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memguard.c (238502) memguard.c (254025)
1/*-
2 * Copyright (c) 2005, Bosko Milekic <bmilekic@FreeBSD.org>.
3 * Copyright (c) 2010 Isilon Systems, Inc. (http://www.isilon.com/)
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:

--- 12 unchanged lines hidden (view full) ---

21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
1/*-
2 * Copyright (c) 2005, Bosko Milekic <bmilekic@FreeBSD.org>.
3 * Copyright (c) 2010 Isilon Systems, Inc. (http://www.isilon.com/)
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:

--- 12 unchanged lines hidden (view full) ---

21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/sys/vm/memguard.c 238502 2012-07-15 20:29:48Z mdf $");
29__FBSDID("$FreeBSD: head/sys/vm/memguard.c 254025 2013-08-07 06:21:20Z jeff $");
30
31/*
32 * MemGuard is a simple replacement allocator for debugging only
33 * which provides ElectricFence-style memory barrier protection on
34 * objects being allocated, and is used to detect tampering-after-free
35 * scenarios.
36 *
37 * See the memguard(9) man page for more information on using MemGuard.

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43#include <sys/systm.h>
44#include <sys/kernel.h>
45#include <sys/types.h>
46#include <sys/queue.h>
47#include <sys/lock.h>
48#include <sys/mutex.h>
49#include <sys/malloc.h>
50#include <sys/sysctl.h>
30
31/*
32 * MemGuard is a simple replacement allocator for debugging only
33 * which provides ElectricFence-style memory barrier protection on
34 * objects being allocated, and is used to detect tampering-after-free
35 * scenarios.
36 *
37 * See the memguard(9) man page for more information on using MemGuard.

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43#include <sys/systm.h>
44#include <sys/kernel.h>
45#include <sys/types.h>
46#include <sys/queue.h>
47#include <sys/lock.h>
48#include <sys/mutex.h>
49#include <sys/malloc.h>
50#include <sys/sysctl.h>
51#include <sys/vmem.h>
51
52#include <vm/vm.h>
53#include <vm/uma.h>
54#include <vm/vm_param.h>
55#include <vm/vm_page.h>
56#include <vm/vm_map.h>
57#include <vm/vm_object.h>
58#include <vm/vm_extern.h>

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94 strlcpy(vm_memguard_desc, desc, sizeof(vm_memguard_desc));
95 mtx_unlock(&malloc_mtx);
96 return (error);
97}
98SYSCTL_PROC(_vm_memguard, OID_AUTO, desc,
99 CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0,
100 memguard_sysctl_desc, "A", "Short description of memory type to monitor");
101
52
53#include <vm/vm.h>
54#include <vm/uma.h>
55#include <vm/vm_param.h>
56#include <vm/vm_page.h>
57#include <vm/vm_map.h>
58#include <vm/vm_object.h>
59#include <vm/vm_extern.h>

--- 35 unchanged lines hidden (view full) ---

95 strlcpy(vm_memguard_desc, desc, sizeof(vm_memguard_desc));
96 mtx_unlock(&malloc_mtx);
97 return (error);
98}
99SYSCTL_PROC(_vm_memguard, OID_AUTO, desc,
100 CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0,
101 memguard_sysctl_desc, "A", "Short description of memory type to monitor");
102
102static vm_map_t memguard_map = NULL;
103static vmem_t *memguard_map = NULL;
103static vm_offset_t memguard_cursor;
104static vm_offset_t memguard_cursor;
105static vm_offset_t memguard_base;
104static vm_size_t memguard_mapsize;
105static vm_size_t memguard_physlimit;
106static u_long memguard_wasted;
107static u_long memguard_wrap;
108static u_long memguard_succ;
109static u_long memguard_fail_kva;
110static u_long memguard_fail_pgs;
111
112SYSCTL_ULONG(_vm_memguard, OID_AUTO, cursor, CTLFLAG_RD,
113 &memguard_cursor, 0, "MemGuard cursor");
114SYSCTL_ULONG(_vm_memguard, OID_AUTO, mapsize, CTLFLAG_RD,
106static vm_size_t memguard_mapsize;
107static vm_size_t memguard_physlimit;
108static u_long memguard_wasted;
109static u_long memguard_wrap;
110static u_long memguard_succ;
111static u_long memguard_fail_kva;
112static u_long memguard_fail_pgs;
113
114SYSCTL_ULONG(_vm_memguard, OID_AUTO, cursor, CTLFLAG_RD,
115 &memguard_cursor, 0, "MemGuard cursor");
116SYSCTL_ULONG(_vm_memguard, OID_AUTO, mapsize, CTLFLAG_RD,
115 &memguard_mapsize, 0, "MemGuard private vm_map size");
117 &memguard_mapsize, 0, "MemGuard private arena size");
116SYSCTL_ULONG(_vm_memguard, OID_AUTO, phys_limit, CTLFLAG_RD,
117 &memguard_physlimit, 0, "Limit on MemGuard memory consumption");
118SYSCTL_ULONG(_vm_memguard, OID_AUTO, wasted, CTLFLAG_RD,
119 &memguard_wasted, 0, "Excess memory used through page promotion");
120SYSCTL_ULONG(_vm_memguard, OID_AUTO, wrapcnt, CTLFLAG_RD,
121 &memguard_wrap, 0, "MemGuard cursor wrap count");
122SYSCTL_ULONG(_vm_memguard, OID_AUTO, numalloc, CTLFLAG_RD,
123 &memguard_succ, 0, "Count of successful MemGuard allocations");

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195 return (km_size + memguard_mapsize);
196}
197
198/*
199 * Initialize the MemGuard mock allocator. All objects from MemGuard come
200 * out of a single VM map (contiguous chunk of address space).
201 */
202void
118SYSCTL_ULONG(_vm_memguard, OID_AUTO, phys_limit, CTLFLAG_RD,
119 &memguard_physlimit, 0, "Limit on MemGuard memory consumption");
120SYSCTL_ULONG(_vm_memguard, OID_AUTO, wasted, CTLFLAG_RD,
121 &memguard_wasted, 0, "Excess memory used through page promotion");
122SYSCTL_ULONG(_vm_memguard, OID_AUTO, wrapcnt, CTLFLAG_RD,
123 &memguard_wrap, 0, "MemGuard cursor wrap count");
124SYSCTL_ULONG(_vm_memguard, OID_AUTO, numalloc, CTLFLAG_RD,
125 &memguard_succ, 0, "Count of successful MemGuard allocations");

--- 71 unchanged lines hidden (view full) ---

197 return (km_size + memguard_mapsize);
198}
199
200/*
201 * Initialize the MemGuard mock allocator. All objects from MemGuard come
202 * out of a single VM map (contiguous chunk of address space).
203 */
204void
203memguard_init(vm_map_t parent_map)
205memguard_init(vmem_t *parent)
204{
206{
205 vm_offset_t base, limit;
207 vm_offset_t base;
206
208
207 memguard_map = kmem_suballoc(parent_map, &base, &limit,
208 memguard_mapsize, FALSE);
209 memguard_map->system_map = 1;
210 KASSERT(memguard_mapsize == limit - base,
211 ("Expected %lu, got %lu", (u_long)memguard_mapsize,
212 (u_long)(limit - base)));
209 vmem_alloc(parent, memguard_mapsize, M_WAITOK, &base);
210 memguard_map = vmem_create("memguard arena", base, memguard_mapsize,
211 PAGE_SIZE, 0, M_WAITOK);
213 memguard_cursor = base;
212 memguard_cursor = base;
213 memguard_base = base;
214
215 printf("MEMGUARD DEBUGGING ALLOCATOR INITIALIZED:\n");
216 printf("\tMEMGUARD map base: 0x%lx\n", (u_long)base);
214
215 printf("MEMGUARD DEBUGGING ALLOCATOR INITIALIZED:\n");
216 printf("\tMEMGUARD map base: 0x%lx\n", (u_long)base);
217 printf("\tMEMGUARD map limit: 0x%lx\n", (u_long)limit);
218 printf("\tMEMGUARD map size: %jd KBytes\n",
219 (uintmax_t)memguard_mapsize >> 10);
220}
221
222/*
223 * Run things that can't be done as early as memguard_init().
224 */
225static void
226memguard_sysinit(void)
227{
228 struct sysctl_oid_list *parent;
229
230 parent = SYSCTL_STATIC_CHILDREN(_vm_memguard);
231
232 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "mapstart", CTLFLAG_RD,
217 printf("\tMEMGUARD map size: %jd KBytes\n",
218 (uintmax_t)memguard_mapsize >> 10);
219}
220
221/*
222 * Run things that can't be done as early as memguard_init().
223 */
224static void
225memguard_sysinit(void)
226{
227 struct sysctl_oid_list *parent;
228
229 parent = SYSCTL_STATIC_CHILDREN(_vm_memguard);
230
231 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "mapstart", CTLFLAG_RD,
233 &memguard_map->min_offset, "MemGuard KVA base");
232 &memguard_base, "MemGuard KVA base");
234 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "maplimit", CTLFLAG_RD,
233 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "maplimit", CTLFLAG_RD,
235 &memguard_map->max_offset, "MemGuard KVA end");
234 &memguard_mapsize, "MemGuard KVA size");
235#if 0
236 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "mapused", CTLFLAG_RD,
237 &memguard_map->size, "MemGuard KVA used");
236 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "mapused", CTLFLAG_RD,
237 &memguard_map->size, "MemGuard KVA used");
238#endif
238}
239SYSINIT(memguard, SI_SUB_KLD, SI_ORDER_ANY, memguard_sysinit, NULL);
240
241/*
242 * v2sizep() converts a virtual address of the first page allocated for
243 * an item to a pointer to u_long recording the size of the original
244 * allocation request.
245 *

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258 if (pa == 0)
259 panic("MemGuard detected double-free of %p", (void *)va);
260 p = PHYS_TO_VM_PAGE(pa);
261 KASSERT(p->wire_count != 0 && p->queue == PQ_NONE,
262 ("MEMGUARD: Expected wired page %p in vtomgfifo!", p));
263 return ((u_long *)&p->pageq.tqe_next);
264}
265
239}
240SYSINIT(memguard, SI_SUB_KLD, SI_ORDER_ANY, memguard_sysinit, NULL);
241
242/*
243 * v2sizep() converts a virtual address of the first page allocated for
244 * an item to a pointer to u_long recording the size of the original
245 * allocation request.
246 *

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259 if (pa == 0)
260 panic("MemGuard detected double-free of %p", (void *)va);
261 p = PHYS_TO_VM_PAGE(pa);
262 KASSERT(p->wire_count != 0 && p->queue == PQ_NONE,
263 ("MEMGUARD: Expected wired page %p in vtomgfifo!", p));
264 return ((u_long *)&p->pageq.tqe_next);
265}
266
267static u_long *
268v2sizev(vm_offset_t va)
269{
270 vm_paddr_t pa;
271 struct vm_page *p;
272
273 pa = pmap_kextract(va);
274 if (pa == 0)
275 panic("MemGuard detected double-free of %p", (void *)va);
276 p = PHYS_TO_VM_PAGE(pa);
277 KASSERT(p->wire_count != 0 && p->queue == PQ_NONE,
278 ("MEMGUARD: Expected wired page %p in vtomgfifo!", p));
279 return ((u_long *)&p->pageq.tqe_prev);
280}
281
266/*
267 * Allocate a single object of specified size with specified flags
268 * (either M_WAITOK or M_NOWAIT).
269 */
270void *
271memguard_alloc(unsigned long req_size, int flags)
272{
273 vm_offset_t addr;

--- 10 unchanged lines hidden (view full) ---

284 * the value of memguard_options so we have a consistent
285 * value.
286 */
287 size_v = size_p;
288 do_guard = (memguard_options & MG_GUARD_AROUND) != 0;
289 if (do_guard)
290 size_v += 2 * PAGE_SIZE;
291
282/*
283 * Allocate a single object of specified size with specified flags
284 * (either M_WAITOK or M_NOWAIT).
285 */
286void *
287memguard_alloc(unsigned long req_size, int flags)
288{
289 vm_offset_t addr;

--- 10 unchanged lines hidden (view full) ---

300 * the value of memguard_options so we have a consistent
301 * value.
302 */
303 size_v = size_p;
304 do_guard = (memguard_options & MG_GUARD_AROUND) != 0;
305 if (do_guard)
306 size_v += 2 * PAGE_SIZE;
307
292 vm_map_lock(memguard_map);
293 /*
294 * When we pass our memory limit, reject sub-page allocations.
295 * Page-size and larger allocations will use the same amount
296 * of physical memory whether we allocate or hand off to
297 * uma_large_alloc(), so keep those.
298 */
308 /*
309 * When we pass our memory limit, reject sub-page allocations.
310 * Page-size and larger allocations will use the same amount
311 * of physical memory whether we allocate or hand off to
312 * uma_large_alloc(), so keep those.
313 */
299 if (memguard_map->size >= memguard_physlimit &&
314 if (vmem_size(memguard_map, VMEM_ALLOC) >= memguard_physlimit &&
300 req_size < PAGE_SIZE) {
301 addr = (vm_offset_t)NULL;
302 memguard_fail_pgs++;
303 goto out;
304 }
305 /*
306 * Keep a moving cursor so we don't recycle KVA as long as
307 * possible. It's not perfect, since we don't know in what
308 * order previous allocations will be free'd, but it's simple
309 * and fast, and requires O(1) additional storage if guard
310 * pages are not used.
311 *
312 * XXX This scheme will lead to greater fragmentation of the
313 * map, unless vm_map_findspace() is tweaked.
314 */
315 for (;;) {
315 req_size < PAGE_SIZE) {
316 addr = (vm_offset_t)NULL;
317 memguard_fail_pgs++;
318 goto out;
319 }
320 /*
321 * Keep a moving cursor so we don't recycle KVA as long as
322 * possible. It's not perfect, since we don't know in what
323 * order previous allocations will be free'd, but it's simple
324 * and fast, and requires O(1) additional storage if guard
325 * pages are not used.
326 *
327 * XXX This scheme will lead to greater fragmentation of the
328 * map, unless vm_map_findspace() is tweaked.
329 */
330 for (;;) {
316 rv = vm_map_findspace(memguard_map, memguard_cursor,
317 size_v, &addr);
318 if (rv == KERN_SUCCESS)
331 if (vmem_xalloc(memguard_map, size_v, 0, 0, 0, memguard_cursor,
332 VMEM_ADDR_MAX, M_BESTFIT | M_NOWAIT, &addr) == 0)
319 break;
320 /*
321 * The map has no space. This may be due to
322 * fragmentation, or because the cursor is near the
323 * end of the map.
324 */
333 break;
334 /*
335 * The map has no space. This may be due to
336 * fragmentation, or because the cursor is near the
337 * end of the map.
338 */
325 if (memguard_cursor == vm_map_min(memguard_map)) {
339 if (memguard_cursor == memguard_base) {
326 memguard_fail_kva++;
327 addr = (vm_offset_t)NULL;
328 goto out;
329 }
330 memguard_wrap++;
340 memguard_fail_kva++;
341 addr = (vm_offset_t)NULL;
342 goto out;
343 }
344 memguard_wrap++;
331 memguard_cursor = vm_map_min(memguard_map);
345 memguard_cursor = memguard_base;
332 }
333 if (do_guard)
334 addr += PAGE_SIZE;
346 }
347 if (do_guard)
348 addr += PAGE_SIZE;
335 rv = kmem_back(memguard_map, addr, size_p, flags);
349 rv = kmem_back(kmem_object, addr, size_p, flags);
336 if (rv != KERN_SUCCESS) {
350 if (rv != KERN_SUCCESS) {
351 vmem_xfree(memguard_map, addr, size_v);
337 memguard_fail_pgs++;
338 addr = (vm_offset_t)NULL;
339 goto out;
340 }
352 memguard_fail_pgs++;
353 addr = (vm_offset_t)NULL;
354 goto out;
355 }
341 memguard_cursor = addr + size_p;
356 memguard_cursor = addr + size_v;
342 *v2sizep(trunc_page(addr)) = req_size;
357 *v2sizep(trunc_page(addr)) = req_size;
358 *v2sizev(trunc_page(addr)) = size_v;
343 memguard_succ++;
344 if (req_size < PAGE_SIZE) {
345 memguard_wasted += (PAGE_SIZE - req_size);
346 if (do_guard) {
347 /*
348 * Align the request to 16 bytes, and return
349 * an address near the end of the page, to
350 * better detect array overrun.
351 */
352 req_size = roundup2(req_size, 16);
353 addr += (PAGE_SIZE - req_size);
354 }
355 }
356out:
359 memguard_succ++;
360 if (req_size < PAGE_SIZE) {
361 memguard_wasted += (PAGE_SIZE - req_size);
362 if (do_guard) {
363 /*
364 * Align the request to 16 bytes, and return
365 * an address near the end of the page, to
366 * better detect array overrun.
367 */
368 req_size = roundup2(req_size, 16);
369 addr += (PAGE_SIZE - req_size);
370 }
371 }
372out:
357 vm_map_unlock(memguard_map);
358 return ((void *)addr);
359}
360
361int
362is_memguard_addr(void *addr)
363{
364 vm_offset_t a = (vm_offset_t)(uintptr_t)addr;
365
373 return ((void *)addr);
374}
375
376int
377is_memguard_addr(void *addr)
378{
379 vm_offset_t a = (vm_offset_t)(uintptr_t)addr;
380
366 return (a >= memguard_map->min_offset && a < memguard_map->max_offset);
381 return (a >= memguard_base && a < memguard_base + memguard_mapsize);
367}
368
369/*
370 * Free specified single object.
371 */
372void
373memguard_free(void *ptr)
374{
375 vm_offset_t addr;
382}
383
384/*
385 * Free specified single object.
386 */
387void
388memguard_free(void *ptr)
389{
390 vm_offset_t addr;
376 u_long req_size, size;
391 u_long req_size, size, sizev;
377 char *temp;
378 int i;
379
380 addr = trunc_page((uintptr_t)ptr);
381 req_size = *v2sizep(addr);
392 char *temp;
393 int i;
394
395 addr = trunc_page((uintptr_t)ptr);
396 req_size = *v2sizep(addr);
397 sizev = *v2sizev(addr);
382 size = round_page(req_size);
383
384 /*
385 * Page should not be guarded right now, so force a write.
386 * The purpose of this is to increase the likelihood of
387 * catching a double-free, but not necessarily a
388 * tamper-after-free (the second thread freeing might not
389 * write before freeing, so this forces it to and,

--- 5 unchanged lines hidden (view full) ---

395
396 /*
397 * This requires carnal knowledge of the implementation of
398 * kmem_free(), but since we've already replaced kmem_malloc()
399 * above, it's not really any worse. We want to use the
400 * vm_map lock to serialize updates to memguard_wasted, since
401 * we had the lock at increment.
402 */
398 size = round_page(req_size);
399
400 /*
401 * Page should not be guarded right now, so force a write.
402 * The purpose of this is to increase the likelihood of
403 * catching a double-free, but not necessarily a
404 * tamper-after-free (the second thread freeing might not
405 * write before freeing, so this forces it to and,

--- 5 unchanged lines hidden (view full) ---

411
412 /*
413 * This requires carnal knowledge of the implementation of
414 * kmem_free(), but since we've already replaced kmem_malloc()
415 * above, it's not really any worse. We want to use the
416 * vm_map lock to serialize updates to memguard_wasted, since
417 * we had the lock at increment.
418 */
403 vm_map_lock(memguard_map);
419 kmem_unback(kmem_object, addr, size);
420 if (sizev > size)
421 addr -= PAGE_SIZE;
422 vmem_xfree(memguard_map, addr, sizev);
404 if (req_size < PAGE_SIZE)
405 memguard_wasted -= (PAGE_SIZE - req_size);
423 if (req_size < PAGE_SIZE)
424 memguard_wasted -= (PAGE_SIZE - req_size);
406 (void)vm_map_delete(memguard_map, addr, addr + size);
407 vm_map_unlock(memguard_map);
408}
409
410/*
411 * Re-allocate an allocation that was originally guarded.
412 */
413void *
414memguard_realloc(void *addr, unsigned long size, struct malloc_type *mtp,
415 int flags)

--- 86 unchanged lines hidden --- 		425}
426
427/*
428 * Re-allocate an allocation that was originally guarded.
429 */
430void *
431memguard_realloc(void *addr, unsigned long size, struct malloc_type *mtp,
432 int flags)

--- 86 unchanged lines hidden ---