Re: [libvirt] [PATCH] proxy: Fix use of uninitalized memory
"Rasputin" <rasputin(a)email.ru> wrote:
On short read, members of packet header are checked before actually
read.
If uninitialized values can pass the test, they can be set to arbitrary
values while reading remaining portion of a packet.
Buffer overflow is possible. libvirt_proxy is suid-root.
diff -urp libvirt-0.5.1/proxy/libvirt_proxy.c libvirt-dev/proxy/libvirt_proxy.c
--- libvirt-0.5.1/proxy/libvirt_proxy.c 2008-11-20 08:58:43.000000000 +0100
+++ libvirt-dev/proxy/libvirt_proxy.c 2009-01-25 12:51:33.000000000 +0100
@@ -385,7 +385,8 @@ retry:
fprintf(stderr, "read %d bytes from client %d on socket %d\n",
ret, nr, pollInfos[nr].fd);
- if ((req->version != PROXY_PROTO_VERSION) ||
+ if ((ret != sizeof(virProxyPacket)) ||
+ (req->version != PROXY_PROTO_VERSION) ||
(req->len < sizeof(virProxyPacket)) ||
(req->len > sizeof(virProxyFullPacket)))
goto comm_error;
Thanks again.
Here's what I expect to commit.
If you would like different attribution, let me know.
From 0abc169e868d7b7b5d1edd75aec0e021b1e67c53 Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering(a)redhat.com>
Date: Wed, 28 Jan 2009 14:27:11 +0100
Subject: [PATCH] libvirt_proxy: avoid potential buffer overflow
* proxy/libvirt_proxy.c (proxyReadClientSocket): Ensure that
we've read an entire virProxyPacket before dereferencing "req".
Analysis and patch by "Rasputin" <rasputin(a)email.ru>. Details in
<http://thread.gmane.org/gmane.comp.emulators.libvirt/11459>;.
---
proxy/libvirt_proxy.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/proxy/libvirt_proxy.c b/proxy/libvirt_proxy.c
index f3d9ede..863dc32 100644
--- a/proxy/libvirt_proxy.c
+++ b/proxy/libvirt_proxy.c
@@ -2,7 +2,7 @@
* proxy_svr.c: root suid proxy server for Xen access to APIs with no
* side effects from unauthenticated clients.
*
- * Copyright (C) 2006, 2007, 2008 Red Hat, Inc.
+ * Copyright (C) 2006, 2007, 2008, 2009 Red Hat, Inc.
*
* See COPYING.LIB for the License of this software
*
@@ -382,7 +382,8 @@ retry:
fprintf(stderr, "read %d bytes from client %d on socket %d\n",
ret, nr, pollInfos[nr].fd);
- if ((req->version != PROXY_PROTO_VERSION) ||
+ if ((ret != sizeof(virProxyPacket)) ||
+ (req->version != PROXY_PROTO_VERSION) ||
(req->len < sizeof(virProxyPacket)) ||
(req->len > sizeof(virProxyFullPacket)))
goto comm_error;
--
1.6.1.1.374.g0d9d7