crypto/openssh/monitor_mm.c

   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
  49 static int
  50 mm_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
  62 RB_GENERATE(mmtree, mm_share, next, mm_compare)
  63
  64 static struct mm_share *
  65 mm_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
  87 struct mm_master *
  88 mm_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
 122 static void
 123 mm_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
 139 void
 140 mm_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
 159 void *
 160 mm_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
 174 void *
 175 mm_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
 216 void
 217 mm_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
 291 static void
 292 mm_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
 310 void
 311 mm_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
 346 void
 347 mm_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 }