1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280
|
/* checkpeerlocal.c -- check if the peer address of a socket is on a
* local network.
* (C) 2002 by Matthias Andree <matthias.andree@gmx.de>
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU Lesser General Public License as
* published by the Free Software Foundation.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library (look for the COPYING.LGPL file); if
* not, write to the Free Software Foundation, Inc., 59 Temple Place,
* Suite 330, Boston, MA 02111-1307 USA
*/
#include "config.h"
#include "mastring.h"
#include "critmem.h"
#include "leafnode.h"
#include <sys/types.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_SOCKIO_H
/* needed for SunOS 5, IRIX, ... */
#include <sys/sockio.h>
#endif
#include <sys/ioctl.h>
#include <net/if.h>
#include <netinet/in.h>
#include <errno.h>
#ifndef __LCLINT__
#include <arpa/inet.h>
#endif /* not __LCLINT__ */
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include "strlcpy.h"
#ifdef TEST
#define D(a) a
#else
#define D(a)
#endif
#ifdef TEST
static void pat(struct sockaddr *addr)
{
char buf[512]; /* RATS: ignore */
char *tag = "";
switch (addr->sa_family) {
#ifdef HAVE_IPV6
case AF_INET6:
inet_ntop(addr->sa_family,
&((struct sockaddr_in6 *)addr)->sin6_addr, buf, sizeof(buf));
tag = "IPv6: ";
break;
#endif
case AF_INET:
strlcpy(buf, inet_ntoa(((struct sockaddr_in *)addr)->sin_addr),
sizeof(buf));
tag = "IPv4: ";
break;
default:
strlcpy(buf, "unsupported address type", sizeof(buf));
break;
}
printf("%s%s\n", tag, buf);
}
#endif
/*
* checks whether the peer of the socket is local to any of our network
* interfaces, returns -1 for error (check errno), -2 for other error,
* 0 for no, 1 for yes. If sock is not a socket, also returns 1.
*/
int checkpeerlocal(int sock)
{
char addr[128]; /* RATS: ignore */
mastr *buf;
struct ifconf ifc;
struct ifreq *ifr, *end;
int type;
socklen_t size;
int newsock;
/* obtain peer address */
size = sizeof(addr);
#ifdef TEST_LOCAL
sock = socket(AF_INET, SOCK_DGRAM, 0);
if (getsockname(sock, (struct sockaddr *)addr, &size)) {
#else
if (getpeername(sock, (struct sockaddr *)addr, &size)) {
#endif
if (errno == ENOTSOCK)
return 1;
else
return -1;
}
type = ((struct sockaddr *)addr)->sa_family;
D(printf("address type of peer socket: %d\n", type));
switch(type) {
case AF_INET:
break;
#ifdef HAVE_IPV6
case AF_INET6:
break;
#endif
default:
D(printf("address type not supported.\n"));
return -2;
}
D(pat((struct sockaddr *)addr));
#ifdef HAVE_IPV6
if (type == AF_INET6) {
struct sockaddr_in6 *i6 = (struct sockaddr_in6 *)addr;
D((printf("IPv6 address\n")));
/* IPv6 localhost */
if (IN6_IS_ADDR_LOOPBACK(&i6->sin6_addr)) {
D((printf("IPv6 loopback address\n")));
return 1;
} else if (IN6_IS_ADDR_LINKLOCAL(&i6->sin6_addr)) {
D((printf("IPv6 link local address\n")));
return 1;
} else if (IN6_IS_ADDR_SITELOCAL(&i6->sin6_addr)) {
D((printf("IPv6 site local address\n")));
return 1;
} else if (IN6_IS_ADDR_V4MAPPED(&i6->sin6_addr)) {
/* map to IPv4 */
struct sockaddr_in si;
D((printf("IPv4 mapped IPv6 address\n")));
si.sin_family = AF_INET;
si.sin_port = i6->sin6_port;
memcpy(&si.sin_addr, &(i6->sin6_addr.s6_addr[12]), 4);
memcpy(addr, &si, sizeof(struct sockaddr_in));
} else {
return 0;
}
}
#endif
D(pat((struct sockaddr *)addr));
buf = mastr_new(2048);
newsock = socket(PF_INET, SOCK_DGRAM, 0);
if (sock < 0)
return -1;
/* get list of address information */
for (;;) {
ifc.ifc_len = mastr_size(buf);
ifc.ifc_buf = mastr_modifyable_str(buf);
if (ioctl(newsock, SIOCGIFCONF, (char *)&ifc) < 0) {
if (errno != EINVAL) {
close(sock);
mastr_delete(buf);
return -1;
}
}
/* work around bugs in old Solaris (see Postfix'
* inet_addr_local.c for details) */
if ((unsigned)ifc.ifc_len < mastr_size(buf) / 2) {
break;
}
mastr_resizekill(buf, mastr_size(buf) * 2);
}
/* get addresses and netmasks */
end = (struct ifreq *)((char *)ifc.ifc_buf + ifc.ifc_len);
for (ifr = ifc.ifc_req ; ifr < end ;
#ifdef HAVE_SALEN
ifr = ((struct ifreq *)
((char *) ifr + sizeof(ifr->ifr_name)
+ ifr->ifr_addr.sa_len))
#else
ifr++
#endif
)
{
struct in_addr sia;
#ifdef HAVE_SALEN
D(printf("interface: name %s, address type: %d, sa_len: %d\n", ifr->ifr_name,
ifr->ifr_addr.sa_family, ifr->ifr_addr.sa_len));
#else
D(printf("interface: name %s, address type: %d\n", ifr->ifr_name,
ifr->ifr_addr.sa_family));
#endif
sia = ((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr;
switch (ifr->ifr_addr.sa_family) {
case AF_INET:
break;
#ifdef HAVE_IPV6
case AF_INET6:
break;
#endif
default:
continue;
}
D(pat((struct sockaddr *)&ifr->ifr_addr));
if (sia.s_addr != INADDR_ANY) {
struct in_addr adr, msk;
struct ifreq ir;
memcpy(&ir, ifr, sizeof(struct ifreq));
/* Prevent nasty surprises on old Linux kernels with
* BSD-style IP aliasing (more than one IPv4 address on
* the same interface) -- SIOCGIFADDR/...NETMASK will
* return address and netmask for the first address,
* while SIOCGIFCONF will return the alias address, so
* there's no way to figure the NETMASK for these
* addresses. */
if (ioctl(newsock, SIOCGIFADDR, &ir) < 0)
goto bail_errno;
adr = ((struct sockaddr_in *)(&ir.ifr_addr))->sin_addr;
if (adr.s_addr != sia.s_addr) {
char *buf;
buf = critstrdup(inet_ntoa(sia), "checkpeerlocal");
syslog(LOG_CRIT, "Problem: your kernel cannot deal with 4.4BSD-style IP aliases properly. "
"SIOCGIFADDR for interface %s address %s yields %s -> mismatch. "
"Configure Solaris-style aliases like %s:0 instead. Ignoring this interface, addresses in its range will be considered remote.",
ifr->ifr_name, buf, inet_ntoa(adr),
ifr->ifr_name);
D(printf("Kernel does not handle 4.4BSD-style IP alias for interface %s address %s, ignoring this interface.\n",
ifr->ifr_name, buf));
free(buf);
continue;
}
memcpy(&ir, ifr, sizeof(struct ifreq));
if (ioctl(newsock, SIOCGIFNETMASK, &ir) < 0)
goto bail_errno;
msk = ((struct sockaddr_in *)(&ir.ifr_addr))->sin_addr;
D(printf("address/netmask: %s/", inet_ntoa(adr)));
D(printf("%s\n", inet_ntoa(msk)));
if ((((struct sockaddr_in *)addr)->sin_addr.s_addr & msk.s_addr)
== (adr.s_addr & msk.s_addr)) {
D(printf("found\n"));
close(newsock);
mastr_delete(buf);
return 1;
}
}
}
close(newsock);
mastr_delete(buf);
return 0;
bail_errno:
close(newsock);
mastr_delete(buf);
return -1;
}
#ifdef TEST
#include <string.h>
int verbose = 0;
int debug = 0;
int main(void)
{
int r;
printf("checkpeerlocal returned: %d\n", (r = checkpeerlocal(0)));
if (r == -1) printf("errno: %d (%s)\n", errno, strerror(errno));
return 0;
}
#endif
|