From 333a655d5447c1d66f091051f2024e6a18d2246a Mon Sep 17 00:00:00 2001 From: Josh Boyer Date: Fri, 5 Jul 2013 09:01:24 -0400 Subject: Add vhost-net use-after-free fix (rhbz 976789 980643) --- ...net-fix-use-after-free-in-vhost_net_flush.patch | 76 ++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 vhost-net-fix-use-after-free-in-vhost_net_flush.patch (limited to 'vhost-net-fix-use-after-free-in-vhost_net_flush.patch') diff --git a/vhost-net-fix-use-after-free-in-vhost_net_flush.patch b/vhost-net-fix-use-after-free-in-vhost_net_flush.patch new file mode 100644 index 000000000..b90095e54 --- /dev/null +++ b/vhost-net-fix-use-after-free-in-vhost_net_flush.patch @@ -0,0 +1,76 @@ +Date: Tue, 25 Jun 2013 17:29:46 +0300 +From: "Michael S. Tsirkin" +To: linux-kernel@vger.kernel.org +Cc: "David S. Miller" , + Asias He , Jason Wang , + kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, + netdev@vger.kernel.org +Subject: [PATCHv2] vhost-net: fix use-after-free in vhost_net_flush +Message-ID: <20130625142946.GA17414@redhat.com> +MIME-Version: 1.0 +Content-Type: text/plain; charset=us-ascii +Content-Disposition: inline +X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 +Sender: linux-kernel-owner@vger.kernel.org +Precedence: bulk +List-ID: +X-Mailing-List: linux-kernel@vger.kernel.org + +vhost_net_ubuf_put_and_wait has a confusing name: +it will actually also free it's argument. +Thus since commit 1280c27f8e29acf4af2da914e80ec27c3dbd5c01 + "vhost-net: flush outstanding DMAs on memory change" +vhost_net_flush tries to use the argument after passing it +to vhost_net_ubuf_put_and_wait, this results +in use after free. +To fix, don't free the argument in vhost_net_ubuf_put_and_wait, +add an new API for callers that want to free ubufs. + +Acked-by: Asias He +Acked-by: Jason Wang +Signed-off-by: Michael S. Tsirkin + +--- + +Please review, and queue for 3.10 and stable. +Changes since v1: + - no functional change, tweaked the commit message + + drivers/vhost/net.c | 9 +++++++-- + 1 file changed, 7 insertions(+), 2 deletions(-) + +diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c +index 5c77d6a..534adb0 100644 +--- a/drivers/vhost/net.c ++++ b/drivers/vhost/net.c +@@ -149,6 +149,11 @@ static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) + { + kref_put(&ubufs->kref, vhost_net_zerocopy_done_signal); + wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount)); ++} ++ ++static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) ++{ ++ vhost_net_ubuf_put_and_wait(ubufs); + kfree(ubufs); + } + +@@ -1073,7 +1078,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) + mutex_unlock(&vq->mutex); + + if (oldubufs) { +- vhost_net_ubuf_put_and_wait(oldubufs); ++ vhost_net_ubuf_put_wait_and_free(oldubufs); + mutex_lock(&vq->mutex); + vhost_zerocopy_signal_used(n, vq); + mutex_unlock(&vq->mutex); +@@ -1091,7 +1096,7 @@ err_used: + vq->private_data = oldsock; + vhost_net_enable_vq(n, vq); + if (ubufs) +- vhost_net_ubuf_put_and_wait(ubufs); ++ vhost_net_ubuf_put_wait_and_free(ubufs); + err_ubufs: + fput(sock->file); + err_vq: + -- cgit