[PATCH v2 7/8] LXC: change the owner of tty devices to the root user of container

[Gao feng <gaofeng@xxxxxxxxxxxxxx>]

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

Signed-off-by: Gao feng <gaofeng@xxxxxxxxxxxxxx>
---
 src/lxc/lxc_controller.c | 46 +++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 41 insertions(+), 5 deletions(-)

diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c
index f7bdf54..31c7cd5 100644
--- a/src/lxc/lxc_controller.c
+++ b/src/lxc/lxc_controller.c
@@ -1288,13 +1288,14 @@ 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)
@@ -1315,6 +1316,15 @@ lxcCreateTty(char *ptmx, int *ttymaster, char **ttyName)
         goto cleanup;
     }
 
+    /* Change the owner of this new created tty device to the root
+     * user of container. */
+    if (virAsprintf(ttyHostPath, "%s/%s.devpts/%d", LXC_STATE_DIR,
+                    ctrl->def->name, ptyno) < 0) {
+        virReportOOMError();
+        errno = ENOMEM;
+        goto cleanup;
+    }
+
     ret = 0;
 
 cleanup:
@@ -1452,18 +1462,44 @@ virLXCControllerSetupConsoles(virLXCControllerPtr ctrl,
                               char **containerTTYPaths)
 {
     size_t i;
+    int ret = -1;
+    uid_t uid = -1;
+    gid_t gid = -1;
+    bool userns_enabled = false;
+    char *ttyHostPath = NULL;
+
+    if (ctrl->def->idmap.uidmap && ctrl->def->idmap.gidmap) {
+        uid = ctrl->def->idmap.uidmap[0].target;
+        gid = ctrl->def->idmap.gidmap[0].target;
+        userns_enabled = true;
+    }
 
     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;
         }
+
+        /* Change the owner of this new created tty device to the root
+         * user of container. */
+        if (userns_enabled && (chown(ttyHostPath, uid, gid) < 0)) {
+            virReportSystemError(errno,
+                                 _("Failed to change owner of tty"
+                                 " %s to %u:%u"),
+                                 ttyHostPath, uid, gid);
+            goto out;
+        }
+        VIR_FREE(ttyHostPath);
     }
-    return 0;
+
+    ret = 0;
+out:
+    VIR_FREE(ttyHostPath);
+    return ret;
 }
 
 
-- 
1.8.1.4

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