[Pkg-libvirt-commits] [libvirt] 01/02: qemu: ensure TLS clients always verify the server certificate

Guido Guenther agx at moszumanska.debian.org
Tue Oct 17 06:45:01 UTC 2017


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agx pushed a commit to annotated tag debian/3.8.0-3
in repository libvirt.

commit 3f18a26b76d6672d7174a1b27a9aa1e1ae95a8fd
Author: Guido Günther <agx at sigxcpu.org>
Date:   Mon Oct 16 19:36:19 2017 +0200

    qemu: ensure TLS clients always verify the server certificate
---
 ...clients-always-verify-the-server-certific.patch | 70 ++++++++++++++++++++++
 debian/patches/series                              |  1 +
 2 files changed, 71 insertions(+)

diff --git a/debian/patches/qemu-ensure-TLS-clients-always-verify-the-server-certific.patch b/debian/patches/qemu-ensure-TLS-clients-always-verify-the-server-certific.patch
new file mode 100644
index 0000000..c8798b1
--- /dev/null
+++ b/debian/patches/qemu-ensure-TLS-clients-always-verify-the-server-certific.patch
@@ -0,0 +1,70 @@
+From: "Daniel P. Berrange" <berrange at redhat.com>
+Date: Thu, 5 Oct 2017 17:54:28 +0100
+Subject: qemu: ensure TLS clients always verify the server certificate
+
+The default_tls_x509_verify (and related) parameters in qemu.conf
+control whether the QEMU TLS servers request & verify certificates
+from clients. This works as a simple access control system for
+servers by requiring the CA to issue certs to permitted clients.
+This use of client certificates is disabled by default, since it
+requires extra work to issue client certificates.
+
+Unfortunately the code was using this configuration parameter when
+setting up both TLS clients and servers in QEMU. The result was that
+TLS clients for character devices and disk devices had verification
+turned off, meaning they would ignore errors while validating the
+server certificate.
+
+This allows for trivial MITM attacks between client and server,
+as any certificate returned by the attacker will be accepted by
+the client.
+
+This is assigned CVE-2017-1000256  / LSN-2017-0002
+
+Reviewed-by: Eric Blake <eblake at redhat.com>
+Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
+---
+ src/qemu/qemu_command.c                                                 | 2 +-
+ tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-tlsx509-chardev.args     | 2 +-
+ .../qemuxml2argv-serial-tcp-tlsx509-secret-chardev.args                 | 2 +-
+ 3 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
+index 4f141e0..69e14e6 100644
+--- a/src/qemu/qemu_command.c
++++ b/src/qemu/qemu_command.c
+@@ -721,7 +721,7 @@ qemuBuildTLSx509BackendProps(const char *tlspath,
+     if (virJSONValueObjectCreate(propsret,
+                                  "s:dir", path,
+                                  "s:endpoint", (isListen ? "server": "client"),
+-                                 "b:verify-peer", verifypeer,
++                                 "b:verify-peer", (isListen ? verifypeer : true),
+                                  NULL) < 0)
+         goto cleanup;
+ 
+diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-tlsx509-chardev.args b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-tlsx509-chardev.args
+index 5aff773..ab5f7e2 100644
+--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-tlsx509-chardev.args
++++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-tlsx509-chardev.args
+@@ -26,7 +26,7 @@ server,nowait \
+ localport=1111 \
+ -device isa-serial,chardev=charserial0,id=serial0 \
+ -object tls-creds-x509,id=objcharserial1_tls0,dir=/etc/pki/libvirt-chardev,\
+-endpoint=client,verify-peer=no \
++endpoint=client,verify-peer=yes \
+ -chardev socket,id=charserial1,host=127.0.0.1,port=5555,\
+ tls-creds=objcharserial1_tls0 \
+ -device isa-serial,chardev=charserial1,id=serial1 \
+diff --git a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-tlsx509-secret-chardev.args b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-tlsx509-secret-chardev.args
+index 91f1fe0..2567abb 100644
+--- a/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-tlsx509-secret-chardev.args
++++ b/tests/qemuxml2argvdata/qemuxml2argv-serial-tcp-tlsx509-secret-chardev.args
+@@ -31,7 +31,7 @@ localport=1111 \
+ data=9eao5F8qtkGt+seB1HYivWIxbtwUu6MQtg1zpj/oDtUsPr1q8wBYM91uEHCn6j/1,\
+ keyid=masterKey0,iv=AAECAwQFBgcICQoLDA0ODw==,format=base64 \
+ -object tls-creds-x509,id=objcharserial1_tls0,dir=/etc/pki/libvirt-chardev,\
+-endpoint=client,verify-peer=no,passwordid=charserial1-secret0 \
++endpoint=client,verify-peer=yes,passwordid=charserial1-secret0 \
+ -chardev socket,id=charserial1,host=127.0.0.1,port=5555,\
+ tls-creds=objcharserial1_tls0 \
+ -device isa-serial,chardev=charserial1,id=serial1 \
diff --git a/debian/patches/series b/debian/patches/series
index 48b4ea5..f13b179 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -18,3 +18,4 @@ Set-defaults-for-zfs-tools.patch
 Pass-GPG_TTY-env-var-to-the-ssh-binary.patch
 apparmor-add-dnsmasq-ptrace-rule-to-libvirtd-profile.patch
 virt-host-validate-require-fuse-for-LXC-if-compiled-in.patch
+qemu-ensure-TLS-clients-always-verify-the-server-certific.patch

-- 
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