monitor_mm.c

   1 /* $OpenBSD: monitor_mm.c,v 1.15 2006/08/03 03:34:42 deraadt 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 <string.h>
  39
  40 #include "xmalloc.h"
  41 #include "ssh.h"
  42 #include "log.h"
  43 #include "monitor_mm.h"
  44
  45 static int
  46 mm_compare(struct mm_share *a, struct mm_share *b)
  47 {
  48         long diff = (char *)a->address - (char *)b->address;
  49
  50         if (diff == 0)
  51                 return (0);
  52         else if (diff < 0)
  53                 return (-1);
  54         else
  55                 return (1);
  56 }
  57
  58 RB_GENERATE(mmtree, mm_share, next, mm_compare)
  59
  60 static struct mm_share *
  61 mm_make_entry(struct mm_master *mm, struct mmtree *head,
  62     void *address, size_t size)
  63 {
  64         struct mm_share *tmp, *tmp2;
  65
  66         if (mm->mmalloc == NULL)
  67                 tmp = xmalloc(sizeof(struct mm_share));
  68         else
  69                 tmp = mm_xmalloc(mm->mmalloc, sizeof(struct mm_share));
  70         tmp->address = address;
  71         tmp->size = size;
  72
  73         tmp2 = RB_INSERT(mmtree, head, tmp);
  74         if (tmp2 != NULL)
  75                 fatal("mm_make_entry(%p): double address %p->%p(%lu)",
  76                     mm, tmp2, address, (u_long)size);
  77
  78         return (tmp);
  79 }
  80
  81 /* Creates a shared memory area of a certain size */
  82
  83 struct mm_master *
  84 mm_create(struct mm_master *mmalloc, size_t size)
  85 {
  86         void *address;
  87         struct mm_master *mm;
  88
  89         if (mmalloc == NULL)
  90                 mm = xmalloc(sizeof(struct mm_master));
  91         else
  92                 mm = mm_xmalloc(mmalloc, sizeof(struct mm_master));
  93
  94         /*
  95          * If the memory map has a mm_master it can be completely
  96          * shared including authentication between the child
  97          * and the client.
  98          */
  99         mm->mmalloc = mmalloc;
 100
 101         address = xmmap(size);
 102         if (address == (void *)MAP_FAILED)
 103                 fatal("mmap(%lu): %s", (u_long)size, strerror(errno));
 104
 105         mm->address = address;
 106         mm->size = size;
 107
 108         RB_INIT(&mm->rb_free);
 109         RB_INIT(&mm->rb_allocated);
 110
 111         mm_make_entry(mm, &mm->rb_free, address, size);
 112
 113         return (mm);
 114 }
 115
 116 /* Frees either the allocated or the free list */
 117
 118 static void
 119 mm_freelist(struct mm_master *mmalloc, struct mmtree *head)
 120 {
 121         struct mm_share *mms, *next;
 122
 123         for (mms = RB_ROOT(head); mms; mms = next) {
 124                 next = RB_NEXT(mmtree, head, mms);
 125                 RB_REMOVE(mmtree, head, mms);
 126                 if (mmalloc == NULL)
 127                         xfree(mms);
 128                 else
 129                         mm_free(mmalloc, mms);
 130         }
 131 }
 132
 133 /* Destroys a memory mapped area */
 134
 135 void
 136 mm_destroy(struct mm_master *mm)
 137 {
 138         mm_freelist(mm->mmalloc, &mm->rb_free);
 139         mm_freelist(mm->mmalloc, &mm->rb_allocated);
 140
 141 #ifdef HAVE_MMAP
 142         if (munmap(mm->address, mm->size) == -1)
 143                 fatal("munmap(%p, %lu): %s", mm->address, (u_long)mm->size,
 144                     strerror(errno));
 145 #else
 146         fatal("%s: UsePrivilegeSeparation=yes and Compression=yes not supported",
 147             __func__);
 148 #endif
 149         if (mm->mmalloc == NULL)
 150                 xfree(mm);
 151         else
 152                 mm_free(mm->mmalloc, mm);
 153 }
 154
 155 void *
 156 mm_xmalloc(struct mm_master *mm, size_t size)
 157 {
 158         void *address;
 159
 160         address = mm_malloc(mm, size);
 161         if (address == NULL)
 162                 fatal("%s: mm_malloc(%lu)", __func__, (u_long)size);
 163         return (address);
 164 }
 165
 166
 167 /* Allocates data from a memory mapped area */
 168
 169 void *
 170 mm_malloc(struct mm_master *mm, size_t size)
 171 {
 172         struct mm_share *mms, *tmp;
 173
 174         if (size == 0)
 175                 fatal("mm_malloc: try to allocate 0 space");
 176         if (size > SIZE_T_MAX - MM_MINSIZE + 1)
 177                 fatal("mm_malloc: size too big");
 178
 179         size = ((size + (MM_MINSIZE - 1)) / MM_MINSIZE) * MM_MINSIZE;
 180
 181         RB_FOREACH(mms, mmtree, &mm->rb_free) {
 182                 if (mms->size >= size)
 183                         break;
 184         }
 185
 186         if (mms == NULL)
 187                 return (NULL);
 188
 189         /* Debug */
 190         memset(mms->address, 0xd0, size);
 191
 192         tmp = mm_make_entry(mm, &mm->rb_allocated, mms->address, size);
 193
 194         /* Does not change order in RB tree */
 195         mms->size -= size;
 196         mms->address = (u_char *)mms->address + size;
 197
 198         if (mms->size == 0) {
 199                 RB_REMOVE(mmtree, &mm->rb_free, mms);
 200                 if (mm->mmalloc == NULL)
 201                         xfree(mms);
 202                 else
 203                         mm_free(mm->mmalloc, mms);
 204         }
 205
 206         return (tmp->address);
 207 }
 208
 209 /* Frees memory in a memory mapped area */
 210
 211 void
 212 mm_free(struct mm_master *mm, void *address)
 213 {
 214         struct mm_share *mms, *prev, tmp;
 215
 216         tmp.address = address;
 217         mms = RB_FIND(mmtree, &mm->rb_allocated, &tmp);
 218         if (mms == NULL)
 219                 fatal("mm_free(%p): can not find %p", mm, address);
 220
 221         /* Debug */
 222         memset(mms->address, 0xd0, mms->size);
 223
 224         /* Remove from allocated list and insert in free list */
 225         RB_REMOVE(mmtree, &mm->rb_allocated, mms);
 226         if (RB_INSERT(mmtree, &mm->rb_free, mms) != NULL)
 227                 fatal("mm_free(%p): double address %p", mm, address);
 228
 229         /* Find previous entry */
 230         prev = mms;
 231         if (RB_LEFT(prev, next)) {
 232                 prev = RB_LEFT(prev, next);
 233                 while (RB_RIGHT(prev, next))
 234                         prev = RB_RIGHT(prev, next);
 235         } else {
 236                 if (RB_PARENT(prev, next) &&
 237                     (prev == RB_RIGHT(RB_PARENT(prev, next), next)))
 238                         prev = RB_PARENT(prev, next);
 239                 else {
 240                         while (RB_PARENT(prev, next) &&
 241                             (prev == RB_LEFT(RB_PARENT(prev, next), next)))
 242                                 prev = RB_PARENT(prev, next);
 243                         prev = RB_PARENT(prev, next);
 244                 }
 245         }
 246
 247         /* Check if range does not overlap */
 248         if (prev != NULL && MM_ADDRESS_END(prev) > address)
 249                 fatal("mm_free: memory corruption: %p(%lu) > %p",
 250                     prev->address, (u_long)prev->size, address);
 251
 252         /* See if we can merge backwards */
 253         if (prev != NULL && MM_ADDRESS_END(prev) == address) {
 254                 prev->size += mms->size;
 255                 RB_REMOVE(mmtree, &mm->rb_free, mms);
 256                 if (mm->mmalloc == NULL)
 257                         xfree(mms);
 258                 else
 259                         mm_free(mm->mmalloc, mms);
 260         } else
 261                 prev = mms;
 262
 263         if (prev == NULL)
 264                 return;
 265
 266         /* Check if we can merge forwards */
 267         mms = RB_NEXT(mmtree, &mm->rb_free, prev);
 268         if (mms == NULL)
 269                 return;
 270
 271         if (MM_ADDRESS_END(prev) > mms->address)
 272                 fatal("mm_free: memory corruption: %p < %p(%lu)",
 273                     mms->address, prev->address, (u_long)prev->size);
 274         if (MM_ADDRESS_END(prev) != mms->address)
 275                 return;
 276
 277         prev->size += mms->size;
 278         RB_REMOVE(mmtree, &mm->rb_free, mms);
 279
 280         if (mm->mmalloc == NULL)
 281                 xfree(mms);
 282         else
 283                 mm_free(mm->mmalloc, mms);
 284 }
 285
 286 static void
 287 mm_sync_list(struct mmtree *oldtree, struct mmtree *newtree,
 288     struct mm_master *mm, struct mm_master *mmold)
 289 {
 290         struct mm_master *mmalloc = mm->mmalloc;
 291         struct mm_share *mms, *new;
 292
 293         /* Sync free list */
 294         RB_FOREACH(mms, mmtree, oldtree) {
 295                 /* Check the values */
 296                 mm_memvalid(mmold, mms, sizeof(struct mm_share));
 297                 mm_memvalid(mm, mms->address, mms->size);
 298
 299                 new = mm_xmalloc(mmalloc, sizeof(struct mm_share));
 300                 memcpy(new, mms, sizeof(struct mm_share));
 301                 RB_INSERT(mmtree, newtree, new);
 302         }
 303 }
 304
 305 void
 306 mm_share_sync(struct mm_master **pmm, struct mm_master **pmmalloc)
 307 {
 308         struct mm_master *mm;
 309         struct mm_master *mmalloc;
 310         struct mm_master *mmold;
 311         struct mmtree rb_free, rb_allocated;
 312
 313         debug3("%s: Share sync", __func__);
 314
 315         mm = *pmm;
 316         mmold = mm->mmalloc;
 317         mm_memvalid(mmold, mm, sizeof(*mm));
 318
 319         mmalloc = mm_create(NULL, mm->size);
 320         mm = mm_xmalloc(mmalloc, sizeof(struct mm_master));
 321         memcpy(mm, *pmm, sizeof(struct mm_master));
 322         mm->mmalloc = mmalloc;
 323
 324         rb_free = mm->rb_free;
 325         rb_allocated = mm->rb_allocated;
 326
 327         RB_INIT(&mm->rb_free);
 328         RB_INIT(&mm->rb_allocated);
 329
 330         mm_sync_list(&rb_free, &mm->rb_free, mm, mmold);
 331         mm_sync_list(&rb_allocated, &mm->rb_allocated, mm, mmold);
 332
 333         mm_destroy(mmold);
 334
 335         *pmm = mm;
 336         *pmmalloc = mmalloc;
 337
 338         debug3("%s: Share sync end", __func__);
 339 }
 340
 341 void
 342 mm_memvalid(struct mm_master *mm, void *address, size_t size)
 343 {
 344         void *end = (u_char *)address + size;
 345
 346         if (address < mm->address)
 347                 fatal("mm_memvalid: address too small: %p", address);
 348         if (end < address)
 349                 fatal("mm_memvalid: end < address: %p < %p", end, address);
 350         if (end > (void *)((u_char *)mm->address + mm->size))
 351                 fatal("mm_memvalid: address too large: %p", address);
 352 }