monitor_mm.c revision 258343 
1/* $OpenBSD: monitor_mm.c,v 1.18 2013/11/08 00:39:15 djm 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 <sys/param.h>
34#include "openbsd-compat/sys-tree.h"
35
36#include <errno.h>
37#include <stdarg.h>
38#include <stdlib.h>
39#include <string.h>
40
41#include "xmalloc.h"
42#include "ssh.h"
43#include "log.h"
44#include "monitor_mm.h"
45
46static int
47mm_compare(struct mm_share *a, struct mm_share *b)
48{
49	long diff = (char *)a->address - (char *)b->address;
50
51	if (diff == 0)
52		return (0);
53	else if (diff < 0)
54		return (-1);
55	else
56		return (1);
57}
58
59RB_GENERATE(mmtree, mm_share, next, mm_compare)
60
61static struct mm_share *
62mm_make_entry(struct mm_master *mm, struct mmtree *head,
63    void *address, size_t size)
64{
65	struct mm_share *tmp, *tmp2;
66
67	if (mm->mmalloc == NULL)
68		tmp = xcalloc(1, sizeof(struct mm_share));
69	else
70		tmp = mm_xmalloc(mm->mmalloc, sizeof(struct mm_share));
71	tmp->address = address;
72	tmp->size = size;
73
74	tmp2 = RB_INSERT(mmtree, head, tmp);
75	if (tmp2 != NULL)
76		fatal("mm_make_entry(%p): double address %p->%p(%lu)",
77		    mm, tmp2, address, (u_long)size);
78
79	return (tmp);
80}
81
82/* Creates a shared memory area of a certain size */
83
84struct mm_master *
85mm_create(struct mm_master *mmalloc, size_t size)
86{
87	void *address;
88	struct mm_master *mm;
89
90	if (mmalloc == NULL)
91		mm = xcalloc(1, sizeof(struct mm_master));
92	else
93		mm = mm_xmalloc(mmalloc, sizeof(struct mm_master));
94
95	/*
96	 * If the memory map has a mm_master it can be completely
97	 * shared including authentication between the child
98	 * and the client.
99	 */
100	mm->mmalloc = mmalloc;
101
102	address = xmmap(size);
103	if (address == (void *)MAP_FAILED)
104		fatal("mmap(%lu): %s", (u_long)size, strerror(errno));
105
106	mm->address = address;
107	mm->size = size;
108
109	RB_INIT(&mm->rb_free);
110	RB_INIT(&mm->rb_allocated);
111
112	mm_make_entry(mm, &mm->rb_free, address, size);
113
114	return (mm);
115}
116
117/* Frees either the allocated or the free list */
118
119static void
120mm_freelist(struct mm_master *mmalloc, struct mmtree *head)
121{
122	struct mm_share *mms, *next;
123
124	for (mms = RB_ROOT(head); mms; mms = next) {
125		next = RB_NEXT(mmtree, head, mms);
126		RB_REMOVE(mmtree, head, mms);
127		if (mmalloc == NULL)
128			free(mms);
129		else
130			mm_free(mmalloc, mms);
131	}
132}
133
134/* Destroys a memory mapped area */
135
136void
137mm_destroy(struct mm_master *mm)
138{
139	mm_freelist(mm->mmalloc, &mm->rb_free);
140	mm_freelist(mm->mmalloc, &mm->rb_allocated);
141
142#ifdef HAVE_MMAP
143	if (munmap(mm->address, mm->size) == -1)
144		fatal("munmap(%p, %lu): %s", mm->address, (u_long)mm->size,
145		    strerror(errno));
146#else
147	fatal("%s: UsePrivilegeSeparation=yes and Compression=yes not supported",
148	    __func__);
149#endif
150	if (mm->mmalloc == NULL)
151		free(mm);
152	else
153		mm_free(mm->mmalloc, mm);
154}
155
156void *
157mm_xmalloc(struct mm_master *mm, size_t size)
158{
159	void *address;
160
161	address = mm_malloc(mm, size);
162	if (address == NULL)
163		fatal("%s: mm_malloc(%lu)", __func__, (u_long)size);
164	memset(address, 0, size);
165	return (address);
166}
167
168
169/* Allocates data from a memory mapped area */
170
171void *
172mm_malloc(struct mm_master *mm, size_t size)
173{
174	struct mm_share *mms, *tmp;
175
176	if (size == 0)
177		fatal("mm_malloc: try to allocate 0 space");
178	if (size > SIZE_T_MAX - MM_MINSIZE + 1)
179		fatal("mm_malloc: size too big");
180
181	size = ((size + (MM_MINSIZE - 1)) / MM_MINSIZE) * MM_MINSIZE;
182
183	RB_FOREACH(mms, mmtree, &mm->rb_free) {
184		if (mms->size >= size)
185			break;
186	}
187
188	if (mms == NULL)
189		return (NULL);
190
191	/* Debug */
192	memset(mms->address, 0xd0, size);
193
194	tmp = mm_make_entry(mm, &mm->rb_allocated, mms->address, size);
195
196	/* Does not change order in RB tree */
197	mms->size -= size;
198	mms->address = (u_char *)mms->address + size;
199
200	if (mms->size == 0) {
201		RB_REMOVE(mmtree, &mm->rb_free, mms);
202		if (mm->mmalloc == NULL)
203			free(mms);
204		else
205			mm_free(mm->mmalloc, mms);
206	}
207
208	return (tmp->address);
209}
210
211/* Frees memory in a memory mapped area */
212
213void
214mm_free(struct mm_master *mm, void *address)
215{
216	struct mm_share *mms, *prev, tmp;
217
218	tmp.address = address;
219	mms = RB_FIND(mmtree, &mm->rb_allocated, &tmp);
220	if (mms == NULL)
221		fatal("mm_free(%p): can not find %p", mm, address);
222
223	/* Debug */
224	memset(mms->address, 0xd0, mms->size);
225
226	/* Remove from allocated list and insert in free list */
227	RB_REMOVE(mmtree, &mm->rb_allocated, mms);
228	if (RB_INSERT(mmtree, &mm->rb_free, mms) != NULL)
229		fatal("mm_free(%p): double address %p", mm, address);
230
231	/* Find previous entry */
232	prev = mms;
233	if (RB_LEFT(prev, next)) {
234		prev = RB_LEFT(prev, next);
235		while (RB_RIGHT(prev, next))
236			prev = RB_RIGHT(prev, next);
237	} else {
238		if (RB_PARENT(prev, next) &&
239		    (prev == RB_RIGHT(RB_PARENT(prev, next), next)))
240			prev = RB_PARENT(prev, next);
241		else {
242			while (RB_PARENT(prev, next) &&
243			    (prev == RB_LEFT(RB_PARENT(prev, next), next)))
244				prev = RB_PARENT(prev, next);
245			prev = RB_PARENT(prev, next);
246		}
247	}
248
249	/* Check if range does not overlap */
250	if (prev != NULL && MM_ADDRESS_END(prev) > address)
251		fatal("mm_free: memory corruption: %p(%lu) > %p",
252		    prev->address, (u_long)prev->size, address);
253
254	/* See if we can merge backwards */
255	if (prev != NULL && MM_ADDRESS_END(prev) == address) {
256		prev->size += mms->size;
257		RB_REMOVE(mmtree, &mm->rb_free, mms);
258		if (mm->mmalloc == NULL)
259			free(mms);
260		else
261			mm_free(mm->mmalloc, mms);
262	} else
263		prev = mms;
264
265	if (prev == NULL)
266		return;
267
268	/* Check if we can merge forwards */
269	mms = RB_NEXT(mmtree, &mm->rb_free, prev);
270	if (mms == NULL)
271		return;
272
273	if (MM_ADDRESS_END(prev) > mms->address)
274		fatal("mm_free: memory corruption: %p < %p(%lu)",
275		    mms->address, prev->address, (u_long)prev->size);
276	if (MM_ADDRESS_END(prev) != mms->address)
277		return;
278
279	prev->size += mms->size;
280	RB_REMOVE(mmtree, &mm->rb_free, mms);
281
282	if (mm->mmalloc == NULL)
283		free(mms);
284	else
285		mm_free(mm->mmalloc, mms);
286}
287
288static void
289mm_sync_list(struct mmtree *oldtree, struct mmtree *newtree,
290    struct mm_master *mm, struct mm_master *mmold)
291{
292	struct mm_master *mmalloc = mm->mmalloc;
293	struct mm_share *mms, *new;
294
295	/* Sync free list */
296	RB_FOREACH(mms, mmtree, oldtree) {
297		/* Check the values */
298		mm_memvalid(mmold, mms, sizeof(struct mm_share));
299		mm_memvalid(mm, mms->address, mms->size);
300
301		new = mm_xmalloc(mmalloc, sizeof(struct mm_share));
302		memcpy(new, mms, sizeof(struct mm_share));
303		RB_INSERT(mmtree, newtree, new);
304	}
305}
306
307void
308mm_share_sync(struct mm_master **pmm, struct mm_master **pmmalloc)
309{
310	struct mm_master *mm;
311	struct mm_master *mmalloc;
312	struct mm_master *mmold;
313	struct mmtree rb_free, rb_allocated;
314
315	debug3("%s: Share sync", __func__);
316
317	mm = *pmm;
318	mmold = mm->mmalloc;
319	mm_memvalid(mmold, mm, sizeof(*mm));
320
321	mmalloc = mm_create(NULL, mm->size);
322	mm = mm_xmalloc(mmalloc, sizeof(struct mm_master));
323	memcpy(mm, *pmm, sizeof(struct mm_master));
324	mm->mmalloc = mmalloc;
325
326	rb_free = mm->rb_free;
327	rb_allocated = mm->rb_allocated;
328
329	RB_INIT(&mm->rb_free);
330	RB_INIT(&mm->rb_allocated);
331
332	mm_sync_list(&rb_free, &mm->rb_free, mm, mmold);
333	mm_sync_list(&rb_allocated, &mm->rb_allocated, mm, mmold);
334
335	mm_destroy(mmold);
336
337	*pmm = mm;
338	*pmmalloc = mmalloc;
339
340	debug3("%s: Share sync end", __func__);
341}
342
343void
344mm_memvalid(struct mm_master *mm, void *address, size_t size)
345{
346	void *end = (u_char *)address + size;
347
348	if (address < mm->address)
349		fatal("mm_memvalid: address too small: %p", address);
350	if (end < address)
351		fatal("mm_memvalid: end < address: %p < %p", end, address);
352	if (end > (void *)((u_char *)mm->address + mm->size))
353		fatal("mm_memvalid: address too large: %p", address);
354}
355