Re: [PATCH V3] libxl: Reject VM config referencing nwfilters

The Xen libxl driver does not support nwfilter. Introduce a deviceValidateCallback function with a check for nwfilters, returning VIR_ERR_CONFIG_UNSUPPORTED if any are found. Also fail to start any existing VMs referencing nwfilters. Drivers generally ignore unrecognized XML configuration, but ignoring a user's request to filter VM network traffic can be viewed as a security issue. Signed-off-by: Jim Fehlig <jfehlig(a)suse.com&gt;

--- V2: https://lists.libvirt.org/archives/list/devel@lists.libvirt.org/message/U... Changes in V3: When starting a VM, use virDomainDefValidate to validate the def instead of duplicating the checks. Note: With the change in V3, the validation is only done when starting a new VM. Validation is skipped if restoring a managed saved VM. src/libxl/libxl_domain.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c index 0f129ec69c..029b12fa3b 100644 --- a/src/libxl/libxl_domain.c +++ b/src/libxl/libxl_domain.c @@ -356,12 +356,30 @@ libxlDomainDefValidate(const virDomainDef *def, return 0; } +static int +libxlDomainDeviceDefValidate(const virDomainDeviceDef *dev, + const virDomainDef *def, + void *opaque G_GNUC_UNUSED, + void *parseOpaque G_GNUC_UNUSED) +{ + if (dev->type == VIR_DOMAIN_DEVICE_NET && dev->data.net->filter) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("filterref is not supported in %1$s"), + virDomainVirtTypeToString(def->virtType)); + return -1; + } + + return 0; +} + + virDomainDefParserConfig libxlDomainDefParserConfig = { .macPrefix = { 0x00, 0x16, 0x3e }, .netPrefix = LIBXL_GENERATED_PREFIX_XEN, .devicesPostParseCallback = libxlDomainDeviceDefPostParse, .domainPostParseCallback = libxlDomainDefPostParse, .domainValidateCallback = libxlDomainDefValidate, + .deviceValidateCallback = libxlDomainDeviceDefValidate, .features = VIR_DOMAIN_DEF_FEATURE_USER_ALIAS | VIR_DOMAIN_DEF_FEATURE_FW_AUTOSELECT | @@ -1460,6 +1478,10 @@ libxlDomainStartNew(libxlDriverPrivate *driver, managed_save_path); vm->hasManagedSave = false; + } else { + /* Validate configuration if starting a new VM */ + if (virDomainDefValidate(vm->def, 0, driver->xmlopt, NULL) < 0) + goto cleanup; } ret = libxlDomainStart(driver, vm, start_paused, restore_fd, restore_ver); -- 2.35.3