monitor_mm.c revision 262566 
1/* $OpenBSD: monitor_mm.c,v 1.19 2014/01/04 17:50:55 tedu 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 <stddef.h>
39#include <stdlib.h>
40#include <string.h>
41
42#include "xmalloc.h"
43#include "ssh.h"
44#include "log.h"
45#include "monitor_mm.h"
46
47static int
48mm_compare(struct mm_share *a, struct mm_share *b)
49{
50	ptrdiff_t diff = (char *)a->address - (char *)b->address;
51
52	if (diff == 0)
53		return (0);
54	else if (diff < 0)
55		return (-1);
56	else
57		return (1);
58}
59
60RB_GENERATE(mmtree, mm_share, next, mm_compare)
61
62static struct mm_share *
63mm_make_entry(struct mm_master *mm, struct mmtree *head,
64    void *address, size_t size)
65{
66	struct mm_share *tmp, *tmp2;
67
68	if (mm->mmalloc == NULL)
69		tmp = xcalloc(1, sizeof(struct mm_share));
70	else
71		tmp = mm_xmalloc(mm->mmalloc, sizeof(struct mm_share));
72	tmp->address = address;
73	tmp->size = size;
74
75	tmp2 = RB_INSERT(mmtree, head, tmp);
76	if (tmp2 != NULL)
77		fatal("mm_make_entry(%p): double address %p->%p(%zu)",
78		    mm, tmp2, address, size);
79
80	return (tmp);
81}
82
83/* Creates a shared memory area of a certain size */
84
85struct mm_master *
86mm_create(struct mm_master *mmalloc, size_t size)
87{
88	void *address;
89	struct mm_master *mm;
90
91	if (mmalloc == NULL)
92		mm = xcalloc(1, sizeof(struct mm_master));
93	else
94		mm = mm_xmalloc(mmalloc, sizeof(struct mm_master));
95
96	/*
97	 * If the memory map has a mm_master it can be completely
98	 * shared including authentication between the child
99	 * and the client.
100	 */
101	mm->mmalloc = mmalloc;
102
103	address = xmmap(size);
104	if (address == (void *)MAP_FAILED)
105		fatal("mmap(%zu): %s", size, strerror(errno));
106
107	mm->address = address;
108	mm->size = size;
109
110	RB_INIT(&mm->rb_free);
111	RB_INIT(&mm->rb_allocated);
112
113	mm_make_entry(mm, &mm->rb_free, address, size);
114
115	return (mm);
116}
117
118/* Frees either the allocated or the free list */
119
120static void
121mm_freelist(struct mm_master *mmalloc, struct mmtree *head)
122{
123	struct mm_share *mms, *next;
124
125	for (mms = RB_ROOT(head); mms; mms = next) {
126		next = RB_NEXT(mmtree, head, mms);
127		RB_REMOVE(mmtree, head, mms);
128		if (mmalloc == NULL)
129			free(mms);
130		else
131			mm_free(mmalloc, mms);
132	}
133}
134
135/* Destroys a memory mapped area */
136
137void
138mm_destroy(struct mm_master *mm)
139{
140	mm_freelist(mm->mmalloc, &mm->rb_free);
141	mm_freelist(mm->mmalloc, &mm->rb_allocated);
142
143#ifdef HAVE_MMAP
144	if (munmap(mm->address, mm->size) == -1)
145		fatal("munmap(%p, %zu): %s", mm->address, mm->size,
146		    strerror(errno));
147#else
148	fatal("%s: UsePrivilegeSeparation=yes and Compression=yes not supported",
149	    __func__);
150#endif
151	if (mm->mmalloc == NULL)
152		free(mm);
153	else
154		mm_free(mm->mmalloc, mm);
155}
156
157void *
158mm_xmalloc(struct mm_master *mm, size_t size)
159{
160	void *address;
161
162	address = mm_malloc(mm, size);
163	if (address == NULL)
164		fatal("%s: mm_malloc(%zu)", __func__, size);
165	memset(address, 0, size);
166	return (address);
167}
168
169
170/* Allocates data from a memory mapped area */
171
172void *
173mm_malloc(struct mm_master *mm, size_t size)
174{
175	struct mm_share *mms, *tmp;
176
177	if (size == 0)
178		fatal("mm_malloc: try to allocate 0 space");
179	if (size > SIZE_T_MAX - MM_MINSIZE + 1)
180		fatal("mm_malloc: size too big");
181
182	size = ((size + (MM_MINSIZE - 1)) / MM_MINSIZE) * MM_MINSIZE;
183
184	RB_FOREACH(mms, mmtree, &mm->rb_free) {
185		if (mms->size >= size)
186			break;
187	}
188
189	if (mms == NULL)
190		return (NULL);
191
192	/* Debug */
193	memset(mms->address, 0xd0, size);
194
195	tmp = mm_make_entry(mm, &mm->rb_allocated, mms->address, size);
196
197	/* Does not change order in RB tree */
198	mms->size -= size;
199	mms->address = (char *)mms->address + size;
200
201	if (mms->size == 0) {
202		RB_REMOVE(mmtree, &mm->rb_free, mms);
203		if (mm->mmalloc == NULL)
204			free(mms);
205		else
206			mm_free(mm->mmalloc, mms);
207	}
208
209	return (tmp->address);
210}
211
212/* Frees memory in a memory mapped area */
213
214void
215mm_free(struct mm_master *mm, void *address)
216{
217	struct mm_share *mms, *prev, tmp;
218
219	tmp.address = address;
220	mms = RB_FIND(mmtree, &mm->rb_allocated, &tmp);
221	if (mms == NULL)
222		fatal("mm_free(%p): can not find %p", mm, address);
223
224	/* Debug */
225	memset(mms->address, 0xd0, mms->size);
226
227	/* Remove from allocated list and insert in free list */
228	RB_REMOVE(mmtree, &mm->rb_allocated, mms);
229	if (RB_INSERT(mmtree, &mm->rb_free, mms) != NULL)
230		fatal("mm_free(%p): double address %p", mm, address);
231
232	/* Find previous entry */
233	prev = mms;
234	if (RB_LEFT(prev, next)) {
235		prev = RB_LEFT(prev, next);
236		while (RB_RIGHT(prev, next))
237			prev = RB_RIGHT(prev, next);
238	} else {
239		if (RB_PARENT(prev, next) &&
240		    (prev == RB_RIGHT(RB_PARENT(prev, next), next)))
241			prev = RB_PARENT(prev, next);
242		else {
243			while (RB_PARENT(prev, next) &&
244			    (prev == RB_LEFT(RB_PARENT(prev, next), next)))
245				prev = RB_PARENT(prev, next);
246			prev = RB_PARENT(prev, next);
247		}
248	}
249
250	/* Check if range does not overlap */
251	if (prev != NULL && MM_ADDRESS_END(prev) > address)
252		fatal("mm_free: memory corruption: %p(%zu) > %p",
253		    prev->address, prev->size, address);
254
255	/* See if we can merge backwards */
256	if (prev != NULL && MM_ADDRESS_END(prev) == address) {
257		prev->size += mms->size;
258		RB_REMOVE(mmtree, &mm->rb_free, mms);
259		if (mm->mmalloc == NULL)
260			free(mms);
261		else
262			mm_free(mm->mmalloc, mms);
263	} else
264		prev = mms;
265
266	if (prev == NULL)
267		return;
268
269	/* Check if we can merge forwards */
270	mms = RB_NEXT(mmtree, &mm->rb_free, prev);
271	if (mms == NULL)
272		return;
273
274	if (MM_ADDRESS_END(prev) > mms->address)
275		fatal("mm_free: memory corruption: %p < %p(%zu)",
276		    mms->address, prev->address, prev->size);
277	if (MM_ADDRESS_END(prev) != mms->address)
278		return;
279
280	prev->size += mms->size;
281	RB_REMOVE(mmtree, &mm->rb_free, mms);
282
283	if (mm->mmalloc == NULL)
284		free(mms);
285	else
286		mm_free(mm->mmalloc, mms);
287}
288
289static void
290mm_sync_list(struct mmtree *oldtree, struct mmtree *newtree,
291    struct mm_master *mm, struct mm_master *mmold)
292{
293	struct mm_master *mmalloc = mm->mmalloc;
294	struct mm_share *mms, *new;
295
296	/* Sync free list */
297	RB_FOREACH(mms, mmtree, oldtree) {
298		/* Check the values */
299		mm_memvalid(mmold, mms, sizeof(struct mm_share));
300		mm_memvalid(mm, mms->address, mms->size);
301
302		new = mm_xmalloc(mmalloc, sizeof(struct mm_share));
303		memcpy(new, mms, sizeof(struct mm_share));
304		RB_INSERT(mmtree, newtree, new);
305	}
306}
307
308void
309mm_share_sync(struct mm_master **pmm, struct mm_master **pmmalloc)
310{
311	struct mm_master *mm;
312	struct mm_master *mmalloc;
313	struct mm_master *mmold;
314	struct mmtree rb_free, rb_allocated;
315
316	debug3("%s: Share sync", __func__);
317
318	mm = *pmm;
319	mmold = mm->mmalloc;
320	mm_memvalid(mmold, mm, sizeof(*mm));
321
322	mmalloc = mm_create(NULL, mm->size);
323	mm = mm_xmalloc(mmalloc, sizeof(struct mm_master));
324	memcpy(mm, *pmm, sizeof(struct mm_master));
325	mm->mmalloc = mmalloc;
326
327	rb_free = mm->rb_free;
328	rb_allocated = mm->rb_allocated;
329
330	RB_INIT(&mm->rb_free);
331	RB_INIT(&mm->rb_allocated);
332
333	mm_sync_list(&rb_free, &mm->rb_free, mm, mmold);
334	mm_sync_list(&rb_allocated, &mm->rb_allocated, mm, mmold);
335
336	mm_destroy(mmold);
337
338	*pmm = mm;
339	*pmmalloc = mmalloc;
340
341	debug3("%s: Share sync end", __func__);
342}
343
344void
345mm_memvalid(struct mm_master *mm, void *address, size_t size)
346{
347	void *end = (char *)address + size;
348
349	if (address < mm->address)
350		fatal("mm_memvalid: address too small: %p", address);
351	if (end < address)
352		fatal("mm_memvalid: end < address: %p < %p", end, address);
353	if (end > MM_ADDRESS_END(mm))
354		fatal("mm_memvalid: address too large: %p", address);
355}
356