Description: fix error out on HTTP header larger than 16K
 The uwsgi protocol does not let us serialize more than 16K of HTTP header,
 so fail early with 500 if it happens.
Author: ylavic
Origin: upstream, https://github.com/apache/httpd/commit/0c543e3f
Bug: https://security-tracker.debian.org/tracker/CVE-2020-11984
Forwarded: not-needed
Reviewed-By: Xavier Guimard <yadd@debian.org>
Last-Update: 2020-08-25

--- a/modules/proxy/mod_proxy_uwsgi.c
+++ b/modules/proxy/mod_proxy_uwsgi.c
@@ -136,7 +136,7 @@
     int j;
 
     apr_size_t headerlen = 4;
-    apr_uint16_t pktsize, keylen, vallen;
+    apr_size_t pktsize, keylen, vallen;
     const char *script_name;
     const char *path_info;
     const char *auth;
@@ -177,6 +177,14 @@
     for (j = 0; j < env_table->nelts; ++j) {
         headerlen += 2 + strlen(env[j].key) + 2 + strlen(env[j].val);
     }
+    pktsize = headerlen - 4;
+    if (pktsize > APR_UINT16_MAX) {
+        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(10259)
+                      "can't send headers to %s:%u: packet size too "
+                      "large (%" APR_SIZE_T_FMT ")",
+                      conn->hostname, conn->port, pktsize);
+        return HTTP_INTERNAL_SERVER_ERROR;
+    }
 
     ptr = buf = apr_palloc(r->pool, headerlen);
 
@@ -196,8 +204,6 @@
         ptr += vallen;
     }
 
-    pktsize = headerlen - 4;
-
     buf[0] = 0;
     buf[1] = (apr_byte_t) (pktsize & 0xff);
     buf[2] = (apr_byte_t) ((pktsize >> 8) & 0xff);