This patch is generated from the follow_xff-2_6 branch of HEAD in squid
Fri Aug 18 22:56:46 2006 GMT
See http://devel.squid-cache.org/
Index: squid/configure.in
diff -u squid/configure.in:1.118 squid/configure.in:1.112.2.3
--- squid/configure.in:1.118 Sat Jun 3 18:51:42 2006
+++ squid/configure.in Sat Jun 3 19:18:25 2006
@@ -1396,6 +1396,18 @@
fi
])
+AC_ARG_ENABLE(follow-x-forwarded-for,
+[ --enable-follow-x-forwarded-for
+ Enable support for following the X-Forwarded-For
+ HTTP header to try to find the IP address of the
+ original or indirect client when a request has
+ been forwarded through other proxies.],
+[ if test "$enableval" = "yes" ; then
+ echo "follow X-Forwarded-For enabled"
+ AC_DEFINE(FOLLOW_X_FORWARDED_FOR, 1, [Enable following X-Forwarded-For headers])
+ fi
+])
+
# Force some compilers to use ANSI features
#
case "$host" in
Index: squid/src/acl.c
diff -u squid/src/acl.c:1.72 squid/src/acl.c:1.72.2.1
--- squid/src/acl.c:1.72 Tue May 30 05:50:38 2006
+++ squid/src/acl.c Tue May 30 14:53:57 2006
@@ -2372,6 +2372,11 @@
cbdataLock(A);
if (request != NULL) {
checklist->request = requestLink(request);
+#if FOLLOW_X_FORWARDED_FOR
+ if (Config.onoff.acl_uses_indirect_client) {
+ checklist->src_addr = request->indirect_client_addr;
+ } else
+#endif /* FOLLOW_X_FORWARDED_FOR */
checklist->src_addr = request->client_addr;
checklist->my_addr = request->my_addr;
checklist->my_port = request->my_port;
Index: squid/src/cf.data.pre
diff -u squid/src/cf.data.pre:1.121 squid/src/cf.data.pre:1.118.2.2
--- squid/src/cf.data.pre:1.121 Fri Jun 2 05:54:38 2006
+++ squid/src/cf.data.pre Sat Jun 3 18:01:29 2006
@@ -2723,6 +2723,92 @@
NOCOMMENT_END
DOC_END
+NAME: follow_x_forwarded_for
+TYPE: acl_access
+IFDEF: FOLLOW_X_FORWARDED_FOR
+LOC: Config.accessList.followXFF
+DEFAULT: none
+DEFAULT_IF_NONE: deny all
+DOC_START
+ Allowing or Denying the X-Forwarded-For header to be followed to
+ find the original source of a request.
+
+ Requests may pass through a chain of several other proxies
+ before reaching us. The X-Forwarded-For header will contain a
+ comma-separated list of the IP addresses in the chain, with the
+ rightmost address being the most recent.
+
+ If a request reaches us from a source that is allowed by this
+ configuration item, then we consult the X-Forwarded-For header
+ to see where that host received the request from. If the
+ X-Forwarded-For header contains multiple addresses, and if
+ acl_uses_indirect_client is on, then we continue backtracking
+ until we reach an address for which we are not allowed to
+ follow the X-Forwarded-For header, or until we reach the first
+ address in the list. (If acl_uses_indirect_client is off, then
+ it's impossible to backtrack through more than one level of
+ X-Forwarded-For addresses.)
+
+ The end result of this process is an IP address that we will
+ refer to as the indirect client address. This address may
+ be treated as the client address for access control, delay
+ pools and logging, depending on the acl_uses_indirect_client,
+ delay_pool_uses_indirect_client and log_uses_indirect_client
+ options.
+
+ SECURITY CONSIDERATIONS:
+
+ Any host for which we follow the X-Forwarded-For header
+ can place incorrect information in the header, and Squid
+ will use the incorrect information as if it were the
+ source address of the request. This may enable remote
+ hosts to bypass any access control restrictions that are
+ based on the client's source addresses.
+
+ For example:
+
+ acl localhost src 127.0.0.1
+ acl my_other_proxy srcdomain .proxy.example.com
+ follow_x_forwarded_for allow localhost
+ follow_x_forwarded_for allow my_other_proxy
+DOC_END
+
+NAME: acl_uses_indirect_client
+COMMENT: on|off
+TYPE: onoff
+IFDEF: FOLLOW_X_FORWARDED_FOR
+DEFAULT: on
+LOC: Config.onoff.acl_uses_indirect_client
+DOC_START
+ Controls whether the indirect client address
+ (see follow_x_forwarded_for) is used instead of the
+ direct client address in acl matching.
+DOC_END
+
+NAME: delay_pool_uses_indirect_client
+COMMENT: on|off
+TYPE: onoff
+IFDEF: FOLLOW_X_FORWARDED_FOR && DELAY_POOLS
+DEFAULT: on
+LOC: Config.onoff.delay_pool_uses_indirect_client
+DOC_START
+ Controls whether the indirect client address
+ (see follow_x_forwarded_for) is used instead of the
+ direct client address in delay pools.
+DOC_END
+
+NAME: log_uses_indirect_client
+COMMENT: on|off
+TYPE: onoff
+IFDEF: FOLLOW_X_FORWARDED_FOR
+DEFAULT: on
+LOC: Config.onoff.log_uses_indirect_client
+DOC_START
+ Controls whether the indirect client address
+ (see follow_x_forwarded_for) is used instead of the
+ direct client address in the access log.
+DOC_END
+
NAME: http_access
TYPE: acl_access
LOC: Config.accessList.http
Index: squid/src/client_side.c
diff -u squid/src/client_side.c:1.111 squid/src/client_side.c:1.107.2.3
--- squid/src/client_side.c:1.111 Sat Jun 3 17:50:50 2006
+++ squid/src/client_side.c Sat Jun 3 18:01:30 2006
@@ -128,6 +128,11 @@
#if USE_IDENT
static IDCB clientIdentDone;
#endif
+#if FOLLOW_X_FORWARDED_FOR
+static void clientFollowXForwardedForStart(void *data);
+static void clientFollowXForwardedForNext(void *data);
+static void clientFollowXForwardedForDone(int answer, void *data);
+#endif /* FOLLOW_X_FORWARDED_FOR */
static int clientOnlyIfCached(clientHttpRequest * http);
static STCB clientSendMoreData;
static STCB clientSendMoreHeaderData;
@@ -191,6 +196,160 @@
return ch;
}
+#if FOLLOW_X_FORWARDED_FOR
+/*
+ * clientFollowXForwardedForStart() copies the X-Forwarded-For
+ * header into x_forwarded_for_iterator and passes control to
+ * clientFollowXForwardedForNext().
+ *
+ * clientFollowXForwardedForNext() checks the indirect_client_addr
+ * against the followXFF ACL and passes the result to
+ * clientFollowXForwardedForDone().
+ *
+ * clientFollowXForwardedForDone() either grabs the next address
+ * from the tail of x_forwarded_for_iterator and loops back to
+ * clientFollowXForwardedForNext(), or cleans up and passes control to
+ * clientAccessCheck().
+ */
+
+static void
+clientFollowXForwardedForStart(void *data)
+{
+ clientHttpRequest *http = data;
+ request_t *request = http->request;
+ request->x_forwarded_for_iterator = httpHeaderGetList(
+ &request->header, HDR_X_FORWARDED_FOR);
+ debug(33, 5) ("clientFollowXForwardedForStart: indirect_client_addr=%s XFF='%s'\n",
+ inet_ntoa(request->indirect_client_addr),
+ strBuf(request->x_forwarded_for_iterator));
+ clientFollowXForwardedForNext(http);
+}
+
+static void
+clientFollowXForwardedForNext(void *data)
+{
+ clientHttpRequest *http = data;
+ request_t *request = http->request;
+ debug(33, 5) ("clientFollowXForwardedForNext: indirect_client_addr=%s XFF='%s'\n",
+ inet_ntoa(request->indirect_client_addr),
+ strBuf(request->x_forwarded_for_iterator));
+ if (strLen(request->x_forwarded_for_iterator) != 0) {
+ /* check the acl to see whether to believe the X-Forwarded-For header */
+ http->acl_checklist = clientAclChecklistCreate(
+ Config.accessList.followXFF, http);
+ aclNBCheck(http->acl_checklist, clientFollowXForwardedForDone, http);
+ } else {
+ /* nothing left to follow */
+ debug(33, 5) ("clientFollowXForwardedForNext: nothing more to do\n");
+ clientFollowXForwardedForDone(-1, http);
+ }
+}
+
+static void
+clientFollowXForwardedForDone(int answer, void *data)
+{
+ clientHttpRequest *http = data;
+ request_t *request = http->request;
+ /*
+ * answer should be be ACCESS_ALLOWED or ACCESS_DENIED if we are
+ * called as a result of ACL checks, or -1 if we are called when
+ * there's nothing left to do.
+ */
+ if (answer == ACCESS_ALLOWED) {
+ /*
+ * The IP address currently in request->indirect_client_addr
+ * is trusted to use X-Forwarded-For. Remove the last
+ * comma-delimited element from x_forwarded_for_iterator and use
+ * it to to replace indirect_client_addr, then repeat the cycle.
+ */
+ const char *p;
+ const char *asciiaddr;
+ int l;
+ struct in_addr addr;
+ debug(33, 5) ("clientFollowXForwardedForDone: indirect_client_addr=%s is trusted\n",
+ inet_ntoa(request->indirect_client_addr));
+ p = strBuf(request->x_forwarded_for_iterator);
+ l = strLen(request->x_forwarded_for_iterator);
+
+ /*
+ * XXX x_forwarded_for_iterator should really be a list of
+ * IP addresses, but it's a String instead. We have to
+ * walk backwards through the String, biting off the last
+ * comma-delimited part each time. As long as the data is in
+ * a String, we should probably implement and use a variant of
+ * strListGetItem() that walks backwards instead of forwards
+ * through a comma-separated list. But we don't even do that;
+ * we just do the work in-line here.
+ */
+ /* skip trailing space and commas */
+ while (l > 0 && (p[l-1] == ',' || xisspace(p[l-1])))
+ l--;
+ strCut(request->x_forwarded_for_iterator, l);
+ /* look for start of last item in list */
+ while (l > 0 && ! (p[l-1] == ',' || xisspace(p[l-1])))
+ l--;
+ asciiaddr = p+l;
+ if (inet_aton(asciiaddr, &addr) == 0) {
+ /* the address is not well formed; do not use it */
+ debug(33, 3) ("clientFollowXForwardedForDone: malformed address '%s'\n",
+ asciiaddr);
+ goto done;
+ }
+ debug(33, 3) ("clientFollowXForwardedForDone: changing indirect_client_addr from %s to '%s'\n",
+ inet_ntoa(request->indirect_client_addr),
+ asciiaddr);
+ request->indirect_client_addr = addr;
+ strCut(request->x_forwarded_for_iterator, l);
+ if (! Config.onoff.acl_uses_indirect_client) {
+ /*
+ * If acl_uses_indirect_client is off, then it's impossible
+ * to follow more than one level of X-Forwarded-For.
+ */
+ goto done;
+ }
+ clientFollowXForwardedForNext(http);
+ return;
+ } else if (answer == ACCESS_DENIED) {
+ debug(33, 5) ("clientFollowXForwardedForDone: indirect_client_addr=%s not trusted\n",
+ inet_ntoa(request->indirect_client_addr));
+ } else {
+ debug(33, 5) ("clientFollowXForwardedForDone: indirect_client_addr=%s nothing more to do\n",
+ inet_ntoa(request->indirect_client_addr));
+ }
+done:
+ /* clean up, and pass control to clientAccessCheck */
+ debug(33, 6) ("clientFollowXForwardedForDone: cleanup\n");
+ if (Config.onoff.log_uses_indirect_client) {
+ /*
+ * Ensure that the access log shows the indirect client
+ * instead of the direct client.
+ */
+ ConnStateData *conn = http->conn;
+ conn->log_addr = request->indirect_client_addr;
+ conn->log_addr.s_addr &= Config.Addrs.client_netmask.s_addr;
+ debug(33, 3) ("clientFollowXForwardedForDone: setting log_addr=%s\n",
+ inet_ntoa(conn->log_addr));
+ }
+ stringClean(&request->x_forwarded_for_iterator);
+ request->flags.done_follow_x_forwarded_for = 1;
+ http->acl_checklist = NULL; /* XXX do we need to aclChecklistFree() ? */
+ clientAccessCheck(http);
+}
+#endif /* FOLLOW_X_FORWARDED_FOR */
+
+static void
+clientCheckFollowXForwardedFor(void *data)
+{
+ clientHttpRequest *http = data;
+#if FOLLOW_X_FORWARDED_FOR
+ if (Config.accessList.followXFF && httpHeaderHas(&http->request->header, HDR_X_FORWARDED_FOR)) {
+ clientFollowXForwardedForStart(data);
+ return;
+ }
+#endif
+ clientAccessCheck(data);
+}
+
static void
clientAccessCheck(void *data)
{
@@ -448,6 +607,9 @@
httpHeaderAppend(&new_request->header, &old_request->header);
new_request->client_addr = old_request->client_addr;
new_request->client_port = old_request->client_port;
+#if FOLLOW_X_FORWARDED_FOR
+ new_request->indirect_client_addr = old_request->indirect_client_addr;
+#endif /* FOLLOW_X_FORWARDED_FOR */
new_request->my_addr = old_request->my_addr;
new_request->my_port = old_request->my_port;
new_request->client_port = old_request->client_port;
@@ -2855,7 +3017,7 @@
*/
/* if it was a pipelined CONNECT kick it alive here */
if (http->request->method == METHOD_CONNECT)
- clientAccessCheck(http);
+ clientCheckFollowXForwardedFor(http);
} else {
debug(33, 2) ("clientKeepaliveNextRequest: FD %d Sending next\n",
conn->fd);
@@ -3744,6 +3906,9 @@
request->flags.internal = http->flags.internal;
request->client_addr = conn->peer.sin_addr;
request->client_port = conn->peer.sin_port;
+#if FOLLOW_X_FORWARDED_FOR
+ request->indirect_client_addr = request->client_addr;
+#endif /* FOLLOW_X_FORWARDED_FOR */
request->my_addr = conn->me.sin_addr;
request->my_port = ntohs(conn->me.sin_port);
request->client_port = ntohs(conn->peer.sin_port);
@@ -3794,7 +3959,7 @@
/* Stop reading requests... */
commSetSelect(fd, COMM_SELECT_READ, NULL, NULL, 0);
if (conn->chr == http)
- clientAccessCheck(http);
+ clientCheckFollowXForwardedFor(http);
else {
debug(33, 1) ("WARNING: pipelined CONNECT request seen from %s\n", inet_ntoa(http->conn->peer.sin_addr));
debugObj(33, 1, "Previous request:\n", conn->chr->request, (ObjPackMethod) & httpRequestPackDebug);
@@ -3802,7 +3967,7 @@
}
break;
} else {
- clientAccessCheck(http);
+ clientCheckFollowXForwardedFor(http);
}
} else if (parser_return_code == 0) {
/*
Index: squid/src/delay_pools.c
diff -u squid/src/delay_pools.c:1.11 squid/src/delay_pools.c:1.11.22.1
--- squid/src/delay_pools.c:1.11 Fri Apr 28 04:10:52 2006
+++ squid/src/delay_pools.c Tue May 30 14:53:58 2006
@@ -319,6 +319,11 @@
r = http->request;
memset(&ch, '\0', sizeof(ch));
+#if FOLLOW_X_FORWARDED_FOR
+ if (Config.onoff.delay_pool_uses_indirect_client) {
+ ch.src_addr = r->indirect_client_addr;
+ } else
+#endif /* FOLLOW_X_FORWARDED_FOR */
ch.src_addr = r->client_addr;
ch.my_addr = r->my_addr;
ch.my_port = r->my_port;
Index: squid/src/structs.h
diff -u squid/src/structs.h:1.102 squid/src/structs.h:1.100.2.2
--- squid/src/structs.h:1.102 Thu Jun 1 17:14:54 2006
+++ squid/src/structs.h Sat Jun 3 18:01:32 2006
@@ -668,6 +668,11 @@
int check_hostnames;
int allow_underscore;
int cache_vary;
+#if FOLLOW_X_FORWARDED_FOR
+ int acl_uses_indirect_client;
+ int delay_pool_uses_indirect_client;
+ int log_uses_indirect_client;
+#endif
} onoff;
#if LINUX_TPROXY
u_short tproxy_port;
@@ -699,6 +704,9 @@
acl_access *htcp;
acl_access *htcp_clr;
#endif
+#if FOLLOW_X_FORWARDED_FOR
+ acl_access *followXFF;
+#endif
} accessList;
acl_deny_info_list *denyInfoList;
struct _authConfig {
@@ -1774,6 +1782,11 @@
unsigned int reset_tcp:1;
unsigned int must_keepalive:1;
unsigned int pinned:1; /* If set, this request is tightly tied to a client-side connection */
+#if FOLLOW_X_FORWARDED_FOR
+ /* XXX this flag could be eliminated;
+ * see comments in clientAccessCheck */
+ unsigned int done_follow_x_forwarded_for;
+#endif
};
struct _link_list {
@@ -1822,6 +1835,9 @@
/* these in_addr's could probably be sockaddr_in's */
in_port_t client_port;
struct in_addr client_addr;
+#if FOLLOW_X_FORWARDED_FOR
+ struct in_addr indirect_client_addr; /* after following X-Forwarded-For */
+#endif /* FOLLOW_X_FORWARDED_FOR */
struct in_addr my_addr;
unsigned short my_port;
HttpHeader header;
@@ -1844,6 +1860,11 @@
String extacl_log; /* String to be used for access.log purposes */
const char *extacl_user; /* User name returned by extacl lookup */
const char *extacl_passwd; /* Password returned by extacl lookup */
+#if FOLLOW_X_FORWARDED_FOR
+ /* XXX a list of IP addresses would be a better data structure
+ * than this String */
+ String x_forwarded_for_iterator;
+#endif /* FOLLOW_X_FORWARDED_FOR */
};
struct _cachemgr_passwd {