LXC: Ensure security context is set when mounting images

When setting up filesystems backed by block devices or file
images, the SELinux mount options must be used to ensure the
correct context is set
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/lxc/lxc_container.c

@@ -111,7 +111,8 @@ struct __lxc_child_argv {
 };
 
 static int lxcContainerMountFSBlock(virDomainFSDefPtr fs,
-                                    const char *srcprefix);
+                                    const char *srcprefix,
+                                    const char *sec_mount_options);
 
 
 /*
@@ -559,7 +560,8 @@ cleanup:
 
 
 static int lxcContainerPrepareRoot(virDomainDefPtr def,
-                                   virDomainFSDefPtr root)
+                                   virDomainFSDefPtr root,
+                                   const char *sec_mount_options)
 {
     char *dst;
     char *tmp;
@@ -589,7 +591,7 @@ static int lxcContainerPrepareRoot(virDomainDefPtr def,
     tmp = root->dst;
     root->dst = dst;
 
-    if (lxcContainerMountFSBlock(root, "") < 0) {
+    if (lxcContainerMountFSBlock(root, "", sec_mount_options) < 0) {
         root->dst = tmp;
         VIR_FREE(dst);
         return -1;
@@ -1201,7 +1203,8 @@ lxcContainerMountDetectFilesystem(const char *src ATTRIBUTE_UNUSED,
 static int lxcContainerMountFSBlockAuto(virDomainFSDefPtr fs,
                                         int fsflags,
                                         const char *src,
-                                        const char *srcprefix)
+                                        const char *srcprefix,
+                                        const char *sec_mount_options)
 {
     FILE *fp = NULL;
     int ret = -1;
@@ -1276,8 +1279,9 @@ retry:
             STREQ(type, "*"))
             gotStar = true;
 
-        VIR_DEBUG("Trying mount %s with %s", src, type);
-        if (mount(src, fs->dst, type, fsflags, NULL) < 0) {
+        VIR_DEBUG("Trying mount '%s' on '%s' with '%s' opts '%s'",
+                  src, fs->dst, type, sec_mount_options);
+        if (mount(src, fs->dst, type, fsflags, sec_mount_options) < 0) {
             /* These errnos indicate a bogus filesystem type for
              * the image we have, so skip to the next type
              */
@@ -1328,7 +1332,8 @@ cleanup:
  */
 static int lxcContainerMountFSBlockHelper(virDomainFSDefPtr fs,
                                           const char *src,
-                                          const char *srcprefix)
+                                          const char *srcprefix,
+                                          const char *sec_mount_options)
 {
     int fsflags = 0;
     int ret = -1;
@@ -1348,9 +1353,9 @@ static int lxcContainerMountFSBlockHelper(virDomainFSDefPtr fs,
         goto cleanup;
 
     if (format) {
-        VIR_DEBUG("Mount '%s' on '%s' with detected format '%s'",
-                  src, fs->dst, format);
-        if (mount(src, fs->dst, format, fsflags, NULL) < 0) {
+        VIR_DEBUG("Mount '%s' on '%s' with detected format '%s' opts '%s'",
+                  src, fs->dst, format, sec_mount_options);
+        if (mount(src, fs->dst, format, fsflags, sec_mount_options) < 0) {
             virReportSystemError(errno,
                                  _("Failed to mount device %s to %s as %s"),
                                  src, fs->dst, format);
@@ -1358,7 +1363,7 @@ static int lxcContainerMountFSBlockHelper(virDomainFSDefPtr fs,
         }
         ret = 0;
     } else {
-        ret = lxcContainerMountFSBlockAuto(fs, fsflags, src, srcprefix);
+        ret = lxcContainerMountFSBlockAuto(fs, fsflags, src, srcprefix, sec_mount_options);
     }
 
 cleanup:
@@ -1368,7 +1373,8 @@ cleanup:
 
 
 static int lxcContainerMountFSBlock(virDomainFSDefPtr fs,
-                                    const char *srcprefix)
+                                    const char *srcprefix,
+                                    const char *sec_mount_options)
 {
     char *src = NULL;
     int ret = -1;
@@ -1378,7 +1384,7 @@ static int lxcContainerMountFSBlock(virDomainFSDefPtr fs,
     if (virAsprintf(&src, "%s%s", srcprefix, fs->src) < 0)
         goto cleanup;
 
-    ret = lxcContainerMountFSBlockHelper(fs, src, srcprefix);
+    ret = lxcContainerMountFSBlockHelper(fs, src, srcprefix, sec_mount_options);
 
     VIR_DEBUG("Done mounting filesystem ret=%d", ret);
 
@@ -1441,7 +1447,7 @@ static int lxcContainerMountFS(virDomainFSDefPtr fs,
             return -1;
         break;
     case VIR_DOMAIN_FS_TYPE_BLOCK:
-        if (lxcContainerMountFSBlock(fs, "/.oldroot") < 0)
+        if (lxcContainerMountFSBlock(fs, "/.oldroot", sec_mount_options) < 0)
             return -1;
         break;
     case VIR_DOMAIN_FS_TYPE_RAM:
@@ -1603,7 +1609,7 @@ static int lxcContainerSetupPivotRoot(virDomainDefPtr vmDef,
         goto cleanup;
 
     /* Ensure the root filesystem is mounted */
-    if (lxcContainerPrepareRoot(vmDef, root) < 0)
+    if (lxcContainerPrepareRoot(vmDef, root, sec_mount_options) < 0)
         goto cleanup;
 
     /* Gives us a private root, leaving all parent OS mounts on /.oldroot */