1206360Sjoel/*- 2211194Smdf * Copyright (c) 2005, Bosko Milekic <bmilekic@FreeBSD.org>. 3211194Smdf * Copyright (c) 2010 Isilon Systems, Inc. (http://www.isilon.com/) 4211194Smdf * All rights reserved. 5140587Sbmilekic * 6140587Sbmilekic * Redistribution and use in source and binary forms, with or without 7140587Sbmilekic * modification, are permitted provided that the following conditions 8140587Sbmilekic * are met: 9140587Sbmilekic * 1. Redistributions of source code must retain the above copyright 10140587Sbmilekic * notice unmodified, this list of conditions, and the following 11140587Sbmilekic * disclaimer. 12140587Sbmilekic * 2. Redistributions in binary form must reproduce the above copyright 13140587Sbmilekic * notice, this list of conditions and the following disclaimer in the 14140587Sbmilekic * documentation and/or other materials provided with the distribution. 15140587Sbmilekic * 16140587Sbmilekic * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17140587Sbmilekic * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18140587Sbmilekic * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19140587Sbmilekic * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20140587Sbmilekic * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21140587Sbmilekic * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22140587Sbmilekic * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23140587Sbmilekic * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24140587Sbmilekic * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25140587Sbmilekic * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26140587Sbmilekic */ 27140587Sbmilekic 28140587Sbmilekic#include <sys/cdefs.h> 29140587Sbmilekic__FBSDID("$FreeBSD$"); 30140587Sbmilekic 31140587Sbmilekic/* 32140587Sbmilekic * MemGuard is a simple replacement allocator for debugging only 33140587Sbmilekic * which provides ElectricFence-style memory barrier protection on 34140587Sbmilekic * objects being allocated, and is used to detect tampering-after-free 35140587Sbmilekic * scenarios. 36140587Sbmilekic * 37140587Sbmilekic * See the memguard(9) man page for more information on using MemGuard. 38140587Sbmilekic */ 39140587Sbmilekic 40211229Smdf#include "opt_vm.h" 41211229Smdf 42140587Sbmilekic#include <sys/param.h> 43140587Sbmilekic#include <sys/systm.h> 44140587Sbmilekic#include <sys/kernel.h> 45140587Sbmilekic#include <sys/types.h> 46140587Sbmilekic#include <sys/queue.h> 47140587Sbmilekic#include <sys/lock.h> 48140587Sbmilekic#include <sys/mutex.h> 49140587Sbmilekic#include <sys/malloc.h> 50153880Spjd#include <sys/sysctl.h> 51254025Sjeff#include <sys/vmem.h> 52140587Sbmilekic 53140587Sbmilekic#include <vm/vm.h> 54211194Smdf#include <vm/uma.h> 55141670Sbmilekic#include <vm/vm_param.h> 56140587Sbmilekic#include <vm/vm_page.h> 57140587Sbmilekic#include <vm/vm_map.h> 58211194Smdf#include <vm/vm_object.h> 59254307Sjeff#include <vm/vm_kern.h> 60140587Sbmilekic#include <vm/vm_extern.h> 61226313Sglebius#include <vm/uma_int.h> 62140587Sbmilekic#include <vm/memguard.h> 63140587Sbmilekic 64227309Sedstatic SYSCTL_NODE(_vm, OID_AUTO, memguard, CTLFLAG_RW, NULL, "MemGuard data"); 65141670Sbmilekic/* 66153880Spjd * The vm_memguard_divisor variable controls how much of kmem_map should be 67153880Spjd * reserved for MemGuard. 68153880Spjd */ 69211194Smdfstatic u_int vm_memguard_divisor; 70211194SmdfSYSCTL_UINT(_vm_memguard, OID_AUTO, divisor, CTLFLAG_RDTUN, 71211194Smdf &vm_memguard_divisor, 72153880Spjd 0, "(kmem_size/memguard_divisor) == memguard submap size"); 73153880Spjd 74153880Spjd/* 75153880Spjd * Short description (ks_shortdesc) of memory type to monitor. 76153880Spjd */ 77153880Spjdstatic char vm_memguard_desc[128] = ""; 78153880Spjdstatic struct malloc_type *vm_memguard_mtype = NULL; 79153880SpjdTUNABLE_STR("vm.memguard.desc", vm_memguard_desc, sizeof(vm_memguard_desc)); 80153880Spjdstatic int 81153880Spjdmemguard_sysctl_desc(SYSCTL_HANDLER_ARGS) 82153880Spjd{ 83211194Smdf char desc[sizeof(vm_memguard_desc)]; 84211194Smdf int error; 85153880Spjd 86153880Spjd strlcpy(desc, vm_memguard_desc, sizeof(desc)); 87153880Spjd error = sysctl_handle_string(oidp, desc, sizeof(desc), req); 88153880Spjd if (error != 0 || req->newptr == NULL) 89153880Spjd return (error); 90153880Spjd 91211194Smdf mtx_lock(&malloc_mtx); 92153880Spjd /* 93211194Smdf * If mtp is NULL, it will be initialized in memguard_cmp(). 94153880Spjd */ 95211194Smdf vm_memguard_mtype = malloc_desc2type(desc); 96211194Smdf strlcpy(vm_memguard_desc, desc, sizeof(vm_memguard_desc)); 97153880Spjd mtx_unlock(&malloc_mtx); 98153880Spjd return (error); 99153880Spjd} 100211194SmdfSYSCTL_PROC(_vm_memguard, OID_AUTO, desc, 101211194Smdf CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0, 102153880Spjd memguard_sysctl_desc, "A", "Short description of memory type to monitor"); 103153880Spjd 104211194Smdfstatic vm_offset_t memguard_cursor; 105254025Sjeffstatic vm_offset_t memguard_base; 106211194Smdfstatic vm_size_t memguard_mapsize; 107211194Smdfstatic vm_size_t memguard_physlimit; 108211194Smdfstatic u_long memguard_wasted; 109211194Smdfstatic u_long memguard_wrap; 110211194Smdfstatic u_long memguard_succ; 111211194Smdfstatic u_long memguard_fail_kva; 112211194Smdfstatic u_long memguard_fail_pgs; 113140587Sbmilekic 114211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, cursor, CTLFLAG_RD, 115211194Smdf &memguard_cursor, 0, "MemGuard cursor"); 116211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, mapsize, CTLFLAG_RD, 117254025Sjeff &memguard_mapsize, 0, "MemGuard private arena size"); 118211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, phys_limit, CTLFLAG_RD, 119211194Smdf &memguard_physlimit, 0, "Limit on MemGuard memory consumption"); 120211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, wasted, CTLFLAG_RD, 121211194Smdf &memguard_wasted, 0, "Excess memory used through page promotion"); 122211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, wrapcnt, CTLFLAG_RD, 123211194Smdf &memguard_wrap, 0, "MemGuard cursor wrap count"); 124211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, numalloc, CTLFLAG_RD, 125211194Smdf &memguard_succ, 0, "Count of successful MemGuard allocations"); 126211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, fail_kva, CTLFLAG_RD, 127211194Smdf &memguard_fail_kva, 0, "MemGuard failures due to lack of KVA"); 128211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, fail_pgs, CTLFLAG_RD, 129211194Smdf &memguard_fail_pgs, 0, "MemGuard failures due to lack of pages"); 130140587Sbmilekic 131226313Sglebius#define MG_GUARD_AROUND 0x001 132226313Sglebius#define MG_GUARD_ALLLARGE 0x002 133226313Sglebius#define MG_GUARD_NOFREE 0x004 134226313Sglebiusstatic int memguard_options = MG_GUARD_AROUND; 135211194SmdfTUNABLE_INT("vm.memguard.options", &memguard_options); 136211194SmdfSYSCTL_INT(_vm_memguard, OID_AUTO, options, CTLFLAG_RW, 137211194Smdf &memguard_options, 0, 138211194Smdf "MemGuard options:\n" 139211194Smdf "\t0x001 - add guard pages around each allocation\n" 140226313Sglebius "\t0x002 - always use MemGuard for allocations over a page\n" 141226313Sglebius "\t0x004 - guard uma(9) zones with UMA_ZONE_NOFREE flag"); 142211194Smdf 143211194Smdfstatic u_int memguard_minsize; 144211194Smdfstatic u_long memguard_minsize_reject; 145211194SmdfSYSCTL_UINT(_vm_memguard, OID_AUTO, minsize, CTLFLAG_RW, 146211194Smdf &memguard_minsize, 0, "Minimum size for page promotion"); 147211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, minsize_reject, CTLFLAG_RD, 148211194Smdf &memguard_minsize_reject, 0, "# times rejected for size"); 149211194Smdf 150211194Smdfstatic u_int memguard_frequency; 151211194Smdfstatic u_long memguard_frequency_hits; 152211194SmdfTUNABLE_INT("vm.memguard.frequency", &memguard_frequency); 153211194SmdfSYSCTL_UINT(_vm_memguard, OID_AUTO, frequency, CTLFLAG_RW, 154211194Smdf &memguard_frequency, 0, "Times in 100000 that MemGuard will randomly run"); 155211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, frequency_hits, CTLFLAG_RD, 156211194Smdf &memguard_frequency_hits, 0, "# times MemGuard randomly chose"); 157211194Smdf 158211194Smdf 159140587Sbmilekic/* 160211194Smdf * Return a fudged value to be used for vm_kmem_size for allocating 161211194Smdf * the kmem_map. The memguard memory will be a submap. 162140587Sbmilekic */ 163211194Smdfunsigned long 164238502Smdfmemguard_fudge(unsigned long km_size, const struct vm_map *parent_map) 165211194Smdf{ 166238502Smdf u_long mem_pgs, parent_size; 167140587Sbmilekic 168211194Smdf vm_memguard_divisor = 10; 169211194Smdf TUNABLE_INT_FETCH("vm.memguard.divisor", &vm_memguard_divisor); 170211194Smdf 171238502Smdf parent_size = vm_map_max(parent_map) - vm_map_min(parent_map) + 172238502Smdf PAGE_SIZE; 173211194Smdf /* Pick a conservative value if provided value sucks. */ 174211194Smdf if ((vm_memguard_divisor <= 0) || 175238502Smdf ((parent_size / vm_memguard_divisor) == 0)) 176211194Smdf vm_memguard_divisor = 10; 177211194Smdf /* 178211194Smdf * Limit consumption of physical pages to 179211194Smdf * 1/vm_memguard_divisor of system memory. If the KVA is 180211194Smdf * smaller than this then the KVA limit comes into play first. 181211194Smdf * This prevents memguard's page promotions from completely 182211194Smdf * using up memory, since most malloc(9) calls are sub-page. 183211194Smdf */ 184238502Smdf mem_pgs = cnt.v_page_count; 185211194Smdf memguard_physlimit = (mem_pgs / vm_memguard_divisor) * PAGE_SIZE; 186211194Smdf /* 187211194Smdf * We want as much KVA as we can take safely. Use at most our 188238502Smdf * allotted fraction of the parent map's size. Limit this to 189238502Smdf * twice the physical memory to avoid using too much memory as 190238502Smdf * pagetable pages (size must be multiple of PAGE_SIZE). 191211194Smdf */ 192238502Smdf memguard_mapsize = round_page(parent_size / vm_memguard_divisor); 193238502Smdf if (memguard_mapsize / (2 * PAGE_SIZE) > mem_pgs) 194211194Smdf memguard_mapsize = mem_pgs * 2 * PAGE_SIZE; 195238502Smdf if (km_size + memguard_mapsize > parent_size) 196238502Smdf memguard_mapsize = 0; 197211194Smdf return (km_size + memguard_mapsize); 198211194Smdf} 199211194Smdf 200140587Sbmilekic/* 201140587Sbmilekic * Initialize the MemGuard mock allocator. All objects from MemGuard come 202140587Sbmilekic * out of a single VM map (contiguous chunk of address space). 203140587Sbmilekic */ 204140587Sbmilekicvoid 205254025Sjeffmemguard_init(vmem_t *parent) 206140587Sbmilekic{ 207254025Sjeff vm_offset_t base; 208140587Sbmilekic 209254307Sjeff vmem_alloc(parent, memguard_mapsize, M_BESTFIT | M_WAITOK, &base); 210254307Sjeff vmem_init(memguard_arena, "memguard arena", base, memguard_mapsize, 211254025Sjeff PAGE_SIZE, 0, M_WAITOK); 212211194Smdf memguard_cursor = base; 213254025Sjeff memguard_base = base; 214140587Sbmilekic 215140587Sbmilekic printf("MEMGUARD DEBUGGING ALLOCATOR INITIALIZED:\n"); 216211194Smdf printf("\tMEMGUARD map base: 0x%lx\n", (u_long)base); 217211194Smdf printf("\tMEMGUARD map size: %jd KBytes\n", 218211194Smdf (uintmax_t)memguard_mapsize >> 10); 219140587Sbmilekic} 220140587Sbmilekic 221140587Sbmilekic/* 222211194Smdf * Run things that can't be done as early as memguard_init(). 223140587Sbmilekic */ 224211194Smdfstatic void 225211194Smdfmemguard_sysinit(void) 226211194Smdf{ 227211194Smdf struct sysctl_oid_list *parent; 228211194Smdf 229211194Smdf parent = SYSCTL_STATIC_CHILDREN(_vm_memguard); 230211194Smdf 231211194Smdf SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "mapstart", CTLFLAG_RD, 232254025Sjeff &memguard_base, "MemGuard KVA base"); 233211194Smdf SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "maplimit", CTLFLAG_RD, 234254025Sjeff &memguard_mapsize, "MemGuard KVA size"); 235254025Sjeff#if 0 236211194Smdf SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "mapused", CTLFLAG_RD, 237211194Smdf &memguard_map->size, "MemGuard KVA used"); 238254025Sjeff#endif 239211194Smdf} 240211194SmdfSYSINIT(memguard, SI_SUB_KLD, SI_ORDER_ANY, memguard_sysinit, NULL); 241211194Smdf 242211194Smdf/* 243211194Smdf * v2sizep() converts a virtual address of the first page allocated for 244211194Smdf * an item to a pointer to u_long recording the size of the original 245211194Smdf * allocation request. 246211194Smdf * 247211194Smdf * This routine is very similar to those defined by UMA in uma_int.h. 248211194Smdf * The difference is that this routine stores the originally allocated 249211194Smdf * size in one of the page's fields that is unused when the page is 250211194Smdf * wired rather than the object field, which is used. 251211194Smdf */ 252211194Smdfstatic u_long * 253211194Smdfv2sizep(vm_offset_t va) 254211194Smdf{ 255212063Smdf vm_paddr_t pa; 256211194Smdf struct vm_page *p; 257211194Smdf 258212063Smdf pa = pmap_kextract(va); 259212063Smdf if (pa == 0) 260212063Smdf panic("MemGuard detected double-free of %p", (void *)va); 261212063Smdf p = PHYS_TO_VM_PAGE(pa); 262211194Smdf KASSERT(p->wire_count != 0 && p->queue == PQ_NONE, 263211194Smdf ("MEMGUARD: Expected wired page %p in vtomgfifo!", p)); 264254182Skib return (&p->plinks.memguard.p); 265211194Smdf} 266211194Smdf 267254025Sjeffstatic u_long * 268254025Sjeffv2sizev(vm_offset_t va) 269254025Sjeff{ 270254025Sjeff vm_paddr_t pa; 271254025Sjeff struct vm_page *p; 272254025Sjeff 273254025Sjeff pa = pmap_kextract(va); 274254025Sjeff if (pa == 0) 275254025Sjeff panic("MemGuard detected double-free of %p", (void *)va); 276254025Sjeff p = PHYS_TO_VM_PAGE(pa); 277254025Sjeff KASSERT(p->wire_count != 0 && p->queue == PQ_NONE, 278254025Sjeff ("MEMGUARD: Expected wired page %p in vtomgfifo!", p)); 279254182Skib return (&p->plinks.memguard.v); 280254025Sjeff} 281254025Sjeff 282211194Smdf/* 283211194Smdf * Allocate a single object of specified size with specified flags 284211194Smdf * (either M_WAITOK or M_NOWAIT). 285211194Smdf */ 286140587Sbmilekicvoid * 287211194Smdfmemguard_alloc(unsigned long req_size, int flags) 288140587Sbmilekic{ 289211194Smdf vm_offset_t addr; 290211194Smdf u_long size_p, size_v; 291211194Smdf int do_guard, rv; 292140587Sbmilekic 293211194Smdf size_p = round_page(req_size); 294211194Smdf if (size_p == 0) 295211194Smdf return (NULL); 296211194Smdf /* 297211194Smdf * To ensure there are holes on both sides of the allocation, 298211194Smdf * request 2 extra pages of KVA. We will only actually add a 299211194Smdf * vm_map_entry and get pages for the original request. Save 300211194Smdf * the value of memguard_options so we have a consistent 301211194Smdf * value. 302211194Smdf */ 303211194Smdf size_v = size_p; 304226313Sglebius do_guard = (memguard_options & MG_GUARD_AROUND) != 0; 305211194Smdf if (do_guard) 306211194Smdf size_v += 2 * PAGE_SIZE; 307140587Sbmilekic 308140587Sbmilekic /* 309211194Smdf * When we pass our memory limit, reject sub-page allocations. 310211194Smdf * Page-size and larger allocations will use the same amount 311211194Smdf * of physical memory whether we allocate or hand off to 312211194Smdf * uma_large_alloc(), so keep those. 313140587Sbmilekic */ 314254307Sjeff if (vmem_size(memguard_arena, VMEM_ALLOC) >= memguard_physlimit && 315211194Smdf req_size < PAGE_SIZE) { 316211194Smdf addr = (vm_offset_t)NULL; 317211194Smdf memguard_fail_pgs++; 318211194Smdf goto out; 319211194Smdf } 320211194Smdf /* 321211194Smdf * Keep a moving cursor so we don't recycle KVA as long as 322211194Smdf * possible. It's not perfect, since we don't know in what 323211194Smdf * order previous allocations will be free'd, but it's simple 324211194Smdf * and fast, and requires O(1) additional storage if guard 325211194Smdf * pages are not used. 326211194Smdf * 327211194Smdf * XXX This scheme will lead to greater fragmentation of the 328211194Smdf * map, unless vm_map_findspace() is tweaked. 329211194Smdf */ 330211194Smdf for (;;) { 331254307Sjeff if (vmem_xalloc(memguard_arena, size_v, 0, 0, 0, 332254307Sjeff memguard_cursor, VMEM_ADDR_MAX, 333254307Sjeff M_BESTFIT | M_NOWAIT, &addr) == 0) 334211194Smdf break; 335211194Smdf /* 336211194Smdf * The map has no space. This may be due to 337211194Smdf * fragmentation, or because the cursor is near the 338211194Smdf * end of the map. 339211194Smdf */ 340254025Sjeff if (memguard_cursor == memguard_base) { 341211194Smdf memguard_fail_kva++; 342211194Smdf addr = (vm_offset_t)NULL; 343211194Smdf goto out; 344140587Sbmilekic } 345211194Smdf memguard_wrap++; 346254025Sjeff memguard_cursor = memguard_base; 347141670Sbmilekic } 348211194Smdf if (do_guard) 349211194Smdf addr += PAGE_SIZE; 350254025Sjeff rv = kmem_back(kmem_object, addr, size_p, flags); 351211194Smdf if (rv != KERN_SUCCESS) { 352254307Sjeff vmem_xfree(memguard_arena, addr, size_v); 353211194Smdf memguard_fail_pgs++; 354211194Smdf addr = (vm_offset_t)NULL; 355211194Smdf goto out; 356140587Sbmilekic } 357254025Sjeff memguard_cursor = addr + size_v; 358211194Smdf *v2sizep(trunc_page(addr)) = req_size; 359254025Sjeff *v2sizev(trunc_page(addr)) = size_v; 360211194Smdf memguard_succ++; 361211194Smdf if (req_size < PAGE_SIZE) { 362211194Smdf memguard_wasted += (PAGE_SIZE - req_size); 363211194Smdf if (do_guard) { 364211194Smdf /* 365211194Smdf * Align the request to 16 bytes, and return 366211194Smdf * an address near the end of the page, to 367211194Smdf * better detect array overrun. 368211194Smdf */ 369211194Smdf req_size = roundup2(req_size, 16); 370211194Smdf addr += (PAGE_SIZE - req_size); 371211194Smdf } 372211194Smdf } 373211194Smdfout: 374211194Smdf return ((void *)addr); 375140587Sbmilekic} 376140587Sbmilekic 377211194Smdfint 378211194Smdfis_memguard_addr(void *addr) 379211194Smdf{ 380211194Smdf vm_offset_t a = (vm_offset_t)(uintptr_t)addr; 381211194Smdf 382254025Sjeff return (a >= memguard_base && a < memguard_base + memguard_mapsize); 383211194Smdf} 384211194Smdf 385140587Sbmilekic/* 386140587Sbmilekic * Free specified single object. 387140587Sbmilekic */ 388140587Sbmilekicvoid 389211194Smdfmemguard_free(void *ptr) 390140587Sbmilekic{ 391211194Smdf vm_offset_t addr; 392254025Sjeff u_long req_size, size, sizev; 393211194Smdf char *temp; 394211194Smdf int i; 395140587Sbmilekic 396211194Smdf addr = trunc_page((uintptr_t)ptr); 397211194Smdf req_size = *v2sizep(addr); 398254025Sjeff sizev = *v2sizev(addr); 399211194Smdf size = round_page(req_size); 400141670Sbmilekic 401141670Sbmilekic /* 402211194Smdf * Page should not be guarded right now, so force a write. 403211194Smdf * The purpose of this is to increase the likelihood of 404211194Smdf * catching a double-free, but not necessarily a 405211194Smdf * tamper-after-free (the second thread freeing might not 406211194Smdf * write before freeing, so this forces it to and, 407211194Smdf * subsequently, trigger a fault). 408141670Sbmilekic */ 409211194Smdf temp = ptr; 410211194Smdf for (i = 0; i < size; i += PAGE_SIZE) 411211194Smdf temp[i] = 'M'; 412141670Sbmilekic 413211194Smdf /* 414211194Smdf * This requires carnal knowledge of the implementation of 415211194Smdf * kmem_free(), but since we've already replaced kmem_malloc() 416211194Smdf * above, it's not really any worse. We want to use the 417211194Smdf * vm_map lock to serialize updates to memguard_wasted, since 418211194Smdf * we had the lock at increment. 419211194Smdf */ 420254025Sjeff kmem_unback(kmem_object, addr, size); 421254025Sjeff if (sizev > size) 422254025Sjeff addr -= PAGE_SIZE; 423254307Sjeff vmem_xfree(memguard_arena, addr, sizev); 424211194Smdf if (req_size < PAGE_SIZE) 425211194Smdf memguard_wasted -= (PAGE_SIZE - req_size); 426140587Sbmilekic} 427140587Sbmilekic 428212058Smdf/* 429212058Smdf * Re-allocate an allocation that was originally guarded. 430212058Smdf */ 431212058Smdfvoid * 432212058Smdfmemguard_realloc(void *addr, unsigned long size, struct malloc_type *mtp, 433212058Smdf int flags) 434212058Smdf{ 435212058Smdf void *newaddr; 436212058Smdf u_long old_size; 437212058Smdf 438212058Smdf /* 439212058Smdf * Allocate the new block. Force the allocation to be guarded 440212058Smdf * as the original may have been guarded through random 441212058Smdf * chance, and that should be preserved. 442212058Smdf */ 443212058Smdf if ((newaddr = memguard_alloc(size, flags)) == NULL) 444212058Smdf return (NULL); 445212058Smdf 446212058Smdf /* Copy over original contents. */ 447212058Smdf old_size = *v2sizep(trunc_page((uintptr_t)addr)); 448212058Smdf bcopy(addr, newaddr, min(size, old_size)); 449212058Smdf memguard_free(addr); 450212058Smdf return (newaddr); 451212058Smdf} 452212058Smdf 453226313Sglebiusstatic int 454226313Sglebiusmemguard_cmp(unsigned long size) 455153880Spjd{ 456153880Spjd 457211194Smdf if (size < memguard_minsize) { 458211194Smdf memguard_minsize_reject++; 459211194Smdf return (0); 460211194Smdf } 461226313Sglebius if ((memguard_options & MG_GUARD_ALLLARGE) != 0 && size >= PAGE_SIZE) 462211194Smdf return (1); 463211194Smdf if (memguard_frequency > 0 && 464211194Smdf (random() % 100000) < memguard_frequency) { 465211194Smdf memguard_frequency_hits++; 466211194Smdf return (1); 467211194Smdf } 468226313Sglebius 469226313Sglebius return (0); 470226313Sglebius} 471226313Sglebius 472226313Sglebiusint 473226313Sglebiusmemguard_cmp_mtp(struct malloc_type *mtp, unsigned long size) 474226313Sglebius{ 475226313Sglebius 476226313Sglebius if (memguard_cmp(size)) 477226313Sglebius return(1); 478226313Sglebius 479153880Spjd#if 1 480153880Spjd /* 481153880Spjd * The safest way of comparsion is to always compare short description 482153880Spjd * string of memory type, but it is also the slowest way. 483153880Spjd */ 484153880Spjd return (strcmp(mtp->ks_shortdesc, vm_memguard_desc) == 0); 485153880Spjd#else 486153880Spjd /* 487153880Spjd * If we compare pointers, there are two possible problems: 488153880Spjd * 1. Memory type was unloaded and new memory type was allocated at the 489153880Spjd * same address. 490153880Spjd * 2. Memory type was unloaded and loaded again, but allocated at a 491153880Spjd * different address. 492153880Spjd */ 493153880Spjd if (vm_memguard_mtype != NULL) 494153880Spjd return (mtp == vm_memguard_mtype); 495153880Spjd if (strcmp(mtp->ks_shortdesc, vm_memguard_desc) == 0) { 496153880Spjd vm_memguard_mtype = mtp; 497153880Spjd return (1); 498153880Spjd } 499153880Spjd return (0); 500153880Spjd#endif 501153880Spjd} 502226313Sglebius 503226313Sglebiusint 504226313Sglebiusmemguard_cmp_zone(uma_zone_t zone) 505226313Sglebius{ 506226313Sglebius 507226313Sglebius if ((memguard_options & MG_GUARD_NOFREE) == 0 && 508226313Sglebius zone->uz_flags & UMA_ZONE_NOFREE) 509226313Sglebius return (0); 510226313Sglebius 511226313Sglebius if (memguard_cmp(zone->uz_size)) 512226313Sglebius return (1); 513226313Sglebius 514226313Sglebius /* 515226313Sglebius * The safest way of comparsion is to always compare zone name, 516226313Sglebius * but it is also the slowest way. 517226313Sglebius */ 518226313Sglebius return (strcmp(zone->uz_name, vm_memguard_desc) == 0); 519226313Sglebius} 520