /* !IN_SUP_R3 */
325	}
326
327
328	/**
329	* Allocates and initializes pages using the IPRT page allocator API.
330	*
331	* @returns VBox status code.
332	* @param pThis The allocator node. Core.Key will be set on successful
333	* return (unscrambled).
334	*/
335	static int rtMemSaferMemAllocPages(PRTMEMSAFERNODE pThis)
336	{
337	/*
338	* Try allocate the memory.
339	*/
340	int rc = VINF_SUCCESS;
341	void pvPages = RTMemPageAllocEx((size_t)pThis->cPages PAGE_SIZE,
342	RTMEMPAGEALLOC_F_ADVISE_LOCKED \| RTMEMPAGEALLOC_F_ADVISE_NO_DUMP \| RTMEMPAGEALLOC_F_ZERO);
343	if (pvPages)
344	{
345	rtMemSaferInitializePages(pThis, pvPages);
346
347	/*
348	* Configure the guard pages.
349	*/
350	rc = RTMemProtect(pvPages, PAGE_SIZE, RTMEM_PROT_NONE);
351	if (RT_SUCCESS(rc))
352	{
353	rc = RTMemProtect((uint8_t )pvPages + (size_t)(pThis->cPages - 1U) PAGE_SIZE, PAGE_SIZE, RTMEM_PROT_NONE);
354	if (RT_SUCCESS(rc))
355	return VINF_SUCCESS;
356	rc = RTMemProtect(pvPages, PAGE_SIZE, RTMEM_PROT_READ \| RTMEM_PROT_WRITE);
357	}
358
359	/* failed. */
360	RTMemPageFree(pvPages, (size_t)pThis->cPages * PAGE_SIZE);
361	}
362	else
363	rc = VERR_NO_PAGE_MEMORY;
364
365	return rc;
366	}
367
368
369	RTDECL(int) RTMemSaferAllocZExTag(void *ppvNew, size_t cb, uint32_t fFlags, const char pszTag) RT_NO_THROW_DEF
370	{
371	RT_NOREF_PV(pszTag);
372
373	/*
374	* Validate input.
375	*/
376	AssertPtrReturn(ppvNew, VERR_INVALID_PARAMETER);
377	*ppvNew = NULL;
378	AssertReturn(cb, VERR_INVALID_PARAMETER);
379	AssertReturn(cb <= 32U_1M - PAGE_SIZE 3U, VERR_ALLOCATION_TOO_BIG); /* Max 32 MB minus padding and guard pages. */
380	AssertReturn(!(fFlags & ~RTMEMSAFER_F_VALID_MASK), VERR_INVALID_FLAGS);
381
382	/*
383	* Initialize globals.
384	*/
385	int rc = RTOnceEx(&g_MemSaferOnce, rtMemSaferOnceInit, rtMemSaferOnceTerm, NULL);
386	if (RT_SUCCESS(rc))
387	{
388	/*
389	* Allocate a tracker node first.
390	*/
391	PRTMEMSAFERNODE pThis = (PRTMEMSAFERNODE)RTMemAllocZ(sizeof(RTMEMSAFERNODE));
392	if (pThis)
393	{
394	/*
395	* Prepare the allocation.
396	*/
397	pThis->cbUser = cb;
398	pThis->offUser = (RTRandU32Ex(0, 128) * RTMEMSAFER_ALIGN) & PAGE_OFFSET_MASK;
399
400	size_t cbNeeded = pThis->offUser + pThis->cbUser;
401	cbNeeded = RT_ALIGN_Z(cbNeeded, PAGE_SIZE);
402
403	pThis->cPages = (uint32_t)(cbNeeded / PAGE_SIZE) + 2; /* +2 for guard pages */
404
405	/*
406	* Try allocate the memory, using the best allocator by default and
407	* falling back on the less safe one.
408	*/
409	rc = rtMemSaferSupR3AllocPages(pThis);
410	if (RT_SUCCESS(rc))
411	pThis->enmAllocator = RTMEMSAFERALLOCATOR_SUPR3;
412	else if (!(fFlags & RTMEMSAFER_F_REQUIRE_NOT_PAGABLE))
413	{
414	rc = rtMemSaferMemAllocPages(pThis);
415	if (RT_SUCCESS(rc))
416	pThis->enmAllocator = RTMEMSAFERALLOCATOR_RTMEMPAGE;
417	}
418	if (RT_SUCCESS(rc))
419	{
420	/*
421	* Insert the node.
422	*/
423	*ppvNew = pThis->Core.Key;
424	rtMemSaferNodeInsert(pThis); /* (Scrambles Core.Key) */
425	return VINF_SUCCESS;
426	}
427
428	RTMemFree(pThis);
429	}
430	else
431	rc = VERR_NO_MEMORY;
432	}
433	return rc;
434	}
435	RT_EXPORT_SYMBOL(RTMemSaferAllocZExTag);
436
437
438	RTDECL(void) RTMemSaferFree(void *pv, size_t cb) RT_NO_THROW_DEF
439	{
440	if (pv)
441	{
442	PRTMEMSAFERNODE pThis = rtMemSaferNodeRemove(pv);
443	AssertReturnVoid(pThis);
444	if (cb == 0) /* for openssl use */
445	cb = pThis->cbUser;
446	else
447	AssertMsg(cb == pThis->cbUser, ("cb=%#zx != %#zx\n", cb, pThis->cbUser));
448
449	/*
450	* Wipe the user memory first.
451	*/
452	RTMemWipeThoroughly(pv, RT_ALIGN_Z(cb, RTMEMSAFER_ALIGN), 3);
453
454	/*
455	* Free the pages.
456	*/
457	uint8_t pbPages = (uint8_t )pv - pThis->offUser - PAGE_SIZE;
458	size_t cbPages = (size_t)pThis->cPages * PAGE_SIZE;
459	switch (pThis->enmAllocator)
460	{
461	#ifdef IN_SUP_R3
462	case RTMEMSAFERALLOCATOR_SUPR3:
463	SUPR3PageProtect(pbPages, NIL_RTR0PTR, 0, PAGE_SIZE, RTMEM_PROT_READ \| RTMEM_PROT_WRITE);
464	SUPR3PageProtect(pbPages, NIL_RTR0PTR, (uint32_t)(cbPages - PAGE_SIZE), PAGE_SIZE, RTMEM_PROT_READ \| RTMEM_PROT_WRITE);
465	SUPR3PageFreeEx(pbPages, pThis->cPages);
466	break;
467	#endif
468	case RTMEMSAFERALLOCATOR_RTMEMPAGE:
469	RTMemProtect(pbPages, PAGE_SIZE, RTMEM_PROT_READ \| RTMEM_PROT_WRITE);
470	RTMemProtect(pbPages + cbPages - PAGE_SIZE, PAGE_SIZE, RTMEM_PROT_READ \| RTMEM_PROT_WRITE);
471	RTMemPageFree(pbPages, cbPages);
472	break;
473
474	default:
475	AssertFailed();
476	}
477
478	/*
479	* Free the tracking node.
480	*/
481	pThis->Core.Key = NULL;
482	pThis->offUser = 0;
483	pThis->cbUser = 0;
484	RTMemFree(pThis);
485	}
486	else
487	Assert(cb == 0);
488	}
489	RT_EXPORT_SYMBOL(RTMemSaferFree);
490
491
492	RTDECL(size_t) RTMemSaferGetSize(void *pv) RT_NO_THROW_DEF
493	{
494	size_t cbRet = 0;
495	if (pv)
496	{
497	void *pvKey = rtMemSaferScramblePointer(pv);
498	RTCritSectRwEnterShared(&g_MemSaferCritSect);
499	PRTMEMSAFERNODE pThis = (PRTMEMSAFERNODE)RTAvlPVGet(&g_pMemSaferTree, pvKey);
500	if (pThis)
501	cbRet = pThis->cbUser;
502	RTCritSectRwLeaveShared(&g_MemSaferCritSect);
503	}
504	return cbRet;
505	}
506	RT_EXPORT_SYMBOL(RTMemSaferGetSize);
507
508
509	/**
510	* The simplest reallocation method: allocate new block, copy over the data,
511	* free old block.
512	*/
513	static int rtMemSaferReallocSimpler(size_t cbOld, void pvOld, size_t cbNew, void ppvNew, uint32_t fFlags, const char pszTag)
514	{
515	void *pvNew;
516	int rc = RTMemSaferAllocZExTag(&pvNew, cbNew, fFlags, pszTag);
517	if (RT_SUCCESS(rc))
518	{
519	memcpy(pvNew, pvOld, RT_MIN(cbNew, cbOld));
520	RTMemSaferFree(pvOld, cbOld);
521	*ppvNew = pvNew;
522	}
523	return rc;
524	}
525
526
527	RTDECL(int) RTMemSaferReallocZExTag(size_t cbOld, void pvOld, size_t cbNew, void ppvNew, uint32_t fFlags, const char pszTag) RT_NO_THROW_DEF
528	{
529	int rc;
530	/* Real realloc. */
531	if (cbNew && cbOld)
532	{
533	PRTMEMSAFERNODE pThis = rtMemSaferNodeLookup(pvOld);
534	AssertReturn(pThis, VERR_INVALID_POINTER);
535	AssertMsgStmt(cbOld == pThis->cbUser, ("cbOld=%#zx != %#zx\n", cbOld, pThis->cbUser), cbOld = pThis->cbUser);
536
537	if (pThis->fFlags == fFlags)
538	{
539	if (cbNew > cbOld)
540	{
541	/*
542	* Is the enough room for us to grow?
543	*/
544	size_t cbMax = (size_t)(pThis->cPages - 2) * PAGE_SIZE;
545	if (cbNew <= cbMax)
546	{
547	size_t const cbAdded = (cbNew - cbOld);
548	size_t const cbAfter = cbMax - pThis->offUser - cbOld;
549	if (cbAfter >= cbAdded)
550	{
551	/*
552	* Sufficient space after the current allocation.
553	*/
554	uint8_t pbNewSpace = (uint8_t )pvOld + cbOld;
555	RT_BZERO(pbNewSpace, cbAdded);
556	*ppvNew = pvOld;
557	}
558	else
559	{
560	/*
561	* Have to move the allocation to make enough room at the
562	* end. In order to make it a little less predictable and
563	* maybe avoid a relocation or two in the next call, divide
564	* the page offset by four until it it fits.
565	*/
566	AssertReturn(rtMemSaferNodeRemove(pvOld) == pThis, VERR_INTERNAL_ERROR_3);
567	uint32_t offNewUser = pThis->offUser;
568	do
569	offNewUser = offNewUser / 2;
570	while ((pThis->offUser - offNewUser) + cbAfter < cbAdded);
571	offNewUser &= ~(RTMEMSAFER_ALIGN - 1U);
572
573	uint32_t const cbMove = pThis->offUser - offNewUser;
574	uint8_t pbNew = (uint8_t )pvOld - cbMove;
575	memmove(pbNew, pvOld, cbOld);
576
577	RT_BZERO(pbNew + cbOld, cbAdded);
578	if (cbMove > cbAdded)
579	RTMemWipeThoroughly(pbNew + cbNew, cbMove - cbAdded, 3);
580
581	pThis->offUser = offNewUser;
582	pThis->Core.Key = pbNew;
583	*ppvNew = pbNew;
584
585	rtMemSaferNodeInsert(pThis);
586	}
587	Assert(((uintptr_t)*ppvNew & PAGE_OFFSET_MASK) == pThis->offUser);
588	pThis->cbUser = cbNew;
589	rc = VINF_SUCCESS;
590	}
591	else
592	{
593	/*
594	* Not enough space, allocate a new block and copy over the data.
595	*/
596	rc = rtMemSaferReallocSimpler(cbOld, pvOld, cbNew, ppvNew, fFlags, pszTag);
597	}
598	}
599	else
600	{
601	/*
602	* Shrinking the allocation, just wipe the memory that is no longer
603	* being used.
604	*/
605	if (cbNew != cbOld)
606	{
607	uint8_t pbAbandond = (uint8_t )pvOld + cbNew;
608	RTMemWipeThoroughly(pbAbandond, cbOld - cbNew, 3);
609	}
610	pThis->cbUser = cbNew;
611	*ppvNew = pvOld;
612	rc = VINF_SUCCESS;
613	}
614	}
615	else if (!pThis->fFlags)
616	{
617	/*
618	* New flags added. Allocate a new block and copy over the old one.
619	*/
620	rc = rtMemSaferReallocSimpler(cbOld, pvOld, cbNew, ppvNew, fFlags, pszTag);
621	}
622	else
623	{
624	/* Compatible flags. */
625	AssertMsgFailed(("fFlags=%#x old=%#x\n", fFlags, pThis->fFlags));
626	rc = VERR_INVALID_FLAGS;
627	}
628	}
629	/*
630	* First allocation. Pass it on.
631	*/
632	else if (!cbOld)
633	{
634	Assert(pvOld == NULL);
635	rc = RTMemSaferAllocZExTag(ppvNew, cbNew, fFlags, pszTag);
636	}
637	/*
638	* Free operation. Pass it on.
639	*/
640	else
641	{
642	RTMemSaferFree(pvOld, cbOld);
643	*ppvNew = NULL;
644	rc = VINF_SUCCESS;
645	}
646	return rc;
647	}
648	RT_EXPORT_SYMBOL(RTMemSaferReallocZExTag);
649
650
651	RTDECL(void ) RTMemSaferAllocZTag(size_t cb, const char pszTag) RT_NO_THROW_DEF
652	{
653	void *pvNew = NULL;
654	int rc = RTMemSaferAllocZExTag(&pvNew, cb, 0 /fFlags/, pszTag);
655	if (RT_SUCCESS(rc))
656	return pvNew;
657	return NULL;
658	}
659	RT_EXPORT_SYMBOL(RTMemSaferAllocZTag);
660
661
662	RTDECL(void ) RTMemSaferReallocZTag(size_t cbOld, void pvOld, size_t cbNew, const char *pszTag) RT_NO_THROW_DEF
663	{
664	void *pvNew = NULL;
665	int rc = RTMemSaferReallocZExTag(cbOld, pvOld, cbNew, &pvNew, 0 /fFlags/, pszTag);
666	if (RT_SUCCESS(rc))
667	return pvNew;
668	return NULL;
669	}
670	RT_EXPORT_SYMBOL(RTMemSaferReallocZTag);
671

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source: vbox/trunk/src/VBox/Runtime/r3/memsafer-r3.cpp@ 78403

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