On 20.08.2014 05:49, Martin Kletzander wrote:
On Tue, Aug 19, 2014 at 03:18:02PM +0200, Michal Privoznik wrote:
https://bugzilla.redhat.com/show_bug.cgi?id=1095636
When starting up the domain the domain's NICs are allocated. As of 1f24f682 (v1.0.6) we are able to use multiqueue feature on virtio NICs. It breaks network processing into multiple queues which can be processed in parallel by different host CPUs. The queues are, however, created by opening /dev/net/tun several times. Unfortunately, only the first FD in the row is labelled so when turning the multiqueue feature on in the guest, qemu will get AVC denial. Make sure we label all the FDs needed.
Moreover, the default label of /dev/net/tun doesn't allow attaching a queue:
type=AVC msg=audit(1399622478.790:893): avc: denied { attach_queue } for pid=7585 comm="qemu-kvm" scontext=system_u:system_r:svirt_t:s0:c638,c877 tcontext=system_u:system_r:virtd_t:s0-s0:c0.c1023
Wow, I didn't even know you could have range in the "level" field (I think it doesn't make sense, but I don't understand why it is allowed by SELinux).
tclass=tun_socket
And as suggested by SELinux maintainers, the tun FD should be labeled as svirt_t. Therefore, we don't need to adjust any range (as done previously by Guannan in ae368ebf) rather set the seclabel of the domain directly.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/qemu/qemu_command.c | 18 +++--------------- src/qemu/qemu_hotplug.c | 6 ++++++ src/security/security_selinux.c | 34 ++-------------------------------- 3 files changed, 11 insertions(+), 47 deletions(-)
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index a92315a..4bc0368 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -192,10 +192,6 @@ qemuPhysIfaceConnect(virDomainDefPtr def, vmop, cfg->stateDir, virDomainNetGetActualBandwidth(net)); if (rc >= 0) { - if (virSecurityManagerSetTapFDLabel(driver->securityManager, - def, rc) < 0) - goto error; - virDomainAuditNetDevice(def, net, res_ifname, true); VIR_FREE(net->ifname); net->ifname = res_ifname; @@ -203,17 +199,6 @@ qemuPhysIfaceConnect(virDomainDefPtr def,
virObjectUnref(cfg); return rc; - - error: - ignore_value(virNetDevMacVLanDeleteWithVPortProfile( - res_ifname, &net->mac, - virDomainNetGetActualDirectDev(net), - virDomainNetGetActualDirectMode(net), - virDomainNetGetActualVirtPortProfile(net), - cfg->stateDir)); - VIR_FREE(res_ifname); - virObjectUnref(cfg); - return -1; }
@@ -7201,6 +7186,9 @@ qemuBuildInterfaceCommandLine(virCommandPtr cmd, }
for (i = 0; i < tapfdSize; i++) { + if (virSecurityManagerSetTapFDLabel(driver->securityManager, + def, tapfd[i]) < 0) + goto cleanup; virCommandPassFD(cmd, tapfd[i], VIR_COMMAND_PASS_FD_CLOSE_PARENT); if (virAsprintf(&tapfdName[i], "%d", tapfd[i]) < 0) diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index f7e223a..b60bd22 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -922,6 +922,12 @@ int qemuDomainAttachNetDevice(virConnectPtr conn, goto cleanup; }
+ for (i = 0; i < tapfdSize; i++) { + if (virSecurityManagerSetTapFDLabel(driver->securityManager, + vm->def, tapfd[i]) < 0) + goto cleanup; + } +
Shouldn't there be the same loop for vhostfd[i]? Although it won't probably be > 1. Just ckecking.
No, vhost FDs are not connected queue to. Frankly, I don't fully understand all the details, but hey - it works :-)
if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_NET_NAME) || virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) { if (qemuAssignDeviceNetAlias(vm->def, net, -1) < 0) diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c index c078cab..5d18493 100644 --- a/src/security/security_selinux.c +++ b/src/security/security_selinux.c @@ -2330,47 +2330,17 @@ virSecuritySELinuxSetImageFDLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED, }
static int -virSecuritySELinuxSetTapFDLabel(virSecurityManagerPtr mgr, +virSecuritySELinuxSetTapFDLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED, virDomainDefPtr def, int fd) { - struct stat buf; - security_context_t fcon = NULL; virSecurityLabelDefPtr secdef; - char *str = NULL; - int rc = -1;
secdef = virDomainDefGetSecurityLabelDef(def, SECURITY_SELINUX_NAME); if (!secdef || !secdef->label) return 0;
- if (fstat(fd, &buf) < 0) { - virReportSystemError(errno, _("cannot stat tap fd %d"), fd); - goto cleanup; - } - - if ((buf.st_mode & S_IFMT) != S_IFCHR) { - virReportError(VIR_ERR_INTERNAL_ERROR, - _("tap fd %d is not character device"), fd); - goto cleanup; - } - - if (getContext(mgr, "/dev/tap.*", buf.st_mode, &fcon) < 0) { - virReportError(VIR_ERR_INTERNAL_ERROR, - _("cannot lookup default selinux label for tap fd %d"), fd); - goto cleanup; - } - - if (!(str = virSecuritySELinuxContextAddRange(secdef->label, fcon))) { - goto cleanup; - } else { - rc = virSecuritySELinuxFSetFilecon(fd, str); - } - - cleanup: - freecon(fcon); - VIR_FREE(str); - return rc; + return virSecuritySELinuxFSetFilecon(fd, secdef->label); }
This looks much better now. Although it looks way too similar to virSecuritySELinuxSetImageFDLabel() :) I think it might be worth keeping just one of these two functions, let's say ...SetFDLabel() in order not to complicate things, and assign it to both needed fields in the domain structure.
Yes and no. While SetTapFDLabel needs to set domain process label (seclabel->label) SetImageFDLabel needs to use image label (seclabel->imagelabel). And I don't think it's worth wrap these two functions into one wrapper function (I doubt it'll be readable more too).
ACK with that changed.
So I'm taking this as ACK without any change required and pushing. Thanks! Michal