public
Last active

Working backport (doesn't crash when using Allow/Deny ACLs) of Apache 2.3 module mod_remoteip to Apache 2.2.x

  • Download Gist
apache-2.2-mod_remoteip.c
C
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489
/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
 
#include "ap_config.h"
#include "ap_mmn.h"
#include "httpd.h"
#include "http_config.h"
#include "http_connection.h"
#include "http_protocol.h"
#include "http_log.h"
#include "apr_strings.h"
#include "apr_lib.h"
#define APR_WANT_BYTEFUNC
#include "apr_want.h"
#include "apr_network_io.h"
 
module AP_MODULE_DECLARE_DATA remoteip_module;
 
typedef struct {
/** A proxy IP mask to match */
apr_ipsubnet_t *ip;
/** Flagged if internal, otherwise an external trusted proxy */
void *internal;
} remoteip_proxymatch_t;
 
typedef struct {
/** The header to retrieve a proxy-via ip list */
const char *header_name;
/** A header to record the proxied IP's
* (removed as the physical connection and
* from the proxy-via ip header value list)
*/
const char *proxies_header_name;
/** A list of trusted proxies, ideally configured
* with the most commonly encountered listed first
*/
apr_array_header_t *proxymatch_ip;
} remoteip_config_t;
 
typedef struct {
/** The previous proxy-via request header value */
const char *prior_remote;
/** The unmodified original ip and address */
const char *orig_ip;
apr_sockaddr_t *orig_addr;
/** The list of proxy ip's ignored as remote ip's */
const char *proxy_ips;
/** The remaining list of untrusted proxied remote ip's */
const char *proxied_remote;
/** The most recently modified ip and address record */
const char *proxied_ip;
apr_sockaddr_t proxied_addr;
} remoteip_conn_t;
 
static void *create_remoteip_server_config(apr_pool_t *p, server_rec *s)
{
remoteip_config_t *config = apr_pcalloc(p, sizeof *config);
/* config->header_name = NULL;
* config->proxies_header_name = NULL;
*/
return config;
}
 
static void *merge_remoteip_server_config(apr_pool_t *p, void *globalv,
void *serverv)
{
remoteip_config_t *global = (remoteip_config_t *) globalv;
remoteip_config_t *server = (remoteip_config_t *) serverv;
remoteip_config_t *config;
 
config = (remoteip_config_t *) apr_palloc(p, sizeof(*config));
config->header_name = server->header_name
? server->header_name
: global->header_name;
config->proxies_header_name = server->proxies_header_name
? server->proxies_header_name
: global->proxies_header_name;
config->proxymatch_ip = server->proxymatch_ip
? server->proxymatch_ip
: global->proxymatch_ip;
return config;
}
 
static const char *header_name_set(cmd_parms *cmd, void *dummy,
const char *arg)
{
remoteip_config_t *config = ap_get_module_config(cmd->server->module_config,
&remoteip_module);
config->header_name = arg;
return NULL;
}
 
static const char *proxies_header_name_set(cmd_parms *cmd, void *dummy,
const char *arg)
{
remoteip_config_t *config = ap_get_module_config(cmd->server->module_config,
&remoteip_module);
config->proxies_header_name = arg;
return NULL;
}
 
/* Would be quite nice if APR exported this */
/* apr:network_io/unix/sockaddr.c */
static int looks_like_ip(const char *ipstr)
{
if (ap_strchr_c(ipstr, ':')) {
/* definitely not a hostname; assume it is intended to be an IPv6 address */
return 1;
}
 
/* simple IPv4 address string check */
while ((*ipstr == '.') || apr_isdigit(*ipstr))
ipstr++;
return (*ipstr == '\0');
}
 
static const char *proxies_set(cmd_parms *cmd, void *internal,
const char *arg)
{
remoteip_config_t *config = ap_get_module_config(cmd->server->module_config,
&remoteip_module);
remoteip_proxymatch_t *match;
apr_status_t rv;
char *ip = apr_pstrdup(cmd->temp_pool, arg);
char *s = ap_strchr(ip, '/');
if (s)
*s++ = '\0';
 
if (!config->proxymatch_ip)
config->proxymatch_ip = apr_array_make(cmd->pool, 1, sizeof(*match));
match = (remoteip_proxymatch_t *) apr_array_push(config->proxymatch_ip);
match->internal = internal;
 
if (looks_like_ip(ip)) {
/* Note s may be null, that's fine (explicit host) */
rv = apr_ipsubnet_create(&match->ip, ip, s, cmd->pool);
}
else
{
apr_sockaddr_t *temp_sa;
 
if (s) {
return apr_pstrcat(cmd->pool, "RemoteIP: Error parsing IP ", arg,
" the subnet /", s, " is invalid for ",
cmd->cmd->name, NULL);
}
 
rv = apr_sockaddr_info_get(&temp_sa, ip, APR_UNSPEC, 0,
APR_IPV4_ADDR_OK, cmd->temp_pool);
while (rv == APR_SUCCESS)
{
apr_sockaddr_ip_get(&ip, temp_sa);
rv = apr_ipsubnet_create(&match->ip, ip, NULL, cmd->pool);
if (!(temp_sa = temp_sa->next))
break;
match = (remoteip_proxymatch_t *)
apr_array_push(config->proxymatch_ip);
match->internal = internal;
}
}
 
if (rv != APR_SUCCESS) {
char msgbuf[128];
apr_strerror(rv, msgbuf, sizeof(msgbuf));
return apr_pstrcat(cmd->pool, "RemoteIP: Error parsing IP ", arg,
" (", msgbuf, " error) for ", cmd->cmd->name, NULL);
}
 
return NULL;
}
 
static const char *proxylist_read(cmd_parms *cmd, void *internal,
const char *filename)
{
char lbuf[MAX_STRING_LEN];
char *arg;
const char *args;
const char *errmsg;
ap_configfile_t *cfp;
apr_status_t rv;
 
filename = ap_server_root_relative(cmd->temp_pool, filename);
rv = ap_pcfg_openfile(&cfp, cmd->temp_pool, filename);
if (rv != APR_SUCCESS) {
return apr_psprintf(cmd->pool, "%s: Could not open file %s: %s",
cmd->cmd->name, filename,
apr_strerror(rv, lbuf, sizeof(lbuf)));
}
 
while (!(ap_cfg_getline(lbuf, MAX_STRING_LEN, cfp))) {
args = lbuf;
while (*(arg = ap_getword_conf(cmd->temp_pool, &args)) != '\0') {
if (*arg == '#' || *arg == '\0')
break;
errmsg = proxies_set(cmd, internal, arg);
if (errmsg) {
errmsg = apr_psprintf(cmd->pool, "%s at line %d of %s",
errmsg, cfp->line_number, filename);
return errmsg;
}
}
}
 
ap_cfg_closefile(cfp);
return NULL;
}
 
static int remoteip_modify_connection(request_rec *r)
{
conn_rec *c = r->connection;
remoteip_config_t *config = (remoteip_config_t *)
ap_get_module_config(r->server->module_config, &remoteip_module);
remoteip_conn_t *conn;
#ifdef REMOTEIP_OPTIMIZED
apr_sockaddr_t temp_sa_buff;
apr_sockaddr_t *temp_sa = &temp_sa_buff;
#else
apr_sockaddr_t *temp_sa;
#endif
apr_status_t rv;
char *remote = (char *) apr_table_get(r->headers_in, config->header_name);
char *proxy_ips = NULL;
char *parse_remote;
char *eos;
unsigned char *addrbyte;
void *internal = NULL;
 
apr_pool_userdata_get((void*)&conn, "mod_remoteip-conn", c->pool);
 
if (conn) {
if (remote && (strcmp(remote, conn->prior_remote) == 0)) {
/* TODO: Recycle r-> overrides from previous request
*/
goto ditto_request_rec;
}
else {
/* TODO: Revert connection from previous request
*/
c->remote_addr = conn->orig_addr;
c->remote_ip = (char *) conn->orig_ip;
}
}
 
if (!remote)
return OK;
 
remote = apr_pstrdup(r->pool, remote);
 
#ifdef REMOTEIP_OPTIMIZED
memcpy(temp_sa, c->remote_addr, sizeof(*temp_sa));
temp_sa->pool = r->pool;
#else
temp_sa = c->remote_addr;
#endif
 
while (remote) {
 
/* verify c->remote_addr is trusted if there is a trusted proxy list
*/
if (config->proxymatch_ip) {
int i;
remoteip_proxymatch_t *match;
match = (remoteip_proxymatch_t *)config->proxymatch_ip->elts;
for (i = 0; i < config->proxymatch_ip->nelts; ++i) {
if (apr_ipsubnet_test(match[i].ip, c->remote_addr)) {
internal = match[i].internal;
break;
}
}
if (i && i >= config->proxymatch_ip->nelts)
break;
}
 
if ((parse_remote = strrchr(remote, ',')) == NULL) {
parse_remote = remote;
remote = NULL;
}
else {
*(parse_remote++) = '\0';
}
 
while (*parse_remote == ' ')
++parse_remote;
 
eos = parse_remote + strlen(parse_remote) - 1;
while (eos >= parse_remote && *eos == ' ')
*(eos--) = '\0';
 
if (eos < parse_remote) {
if (remote)
*(remote + strlen(remote)) = ',';
else
remote = parse_remote;
break;
}
 
#ifdef REMOTEIP_OPTIMIZED
/* Decode remote_addr - sucks; apr_sockaddr_vars_set isn't 'public' */
if (inet_pton(AF_INET, parse_remote,
&temp_sa->sa.sin.sin_addr) > 0) {
apr_sockaddr_vars_set(temp_sa, APR_INET, temp_sa.port);
}
#if APR_HAVE_IPV6
else if (inet_pton(AF_INET6, parse_remote,
&temp_sa->sa.sin6.sin6_addr) > 0) {
apr_sockaddr_vars_set(temp_sa, APR_INET6, temp_sa.port);
}
#endif
else {
rv = apr_get_netos_error();
#else /* !REMOTEIP_OPTIMIZED */
/* We map as IPv4 rather than IPv6 for equivilant host names
* or IPV4OVERIPV6
*/
rv = apr_sockaddr_info_get(&temp_sa, parse_remote,
APR_UNSPEC, temp_sa->port,
APR_IPV4_ADDR_OK, r->pool);
if (rv != APR_SUCCESS) {
#endif
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
"RemoteIP: Header %s value of %s cannot be parsed "
"as a client IP",
config->header_name, parse_remote);
if (remote)
*(remote + strlen(remote)) = ',';
else
remote = parse_remote;
break;
}
 
addrbyte = (unsigned char *) &temp_sa->sa.sin.sin_addr;
 
/* For intranet (Internal proxies) ignore all restrictions below */
if (!internal
&& ((temp_sa->family == APR_INET
/* For internet (non-Internal proxies) deny all
* RFC3330 designated local/private subnets:
* 10.0.0.0/8 169.254.0.0/16 192.168.0.0/16
* 127.0.0.0/8 172.16.0.0/12
*/
&& (addrbyte[0] == 10
|| addrbyte[0] == 127
|| (addrbyte[0] == 169 && addrbyte[1] == 254)
|| (addrbyte[0] == 172 && (addrbyte[1] & 0xf0) == 16)
|| (addrbyte[0] == 192 && addrbyte[1] == 168)))
#if APR_HAVE_IPV6
|| (temp_sa->family == APR_INET6
/* For internet (non-Internal proxies) we translated
* IPv4-over-IPv6-mapped addresses as IPv4, above.
* Accept only Global Unicast 2000::/3 defined by RFC4291
*/
&& ((temp_sa->sa.sin6.sin6_addr.s6_addr[0] & 0xe0) != 0x20))
#endif
)) {
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r,
"RemoteIP: Header %s value of %s appears to be "
"a private IP or nonsensical. Ignored",
config->header_name, parse_remote);
if (remote)
*(remote + strlen(remote)) = ',';
else
remote = parse_remote;
break;
}
 
if (!conn) {
conn = (remoteip_conn_t *) apr_palloc(c->pool, sizeof(*conn));
apr_pool_userdata_set(conn, "mod_remoteip-conn", NULL, c->pool);
conn->orig_addr = c->remote_addr;
conn->orig_ip = c->remote_ip;
}
 
/* Set remote_ip string */
if (!internal) {
if (proxy_ips)
proxy_ips = apr_pstrcat(r->pool, proxy_ips, ", ",
c->remote_ip, NULL);
else
proxy_ips = c->remote_ip;
}
 
c->remote_addr = temp_sa;
apr_sockaddr_ip_get(&c->remote_ip, c->remote_addr);
}
 
/* Nothing happened? */
if (!conn || (c->remote_addr == conn->orig_addr))
return OK;
 
/* Fixups here, remote becomes the new Via header value, etc
* In the heavy operations above we used request scope, to limit
* conn pool memory growth on keepalives, so here we must scope
* the final results to the connection pool lifetime.
* To limit memory growth, we keep recycling the same buffer
* for the final apr_sockaddr_t in the remoteip conn rec.
*/
c->remote_ip = apr_pstrdup(c->pool, c->remote_ip);
conn->proxied_ip = c->remote_ip;
memcpy(&conn->proxied_addr, temp_sa, sizeof(*temp_sa));
conn->proxied_addr.pool = c->pool;
c->remote_addr = &conn->proxied_addr;
 
if (remote)
remote = apr_pstrdup(c->pool, remote);
conn->proxied_remote = remote;
conn->prior_remote = apr_pstrdup(c->pool, apr_table_get(r->headers_in,
config->header_name));
if (proxy_ips)
proxy_ips = apr_pstrdup(c->pool, proxy_ips);
conn->proxy_ips = proxy_ips;
 
/* Unset remote_host string DNS lookups */
c->remote_host = NULL;
c->remote_logname = NULL;
 
ditto_request_rec:
if (conn->proxied_remote)
apr_table_setn(r->headers_in, config->header_name,
conn->proxied_remote);
else
apr_table_unset(r->headers_in, config->header_name);
if (conn->proxy_ips) {
apr_table_setn(r->notes, "remoteip-proxy-ip-list", conn->proxy_ips);
if (config->proxies_header_name)
apr_table_setn(r->headers_in, config->proxies_header_name,
conn->proxy_ips);
}
 
ap_log_rerror(APLOG_MARK, APLOG_INFO|APLOG_NOERRNO, 0, r,
conn->proxy_ips
? "Using %s as client's IP by proxies %s"
: "Using %s as client's IP by internal proxies",
conn->proxied_ip, conn->proxy_ips);
return OK;
}
 
static const command_rec remoteip_cmds[] =
{
AP_INIT_TAKE1("RemoteIPHeader", header_name_set, NULL, RSRC_CONF,
"Specifies a request header to trust as the client IP, "
"e.g. X-Forwarded-For"),
AP_INIT_TAKE1("RemoteIPProxiesHeader", proxies_header_name_set,
NULL, RSRC_CONF,
"Specifies a request header to record proxy IP's, "
"e.g. X-Forwarded-By; if not given then do not record"),
AP_INIT_ITERATE("RemoteIPTrustedProxy", proxies_set, 0, RSRC_CONF,
"Specifies one or more proxies which are trusted "
"to present IP headers"),
AP_INIT_ITERATE("RemoteIPInternalProxy", proxies_set, (void*)1, RSRC_CONF,
"Specifies one or more internal (transparent) proxies "
"which are trusted to present IP headers"),
AP_INIT_TAKE1("RemoteIPTrustedProxyList", proxylist_read, 0,
RSRC_CONF | EXEC_ON_READ,
"The filename to read the list of trusted proxies, "
"see the RemoteIPTrustedProxy directive"),
AP_INIT_TAKE1("RemoteIPInternalProxyList", proxylist_read, (void*)1,
RSRC_CONF | EXEC_ON_READ,
"The filename to read the list of internal proxies, "
"see the RemoteIPInternalProxy directive"),
{ NULL }
};
 
static void register_hooks(apr_pool_t *p)
{
ap_hook_post_read_request(remoteip_modify_connection, NULL, NULL, APR_HOOK_FIRST);
}
 
module AP_MODULE_DECLARE_DATA remoteip_module = {
STANDARD20_MODULE_STUFF,
NULL, /* create per-directory config structure */
NULL, /* merge per-directory config structures */
create_remoteip_server_config, /* create per-server config structure */
merge_remoteip_server_config, /* merge per-server config structures */
remoteip_cmds, /* command apr_table_t */
register_hooks /* register hooks */
};

Please sign in to comment on this gist.

Something went wrong with that request. Please try again.