From 6d855abc14338f72b61e297ce73c113195c1b2c6 Mon Sep 17 00:00:00 2001
From: Michal Privoznik <mprivozn@redhat.com>
Date: Mon, 10 Sep 2018 11:19:55 +0200
Subject: [PATCH] security_selinux: Lock metadata when running transaction

Lock all the paths we want to relabel to mutually exclude other
libvirt daemons.

The only hitch here is that directories can't be locked.
Therefore, when relabeling a directory do not lock it (this
happens only when setting up some domain private paths anyway,
e.g. huge pages directory).

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
---
 src/security/security_selinux.c | 43 ++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 6 deletions(-)

diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index f6416010f9..056637e4cb 100644
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -90,7 +90,7 @@ struct _virSecuritySELinuxContextItem {
 typedef struct _virSecuritySELinuxContextList virSecuritySELinuxContextList;
 typedef virSecuritySELinuxContextList *virSecuritySELinuxContextListPtr;
 struct _virSecuritySELinuxContextList {
-    bool privileged;
+    virSecurityManagerPtr manager;
     virSecuritySELinuxContextItemPtr *items;
     size_t nItems;
 };
@@ -212,8 +212,29 @@ virSecuritySELinuxTransactionRun(pid_t pid ATTRIBUTE_UNUSED,
                                  void *opaque)
 {
     virSecuritySELinuxContextListPtr list = opaque;
+    bool privileged = virSecurityManagerGetPrivileged(list->manager);
+    const char **paths = NULL;
+    size_t npaths = 0;
     size_t i;
+    int rv;
+    int ret = -1;
 
+    if (VIR_ALLOC_N(paths, list->nItems) < 0)
+        return -1;
+
+    for (i = 0; i < list->nItems; i++) {
+        const char *p = list->items[i]->path;
+
+        if (virFileIsDir(p))
+            continue;
+
+        VIR_APPEND_ELEMENT_COPY_INPLACE(paths, npaths, p);
+    }
+
+    if (virSecurityManagerMetadataLock(list->manager, paths, npaths) < 0)
+        goto cleanup;
+
+    rv = 0;
     for (i = 0; i < list->nItems; i++) {
         virSecuritySELinuxContextItemPtr item = list->items[i];
 
@@ -221,11 +242,22 @@ virSecuritySELinuxTransactionRun(pid_t pid ATTRIBUTE_UNUSED,
         if (virSecuritySELinuxSetFileconHelper(item->path,
                                                item->tcon,
                                                item->optional,
-                                               list->privileged) < 0)
-            return -1;
+                                               privileged) < 0) {
+            rv = -1;
+            break;
+        }
     }
 
-    return 0;
+    if (virSecurityManagerMetadataUnlock(list->manager, paths, npaths) < 0)
+        goto cleanup;
+
+    if (rv < 0)
+        goto cleanup;
+
+    ret = 0;
+ cleanup:
+    VIR_FREE(paths);
+    return ret;
 }
 
 
@@ -1010,7 +1042,6 @@ virSecuritySELinuxGetDOI(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED)
 static int
 virSecuritySELinuxTransactionStart(virSecurityManagerPtr mgr)
 {
-    bool privileged = virSecurityManagerGetPrivileged(mgr);
     virSecuritySELinuxContextListPtr list;
 
     list = virThreadLocalGet(&contextList);
@@ -1023,7 +1054,7 @@ virSecuritySELinuxTransactionStart(virSecurityManagerPtr mgr)
     if (VIR_ALLOC(list) < 0)
         return -1;
 
-    list->privileged = privileged;
+    list->manager = mgr;
 
     if (virThreadLocalSet(&contextList, list) < 0) {
         virReportSystemError(errno, "%s",