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From 956f708b094698ac9ad570d640d4f30eb0df7305 Mon Sep 17 00:00:00 2001
From: Stefan Eissing <icing@apache.org>
Date: Wed, 1 Jun 2022 07:51:04 +0000
Subject: [PATCH] Merge r1901461 from trunk via #320:
*) mod_proxy: ap_proxy_create_hdrbrgd() to clear hop-by-hop first and fixup last.
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1901480 13f79535-47bb-0310-9956-ffa450edef68
Origin: https://github.com/apache/httpd/commit/956f708b094698ac9ad570d640d4f30eb0df7305
---
modules/proxy/proxy_util.c | 153 ++++++++++++++++++++++-----------------------
1 file changed, 77 insertions(+), 76 deletions(-)
--- a/modules/proxy/proxy_util.c
+++ b/modules/proxy/proxy_util.c
@@ -3396,12 +3396,14 @@
char **old_cl_val,
char **old_te_val)
{
+ int rc = OK;
conn_rec *c = r->connection;
int counter;
char *buf;
+ apr_table_t *saved_headers_in = r->headers_in;
+ const char *saved_host = apr_table_get(saved_headers_in, "Host");
const apr_array_header_t *headers_in_array;
const apr_table_entry_t *headers_in;
- apr_table_t *saved_headers_in;
apr_bucket *e;
int do_100_continue;
conn_rec *origin = p_conn->connection;
@@ -3437,6 +3439,52 @@
ap_xlate_proto_to_ascii(buf, strlen(buf));
e = apr_bucket_pool_create(buf, strlen(buf), p, c->bucket_alloc);
APR_BRIGADE_INSERT_TAIL(header_brigade, e);
+
+ /*
+ * Make a copy on r->headers_in for the request we make to the backend,
+ * modify the copy in place according to our configuration and connection
+ * handling, use it to fill in the forwarded headers' brigade, and finally
+ * restore the saved/original ones in r->headers_in.
+ *
+ * Note: We need to take r->pool for apr_table_copy as the key / value
+ * pairs in r->headers_in have been created out of r->pool and
+ * p might be (and actually is) a longer living pool.
+ * This would trigger the bad pool ancestry abort in apr_table_copy if
+ * apr is compiled with APR_POOL_DEBUG.
+ *
+ * icing: if p indeed lives longer than r->pool, we should allocate
+ * all new header values from r->pool as well and avoid leakage.
+ */
+ r->headers_in = apr_table_copy(r->pool, saved_headers_in);
+
+ /* Return the original Transfer-Encoding and/or Content-Length values
+ * then drop the headers, they must be set by the proxy handler based
+ * on the actual body being forwarded.
+ */
+ if ((*old_te_val = (char *)apr_table_get(r->headers_in,
+ "Transfer-Encoding"))) {
+ apr_table_unset(r->headers_in, "Transfer-Encoding");
+ }
+ if ((*old_cl_val = (char *)apr_table_get(r->headers_in,
+ "Content-Length"))) {
+ apr_table_unset(r->headers_in, "Content-Length");
+ }
+
+ /* Clear out hop-by-hop request headers not to forward */
+ if (ap_proxy_clear_connection(r, r->headers_in) < 0) {
+ rc = HTTP_BAD_REQUEST;
+ goto cleanup;
+ }
+
+ /* RFC2616 13.5.1 says we should strip these */
+ apr_table_unset(r->headers_in, "Keep-Alive");
+ apr_table_unset(r->headers_in, "Upgrade");
+ apr_table_unset(r->headers_in, "Trailer");
+ apr_table_unset(r->headers_in, "TE");
+
+ /* We used to send `Host: ` always first, so let's keep it that
+ * way. No telling which legacy backend is relying no this.
+ */
if (dconf->preserve_host == 0) {
if (ap_strchr_c(uri->hostname, ':')) { /* if literal IPv6 address */
if (uri->port_str && uri->port != DEFAULT_HTTP_PORT) {
@@ -3458,7 +3506,7 @@
/* don't want to use r->hostname, as the incoming header might have a
* port attached
*/
- const char* hostname = apr_table_get(r->headers_in,"Host");
+ const char* hostname = saved_host;
if (!hostname) {
hostname = r->server->server_hostname;
ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, r, APLOGNO(01092)
@@ -3472,21 +3520,7 @@
ap_xlate_proto_to_ascii(buf, strlen(buf));
e = apr_bucket_pool_create(buf, strlen(buf), p, c->bucket_alloc);
APR_BRIGADE_INSERT_TAIL(header_brigade, e);
-
- /*
- * Save the original headers in here and restore them when leaving, since
- * we will apply proxy purpose only modifications (eg. clearing hop-by-hop
- * headers, add Via or X-Forwarded-* or Expect...), whereas the originals
- * will be needed later to prepare the correct response and logging.
- *
- * Note: We need to take r->pool for apr_table_copy as the key / value
- * pairs in r->headers_in have been created out of r->pool and
- * p might be (and actually is) a longer living pool.
- * This would trigger the bad pool ancestry abort in apr_table_copy if
- * apr is compiled with APR_POOL_DEBUG.
- */
- saved_headers_in = r->headers_in;
- r->headers_in = apr_table_copy(r->pool, saved_headers_in);
+ apr_table_unset(r->headers_in, "Host");
/* handle Via */
if (conf->viaopt == via_block) {
@@ -3561,8 +3595,6 @@
*/
if (dconf->add_forwarded_headers) {
if (PROXYREQ_REVERSE == r->proxyreq) {
- const char *buf;
-
/* Add X-Forwarded-For: so that the upstream has a chance to
* determine, where the original request came from.
*/
@@ -3572,8 +3604,9 @@
/* Add X-Forwarded-Host: so that upstream knows what the
* original request hostname was.
*/
- if ((buf = apr_table_get(r->headers_in, "Host"))) {
- apr_table_mergen(r->headers_in, "X-Forwarded-Host", buf);
+ if (saved_host) {
+ apr_table_mergen(r->headers_in, "X-Forwarded-Host",
+ saved_host);
}
/* Add X-Forwarded-Server: so that upstream knows what the
@@ -3585,67 +3618,37 @@
}
}
- proxy_run_fixups(r);
- if (ap_proxy_clear_connection(r, r->headers_in) < 0) {
- return HTTP_BAD_REQUEST;
+ /* Do we want to strip Proxy-Authorization ?
+ * If we haven't used it, then NO
+ * If we have used it then MAYBE: RFC2616 says we MAY propagate it.
+ * So let's make it configurable by env.
+ */
+ if (r->user != NULL /* we've authenticated */
+ && !apr_table_get(r->subprocess_env, "Proxy-Chain-Auth")) {
+ apr_table_unset(r->headers_in, "Proxy-Authorization");
}
+ /* for sub-requests, ignore freshness/expiry headers */
+ if (r->main) {
+ apr_table_unset(r->headers_in, "If-Match");
+ apr_table_unset(r->headers_in, "If-Modified-Since");
+ apr_table_unset(r->headers_in, "If-Range");
+ apr_table_unset(r->headers_in, "If-Unmodified-Since");
+ apr_table_unset(r->headers_in, "If-None-Match");
+ }
+
+ /* run hook to fixup the request we are about to send */
+ proxy_run_fixups(r);
+
/* send request headers */
headers_in_array = apr_table_elts(r->headers_in);
headers_in = (const apr_table_entry_t *) headers_in_array->elts;
for (counter = 0; counter < headers_in_array->nelts; counter++) {
if (headers_in[counter].key == NULL
- || headers_in[counter].val == NULL
-
- /* Already sent */
- || !strcasecmp(headers_in[counter].key, "Host")
-
- /* Clear out hop-by-hop request headers not to send
- * RFC2616 13.5.1 says we should strip these headers
- */
- || !strcasecmp(headers_in[counter].key, "Keep-Alive")
- || !strcasecmp(headers_in[counter].key, "TE")
- || !strcasecmp(headers_in[counter].key, "Trailer")
- || !strcasecmp(headers_in[counter].key, "Upgrade")
-
- ) {
- continue;
- }
- /* Do we want to strip Proxy-Authorization ?
- * If we haven't used it, then NO
- * If we have used it then MAYBE: RFC2616 says we MAY propagate it.
- * So let's make it configurable by env.
- */
- if (!strcasecmp(headers_in[counter].key,"Proxy-Authorization")) {
- if (r->user != NULL) { /* we've authenticated */
- if (!apr_table_get(r->subprocess_env, "Proxy-Chain-Auth")) {
- continue;
- }
- }
- }
-
- /* Skip Transfer-Encoding and Content-Length for now.
- */
- if (!strcasecmp(headers_in[counter].key, "Transfer-Encoding")) {
- *old_te_val = headers_in[counter].val;
- continue;
- }
- if (!strcasecmp(headers_in[counter].key, "Content-Length")) {
- *old_cl_val = headers_in[counter].val;
+ || headers_in[counter].val == NULL) {
continue;
}
- /* for sub-requests, ignore freshness/expiry headers */
- if (r->main) {
- if ( !strcasecmp(headers_in[counter].key, "If-Match")
- || !strcasecmp(headers_in[counter].key, "If-Modified-Since")
- || !strcasecmp(headers_in[counter].key, "If-Range")
- || !strcasecmp(headers_in[counter].key, "If-Unmodified-Since")
- || !strcasecmp(headers_in[counter].key, "If-None-Match")) {
- continue;
- }
- }
-
buf = apr_pstrcat(p, headers_in[counter].key, ": ",
headers_in[counter].val, CRLF,
NULL);
@@ -3654,11 +3657,9 @@
APR_BRIGADE_INSERT_TAIL(header_brigade, e);
}
- /* Restore the original headers in (see comment above),
- * we won't modify them anymore.
- */
+cleanup:
r->headers_in = saved_headers_in;
- return OK;
+ return rc;
}
PROXY_DECLARE(int) ap_proxy_pass_brigade(apr_bucket_alloc_t *bucket_alloc,
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