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: stable/10/sys/vm/memguard.c 325037 2017-10-27 14:23:53Z markj $"); 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); 92280338Sngie /* If mtp is NULL, it will be initialized in memguard_cmp() */ 93211194Smdf vm_memguard_mtype = malloc_desc2type(desc); 94211194Smdf strlcpy(vm_memguard_desc, desc, sizeof(vm_memguard_desc)); 95153880Spjd mtx_unlock(&malloc_mtx); 96153880Spjd return (error); 97153880Spjd} 98211194SmdfSYSCTL_PROC(_vm_memguard, OID_AUTO, desc, 99211194Smdf CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0, 100153880Spjd memguard_sysctl_desc, "A", "Short description of memory type to monitor"); 101153880Spjd 102211194Smdfstatic vm_offset_t memguard_cursor; 103254025Sjeffstatic vm_offset_t memguard_base; 104211194Smdfstatic vm_size_t memguard_mapsize; 105211194Smdfstatic vm_size_t memguard_physlimit; 106211194Smdfstatic u_long memguard_wasted; 107211194Smdfstatic u_long memguard_wrap; 108211194Smdfstatic u_long memguard_succ; 109211194Smdfstatic u_long memguard_fail_kva; 110211194Smdfstatic u_long memguard_fail_pgs; 111140587Sbmilekic 112211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, cursor, CTLFLAG_RD, 113211194Smdf &memguard_cursor, 0, "MemGuard cursor"); 114211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, mapsize, CTLFLAG_RD, 115254025Sjeff &memguard_mapsize, 0, "MemGuard private arena size"); 116211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, phys_limit, CTLFLAG_RD, 117211194Smdf &memguard_physlimit, 0, "Limit on MemGuard memory consumption"); 118211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, wasted, CTLFLAG_RD, 119211194Smdf &memguard_wasted, 0, "Excess memory used through page promotion"); 120211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, wrapcnt, CTLFLAG_RD, 121211194Smdf &memguard_wrap, 0, "MemGuard cursor wrap count"); 122211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, numalloc, CTLFLAG_RD, 123211194Smdf &memguard_succ, 0, "Count of successful MemGuard allocations"); 124211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, fail_kva, CTLFLAG_RD, 125211194Smdf &memguard_fail_kva, 0, "MemGuard failures due to lack of KVA"); 126211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, fail_pgs, CTLFLAG_RD, 127211194Smdf &memguard_fail_pgs, 0, "MemGuard failures due to lack of pages"); 128140587Sbmilekic 129226313Sglebius#define MG_GUARD_AROUND 0x001 130226313Sglebius#define MG_GUARD_ALLLARGE 0x002 131226313Sglebius#define MG_GUARD_NOFREE 0x004 132226313Sglebiusstatic int memguard_options = MG_GUARD_AROUND; 133211194SmdfTUNABLE_INT("vm.memguard.options", &memguard_options); 134211194SmdfSYSCTL_INT(_vm_memguard, OID_AUTO, options, CTLFLAG_RW, 135211194Smdf &memguard_options, 0, 136211194Smdf "MemGuard options:\n" 137211194Smdf "\t0x001 - add guard pages around each allocation\n" 138226313Sglebius "\t0x002 - always use MemGuard for allocations over a page\n" 139226313Sglebius "\t0x004 - guard uma(9) zones with UMA_ZONE_NOFREE flag"); 140211194Smdf 141211194Smdfstatic u_int memguard_minsize; 142211194Smdfstatic u_long memguard_minsize_reject; 143211194SmdfSYSCTL_UINT(_vm_memguard, OID_AUTO, minsize, CTLFLAG_RW, 144211194Smdf &memguard_minsize, 0, "Minimum size for page promotion"); 145211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, minsize_reject, CTLFLAG_RD, 146211194Smdf &memguard_minsize_reject, 0, "# times rejected for size"); 147211194Smdf 148211194Smdfstatic u_int memguard_frequency; 149211194Smdfstatic u_long memguard_frequency_hits; 150211194SmdfTUNABLE_INT("vm.memguard.frequency", &memguard_frequency); 151211194SmdfSYSCTL_UINT(_vm_memguard, OID_AUTO, frequency, CTLFLAG_RW, 152211194Smdf &memguard_frequency, 0, "Times in 100000 that MemGuard will randomly run"); 153211194SmdfSYSCTL_ULONG(_vm_memguard, OID_AUTO, frequency_hits, CTLFLAG_RD, 154211194Smdf &memguard_frequency_hits, 0, "# times MemGuard randomly chose"); 155211194Smdf 156211194Smdf 157140587Sbmilekic/* 158211194Smdf * Return a fudged value to be used for vm_kmem_size for allocating 159211194Smdf * the kmem_map. The memguard memory will be a submap. 160140587Sbmilekic */ 161211194Smdfunsigned long 162238502Smdfmemguard_fudge(unsigned long km_size, const struct vm_map *parent_map) 163211194Smdf{ 164238502Smdf u_long mem_pgs, parent_size; 165140587Sbmilekic 166211194Smdf vm_memguard_divisor = 10; 167211194Smdf TUNABLE_INT_FETCH("vm.memguard.divisor", &vm_memguard_divisor); 168211194Smdf 169238502Smdf parent_size = vm_map_max(parent_map) - vm_map_min(parent_map) + 170238502Smdf PAGE_SIZE; 171211194Smdf /* Pick a conservative value if provided value sucks. */ 172211194Smdf if ((vm_memguard_divisor <= 0) || 173238502Smdf ((parent_size / vm_memguard_divisor) == 0)) 174211194Smdf vm_memguard_divisor = 10; 175211194Smdf /* 176211194Smdf * Limit consumption of physical pages to 177211194Smdf * 1/vm_memguard_divisor of system memory. If the KVA is 178211194Smdf * smaller than this then the KVA limit comes into play first. 179211194Smdf * This prevents memguard's page promotions from completely 180211194Smdf * using up memory, since most malloc(9) calls are sub-page. 181211194Smdf */ 182238502Smdf mem_pgs = cnt.v_page_count; 183211194Smdf memguard_physlimit = (mem_pgs / vm_memguard_divisor) * PAGE_SIZE; 184211194Smdf /* 185211194Smdf * We want as much KVA as we can take safely. Use at most our 186238502Smdf * allotted fraction of the parent map's size. Limit this to 187238502Smdf * twice the physical memory to avoid using too much memory as 188238502Smdf * pagetable pages (size must be multiple of PAGE_SIZE). 189211194Smdf */ 190238502Smdf memguard_mapsize = round_page(parent_size / vm_memguard_divisor); 191238502Smdf if (memguard_mapsize / (2 * PAGE_SIZE) > mem_pgs) 192211194Smdf memguard_mapsize = mem_pgs * 2 * PAGE_SIZE; 193238502Smdf if (km_size + memguard_mapsize > parent_size) 194238502Smdf memguard_mapsize = 0; 195211194Smdf return (km_size + memguard_mapsize); 196211194Smdf} 197211194Smdf 198140587Sbmilekic/* 199140587Sbmilekic * Initialize the MemGuard mock allocator. All objects from MemGuard come 200140587Sbmilekic * out of a single VM map (contiguous chunk of address space). 201140587Sbmilekic */ 202140587Sbmilekicvoid 203254025Sjeffmemguard_init(vmem_t *parent) 204140587Sbmilekic{ 205254025Sjeff vm_offset_t base; 206140587Sbmilekic 207254307Sjeff vmem_alloc(parent, memguard_mapsize, M_BESTFIT | M_WAITOK, &base); 208254307Sjeff vmem_init(memguard_arena, "memguard arena", base, memguard_mapsize, 209254025Sjeff PAGE_SIZE, 0, M_WAITOK); 210211194Smdf memguard_cursor = base; 211254025Sjeff memguard_base = base; 212140587Sbmilekic 213140587Sbmilekic printf("MEMGUARD DEBUGGING ALLOCATOR INITIALIZED:\n"); 214211194Smdf printf("\tMEMGUARD map base: 0x%lx\n", (u_long)base); 215211194Smdf printf("\tMEMGUARD map size: %jd KBytes\n", 216211194Smdf (uintmax_t)memguard_mapsize >> 10); 217140587Sbmilekic} 218140587Sbmilekic 219140587Sbmilekic/* 220211194Smdf * Run things that can't be done as early as memguard_init(). 221140587Sbmilekic */ 222211194Smdfstatic void 223211194Smdfmemguard_sysinit(void) 224211194Smdf{ 225211194Smdf struct sysctl_oid_list *parent; 226211194Smdf 227211194Smdf parent = SYSCTL_STATIC_CHILDREN(_vm_memguard); 228211194Smdf 229273736Shselasky SYSCTL_ADD_UAUTO(NULL, parent, OID_AUTO, "mapstart", CTLFLAG_RD, 230254025Sjeff &memguard_base, "MemGuard KVA base"); 231273736Shselasky SYSCTL_ADD_UAUTO(NULL, parent, OID_AUTO, "maplimit", CTLFLAG_RD, 232254025Sjeff &memguard_mapsize, "MemGuard KVA size"); 233254025Sjeff#if 0 234211194Smdf SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "mapused", CTLFLAG_RD, 235211194Smdf &memguard_map->size, "MemGuard KVA used"); 236254025Sjeff#endif 237211194Smdf} 238211194SmdfSYSINIT(memguard, SI_SUB_KLD, SI_ORDER_ANY, memguard_sysinit, NULL); 239211194Smdf 240211194Smdf/* 241211194Smdf * v2sizep() converts a virtual address of the first page allocated for 242211194Smdf * an item to a pointer to u_long recording the size of the original 243211194Smdf * allocation request. 244211194Smdf * 245211194Smdf * This routine is very similar to those defined by UMA in uma_int.h. 246211194Smdf * The difference is that this routine stores the originally allocated 247211194Smdf * size in one of the page's fields that is unused when the page is 248211194Smdf * wired rather than the object field, which is used. 249211194Smdf */ 250211194Smdfstatic u_long * 251211194Smdfv2sizep(vm_offset_t va) 252211194Smdf{ 253212063Smdf vm_paddr_t pa; 254211194Smdf struct vm_page *p; 255211194Smdf 256212063Smdf pa = pmap_kextract(va); 257212063Smdf if (pa == 0) 258212063Smdf panic("MemGuard detected double-free of %p", (void *)va); 259212063Smdf p = PHYS_TO_VM_PAGE(pa); 260211194Smdf KASSERT(p->wire_count != 0 && p->queue == PQ_NONE, 261211194Smdf ("MEMGUARD: Expected wired page %p in vtomgfifo!", p)); 262254182Skib return (&p->plinks.memguard.p); 263211194Smdf} 264211194Smdf 265254025Sjeffstatic u_long * 266254025Sjeffv2sizev(vm_offset_t va) 267254025Sjeff{ 268254025Sjeff vm_paddr_t pa; 269254025Sjeff struct vm_page *p; 270254025Sjeff 271254025Sjeff pa = pmap_kextract(va); 272254025Sjeff if (pa == 0) 273254025Sjeff panic("MemGuard detected double-free of %p", (void *)va); 274254025Sjeff p = PHYS_TO_VM_PAGE(pa); 275254025Sjeff KASSERT(p->wire_count != 0 && p->queue == PQ_NONE, 276254025Sjeff ("MEMGUARD: Expected wired page %p in vtomgfifo!", p)); 277254182Skib return (&p->plinks.memguard.v); 278254025Sjeff} 279254025Sjeff 280211194Smdf/* 281211194Smdf * Allocate a single object of specified size with specified flags 282211194Smdf * (either M_WAITOK or M_NOWAIT). 283211194Smdf */ 284140587Sbmilekicvoid * 285211194Smdfmemguard_alloc(unsigned long req_size, int flags) 286140587Sbmilekic{ 287325037Smarkj vm_offset_t addr, origaddr; 288211194Smdf u_long size_p, size_v; 289211194Smdf int do_guard, rv; 290140587Sbmilekic 291211194Smdf size_p = round_page(req_size); 292211194Smdf if (size_p == 0) 293211194Smdf return (NULL); 294211194Smdf /* 295211194Smdf * To ensure there are holes on both sides of the allocation, 296211194Smdf * request 2 extra pages of KVA. We will only actually add a 297211194Smdf * vm_map_entry and get pages for the original request. Save 298211194Smdf * the value of memguard_options so we have a consistent 299211194Smdf * value. 300211194Smdf */ 301211194Smdf size_v = size_p; 302226313Sglebius do_guard = (memguard_options & MG_GUARD_AROUND) != 0; 303211194Smdf if (do_guard) 304211194Smdf size_v += 2 * PAGE_SIZE; 305140587Sbmilekic 306140587Sbmilekic /* 307211194Smdf * When we pass our memory limit, reject sub-page allocations. 308211194Smdf * Page-size and larger allocations will use the same amount 309211194Smdf * of physical memory whether we allocate or hand off to 310211194Smdf * uma_large_alloc(), so keep those. 311140587Sbmilekic */ 312254307Sjeff if (vmem_size(memguard_arena, VMEM_ALLOC) >= memguard_physlimit && 313211194Smdf req_size < PAGE_SIZE) { 314211194Smdf addr = (vm_offset_t)NULL; 315211194Smdf memguard_fail_pgs++; 316211194Smdf goto out; 317211194Smdf } 318211194Smdf /* 319211194Smdf * Keep a moving cursor so we don't recycle KVA as long as 320211194Smdf * possible. It's not perfect, since we don't know in what 321211194Smdf * order previous allocations will be free'd, but it's simple 322211194Smdf * and fast, and requires O(1) additional storage if guard 323211194Smdf * pages are not used. 324211194Smdf * 325211194Smdf * XXX This scheme will lead to greater fragmentation of the 326211194Smdf * map, unless vm_map_findspace() is tweaked. 327211194Smdf */ 328211194Smdf for (;;) { 329254307Sjeff if (vmem_xalloc(memguard_arena, size_v, 0, 0, 0, 330254307Sjeff memguard_cursor, VMEM_ADDR_MAX, 331325037Smarkj M_BESTFIT | M_NOWAIT, &origaddr) == 0) 332211194Smdf break; 333211194Smdf /* 334211194Smdf * The map has no space. This may be due to 335211194Smdf * fragmentation, or because the cursor is near the 336211194Smdf * end of the map. 337211194Smdf */ 338254025Sjeff if (memguard_cursor == memguard_base) { 339211194Smdf memguard_fail_kva++; 340211194Smdf addr = (vm_offset_t)NULL; 341211194Smdf goto out; 342140587Sbmilekic } 343211194Smdf memguard_wrap++; 344254025Sjeff memguard_cursor = memguard_base; 345141670Sbmilekic } 346325037Smarkj addr = origaddr; 347211194Smdf if (do_guard) 348211194Smdf addr += PAGE_SIZE; 349254025Sjeff rv = kmem_back(kmem_object, addr, size_p, flags); 350211194Smdf if (rv != KERN_SUCCESS) { 351325037Smarkj vmem_xfree(memguard_arena, origaddr, size_v); 352211194Smdf memguard_fail_pgs++; 353211194Smdf addr = (vm_offset_t)NULL; 354211194Smdf goto out; 355140587Sbmilekic } 356254025Sjeff memguard_cursor = addr + size_v; 357211194Smdf *v2sizep(trunc_page(addr)) = req_size; 358254025Sjeff *v2sizev(trunc_page(addr)) = size_v; 359211194Smdf memguard_succ++; 360211194Smdf if (req_size < PAGE_SIZE) { 361211194Smdf memguard_wasted += (PAGE_SIZE - req_size); 362211194Smdf if (do_guard) { 363211194Smdf /* 364211194Smdf * Align the request to 16 bytes, and return 365211194Smdf * an address near the end of the page, to 366211194Smdf * better detect array overrun. 367211194Smdf */ 368211194Smdf req_size = roundup2(req_size, 16); 369211194Smdf addr += (PAGE_SIZE - req_size); 370211194Smdf } 371211194Smdf } 372211194Smdfout: 373211194Smdf return ((void *)addr); 374140587Sbmilekic} 375140587Sbmilekic 376211194Smdfint 377211194Smdfis_memguard_addr(void *addr) 378211194Smdf{ 379211194Smdf vm_offset_t a = (vm_offset_t)(uintptr_t)addr; 380211194Smdf 381254025Sjeff return (a >= memguard_base && a < memguard_base + memguard_mapsize); 382211194Smdf} 383211194Smdf 384140587Sbmilekic/* 385140587Sbmilekic * Free specified single object. 386140587Sbmilekic */ 387140587Sbmilekicvoid 388211194Smdfmemguard_free(void *ptr) 389140587Sbmilekic{ 390211194Smdf vm_offset_t addr; 391254025Sjeff u_long req_size, size, sizev; 392211194Smdf char *temp; 393211194Smdf int i; 394140587Sbmilekic 395211194Smdf addr = trunc_page((uintptr_t)ptr); 396211194Smdf req_size = *v2sizep(addr); 397254025Sjeff sizev = *v2sizev(addr); 398211194Smdf size = round_page(req_size); 399141670Sbmilekic 400141670Sbmilekic /* 401211194Smdf * Page should not be guarded right now, so force a write. 402211194Smdf * The purpose of this is to increase the likelihood of 403211194Smdf * catching a double-free, but not necessarily a 404211194Smdf * tamper-after-free (the second thread freeing might not 405211194Smdf * write before freeing, so this forces it to and, 406211194Smdf * subsequently, trigger a fault). 407141670Sbmilekic */ 408211194Smdf temp = ptr; 409211194Smdf for (i = 0; i < size; i += PAGE_SIZE) 410211194Smdf temp[i] = 'M'; 411141670Sbmilekic 412211194Smdf /* 413211194Smdf * This requires carnal knowledge of the implementation of 414211194Smdf * kmem_free(), but since we've already replaced kmem_malloc() 415211194Smdf * above, it's not really any worse. We want to use the 416211194Smdf * vm_map lock to serialize updates to memguard_wasted, since 417211194Smdf * we had the lock at increment. 418211194Smdf */ 419254025Sjeff kmem_unback(kmem_object, addr, size); 420254025Sjeff if (sizev > size) 421254025Sjeff addr -= PAGE_SIZE; 422254307Sjeff vmem_xfree(memguard_arena, addr, sizev); 423211194Smdf if (req_size < PAGE_SIZE) 424211194Smdf memguard_wasted -= (PAGE_SIZE - req_size); 425140587Sbmilekic} 426140587Sbmilekic 427212058Smdf/* 428212058Smdf * Re-allocate an allocation that was originally guarded. 429212058Smdf */ 430212058Smdfvoid * 431212058Smdfmemguard_realloc(void *addr, unsigned long size, struct malloc_type *mtp, 432212058Smdf int flags) 433212058Smdf{ 434212058Smdf void *newaddr; 435212058Smdf u_long old_size; 436212058Smdf 437212058Smdf /* 438212058Smdf * Allocate the new block. Force the allocation to be guarded 439212058Smdf * as the original may have been guarded through random 440212058Smdf * chance, and that should be preserved. 441212058Smdf */ 442212058Smdf if ((newaddr = memguard_alloc(size, flags)) == NULL) 443212058Smdf return (NULL); 444212058Smdf 445212058Smdf /* Copy over original contents. */ 446212058Smdf old_size = *v2sizep(trunc_page((uintptr_t)addr)); 447212058Smdf bcopy(addr, newaddr, min(size, old_size)); 448212058Smdf memguard_free(addr); 449212058Smdf return (newaddr); 450212058Smdf} 451212058Smdf 452226313Sglebiusstatic int 453226313Sglebiusmemguard_cmp(unsigned long size) 454153880Spjd{ 455153880Spjd 456211194Smdf if (size < memguard_minsize) { 457211194Smdf memguard_minsize_reject++; 458211194Smdf return (0); 459211194Smdf } 460226313Sglebius if ((memguard_options & MG_GUARD_ALLLARGE) != 0 && size >= PAGE_SIZE) 461211194Smdf return (1); 462211194Smdf if (memguard_frequency > 0 && 463211194Smdf (random() % 100000) < memguard_frequency) { 464211194Smdf memguard_frequency_hits++; 465211194Smdf return (1); 466211194Smdf } 467226313Sglebius 468226313Sglebius return (0); 469226313Sglebius} 470226313Sglebius 471226313Sglebiusint 472226313Sglebiusmemguard_cmp_mtp(struct malloc_type *mtp, unsigned long size) 473226313Sglebius{ 474226313Sglebius 475226313Sglebius if (memguard_cmp(size)) 476226313Sglebius return(1); 477226313Sglebius 478153880Spjd#if 1 479153880Spjd /* 480153880Spjd * The safest way of comparsion is to always compare short description 481153880Spjd * string of memory type, but it is also the slowest way. 482153880Spjd */ 483153880Spjd return (strcmp(mtp->ks_shortdesc, vm_memguard_desc) == 0); 484153880Spjd#else 485153880Spjd /* 486153880Spjd * If we compare pointers, there are two possible problems: 487153880Spjd * 1. Memory type was unloaded and new memory type was allocated at the 488153880Spjd * same address. 489153880Spjd * 2. Memory type was unloaded and loaded again, but allocated at a 490153880Spjd * different address. 491153880Spjd */ 492153880Spjd if (vm_memguard_mtype != NULL) 493153880Spjd return (mtp == vm_memguard_mtype); 494153880Spjd if (strcmp(mtp->ks_shortdesc, vm_memguard_desc) == 0) { 495153880Spjd vm_memguard_mtype = mtp; 496153880Spjd return (1); 497153880Spjd } 498153880Spjd return (0); 499153880Spjd#endif 500153880Spjd} 501226313Sglebius 502226313Sglebiusint 503226313Sglebiusmemguard_cmp_zone(uma_zone_t zone) 504226313Sglebius{ 505226313Sglebius 506280338Sngie if ((memguard_options & MG_GUARD_NOFREE) == 0 && 507226313Sglebius zone->uz_flags & UMA_ZONE_NOFREE) 508226313Sglebius return (0); 509226313Sglebius 510226313Sglebius if (memguard_cmp(zone->uz_size)) 511226313Sglebius return (1); 512226313Sglebius 513226313Sglebius /* 514226313Sglebius * The safest way of comparsion is to always compare zone name, 515226313Sglebius * but it is also the slowest way. 516226313Sglebius */ 517226313Sglebius return (strcmp(zone->uz_name, vm_memguard_desc) == 0); 518226313Sglebius} 519