implement Ryan's suggested fix for buckets associated with a subrequest

having private data in the wrong (i.e., subrequest) pool, leading to
a segfault later in processing the main request

in the patch posted on new-httpd, the temporary brigade was allocated from
the connection pool; the committed code allocates the brigade from the
main-request pool, as suggested by Ian Holsman

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89284 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/server/request.c b/server/request.c
index 4e2e1edbc58434777b3fcef1c7eb790ea0bbb0db..dc222fb4a65b194048e4fc4f2178f5f407a826c0 100644 (file)
--- a/server/request.c
+++ b/server/request.c
@@ -808,7 +808,40 @@ AP_CORE_DECLARE_NONSTD(apr_status_t) ap_sub_req_output_filter(ap_filter_t *f,
     apr_bucket *e = APR_BRIGADE_LAST(bb);
 
     if (APR_BUCKET_IS_EOS(e)) {
+        apr_bucket_brigade *tmpbb;
+
         apr_bucket_delete(e);
+
+        if (!APR_BRIGADE_EMPTY(bb)) { /* avoid brigade create/destroy */
+
+            /* We need to be certain that any data in a bucket is valid
+             * after the subrequest pool is cleared.
+             */ 
+            tmpbb = apr_brigade_create(f->r->main->pool);
+            
+            APR_BRIGADE_FOREACH(e, bb) {
+                const char *str;
+                apr_size_t n;
+                apr_status_t rv;
+                
+                rv = apr_bucket_read(e, &str, &n, APR_BLOCK_READ);
+                /* XXX handle rv! */
+                
+                /* This apr_brigade_write does not use a flush function
+                   because we assume that we will not write enough data
+                   into it to cause a flush. However, if we *do* write
+                   "too much", then we could end up with transient
+                   buckets which would suck. This works for now, but is
+                   a bit shaky if changes are made to some of the
+                   buffering sizes. Let's do an assert to prevent
+                   potential future problems... */
+                AP_DEBUG_ASSERT(AP_MIN_BYTES_TO_WRITE <=
+                                APR_BUCKET_BUFF_SIZE);
+                apr_brigade_write(tmpbb, NULL, NULL, str, n);
+            }
+            apr_brigade_destroy(bb);
+            bb = tmpbb;
+        }
     }
     return ap_pass_brigade(f->next, bb);
 }