From owner-svn-src-head@FreeBSD.ORG  Tue May 21 21:58:02 2013
Return-Path: <owner-svn-src-head@FreeBSD.ORG>
Delivered-To: svn-src-head@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by hub.freebsd.org (Postfix) with ESMTP id 6422534E;
 Tue, 21 May 2013 21:58:02 +0000 (UTC) (envelope-from mjg@FreeBSD.org)
Received: from svn.freebsd.org (svn.freebsd.org
 [IPv6:2001:1900:2254:2068::e6a:0])
 by mx1.freebsd.org (Postfix) with ESMTP id 5602A112;
 Tue, 21 May 2013 21:58:02 +0000 (UTC)
Received: from svn.freebsd.org ([127.0.1.70])
 by svn.freebsd.org (8.14.6/8.14.6) with ESMTP id r4LLw1p5076596;
 Tue, 21 May 2013 21:58:01 GMT (envelope-from mjg@svn.freebsd.org)
Received: (from mjg@localhost)
 by svn.freebsd.org (8.14.6/8.14.5/Submit) id r4LLw1Ed076595;
 Tue, 21 May 2013 21:58:01 GMT (envelope-from mjg@svn.freebsd.org)
Message-Id: <201305212158.r4LLw1Ed076595@svn.freebsd.org>
From: Mateusz Guzik <mjg@FreeBSD.org>
Date: Tue, 21 May 2013 21:58:01 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r250890 - head/sys/kern
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 21 May 2013 21:58:02 -0000

Author: mjg
Date: Tue May 21 21:58:00 2013
New Revision: 250890
URL: http://svnweb.freebsd.org/changeset/base/250890

Log:
  passing fd over unix socket: fix a corner case where caller
  wants to pass no descriptors.
  
  Previously the kernel would leak memory and try to free a potentially
  arbitrary pointer.
  
  Reviewed by:	pjd

Modified:
  head/sys/kern/uipc_usrreq.c

Modified: head/sys/kern/uipc_usrreq.c
==============================================================================
--- head/sys/kern/uipc_usrreq.c	Tue May 21 21:50:11 2013	(r250889)
+++ head/sys/kern/uipc_usrreq.c	Tue May 21 21:58:00 2013	(r250890)
@@ -1686,6 +1686,8 @@ unp_freerights(struct filedescent **fdep
 	struct file *fp;
 	int i;
 
+	if (fdcount == 0)
+		return;
 	for (i = 0; i < fdcount; i++) {
 		fp = fdep[i]->fde_file;
 		filecaps_free(&fdep[i]->fde_caps);
@@ -1768,7 +1770,8 @@ unp_externalize(struct mbuf *control, st
 				unp_externalize_fp(fde->fde_file);
 			}
 			FILEDESC_XUNLOCK(fdesc);
-			free(fdep[0], M_FILECAPS);
+			if (newfds != 0)
+				free(fdep[0], M_FILECAPS);
 		} else {
 			/* We can just copy anything else across. */
 			if (error || controlp == NULL)
@@ -1925,6 +1928,10 @@ unp_internalize(struct mbuf **controlp, 
 				error = E2BIG;
 				goto out;
 			}
+			if (oldfds == 0) {
+				FILEDESC_SUNLOCK(fdesc);
+				break;
+			}
 			fdp = data;
 			fdep = (struct filedescent **)
 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));