gen.subproj/if_nameindex.c

   1 /*
   2  * Copyright (c) 2018 Apple Inc. All rights reserved.
   3  */
   4 /*      $KAME: if_nameindex.c,v 1.8 2000/11/24 08:20:01 itojun Exp $    */
   5
   6 /*-
   7  * Copyright (c) 1997, 2000
   8  *      Berkeley Software Design, Inc.  All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  *      BSDI Id: if_nameindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
  29  */
  30
  31 #include "libinfo_common.h"
  32
  33 #include <sys/types.h>
  34 #include <sys/socket.h>
  35 #include <net/if_dl.h>
  36 #include <net/if.h>
  37 #include <ifaddrs.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <os/overflow.h>
  41 #include <sys/errno.h>
  42
  43 /*
  44  * From RFC 2553:
  45  *
  46  * 4.3 Return All Interface Names and Indexes
  47  *
  48  *    The if_nameindex structure holds the information about a single
  49  *    interface and is defined as a result of including the <net/if.h>
  50  *    header.
  51  *
  52  *       struct if_nameindex {
  53  *         unsigned int   if_index;
  54  *         char          *if_name;
  55  *       };
  56  *
  57  *    The final function returns an array of if_nameindex structures, one
  58  *    structure per interface.
  59  *
  60  *       struct if_nameindex  *if_nameindex(void);
  61  *
  62  *    The end of the array of structures is indicated by a structure with
  63  *    an if_index of 0 and an if_name of NULL.  The function returns a NULL
  64  *    pointer upon an error, and would set errno to the appropriate value.
  65  *
  66  *    The memory used for this array of structures along with the interface
  67  *    names pointed to by the if_name members is obtained dynamically.
  68  *    This memory is freed by the next function.
  69  *
  70  * 4.4.  Free Memory
  71  *
  72  *    The following function frees the dynamic memory that was allocated by
  73  *    if_nameindex().
  74  *
  75  *        #include <net/if.h>
  76  *
  77  *        void  if_freenameindex(struct if_nameindex *ptr);
  78  *
  79  *    The argument to this function must be a pointer that was returned by
  80  *    if_nameindex().
  81  */
  82
  83 LIBINFO_EXPORT
  84 struct if_nameindex *
  85 if_nameindex(void)
  86 {
  87         struct ifaddrs *ifaddrs, *ifa;
  88         unsigned int ni;
  89         size_t nbytes;
  90         struct if_nameindex *ifni= NULL, *ifni2;
  91         char *cp;
  92         size_t cpsz;
  93
  94         if (getifaddrs(&ifaddrs) < 0)
  95                 return(NULL);
  96
  97         /*
  98          * First, find out how many interfaces there are, and how
  99          * much space we need for the string names.
 100          */
 101         ni = 0;
 102         nbytes = 0;
 103         for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
 104                 if (ifa->ifa_addr &&
 105                     ifa->ifa_addr->sa_family == AF_LINK) {
 106                         /*
 107                          * Security Check: Verify nbytes and ni do not overflow
 108                          */
 109                         if (os_add_overflow(nbytes, strlen(ifa->ifa_name) + 1, &nbytes) ||
 110                                 os_add_overflow(ni, 1, &ni)) {
 111                                 errno = EOVERFLOW;
 112                                 goto out;
 113                         }
 114                 }
 115         }
 116
 117         /*
 118          * Security Check: Verify cpsz does not overflow in next 3 operations
 119          */
 120         if (os_add_overflow(ni, 1, &cpsz)) {
 121                 errno = EOVERFLOW;
 122                 goto out;
 123         }
 124         if (os_mul_overflow(cpsz, sizeof(struct if_nameindex), &cpsz)) {
 125                 errno = EOVERFLOW;
 126                 goto out;
 127         }
 128         if (os_add_overflow(cpsz, nbytes, &cpsz)) {
 129                 errno = EOVERFLOW;
 130                 goto out;
 131         }
 132         /*
 133          * Next, allocate a chunk of memory, use the first part
 134          * for the array of structures, and the last part for
 135          * the strings.
 136          */
 137         cp = malloc(cpsz);
 138         ifni = (struct if_nameindex *)cp;
 139         if (ifni == NULL)
 140                 goto out;
 141         cp += (ni + 1) * sizeof(struct if_nameindex);
 142
 143         /*
 144          * Now just loop through the list of interfaces again,
 145          * filling in the if_nameindex array and making copies
 146          * of all the strings.
 147          */
 148         ifni2 = ifni;
 149         for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
 150                 if (ifa->ifa_addr &&
 151                     ifa->ifa_addr->sa_family == AF_LINK) {
 152                         ifni2->if_index =
 153                             ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index;
 154                         ifni2->if_name = cp;
 155                         strcpy(cp, ifa->ifa_name);
 156                         ifni2++;
 157                         cp += strlen(cp) + 1;
 158                 }
 159         }
 160         /*
 161          * Finally, don't forget to terminate the array.
 162          */
 163         ifni2->if_index = 0;
 164         ifni2->if_name = NULL;
 165 out:
 166         freeifaddrs(ifaddrs);
 167         return(ifni);
 168 }
 169
 170 #ifndef __OpenBSD__
 171 LIBINFO_EXPORT
 172 void
 173 if_freenameindex(struct if_nameindex *ptr)
 174 {
 175         free(ptr);
 176 }
 177 #endif