monitor_mm.c revision 295367 
1/* $OpenBSD: monitor_mm.c,v 1.21 2015/02/06 23:21:59 millert Exp $ */
2/*
3 * Copyright 2002 Niels Provos <provos@citi.umich.edu>
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, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "includes.h"
28
29#include <sys/types.h>
30#ifdef HAVE_SYS_MMAN_H
31#include <sys/mman.h>
32#endif
33#include "openbsd-compat/sys-tree.h"
34
35#include <errno.h>
36#include <stdarg.h>
37#include <stddef.h>
38#ifdef HAVE_STDINT_H
39#include <stdint.h>
40#endif
41#include <stdlib.h>
42#include <string.h>
43
44#include "xmalloc.h"
45#include "ssh.h"
46#include "log.h"
47#include "monitor_mm.h"
48
49static int
50mm_compare(struct mm_share *a, struct mm_share *b)
51{
52	ptrdiff_t diff = (char *)a->address - (char *)b->address;
53
54	if (diff == 0)
55		return (0);
56	else if (diff < 0)
57		return (-1);
58	else
59		return (1);
60}
61
62RB_GENERATE(mmtree, mm_share, next, mm_compare)
63
64static struct mm_share *
65mm_make_entry(struct mm_master *mm, struct mmtree *head,
66    void *address, size_t size)
67{
68	struct mm_share *tmp, *tmp2;
69
70	if (mm->mmalloc == NULL)
71		tmp = xcalloc(1, sizeof(struct mm_share));
72	else
73		tmp = mm_xmalloc(mm->mmalloc, sizeof(struct mm_share));
74	tmp->address = address;
75	tmp->size = size;
76
77	tmp2 = RB_INSERT(mmtree, head, tmp);
78	if (tmp2 != NULL)
79		fatal("mm_make_entry(%p): double address %p->%p(%zu)",
80		    mm, tmp2, address, size);
81
82	return (tmp);
83}
84
85/* Creates a shared memory area of a certain size */
86
87struct mm_master *
88mm_create(struct mm_master *mmalloc, size_t size)
89{
90	void *address;
91	struct mm_master *mm;
92
93	if (mmalloc == NULL)
94		mm = xcalloc(1, sizeof(struct mm_master));
95	else
96		mm = mm_xmalloc(mmalloc, sizeof(struct mm_master));
97
98	/*
99	 * If the memory map has a mm_master it can be completely
100	 * shared including authentication between the child
101	 * and the client.
102	 */
103	mm->mmalloc = mmalloc;
104
105	address = xmmap(size);
106	if (address == (void *)MAP_FAILED)
107		fatal("mmap(%zu): %s", size, strerror(errno));
108
109	mm->address = address;
110	mm->size = size;
111
112	RB_INIT(&mm->rb_free);
113	RB_INIT(&mm->rb_allocated);
114
115	mm_make_entry(mm, &mm->rb_free, address, size);
116
117	return (mm);
118}
119
120/* Frees either the allocated or the free list */
121
122static void
123mm_freelist(struct mm_master *mmalloc, struct mmtree *head)
124{
125	struct mm_share *mms, *next;
126
127	for (mms = RB_ROOT(head); mms; mms = next) {
128		next = RB_NEXT(mmtree, head, mms);
129		RB_REMOVE(mmtree, head, mms);
130		if (mmalloc == NULL)
131			free(mms);
132		else
133			mm_free(mmalloc, mms);
134	}
135}
136
137/* Destroys a memory mapped area */
138
139void
140mm_destroy(struct mm_master *mm)
141{
142	mm_freelist(mm->mmalloc, &mm->rb_free);
143	mm_freelist(mm->mmalloc, &mm->rb_allocated);
144
145#ifdef HAVE_MMAP
146	if (munmap(mm->address, mm->size) == -1)
147		fatal("munmap(%p, %zu): %s", mm->address, mm->size,
148		    strerror(errno));
149#else
150	fatal("%s: UsePrivilegeSeparation=yes and Compression=yes not supported",
151	    __func__);
152#endif
153	if (mm->mmalloc == NULL)
154		free(mm);
155	else
156		mm_free(mm->mmalloc, mm);
157}
158
159void *
160mm_xmalloc(struct mm_master *mm, size_t size)
161{
162	void *address;
163
164	address = mm_malloc(mm, size);
165	if (address == NULL)
166		fatal("%s: mm_malloc(%zu)", __func__, size);
167	memset(address, 0, size);
168	return (address);
169}
170
171
172/* Allocates data from a memory mapped area */
173
174void *
175mm_malloc(struct mm_master *mm, size_t size)
176{
177	struct mm_share *mms, *tmp;
178
179	if (size == 0)
180		fatal("mm_malloc: try to allocate 0 space");
181	if (size > SIZE_MAX - MM_MINSIZE + 1)
182		fatal("mm_malloc: size too big");
183
184	size = ((size + (MM_MINSIZE - 1)) / MM_MINSIZE) * MM_MINSIZE;
185
186	RB_FOREACH(mms, mmtree, &mm->rb_free) {
187		if (mms->size >= size)
188			break;
189	}
190
191	if (mms == NULL)
192		return (NULL);
193
194	/* Debug */
195	memset(mms->address, 0xd0, size);
196
197	tmp = mm_make_entry(mm, &mm->rb_allocated, mms->address, size);
198
199	/* Does not change order in RB tree */
200	mms->size -= size;
201	mms->address = (char *)mms->address + size;
202
203	if (mms->size == 0) {
204		RB_REMOVE(mmtree, &mm->rb_free, mms);
205		if (mm->mmalloc == NULL)
206			free(mms);
207		else
208			mm_free(mm->mmalloc, mms);
209	}
210
211	return (tmp->address);
212}
213
214/* Frees memory in a memory mapped area */
215
216void
217mm_free(struct mm_master *mm, void *address)
218{
219	struct mm_share *mms, *prev, tmp;
220
221	tmp.address = address;
222	mms = RB_FIND(mmtree, &mm->rb_allocated, &tmp);
223	if (mms == NULL)
224		fatal("mm_free(%p): can not find %p", mm, address);
225
226	/* Debug */
227	memset(mms->address, 0xd0, mms->size);
228
229	/* Remove from allocated list and insert in free list */
230	RB_REMOVE(mmtree, &mm->rb_allocated, mms);
231	if (RB_INSERT(mmtree, &mm->rb_free, mms) != NULL)
232		fatal("mm_free(%p): double address %p", mm, address);
233
234	/* Find previous entry */
235	prev = mms;
236	if (RB_LEFT(prev, next)) {
237		prev = RB_LEFT(prev, next);
238		while (RB_RIGHT(prev, next))
239			prev = RB_RIGHT(prev, next);
240	} else {
241		if (RB_PARENT(prev, next) &&
242		    (prev == RB_RIGHT(RB_PARENT(prev, next), next)))
243			prev = RB_PARENT(prev, next);
244		else {
245			while (RB_PARENT(prev, next) &&
246			    (prev == RB_LEFT(RB_PARENT(prev, next), next)))
247				prev = RB_PARENT(prev, next);
248			prev = RB_PARENT(prev, next);
249		}
250	}
251
252	/* Check if range does not overlap */
253	if (prev != NULL && MM_ADDRESS_END(prev) > address)
254		fatal("mm_free: memory corruption: %p(%zu) > %p",
255		    prev->address, prev->size, address);
256
257	/* See if we can merge backwards */
258	if (prev != NULL && MM_ADDRESS_END(prev) == address) {
259		prev->size += mms->size;
260		RB_REMOVE(mmtree, &mm->rb_free, mms);
261		if (mm->mmalloc == NULL)
262			free(mms);
263		else
264			mm_free(mm->mmalloc, mms);
265	} else
266		prev = mms;
267
268	if (prev == NULL)
269		return;
270
271	/* Check if we can merge forwards */
272	mms = RB_NEXT(mmtree, &mm->rb_free, prev);
273	if (mms == NULL)
274		return;
275
276	if (MM_ADDRESS_END(prev) > mms->address)
277		fatal("mm_free: memory corruption: %p < %p(%zu)",
278		    mms->address, prev->address, prev->size);
279	if (MM_ADDRESS_END(prev) != mms->address)
280		return;
281
282	prev->size += mms->size;
283	RB_REMOVE(mmtree, &mm->rb_free, mms);
284
285	if (mm->mmalloc == NULL)
286		free(mms);
287	else
288		mm_free(mm->mmalloc, mms);
289}
290
291static void
292mm_sync_list(struct mmtree *oldtree, struct mmtree *newtree,
293    struct mm_master *mm, struct mm_master *mmold)
294{
295	struct mm_master *mmalloc = mm->mmalloc;
296	struct mm_share *mms, *new;
297
298	/* Sync free list */
299	RB_FOREACH(mms, mmtree, oldtree) {
300		/* Check the values */
301		mm_memvalid(mmold, mms, sizeof(struct mm_share));
302		mm_memvalid(mm, mms->address, mms->size);
303
304		new = mm_xmalloc(mmalloc, sizeof(struct mm_share));
305		memcpy(new, mms, sizeof(struct mm_share));
306		RB_INSERT(mmtree, newtree, new);
307	}
308}
309
310void
311mm_share_sync(struct mm_master **pmm, struct mm_master **pmmalloc)
312{
313	struct mm_master *mm;
314	struct mm_master *mmalloc;
315	struct mm_master *mmold;
316	struct mmtree rb_free, rb_allocated;
317
318	debug3("%s: Share sync", __func__);
319
320	mm = *pmm;
321	mmold = mm->mmalloc;
322	mm_memvalid(mmold, mm, sizeof(*mm));
323
324	mmalloc = mm_create(NULL, mm->size);
325	mm = mm_xmalloc(mmalloc, sizeof(struct mm_master));
326	memcpy(mm, *pmm, sizeof(struct mm_master));
327	mm->mmalloc = mmalloc;
328
329	rb_free = mm->rb_free;
330	rb_allocated = mm->rb_allocated;
331
332	RB_INIT(&mm->rb_free);
333	RB_INIT(&mm->rb_allocated);
334
335	mm_sync_list(&rb_free, &mm->rb_free, mm, mmold);
336	mm_sync_list(&rb_allocated, &mm->rb_allocated, mm, mmold);
337
338	mm_destroy(mmold);
339
340	*pmm = mm;
341	*pmmalloc = mmalloc;
342
343	debug3("%s: Share sync end", __func__);
344}
345
346void
347mm_memvalid(struct mm_master *mm, void *address, size_t size)
348{
349	void *end = (char *)address + size;
350
351	if (address < mm->address)
352		fatal("mm_memvalid: address too small: %p", address);
353	if (end < address)
354		fatal("mm_memvalid: end < address: %p < %p", end, address);
355	if (end > MM_ADDRESS_END(mm))
356		fatal("mm_memvalid: address too large: %p", address);
357}
358