From: Jon Ludlam <Jonathan.Ludlam@eu.citrix.com <Jon Ludlam <Jonathan.Ludlam@eu.citrix.com>
Date: Mon, 8 Mar 2010 11:28:56 +0000 (+0000)
Subject: CA-38105: Fix segfault in fork-and-exec-daemon.
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=924f7628552dcc3f57a6c49b5ee13cee8a184eea;p=xcp%2Fxen-api-libs.git

CA-38105: Fix segfault in fork-and-exec-daemon.

The segfault would have happened when a message was receieved on this socket without an associated fd being sent. This is bad behaviour on the part of the client, but shouldn't cause a segfault. This patch fixes the segfault, but we'll need to fix the client too!

Signed-off-by: Jon Ludlam <Jonathan.Ludlam@eu.citrix.com
---

diff --git a/stdext/unixext_stubs.c b/stdext/unixext_stubs.c
index a01de8f..7941b5a 100644
--- a/stdext/unixext_stubs.c
+++ b/stdext/unixext_stubs.c
@@ -382,7 +382,7 @@ CAMLprim value stub_unix_recv_fd(value sock, value buff, value ofs, value len, v
   if(ret == -1) 
     unixext_error(errno);
 
-  if(ret> 0) {
+  if(ret>0 && msg.msg_controllen>0) {
     cmsg = CMSG_FIRSTHDR(&msg);
     if(cmsg->cmsg_level == SOL_SOCKET && (cmsg->cmsg_type == SCM_RIGHTS)) {
       fd=Val_int(*(int*)CMSG_DATA(cmsg));