[libvirt] [PATCH] CVE-2014-7823: dumpxml: security hole with migratable flag

Commit 28f8dfd (v1.0.0) introduced a security hole: in at least the qemu implementation of virDomainGetXMLDesc, the use of the flag VIR_DOMAIN_XML_MIGRATABLE (which is usable from a read-only connection) triggers the implicit use of VIR_DOMAIN_XML_SECURE prior to calling qemuDomainFormatXML. However, the use of VIR_DOMAIN_XML_SECURE is supposed to be restricted to read-write clients only. This patch treats the migratable flag as requiring the same permissions, rather than analyzing what might break if migratable xml no longer includes secret information. Fortunately, the information leak is low-risk: all that is gated by the VIR_DOMAIN_XML_SECURE flag is the VNC connection password; but VNC passwords are already weak (FIPS forbids their use, and on a non-FIPS machine, anyone stupid enough to trust a max-8-byte password sent in plaintext over the network deserves what they get). SPICE offers better security than VNC, and all other secrets are properly protected by use of virSecret associations rather than direct output in domain XML. * src/remote/remote_protocol.x (REMOTE_PROC_DOMAIN_GET_XML_DESC): Tighten rules on use of migratable flag. * src/libvirt-domain.c (virDomainGetXMLDesc): Likewise. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- The libvirt-security list agreed that this did not need an embargo because it is low-risk; but I'm on the road this week, so while this patch for master can go in now, I won't complete the backport to all the affected stable branches (everything since v1.0.0) or do the Libvirt Security Notice writeup until Monday. src/libvirt-domain.c | 3 ++- src/remote/remote_protocol.x | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c index 7dc3146..2b0defc 100644 --- a/src/libvirt-domain.c +++ b/src/libvirt-domain.c @@ -2607,7 +2607,8 @@ virDomainGetXMLDesc(virDomainPtr domain, unsigned int flags) virCheckDomainReturn(domain, NULL); conn = domain->conn; - if ((conn->flags & VIR_CONNECT_RO) && (flags & VIR_DOMAIN_XML_SECURE)) { + if ((conn->flags & VIR_CONNECT_RO) && + (flags & (VIR_DOMAIN_XML_SECURE | VIR_DOMAIN_XML_MIGRATABLE))) { virReportError(VIR_ERR_OPERATION_DENIED, "%s", _("virDomainGetXMLDesc with secure flag")); goto error; diff --git a/src/remote/remote_protocol.x b/src/remote/remote_protocol.x index db12cda..ebf4530 100644 --- a/src/remote/remote_protocol.x +++ b/src/remote/remote_protocol.x @@ -3255,6 +3255,7 @@ enum remote_procedure { * @generate: both * @acl: domain:read * @acl: domain:read_secure:VIR_DOMAIN_XML_SECURE + * @acl: domain:read_secure:VIR_DOMAIN_XML_MIGRATABLE */ REMOTE_PROC_DOMAIN_GET_XML_DESC = 14, -- 1.9.3