bdf0e9e785
vulnerability in Apache HTTP Server 2.4.52 and earlier Resolves: #2066311 - CVE-2021-44224 httpd: possible NULL dereference or SSRF in forward proxy configurations
253 lines
10 KiB
Diff
253 lines
10 KiB
Diff
diff --git a/include/http_protocol.h b/include/http_protocol.h
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index 9ccac89..20bd202 100644
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--- a/include/http_protocol.h
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+++ b/include/http_protocol.h
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@@ -96,6 +96,13 @@ AP_DECLARE(void) ap_get_mime_headers(request_rec *r);
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AP_DECLARE(void) ap_get_mime_headers_core(request_rec *r,
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apr_bucket_brigade *bb);
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+/**
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+ * Run post_read_request hook and validate.
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+ * @param r The current request
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+ * @return OK or HTTP_...
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+ */
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+AP_DECLARE(int) ap_post_read_request(request_rec *r);
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+
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/* Finish up stuff after a request */
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/**
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diff --git a/modules/http/http_request.c b/modules/http/http_request.c
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index c9ae5af..d59cfe2 100644
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--- a/modules/http/http_request.c
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+++ b/modules/http/http_request.c
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@@ -680,7 +680,7 @@ static request_rec *internal_internal_redirect(const char *new_uri,
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* to do their thing on internal redirects as well. Perhaps this is a
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* misnamed function.
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*/
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- if ((access_status = ap_run_post_read_request(new))) {
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+ if ((access_status = ap_post_read_request(new))) {
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ap_die(access_status, new);
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return NULL;
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}
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diff --git a/modules/proxy/mod_proxy.c b/modules/proxy/mod_proxy.c
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index ee4f1fb..ff9f81d 100644
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--- a/modules/proxy/mod_proxy.c
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+++ b/modules/proxy/mod_proxy.c
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@@ -777,11 +777,12 @@ static int proxy_detect(request_rec *r)
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if (conf->req && r->parsed_uri.scheme) {
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/* but it might be something vhosted */
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- if (!(r->parsed_uri.hostname
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- && !ap_cstr_casecmp(r->parsed_uri.scheme, ap_http_scheme(r))
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- && ap_matches_request_vhost(r, r->parsed_uri.hostname,
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- (apr_port_t)(r->parsed_uri.port_str ? r->parsed_uri.port
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- : ap_default_port(r))))) {
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+ if (!r->parsed_uri.hostname
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+ || ap_cstr_casecmp(r->parsed_uri.scheme, ap_http_scheme(r)) != 0
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+ || !ap_matches_request_vhost(r, r->parsed_uri.hostname,
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+ (apr_port_t)(r->parsed_uri.port_str
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+ ? r->parsed_uri.port
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+ : ap_default_port(r)))) {
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r->proxyreq = PROXYREQ_PROXY;
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r->uri = r->unparsed_uri;
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r->filename = apr_pstrcat(r->pool, "proxy:", r->uri, NULL);
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@@ -2021,6 +2022,7 @@ static const char *
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struct proxy_alias *new;
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char *f = cmd->path;
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char *r = NULL;
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+ const char *real;
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char *word;
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apr_table_t *params = apr_table_make(cmd->pool, 5);
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const apr_array_header_t *arr;
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@@ -2107,6 +2109,10 @@ static const char *
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if (r == NULL) {
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return "ProxyPass|ProxyPassMatch needs a path when not defined in a location";
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}
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+ if (!(real = ap_proxy_de_socketfy(cmd->temp_pool, r))) {
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+ return "ProxyPass|ProxyPassMatch uses an invalid \"unix:\" URL";
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+ }
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+
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/* if per directory, save away the single alias */
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if (cmd->path) {
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@@ -2123,7 +2129,7 @@ static const char *
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}
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new->fake = apr_pstrdup(cmd->pool, f);
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- new->real = apr_pstrdup(cmd->pool, ap_proxy_de_socketfy(cmd->pool, r));
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+ new->real = apr_pstrdup(cmd->pool, real);
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new->flags = flags;
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if (worker_type & AP_PROXY_WORKER_IS_MATCH) {
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new->regex = ap_pregcomp(cmd->pool, f, AP_REG_EXTENDED);
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@@ -2649,6 +2655,7 @@ static const char *add_member(cmd_parms *cmd, void *dummy, const char *arg)
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proxy_worker *worker;
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char *path = cmd->path;
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char *name = NULL;
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+ const char *real;
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char *word;
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apr_table_t *params = apr_table_make(cmd->pool, 5);
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const apr_array_header_t *arr;
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@@ -2689,6 +2696,9 @@ static const char *add_member(cmd_parms *cmd, void *dummy, const char *arg)
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return "BalancerMember must define balancer name when outside <Proxy > section";
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if (!name)
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return "BalancerMember must define remote proxy server";
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+ if (!(real = ap_proxy_de_socketfy(cmd->temp_pool, name))) {
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+ return "BalancerMember uses an invalid \"unix:\" URL";
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+ }
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ap_str_tolower(path); /* lowercase scheme://hostname */
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@@ -2701,8 +2711,7 @@ static const char *add_member(cmd_parms *cmd, void *dummy, const char *arg)
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}
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/* Try to find existing worker */
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- worker = ap_proxy_get_worker(cmd->temp_pool, balancer, conf,
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- ap_proxy_de_socketfy(cmd->temp_pool, name));
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+ worker = ap_proxy_get_worker(cmd->temp_pool, balancer, conf, real);
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if (!worker) {
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ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, cmd->server, APLOGNO(01147)
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"Defining worker '%s' for balancer '%s'",
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@@ -2799,9 +2808,14 @@ static const char *
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}
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}
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else {
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+ const char *real;
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+
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+ if (!(real = ap_proxy_de_socketfy(cmd->temp_pool, name))) {
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+ return "ProxySet uses an invalid \"unix:\" URL";
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+ }
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+
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worker = ap_proxy_get_worker_ex(cmd->temp_pool, NULL, conf,
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- ap_proxy_de_socketfy(cmd->temp_pool, name),
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- worker_type);
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+ real, worker_type);
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if (!worker) {
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if (in_proxy_section) {
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err = ap_proxy_define_worker_ex(cmd->pool, &worker, NULL,
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@@ -2944,9 +2958,14 @@ static const char *proxysection(cmd_parms *cmd, void *mconfig, const char *arg)
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}
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}
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else {
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+ const char *real;
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+
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+ if (!(real = ap_proxy_de_socketfy(cmd->temp_pool, conf->p))) {
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+ return "<Proxy/ProxyMatch > uses an invalid \"unix:\" URL";
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+ }
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+
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worker = ap_proxy_get_worker_ex(cmd->temp_pool, NULL, sconf,
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- ap_proxy_de_socketfy(cmd->temp_pool, conf->p),
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- worker_type);
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+ real, worker_type);
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if (!worker) {
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err = ap_proxy_define_worker_ex(cmd->pool, &worker, NULL, sconf,
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conf->p, worker_type);
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diff --git a/modules/proxy/mod_proxy.h b/modules/proxy/mod_proxy.h
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index 044a6c4..c21c4d8 100644
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--- a/modules/proxy/mod_proxy.h
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+++ b/modules/proxy/mod_proxy.h
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@@ -751,6 +751,7 @@ PROXY_DECLARE(int) ap_proxy_worker_can_upgrade(apr_pool_t *p,
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#define AP_PROXY_WORKER_IS_PREFIX (1u << 0)
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#define AP_PROXY_WORKER_IS_MATCH (1u << 1)
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#define AP_PROXY_WORKER_IS_MALLOCED (1u << 2)
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+#define AP_PROXY_WORKER_NO_UDS (1u << 3)
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/**
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* Get the worker from proxy configuration, looking for either PREFIXED or
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diff --git a/modules/proxy/proxy_util.c b/modules/proxy/proxy_util.c
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index 8225045..cbe300f 100644
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--- a/modules/proxy/proxy_util.c
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+++ b/modules/proxy/proxy_util.c
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@@ -1741,7 +1741,12 @@ PROXY_DECLARE(proxy_worker *) ap_proxy_get_worker_ex(apr_pool_t *p,
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return NULL;
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}
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+ if (!(mask & AP_PROXY_WORKER_NO_UDS)) {
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url = ap_proxy_de_socketfy(p, url);
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+ if (!url) {
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+ return NULL;
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+ }
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+ }
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c = ap_strchr_c(url, ':');
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if (c == NULL || c[1] != '/' || c[2] != '/' || c[3] == '\0') {
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@@ -2323,22 +2328,22 @@ PROXY_DECLARE(int) ap_proxy_pre_request(proxy_worker **worker,
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access_status = proxy_run_pre_request(worker, balancer, r, conf, url);
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if (access_status == DECLINED && *balancer == NULL) {
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- *worker = ap_proxy_get_worker(r->pool, NULL, conf, *url);
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+ const int forward = (r->proxyreq == PROXYREQ_PROXY);
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+ *worker = ap_proxy_get_worker_ex(r->pool, NULL, conf, *url,
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+ forward ? AP_PROXY_WORKER_NO_UDS : 0);
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if (*worker) {
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ap_log_rerror(APLOG_MARK, APLOG_TRACE2, 0, r,
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"%s: found worker %s for %s",
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(*worker)->s->scheme, (*worker)->s->name, *url);
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- *balancer = NULL;
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- if (!fix_uds_filename(r, url)) {
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+ if (!forward && !fix_uds_filename(r, url)) {
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return HTTP_INTERNAL_SERVER_ERROR;
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}
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access_status = OK;
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}
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- else if (r->proxyreq == PROXYREQ_PROXY) {
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+ else if (forward) {
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if (conf->forward) {
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ap_log_rerror(APLOG_MARK, APLOG_TRACE2, 0, r,
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"*: found forward proxy worker for %s", *url);
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- *balancer = NULL;
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*worker = conf->forward;
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access_status = OK;
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/*
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@@ -2352,8 +2357,8 @@ PROXY_DECLARE(int) ap_proxy_pre_request(proxy_worker **worker,
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else if (r->proxyreq == PROXYREQ_REVERSE) {
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if (conf->reverse) {
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ap_log_rerror(APLOG_MARK, APLOG_TRACE2, 0, r,
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- "*: using default reverse proxy worker for %s (no keepalive)", *url);
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- *balancer = NULL;
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+ "*: using default reverse proxy worker for %s "
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+ "(no keepalive)", *url);
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*worker = conf->reverse;
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access_status = OK;
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/*
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diff --git a/server/protocol.c b/server/protocol.c
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index 3d74c5b..2214f72 100644
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--- a/server/protocol.c
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+++ b/server/protocol.c
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@@ -1548,7 +1548,7 @@ request_rec *ap_read_request(conn_rec *conn)
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/* we may have switched to another server */
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apply_server_config(r);
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- if ((access_status = ap_run_post_read_request(r))) {
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+ if ((access_status = ap_post_read_request(r))) {
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goto die;
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}
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@@ -1603,6 +1603,27 @@ ignore:
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return NULL;
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}
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+AP_DECLARE(int) ap_post_read_request(request_rec *r)
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+{
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+ int status;
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+
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+ if ((status = ap_run_post_read_request(r))) {
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+ return status;
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+ }
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+
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+ /* Enforce http(s) only scheme for non-forward-proxy requests */
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+ if (!r->proxyreq
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+ && r->parsed_uri.scheme
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+ && (ap_cstr_casecmpn(r->parsed_uri.scheme, "http", 4) != 0
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+ || (r->parsed_uri.scheme[4] != '\0'
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+ && (apr_tolower(r->parsed_uri.scheme[4]) != 's'
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+ || r->parsed_uri.scheme[5] != '\0')))) {
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+ return HTTP_BAD_REQUEST;
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+ }
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+
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+ return OK;
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+}
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+
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/* if a request with a body creates a subrequest, remove original request's
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* input headers which pertain to the body which has already been read.
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* out-of-line helper function for ap_set_sub_req_protocol.
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