security: Introduce virSecurityManagerMoveImageMetadata

The purpose of this API is to allow caller move XATTRs (or remove
them) from one file to another. This will be needed when moving
top level of disk chain (either by introducing new HEAD or
removing it).

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

src/libvirt_private.syms

@@ -1409,6 +1409,7 @@ virSecurityManagerGetModel;
 virSecurityManagerGetMountOptions;
 virSecurityManagerGetNested;
 virSecurityManagerGetProcessLabel;
+virSecurityManagerMoveImageMetadata;
 virSecurityManagerNew;
 virSecurityManagerNewDAC;
 virSecurityManagerNewStack;

src/security/security_driver.h

@@ -119,6 +119,10 @@ typedef int (*virSecurityDomainRestoreImageLabel) (virSecurityManagerPtr mgr,
                                                    virDomainDefPtr def,
                                                    virStorageSourcePtr src,
                                                    virSecurityDomainImageLabelFlags flags);
+typedef int (*virSecurityDomainMoveImageMetadata) (virSecurityManagerPtr mgr,
+                                                   pid_t pid,
+                                                   virStorageSourcePtr src,
+                                                   virStorageSourcePtr dst);
 typedef int (*virSecurityDomainSetMemoryLabel) (virSecurityManagerPtr mgr,
                                                 virDomainDefPtr def,
                                                 virDomainMemoryDefPtr mem);
@@ -169,6 +173,7 @@ struct _virSecurityDriver {
 
     virSecurityDomainSetImageLabel domainSetSecurityImageLabel;
     virSecurityDomainRestoreImageLabel domainRestoreSecurityImageLabel;
+    virSecurityDomainMoveImageMetadata domainMoveImageMetadata;
 
     virSecurityDomainSetMemoryLabel domainSetSecurityMemoryLabel;
     virSecurityDomainRestoreMemoryLabel domainRestoreSecurityMemoryLabel;

src/security/security_manager.c

@@ -432,6 +432,45 @@ virSecurityManagerRestoreImageLabel(virSecurityManagerPtr mgr,
 }
 
 
+/**
+ * virSecurityManagerMoveImageMetadata:
+ * @mgr: security manager
+ * @pid: domain's PID
+ * @src: source of metadata
+ * @dst: destination to move metadata to
+ *
+ * For given source @src, metadata is moved to destination @dst.
+ *
+ * If @dst is NULL then metadata is removed from @src and not
+ * stored anywhere.
+ *
+ * If @pid is not -1 enther the @pid mount namespace (usually
+ * @pid refers to a domain) and perform the move from there. If
+ * @pid is -1 then the move is performed from the caller's
+ * namespace.
+ *
+ * Returns: 0 on success,
+ *         -1 otherwise.
+ */
+int
+virSecurityManagerMoveImageMetadata(virSecurityManagerPtr mgr,
+                                    pid_t pid,
+                                    virStorageSourcePtr src,
+                                    virStorageSourcePtr dst)
+{
+    if (mgr->drv->domainMoveImageMetadata) {
+        int ret;
+        virObjectLock(mgr);
+        ret = mgr->drv->domainMoveImageMetadata(mgr, pid, src, dst);
+        virObjectUnlock(mgr);
+        return ret;
+    }
+
+    virReportUnsupportedError();
+    return -1;
+}
+
+
 int
 virSecurityManagerSetDaemonSocketLabel(virSecurityManagerPtr mgr,
                                        virDomainDefPtr vm)

src/security/security_manager.h

@@ -159,6 +159,10 @@ int virSecurityManagerRestoreImageLabel(virSecurityManagerPtr mgr,
                                         virDomainDefPtr vm,
                                         virStorageSourcePtr src,
                                         virSecurityDomainImageLabelFlags flags);
+int virSecurityManagerMoveImageMetadata(virSecurityManagerPtr mgr,
+                                        pid_t pid,
+                                        virStorageSourcePtr src,
+                                        virStorageSourcePtr dst);
 
 int virSecurityManagerSetMemoryLabel(virSecurityManagerPtr mgr,
                                      virDomainDefPtr vm,

src/security/security_nop.c

@@ -224,6 +224,15 @@ virSecurityDomainSetImageLabelNop(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
     return 0;
 }
 
+static int
+virSecurityDomainMoveImageMetadataNop(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
+                                      pid_t pid ATTRIBUTE_UNUSED,
+                                      virStorageSourcePtr src ATTRIBUTE_UNUSED,
+                                      virStorageSourcePtr dst ATTRIBUTE_UNUSED)
+{
+    return 0;
+}
+
 static int
 virSecurityDomainSetMemoryLabelNop(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
                                    virDomainDefPtr def ATTRIBUTE_UNUSED,
@@ -280,6 +289,7 @@ virSecurityDriver virSecurityDriverNop = {
 
     .domainSetSecurityImageLabel        = virSecurityDomainSetImageLabelNop,
     .domainRestoreSecurityImageLabel    = virSecurityDomainRestoreImageLabelNop,
+    .domainMoveImageMetadata            = virSecurityDomainMoveImageMetadataNop,
 
     .domainSetSecurityMemoryLabel       = virSecurityDomainSetMemoryLabelNop,
     .domainRestoreSecurityMemoryLabel   = virSecurityDomainRestoreMemoryLabelNop,

src/security/security_stack.c

@@ -599,6 +599,25 @@ virSecurityStackRestoreImageLabel(virSecurityManagerPtr mgr,
     return rc;
 }
 
+static int
+virSecurityStackMoveImageMetadata(virSecurityManagerPtr mgr,
+                                  pid_t pid,
+                                  virStorageSourcePtr src,
+                                  virStorageSourcePtr dst)
+{
+    virSecurityStackDataPtr priv = virSecurityManagerGetPrivateData(mgr);
+    virSecurityStackItemPtr item = priv->itemsHead;
+    int rc = 0;
+
+    for (; item; item = item->next) {
+        if (virSecurityManagerMoveImageMetadata(item->securityManager,
+                                                pid, src, dst) < 0)
+            rc = -1;
+    }
+
+    return rc;
+}
+
 static int
 virSecurityStackSetMemoryLabel(virSecurityManagerPtr mgr,
                                virDomainDefPtr vm,
@@ -785,6 +804,7 @@ virSecurityDriver virSecurityDriverStack = {
 
     .domainSetSecurityImageLabel        = virSecurityStackSetImageLabel,
     .domainRestoreSecurityImageLabel    = virSecurityStackRestoreImageLabel,
+    .domainMoveImageMetadata            = virSecurityStackMoveImageMetadata,
 
     .domainSetSecurityMemoryLabel       = virSecurityStackSetMemoryLabel,
     .domainRestoreSecurityMemoryLabel   = virSecurityStackRestoreMemoryLabel,