From: Gao feng <gaofeng@cn.fujitsu.com>
Date: Fri, 7 Jun 2013 07:12:23 +0000 (+0800)
Subject: LXC: controller: change the owner of tty devices to the root user of container
X-Git-Tag: CVE-2013-2230~95
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ff1a6019e98a634ac5bd002b5f6779a201db4c05;p=thirdparty%2Flibvirt.git

LXC: controller: change the owner of tty devices to the root user of container

Since these tty devices will be used by container,
the owner of them should be the root user of container.

This patch also adds a new function virLXCControllerChown,
we can use this general function to change the owner of
files.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
---

diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c
index be6f6ebbd1..5d721cfccd 100644
--- a/src/lxc/lxc_controller.c
+++ b/src/lxc/lxc_controller.c
@@ -1121,6 +1121,27 @@ cleanup2:
     return rc;
 }
 
+static int
+virLXCControllerChown(virLXCControllerPtr ctrl, char *path)
+{
+    uid_t uid;
+    gid_t gid;
+
+    if (!ctrl->def->idmap.uidmap)
+        return 0;
+
+    uid = ctrl->def->idmap.uidmap[0].target;
+    gid = ctrl->def->idmap.gidmap[0].target;
+
+    if (chown(path, uid, gid) < 0) {
+        virReportSystemError(errno,
+                             _("Failed to change owner of %s to %u:%u"),
+                             path, uid, gid);
+        return -1;
+    }
+
+    return 0;
+}
 
 static int
 virLXCControllerSetupUsernsMap(virDomainIdMapEntryPtr map,
@@ -1383,13 +1404,14 @@ static int lxcSetPersonality(virDomainDefPtr def)
  * *TTYNAME.  Heavily borrowed from glibc, but doesn't require that
  * devpts == "/dev/pts" */
 static int
-lxcCreateTty(char *ptmx, int *ttymaster, char **ttyName)
+lxcCreateTty(virLXCControllerPtr ctrl, int *ttymaster,
+             char **ttyName, char **ttyHostPath)
 {
     int ret = -1;
     int ptyno;
     int unlock = 0;
 
-    if ((*ttymaster = open(ptmx, O_RDWR|O_NOCTTY|O_NONBLOCK)) < 0)
+    if ((*ttymaster = open(ctrl->devptmx, O_RDWR|O_NOCTTY|O_NONBLOCK)) < 0)
         goto cleanup;
 
     if (ioctl(*ttymaster, TIOCSPTLCK, &unlock) < 0)
@@ -1404,7 +1426,9 @@ lxcCreateTty(char *ptmx, int *ttymaster, char **ttyName)
      * while glibc has to fstat(), fchmod(), and fchown() for older
      * kernels, we can skip those steps.  ptyno shouldn't currently be
      * anything other than 0, but let's play it safe.  */
-    if (virAsprintf(ttyName, "/dev/pts/%d", ptyno) < 0) {
+    if ((virAsprintf(ttyName, "/dev/pts/%d", ptyno) < 0) ||
+        (virAsprintf(ttyHostPath, "/%s/%s.devpts/%d", LXC_STATE_DIR,
+                    ctrl->def->name, ptyno) < 0)) {
         virReportOOMError();
         errno = ENOMEM;
         goto cleanup;
@@ -1538,18 +1562,30 @@ virLXCControllerSetupConsoles(virLXCControllerPtr ctrl,
                               char **containerTTYPaths)
 {
     size_t i;
+    int ret = -1;
+    char *ttyHostPath = NULL;
 
     for (i = 0; i < ctrl->nconsoles; i++) {
         VIR_DEBUG("Opening tty on private %s", ctrl->devptmx);
-        if (lxcCreateTty(ctrl->devptmx,
+        if (lxcCreateTty(ctrl,
                          &ctrl->consoles[i].contFd,
-                         &containerTTYPaths[i]) < 0) {
+                         &containerTTYPaths[i], &ttyHostPath) < 0) {
             virReportSystemError(errno, "%s",
                                      _("Failed to allocate tty"));
-            return -1;
+            goto cleanup;
         }
+
+        /* Change the owner of tty device to the root user of container */
+        if (virLXCControllerChown(ctrl, ttyHostPath) < 0)
+            goto cleanup;
+
+        VIR_FREE(ttyHostPath);
     }
-    return 0;
+
+    ret = 0;
+cleanup:
+    VIR_FREE(ttyHostPath);
+    return ret;
 }