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:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice unmodified, this list of conditions, and the following
11 * disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice unmodified, this list of conditions, and the following
11 * disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 216425 2010-12-14 05:47:35Z alc $");
| 29__FBSDID("$FreeBSD: head/sys/vm/memguard.c 226313 2011-10-12 18:08:28Z glebius $");
|
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.
38 */
39
40#include "opt_vm.h"
41
42#include <sys/param.h>
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
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>
| 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.
38 */
39
40#include "opt_vm.h"
41
42#include <sys/param.h>
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
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>
|
| 59#include <vm/uma_int.h>
|
59#include <vm/memguard.h>
60
61SYSCTL_NODE(_vm, OID_AUTO, memguard, CTLFLAG_RW, NULL, "MemGuard data");
62/*
63 * The vm_memguard_divisor variable controls how much of kmem_map should be
64 * reserved for MemGuard.
65 */
66static u_int vm_memguard_divisor;
67SYSCTL_UINT(_vm_memguard, OID_AUTO, divisor, CTLFLAG_RDTUN,
68 &vm_memguard_divisor,
69 0, "(kmem_size/memguard_divisor) == memguard submap size");
70
71/*
72 * Short description (ks_shortdesc) of memory type to monitor.
73 */
74static char vm_memguard_desc[128] = "";
75static struct malloc_type *vm_memguard_mtype = NULL;
76TUNABLE_STR("vm.memguard.desc", vm_memguard_desc, sizeof(vm_memguard_desc));
77static int
78memguard_sysctl_desc(SYSCTL_HANDLER_ARGS)
79{
80 char desc[sizeof(vm_memguard_desc)];
81 int error;
82
83 strlcpy(desc, vm_memguard_desc, sizeof(desc));
84 error = sysctl_handle_string(oidp, desc, sizeof(desc), req);
85 if (error != 0 || req->newptr == NULL)
86 return (error);
87
88 mtx_lock(&malloc_mtx);
89 /*
90 * If mtp is NULL, it will be initialized in memguard_cmp().
91 */
92 vm_memguard_mtype = malloc_desc2type(desc);
93 strlcpy(vm_memguard_desc, desc, sizeof(vm_memguard_desc));
94 mtx_unlock(&malloc_mtx);
95 return (error);
96}
97SYSCTL_PROC(_vm_memguard, OID_AUTO, desc,
98 CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0,
99 memguard_sysctl_desc, "A", "Short description of memory type to monitor");
100
101static vm_map_t memguard_map = NULL;
102static vm_offset_t memguard_cursor;
103static vm_size_t memguard_mapsize;
104static vm_size_t memguard_physlimit;
105static u_long memguard_wasted;
106static u_long memguard_wrap;
107static u_long memguard_succ;
108static u_long memguard_fail_kva;
109static u_long memguard_fail_pgs;
110
111SYSCTL_ULONG(_vm_memguard, OID_AUTO, cursor, CTLFLAG_RD,
112 &memguard_cursor, 0, "MemGuard cursor");
113SYSCTL_ULONG(_vm_memguard, OID_AUTO, mapsize, CTLFLAG_RD,
114 &memguard_mapsize, 0, "MemGuard private vm_map size");
115SYSCTL_ULONG(_vm_memguard, OID_AUTO, phys_limit, CTLFLAG_RD,
116 &memguard_physlimit, 0, "Limit on MemGuard memory consumption");
117SYSCTL_ULONG(_vm_memguard, OID_AUTO, wasted, CTLFLAG_RD,
118 &memguard_wasted, 0, "Excess memory used through page promotion");
119SYSCTL_ULONG(_vm_memguard, OID_AUTO, wrapcnt, CTLFLAG_RD,
120 &memguard_wrap, 0, "MemGuard cursor wrap count");
121SYSCTL_ULONG(_vm_memguard, OID_AUTO, numalloc, CTLFLAG_RD,
122 &memguard_succ, 0, "Count of successful MemGuard allocations");
123SYSCTL_ULONG(_vm_memguard, OID_AUTO, fail_kva, CTLFLAG_RD,
124 &memguard_fail_kva, 0, "MemGuard failures due to lack of KVA");
125SYSCTL_ULONG(_vm_memguard, OID_AUTO, fail_pgs, CTLFLAG_RD,
126 &memguard_fail_pgs, 0, "MemGuard failures due to lack of pages");
127
| 60#include <vm/memguard.h>
61
62SYSCTL_NODE(_vm, OID_AUTO, memguard, CTLFLAG_RW, NULL, "MemGuard data");
63/*
64 * The vm_memguard_divisor variable controls how much of kmem_map should be
65 * reserved for MemGuard.
66 */
67static u_int vm_memguard_divisor;
68SYSCTL_UINT(_vm_memguard, OID_AUTO, divisor, CTLFLAG_RDTUN,
69 &vm_memguard_divisor,
70 0, "(kmem_size/memguard_divisor) == memguard submap size");
71
72/*
73 * Short description (ks_shortdesc) of memory type to monitor.
74 */
75static char vm_memguard_desc[128] = "";
76static struct malloc_type *vm_memguard_mtype = NULL;
77TUNABLE_STR("vm.memguard.desc", vm_memguard_desc, sizeof(vm_memguard_desc));
78static int
79memguard_sysctl_desc(SYSCTL_HANDLER_ARGS)
80{
81 char desc[sizeof(vm_memguard_desc)];
82 int error;
83
84 strlcpy(desc, vm_memguard_desc, sizeof(desc));
85 error = sysctl_handle_string(oidp, desc, sizeof(desc), req);
86 if (error != 0 || req->newptr == NULL)
87 return (error);
88
89 mtx_lock(&malloc_mtx);
90 /*
91 * If mtp is NULL, it will be initialized in memguard_cmp().
92 */
93 vm_memguard_mtype = malloc_desc2type(desc);
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
102static vm_map_t memguard_map = NULL;
103static vm_offset_t memguard_cursor;
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,
115 &memguard_mapsize, 0, "MemGuard private vm_map 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");
124SYSCTL_ULONG(_vm_memguard, OID_AUTO, fail_kva, CTLFLAG_RD,
125 &memguard_fail_kva, 0, "MemGuard failures due to lack of KVA");
126SYSCTL_ULONG(_vm_memguard, OID_AUTO, fail_pgs, CTLFLAG_RD,
127 &memguard_fail_pgs, 0, "MemGuard failures due to lack of pages");
128
|
128#define MG_GUARD 0x001
129#define MG_ALLLARGE 0x002
130static int memguard_options = MG_GUARD;
| 129#define MG_GUARD_AROUND 0x001
130#define MG_GUARD_ALLLARGE 0x002
131#define MG_GUARD_NOFREE 0x004
132static int memguard_options = MG_GUARD_AROUND;
|
131TUNABLE_INT("vm.memguard.options", &memguard_options);
132SYSCTL_INT(_vm_memguard, OID_AUTO, options, CTLFLAG_RW,
133 &memguard_options, 0,
134 "MemGuard options:\n"
135 "\t0x001 - add guard pages around each allocation\n"
| 133TUNABLE_INT("vm.memguard.options", &memguard_options);
134SYSCTL_INT(_vm_memguard, OID_AUTO, options, CTLFLAG_RW,
135 &memguard_options, 0,
136 "MemGuard options:\n"
137 "\t0x001 - add guard pages around each allocation\n"
|
136 "\t0x002 - always use MemGuard for allocations over a page");
| 138 "\t0x002 - always use MemGuard for allocations over a page\n"
139 "\t0x004 - guard uma(9) zones with UMA_ZONE_NOFREE flag");
|
137
138static u_int memguard_minsize;
139static u_long memguard_minsize_reject;
140SYSCTL_UINT(_vm_memguard, OID_AUTO, minsize, CTLFLAG_RW,
141 &memguard_minsize, 0, "Minimum size for page promotion");
142SYSCTL_ULONG(_vm_memguard, OID_AUTO, minsize_reject, CTLFLAG_RD,
143 &memguard_minsize_reject, 0, "# times rejected for size");
144
145static u_int memguard_frequency;
146static u_long memguard_frequency_hits;
147TUNABLE_INT("vm.memguard.frequency", &memguard_frequency);
148SYSCTL_UINT(_vm_memguard, OID_AUTO, frequency, CTLFLAG_RW,
149 &memguard_frequency, 0, "Times in 100000 that MemGuard will randomly run");
150SYSCTL_ULONG(_vm_memguard, OID_AUTO, frequency_hits, CTLFLAG_RD,
151 &memguard_frequency_hits, 0, "# times MemGuard randomly chose");
152
153
154/*
155 * Return a fudged value to be used for vm_kmem_size for allocating
156 * the kmem_map. The memguard memory will be a submap.
157 */
158unsigned long
159memguard_fudge(unsigned long km_size, unsigned long km_max)
160{
161 u_long mem_pgs = cnt.v_page_count;
162
163 vm_memguard_divisor = 10;
164 TUNABLE_INT_FETCH("vm.memguard.divisor", &vm_memguard_divisor);
165
166 /* Pick a conservative value if provided value sucks. */
167 if ((vm_memguard_divisor <= 0) ||
168 ((km_size / vm_memguard_divisor) == 0))
169 vm_memguard_divisor = 10;
170 /*
171 * Limit consumption of physical pages to
172 * 1/vm_memguard_divisor of system memory. If the KVA is
173 * smaller than this then the KVA limit comes into play first.
174 * This prevents memguard's page promotions from completely
175 * using up memory, since most malloc(9) calls are sub-page.
176 */
177 memguard_physlimit = (mem_pgs / vm_memguard_divisor) * PAGE_SIZE;
178 /*
179 * We want as much KVA as we can take safely. Use at most our
180 * allotted fraction of kmem_max. Limit this to twice the
181 * physical memory to avoid using too much memory as pagetable
182 * pages.
183 */
184 memguard_mapsize = km_max / vm_memguard_divisor;
185 /* size must be multiple of PAGE_SIZE */
186 memguard_mapsize = round_page(memguard_mapsize);
187 if (memguard_mapsize == 0 ||
188 memguard_mapsize / (2 * PAGE_SIZE) > mem_pgs)
189 memguard_mapsize = mem_pgs * 2 * PAGE_SIZE;
190 if (km_max > 0 && km_size + memguard_mapsize > km_max)
191 return (km_max);
192 return (km_size + memguard_mapsize);
193}
194
195/*
196 * Initialize the MemGuard mock allocator. All objects from MemGuard come
197 * out of a single VM map (contiguous chunk of address space).
198 */
199void
200memguard_init(vm_map_t parent_map)
201{
202 vm_offset_t base, limit;
203
204 memguard_map = kmem_suballoc(parent_map, &base, &limit,
205 memguard_mapsize, FALSE);
206 memguard_map->system_map = 1;
207 KASSERT(memguard_mapsize == limit - base,
208 ("Expected %lu, got %lu", (u_long)memguard_mapsize,
209 (u_long)(limit - base)));
210 memguard_cursor = base;
211
212 printf("MEMGUARD DEBUGGING ALLOCATOR INITIALIZED:\n");
213 printf("\tMEMGUARD map base: 0x%lx\n", (u_long)base);
214 printf("\tMEMGUARD map limit: 0x%lx\n", (u_long)limit);
215 printf("\tMEMGUARD map size: %jd KBytes\n",
216 (uintmax_t)memguard_mapsize >> 10);
217}
218
219/*
220 * Run things that can't be done as early as memguard_init().
221 */
222static void
223memguard_sysinit(void)
224{
225 struct sysctl_oid_list *parent;
226
227 parent = SYSCTL_STATIC_CHILDREN(_vm_memguard);
228
229 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "mapstart", CTLFLAG_RD,
230 &memguard_map->min_offset, "MemGuard KVA base");
231 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "maplimit", CTLFLAG_RD,
232 &memguard_map->max_offset, "MemGuard KVA end");
233 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "mapused", CTLFLAG_RD,
234 &memguard_map->size, "MemGuard KVA used");
235}
236SYSINIT(memguard, SI_SUB_KLD, SI_ORDER_ANY, memguard_sysinit, NULL);
237
238/*
239 * v2sizep() converts a virtual address of the first page allocated for
240 * an item to a pointer to u_long recording the size of the original
241 * allocation request.
242 *
243 * This routine is very similar to those defined by UMA in uma_int.h.
244 * The difference is that this routine stores the originally allocated
245 * size in one of the page's fields that is unused when the page is
246 * wired rather than the object field, which is used.
247 */
248static u_long *
249v2sizep(vm_offset_t va)
250{
251 vm_paddr_t pa;
252 struct vm_page *p;
253
254 pa = pmap_kextract(va);
255 if (pa == 0)
256 panic("MemGuard detected double-free of %p", (void *)va);
257 p = PHYS_TO_VM_PAGE(pa);
258 KASSERT(p->wire_count != 0 && p->queue == PQ_NONE,
259 ("MEMGUARD: Expected wired page %p in vtomgfifo!", p));
260 return ((u_long *)&p->pageq.tqe_next);
261}
262
263/*
264 * Allocate a single object of specified size with specified flags
265 * (either M_WAITOK or M_NOWAIT).
266 */
267void *
268memguard_alloc(unsigned long req_size, int flags)
269{
270 vm_offset_t addr;
271 u_long size_p, size_v;
272 int do_guard, rv;
273
274 size_p = round_page(req_size);
275 if (size_p == 0)
276 return (NULL);
277 /*
278 * To ensure there are holes on both sides of the allocation,
279 * request 2 extra pages of KVA. We will only actually add a
280 * vm_map_entry and get pages for the original request. Save
281 * the value of memguard_options so we have a consistent
282 * value.
283 */
284 size_v = size_p;
| 140
141static u_int memguard_minsize;
142static u_long memguard_minsize_reject;
143SYSCTL_UINT(_vm_memguard, OID_AUTO, minsize, CTLFLAG_RW,
144 &memguard_minsize, 0, "Minimum size for page promotion");
145SYSCTL_ULONG(_vm_memguard, OID_AUTO, minsize_reject, CTLFLAG_RD,
146 &memguard_minsize_reject, 0, "# times rejected for size");
147
148static u_int memguard_frequency;
149static u_long memguard_frequency_hits;
150TUNABLE_INT("vm.memguard.frequency", &memguard_frequency);
151SYSCTL_UINT(_vm_memguard, OID_AUTO, frequency, CTLFLAG_RW,
152 &memguard_frequency, 0, "Times in 100000 that MemGuard will randomly run");
153SYSCTL_ULONG(_vm_memguard, OID_AUTO, frequency_hits, CTLFLAG_RD,
154 &memguard_frequency_hits, 0, "# times MemGuard randomly chose");
155
156
157/*
158 * Return a fudged value to be used for vm_kmem_size for allocating
159 * the kmem_map. The memguard memory will be a submap.
160 */
161unsigned long
162memguard_fudge(unsigned long km_size, unsigned long km_max)
163{
164 u_long mem_pgs = cnt.v_page_count;
165
166 vm_memguard_divisor = 10;
167 TUNABLE_INT_FETCH("vm.memguard.divisor", &vm_memguard_divisor);
168
169 /* Pick a conservative value if provided value sucks. */
170 if ((vm_memguard_divisor <= 0) ||
171 ((km_size / vm_memguard_divisor) == 0))
172 vm_memguard_divisor = 10;
173 /*
174 * Limit consumption of physical pages to
175 * 1/vm_memguard_divisor of system memory. If the KVA is
176 * smaller than this then the KVA limit comes into play first.
177 * This prevents memguard's page promotions from completely
178 * using up memory, since most malloc(9) calls are sub-page.
179 */
180 memguard_physlimit = (mem_pgs / vm_memguard_divisor) * PAGE_SIZE;
181 /*
182 * We want as much KVA as we can take safely. Use at most our
183 * allotted fraction of kmem_max. Limit this to twice the
184 * physical memory to avoid using too much memory as pagetable
185 * pages.
186 */
187 memguard_mapsize = km_max / vm_memguard_divisor;
188 /* size must be multiple of PAGE_SIZE */
189 memguard_mapsize = round_page(memguard_mapsize);
190 if (memguard_mapsize == 0 ||
191 memguard_mapsize / (2 * PAGE_SIZE) > mem_pgs)
192 memguard_mapsize = mem_pgs * 2 * PAGE_SIZE;
193 if (km_max > 0 && km_size + memguard_mapsize > km_max)
194 return (km_max);
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
203memguard_init(vm_map_t parent_map)
204{
205 vm_offset_t base, limit;
206
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)));
213 memguard_cursor = 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,
233 &memguard_map->min_offset, "MemGuard KVA base");
234 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "maplimit", CTLFLAG_RD,
235 &memguard_map->max_offset, "MemGuard KVA end");
236 SYSCTL_ADD_ULONG(NULL, parent, OID_AUTO, "mapused", CTLFLAG_RD,
237 &memguard_map->size, "MemGuard KVA used");
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 *
246 * This routine is very similar to those defined by UMA in uma_int.h.
247 * The difference is that this routine stores the originally allocated
248 * size in one of the page's fields that is unused when the page is
249 * wired rather than the object field, which is used.
250 */
251static u_long *
252v2sizep(vm_offset_t va)
253{
254 vm_paddr_t pa;
255 struct vm_page *p;
256
257 pa = pmap_kextract(va);
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
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;
274 u_long size_p, size_v;
275 int do_guard, rv;
276
277 size_p = round_page(req_size);
278 if (size_p == 0)
279 return (NULL);
280 /*
281 * To ensure there are holes on both sides of the allocation,
282 * request 2 extra pages of KVA. We will only actually add a
283 * vm_map_entry and get pages for the original request. Save
284 * the value of memguard_options so we have a consistent
285 * value.
286 */
287 size_v = size_p;
|
285 do_guard = (memguard_options & MG_GUARD) != 0;
| 288 do_guard = (memguard_options & MG_GUARD_AROUND) != 0;
|
286 if (do_guard)
287 size_v += 2 * PAGE_SIZE;
288
289 vm_map_lock(memguard_map);
290 /*
291 * When we pass our memory limit, reject sub-page allocations.
292 * Page-size and larger allocations will use the same amount
293 * of physical memory whether we allocate or hand off to
294 * uma_large_alloc(), so keep those.
295 */
296 if (memguard_map->size >= memguard_physlimit &&
297 req_size < PAGE_SIZE) {
298 addr = (vm_offset_t)NULL;
299 memguard_fail_pgs++;
300 goto out;
301 }
302 /*
303 * Keep a moving cursor so we don't recycle KVA as long as
304 * possible. It's not perfect, since we don't know in what
305 * order previous allocations will be free'd, but it's simple
306 * and fast, and requires O(1) additional storage if guard
307 * pages are not used.
308 *
309 * XXX This scheme will lead to greater fragmentation of the
310 * map, unless vm_map_findspace() is tweaked.
311 */
312 for (;;) {
313 rv = vm_map_findspace(memguard_map, memguard_cursor,
314 size_v, &addr);
315 if (rv == KERN_SUCCESS)
316 break;
317 /*
318 * The map has no space. This may be due to
319 * fragmentation, or because the cursor is near the
320 * end of the map.
321 */
322 if (memguard_cursor == vm_map_min(memguard_map)) {
323 memguard_fail_kva++;
324 addr = (vm_offset_t)NULL;
325 goto out;
326 }
327 memguard_wrap++;
328 memguard_cursor = vm_map_min(memguard_map);
329 }
330 if (do_guard)
331 addr += PAGE_SIZE;
332 rv = kmem_back(memguard_map, addr, size_p, flags);
333 if (rv != KERN_SUCCESS) {
334 memguard_fail_pgs++;
335 addr = (vm_offset_t)NULL;
336 goto out;
337 }
338 memguard_cursor = addr + size_p;
339 *v2sizep(trunc_page(addr)) = req_size;
340 memguard_succ++;
341 if (req_size < PAGE_SIZE) {
342 memguard_wasted += (PAGE_SIZE - req_size);
343 if (do_guard) {
344 /*
345 * Align the request to 16 bytes, and return
346 * an address near the end of the page, to
347 * better detect array overrun.
348 */
349 req_size = roundup2(req_size, 16);
350 addr += (PAGE_SIZE - req_size);
351 }
352 }
353out:
354 vm_map_unlock(memguard_map);
355 return ((void *)addr);
356}
357
358int
359is_memguard_addr(void *addr)
360{
361 vm_offset_t a = (vm_offset_t)(uintptr_t)addr;
362
363 return (a >= memguard_map->min_offset && a < memguard_map->max_offset);
364}
365
366/*
367 * Free specified single object.
368 */
369void
370memguard_free(void *ptr)
371{
372 vm_offset_t addr;
373 u_long req_size, size;
374 char *temp;
375 int i;
376
377 addr = trunc_page((uintptr_t)ptr);
378 req_size = *v2sizep(addr);
379 size = round_page(req_size);
380
381 /*
382 * Page should not be guarded right now, so force a write.
383 * The purpose of this is to increase the likelihood of
384 * catching a double-free, but not necessarily a
385 * tamper-after-free (the second thread freeing might not
386 * write before freeing, so this forces it to and,
387 * subsequently, trigger a fault).
388 */
389 temp = ptr;
390 for (i = 0; i < size; i += PAGE_SIZE)
391 temp[i] = 'M';
392
393 /*
394 * This requires carnal knowledge of the implementation of
395 * kmem_free(), but since we've already replaced kmem_malloc()
396 * above, it's not really any worse. We want to use the
397 * vm_map lock to serialize updates to memguard_wasted, since
398 * we had the lock at increment.
399 */
400 vm_map_lock(memguard_map);
401 if (req_size < PAGE_SIZE)
402 memguard_wasted -= (PAGE_SIZE - req_size);
403 (void)vm_map_delete(memguard_map, addr, addr + size);
404 vm_map_unlock(memguard_map);
405}
406
407/*
408 * Re-allocate an allocation that was originally guarded.
409 */
410void *
411memguard_realloc(void *addr, unsigned long size, struct malloc_type *mtp,
412 int flags)
413{
414 void *newaddr;
415 u_long old_size;
416
417 /*
418 * Allocate the new block. Force the allocation to be guarded
419 * as the original may have been guarded through random
420 * chance, and that should be preserved.
421 */
422 if ((newaddr = memguard_alloc(size, flags)) == NULL)
423 return (NULL);
424
425 /* Copy over original contents. */
426 old_size = *v2sizep(trunc_page((uintptr_t)addr));
427 bcopy(addr, newaddr, min(size, old_size));
428 memguard_free(addr);
429 return (newaddr);
430}
431
| 289 if (do_guard)
290 size_v += 2 * PAGE_SIZE;
291
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 */
299 if (memguard_map->size >= 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 (;;) {
316 rv = vm_map_findspace(memguard_map, memguard_cursor,
317 size_v, &addr);
318 if (rv == KERN_SUCCESS)
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 */
325 if (memguard_cursor == vm_map_min(memguard_map)) {
326 memguard_fail_kva++;
327 addr = (vm_offset_t)NULL;
328 goto out;
329 }
330 memguard_wrap++;
331 memguard_cursor = vm_map_min(memguard_map);
332 }
333 if (do_guard)
334 addr += PAGE_SIZE;
335 rv = kmem_back(memguard_map, addr, size_p, flags);
336 if (rv != KERN_SUCCESS) {
337 memguard_fail_pgs++;
338 addr = (vm_offset_t)NULL;
339 goto out;
340 }
341 memguard_cursor = addr + size_p;
342 *v2sizep(trunc_page(addr)) = req_size;
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:
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
366 return (a >= memguard_map->min_offset && a < memguard_map->max_offset);
367}
368
369/*
370 * Free specified single object.
371 */
372void
373memguard_free(void *ptr)
374{
375 vm_offset_t addr;
376 u_long req_size, size;
377 char *temp;
378 int i;
379
380 addr = trunc_page((uintptr_t)ptr);
381 req_size = *v2sizep(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,
390 * subsequently, trigger a fault).
391 */
392 temp = ptr;
393 for (i = 0; i < size; i += PAGE_SIZE)
394 temp[i] = 'M';
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 */
403 vm_map_lock(memguard_map);
404 if (req_size < PAGE_SIZE)
405 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)
416{
417 void *newaddr;
418 u_long old_size;
419
420 /*
421 * Allocate the new block. Force the allocation to be guarded
422 * as the original may have been guarded through random
423 * chance, and that should be preserved.
424 */
425 if ((newaddr = memguard_alloc(size, flags)) == NULL)
426 return (NULL);
427
428 /* Copy over original contents. */
429 old_size = *v2sizep(trunc_page((uintptr_t)addr));
430 bcopy(addr, newaddr, min(size, old_size));
431 memguard_free(addr);
432 return (newaddr);
433}
434
|
432int
433memguard_cmp(struct malloc_type *mtp, unsigned long size)
| 435static int
436memguard_cmp(unsigned long size)
|
434{
435
436 if (size < memguard_minsize) {
437 memguard_minsize_reject++;
438 return (0);
439 }
| 437{
438
439 if (size < memguard_minsize) {
440 memguard_minsize_reject++;
441 return (0);
442 }
|
440 if ((memguard_options & MG_ALLLARGE) != 0 && size >= PAGE_SIZE)
| 443 if ((memguard_options & MG_GUARD_ALLLARGE) != 0 && size >= PAGE_SIZE)
|
441 return (1);
442 if (memguard_frequency > 0 &&
443 (random() % 100000) < memguard_frequency) {
444 memguard_frequency_hits++;
445 return (1);
446 }
| 444 return (1);
445 if (memguard_frequency > 0 &&
446 (random() % 100000) < memguard_frequency) {
447 memguard_frequency_hits++;
448 return (1);
449 }
|
| 450
451 return (0);
452}
453
454int
455memguard_cmp_mtp(struct malloc_type *mtp, unsigned long size)
456{
457
458 if (memguard_cmp(size))
459 return(1);
460
|
447#if 1
448 /*
449 * The safest way of comparsion is to always compare short description
450 * string of memory type, but it is also the slowest way.
451 */
452 return (strcmp(mtp->ks_shortdesc, vm_memguard_desc) == 0);
453#else
454 /*
455 * If we compare pointers, there are two possible problems:
456 * 1. Memory type was unloaded and new memory type was allocated at the
457 * same address.
458 * 2. Memory type was unloaded and loaded again, but allocated at a
459 * different address.
460 */
461 if (vm_memguard_mtype != NULL)
462 return (mtp == vm_memguard_mtype);
463 if (strcmp(mtp->ks_shortdesc, vm_memguard_desc) == 0) {
464 vm_memguard_mtype = mtp;
465 return (1);
466 }
467 return (0);
468#endif
469}
| 461#if 1
462 /*
463 * The safest way of comparsion is to always compare short description
464 * string of memory type, but it is also the slowest way.
465 */
466 return (strcmp(mtp->ks_shortdesc, vm_memguard_desc) == 0);
467#else
468 /*
469 * If we compare pointers, there are two possible problems:
470 * 1. Memory type was unloaded and new memory type was allocated at the
471 * same address.
472 * 2. Memory type was unloaded and loaded again, but allocated at a
473 * different address.
474 */
475 if (vm_memguard_mtype != NULL)
476 return (mtp == vm_memguard_mtype);
477 if (strcmp(mtp->ks_shortdesc, vm_memguard_desc) == 0) {
478 vm_memguard_mtype = mtp;
479 return (1);
480 }
481 return (0);
482#endif
483}
|
| 484
485int
486memguard_cmp_zone(uma_zone_t zone)
487{
488
489 if ((memguard_options & MG_GUARD_NOFREE) == 0 &&
490 zone->uz_flags & UMA_ZONE_NOFREE)
491 return (0);
492
493 if (memguard_cmp(zone->uz_size))
494 return (1);
495
496 /*
497 * The safest way of comparsion is to always compare zone name,
498 * but it is also the slowest way.
499 */
500 return (strcmp(zone->uz_name, vm_memguard_desc) == 0);
501}
|
| |