Consolidate all tcp/http tear down into a single http_close function to prevent a rare UAF for expiring connections

1 files changed, 26 insertions, 10 deletions

diff --git a/ot_http.c b/ot_http.c
index 927d618..c2f7e5e 100644
--- a/ot_http.c
+++ b/ot_http.c
@@ -38,12 +38,34 @@ ssize_t      g_stats_path_len;
 
 enum { SUCCESS_HTTP_HEADER_LENGTH = 80, SUCCESS_HTTP_SIZE_OFF = 17 };
 
+/* Give up a connection: the one place that knows everything hanging off it.
+   The slot is released before anything is freed, so that a late event or the
+   expiry sweep finds a closed descriptor rather than a freed cookie. */
+void http_close(const int64_t sock) {
+  struct http_data *cookie = fdstate_cookie(sock);
+
+  fdstate_close((int)sock);
+
+  if (cookie) {
+    if (cookie->batch)
+      batch_reset(cookie->batch);
+    free(cookie->batch);
+    buf_reset(&cookie->request);
+    if (cookie->flag & (STRUCT_HTTP_FLAG_WAITINGFORTASK | STRUCT_HTTP_FLAG_CHUNKED_IN_TRANSFER))
+      mutex_workqueue_canceltask(sock);
+    free(cookie);
+  }
+
+  event_del((int)sock);
+  close((int)sock);
+}
+
 static void http_senddata(const int64_t sock, struct ot_workstruct *ws) {
   struct http_data *cookie = fdstate_cookie(sock);
   ssize_t           written_size;
 
   if (!cookie) {
-    event_del((int)sock), close((int)sock);
+    http_close(sock);
     return;
   }
 
@@ -65,9 +87,7 @@ static void http_senddata(const int64_t sock, struct ot_workstruct *ws) {
 
   written_size = write(sock, ws->reply, ws->reply_size);
   if ((written_size < 0) || ((written_size == ws->reply_size) && !ws->keep_alive)) {
-    buf_reset(&cookie->request);
-    free(cookie);
-    event_del((int)sock), close((int)sock);
+    http_close(sock);
     return;
   }
 
@@ -75,9 +95,7 @@ static void http_senddata(const int64_t sock, struct ot_workstruct *ws) {
     char   *outbuf;
 
     if (!(outbuf = malloc(ws->reply_size - written_size))) {
-      buf_reset(&cookie->request);
-      free(cookie);
-      event_del((int)sock), close((int)sock);
+      http_close(sock);
       return;
     }
 
@@ -86,9 +104,7 @@ static void http_senddata(const int64_t sock, struct ot_workstruct *ws) {
       cookie->batch = calloc(1, sizeof(ot_batch));
       if (!cookie->batch) {
         free(outbuf);
-        buf_reset(&cookie->request);
-        free(cookie);
-        event_del((int)sock), close((int)sock);
+        http_close(sock);
         return;
       }
     }