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June 23, 2011 09:32
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Working backport (doesn't crash when using Allow/Deny ACLs) of Apache 2.3 module mod_remoteip to Apache 2.2.x
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/* 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 */ | |
}; |
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