[libvirt] [PATCH 2/2] security: Manage SELinux labels on shared/readonly hostdev's

[John Ferlan]

https://bugzilla.redhat.com/show_bug.cgi?id=1082521

Support for shared hostdev's was added in a number of commits, initially
starting with 'f2c1d9a80' and most recently commit id 'fd243fc4' to fix
issues with the initial implementation.  Missed in all those changes was
the need to mimic the virSELinux{Set|Restore}SecurityDiskLabel code to
handle the "shared" (or shareable) and readonly options when Setting
or Restoring the SELinux labels.

This patch will adjust the virSecuritySELinuxSetSecuritySCSILabel to not
use the virSecuritySELinuxSetSecurityHostdevLabelHelper in order to set
the label. Rather follow what the Disk code does by setting the label
differently based on whether shareable/readonly is set.  This patch will
also modify the virSecuritySELinuxRestoreSecuritySCSILabel to follow
the same logic as virSecuritySELinuxRestoreSecurityImageLabelInt and not
restore the label if shared/readonly

Signed-off-by: John Ferlan <jferlan at redhat.com>
---
 src/security/security_selinux.c | 58 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 49 insertions(+), 9 deletions(-)

diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index f96be50..3a794b8 100644
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -71,6 +71,12 @@ struct _virSecuritySELinuxData {
 #define SECURITY_SELINUX_VOID_DOI       "0"
 #define SECURITY_SELINUX_NAME "selinux"
 
+/* Data structure to pass to *FileIterate so we have everything we need */
+struct SELinuxSCSICallbackData {
+    virSecurityManagerPtr mgr;
+    virDomainDefPtr def;
+};
+
 static int
 virSecuritySELinuxRestoreSecurityTPMFileLabelInt(virSecurityManagerPtr mgr,
                                                  virDomainDefPtr def,
@@ -1143,7 +1149,7 @@ virSecuritySELinuxRestoreSecurityImageLabelInt(virSecurityManagerPtr mgr,
         !src->backingStore)
         return 0;
 
-    /* Don't restore labels on readoly/shared disks, because other VMs may
+    /* Don't restore labels on readonly/shared disks, because other VMs may
      * still be accessing these. Alternatively we could iterate over all
      * running domains and try to figure out if it is in use, but this would
      * not work for clustered filesystems, since we can't see running VMs using
@@ -1309,14 +1315,31 @@ virSecuritySELinuxSetSecurityUSBLabel(virUSBDevicePtr dev ATTRIBUTE_UNUSED,
 }
 
 static int
-virSecuritySELinuxSetSecuritySCSILabel(virSCSIDevicePtr dev ATTRIBUTE_UNUSED,
+virSecuritySELinuxSetSecuritySCSILabel(virSCSIDevicePtr dev,
                                        const char *file, void *opaque)
 {
-    return virSecuritySELinuxSetSecurityHostdevLabelHelper(file, opaque);
+    virSecurityLabelDefPtr secdef;
+    struct SELinuxSCSICallbackData *ptr = opaque;
+    virSecurityManagerPtr mgr = ptr->mgr;
+    virSecuritySELinuxDataPtr data = virSecurityManagerGetPrivateData(mgr);
+
+    secdef = virDomainDefGetSecurityLabelDef(ptr->def, SECURITY_SELINUX_NAME);
+    if (secdef == NULL)
+        return 0;
+
+    if (virSCSIDeviceGetShareable(dev))
+        return virSecuritySELinuxSetFileconOptional(file,
+                                                    data->file_context);
+    else if (virSCSIDeviceGetReadonly(dev))
+        return virSecuritySELinuxSetFileconOptional(file,
+                                                    data->content_context);
+    else
+        return virSecuritySELinuxSetFileconOptional(file, secdef->imagelabel);
 }
 
 static int
-virSecuritySELinuxSetSecurityHostdevSubsysLabel(virDomainDefPtr def,
+virSecuritySELinuxSetSecurityHostdevSubsysLabel(virSecurityManagerPtr mgr,
+                                                virDomainDefPtr def,
                                                 virDomainHostdevDefPtr dev,
                                                 const char *vroot)
 
@@ -1377,17 +1400,27 @@ virSecuritySELinuxSetSecurityHostdevSubsysLabel(virDomainDefPtr def,
 
     case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_SCSI: {
         virDomainHostdevSubsysSCSIHostPtr scsihostsrc = &scsisrc->u.host;
+        struct SELinuxSCSICallbackData *ptr;
+
+        if (VIR_ALLOC(ptr) < 0)
+            goto done;
+        ptr->mgr = mgr;
+        ptr->def = def;
+
         virSCSIDevicePtr scsi =
             virSCSIDeviceNew(NULL,
                              scsihostsrc->adapter, scsihostsrc->bus,
                              scsihostsrc->target, scsihostsrc->unit,
                              dev->readonly, dev->shareable);
 
-        if (!scsi)
+        if (!scsi) {
+            VIR_FREE(ptr);
             goto done;
+        }
 
-        ret = virSCSIDeviceFileIterate(scsi, virSecuritySELinuxSetSecuritySCSILabel, def);
+        ret = virSCSIDeviceFileIterate(scsi, virSecuritySELinuxSetSecuritySCSILabel, ptr);
         virSCSIDeviceFree(scsi);
+        VIR_FREE(ptr);
 
         break;
     }
@@ -1454,7 +1487,7 @@ virSecuritySELinuxSetSecurityHostdevCapsLabel(virDomainDefPtr def,
 
 
 static int
-virSecuritySELinuxSetSecurityHostdevLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
+virSecuritySELinuxSetSecurityHostdevLabel(virSecurityManagerPtr mgr,
                                           virDomainDefPtr def,
                                           virDomainHostdevDefPtr dev,
                                           const char *vroot)
@@ -1468,7 +1501,8 @@ virSecuritySELinuxSetSecurityHostdevLabel(virSecurityManagerPtr mgr ATTRIBUTE_UN
 
     switch (dev->mode) {
     case VIR_DOMAIN_HOSTDEV_MODE_SUBSYS:
-        return virSecuritySELinuxSetSecurityHostdevSubsysLabel(def, dev, vroot);
+        return virSecuritySELinuxSetSecurityHostdevSubsysLabel(mgr, def,
+                                                               dev, vroot);
 
     case VIR_DOMAIN_HOSTDEV_MODE_CAPABILITIES:
         return virSecuritySELinuxSetSecurityHostdevCapsLabel(def, dev, vroot);
@@ -1500,12 +1534,18 @@ virSecuritySELinuxRestoreSecurityUSBLabel(virUSBDevicePtr dev ATTRIBUTE_UNUSED,
 
 
 static int
-virSecuritySELinuxRestoreSecuritySCSILabel(virSCSIDevicePtr dev ATTRIBUTE_UNUSED,
+virSecuritySELinuxRestoreSecuritySCSILabel(virSCSIDevicePtr dev,
                                            const char *file,
                                            void *opaque)
 {
     virSecurityManagerPtr mgr = opaque;
 
+    /* Don't restore labels on a shareable or readonly hostdev, because
+     * other VMs may still be accessing.
+     */
+    if (virSCSIDeviceGetShareable(dev) || virSCSIDeviceGetReadonly(dev))
+        return 0;
+
     return virSecuritySELinuxRestoreSecurityFileLabel(mgr, file);
 }
 
-- 
1.9.3