Set the SELinux security label on new directories.

Automatically set the SELinux security label on directories created
by init.rc.  This avoids the need to separately call restorecon on
each such directory from the init.rc file.  Also restorecon /dev
and /dev/socket after initial policy load so that they are labeled
correctly before any other dev nodes or sockets are created.

Change-Id: If6af6c4887cdead949737cebdd673957e9273ead
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

init/builtins.c

@@ -300,7 +300,7 @@ int do_mkdir(int nargs, char **args)
         mode = strtoul(args[2], 0, 8);
     }
 
-    ret = mkdir(args[1], mode);
+    ret = make_dir(args[1], mode);
     /* chmod in case the directory already exists */
     if (ret == -1 && errno == EEXIST) {
         ret = _chmod(args[1], mode);
@@ -735,26 +735,12 @@ int do_chmod(int nargs, char **args) {
 }
 
 int do_restorecon(int nargs, char **args) {
-#ifdef HAVE_SELINUX
-    char *secontext = NULL;
-    struct stat sb;
     int i;
 
-    if (is_selinux_enabled() <= 0 || !sehandle)
-        return 0;
-
     for (i = 1; i < nargs; i++) {
-        if (lstat(args[i], &sb) < 0)
-            return -errno;
-        if (selabel_lookup(sehandle, &secontext, args[i], sb.st_mode) < 0)
+        if (restorecon(args[i]) < 0)
             return -errno;
-        if (lsetfilecon(args[i], secontext) < 0) {
-            freecon(secontext);
-            return -errno;
-        }
-        freecon(secontext);
     }
-#endif
     return 0;
 }
 

init/devices.c

@@ -52,7 +52,7 @@
 #define FIRMWARE_DIR2   "/vendor/firmware"
 
 #ifdef HAVE_SELINUX
-static struct selabel_handle *sehandle;
+extern struct selabel_handle *sehandle;
 #endif
 
 static int device_fd = -1;
@@ -219,32 +219,6 @@ static void make_device(const char *path,
 #endif
 }
 
-
-static int make_dir(const char *path, mode_t mode)
-{
-    int rc;
-
-#ifdef HAVE_SELINUX
-    char *secontext = NULL;
-
-    if (sehandle) {
-        selabel_lookup(sehandle, &secontext, path, mode);
-        setfscreatecon(secontext);
-    }
-#endif
-
-    rc = mkdir(path, mode);
-
-#ifdef HAVE_SELINUX
-    if (secontext) {
-        freecon(secontext);
-        setfscreatecon(NULL);
-    }
-#endif
-    return rc;
-}
-
-
 static void add_platform_device(const char *name)
 {
     int name_len = strlen(name);

init/init.c

@@ -900,6 +900,12 @@ int main(int argc, char **argv)
 #ifdef HAVE_SELINUX
     INFO("loading selinux policy\n");
     selinux_load_policy();
+    /* These directories were necessarily created before policy load
+     * and therefore need their security context restored to the proper value.
+     * This must happen before /dev is populated by ueventd.
+     */
+    restorecon("/dev");
+    restorecon("/dev/socket");
 #endif
 
     is_charger = !strcmp(bootmode, "charger");

init/util.c

@@ -290,12 +290,12 @@ int mkdir_recursive(const char *pathname, mode_t mode)
         memcpy(buf, pathname, width);
         buf[width] = 0;
         if (stat(buf, &info) != 0) {
-            ret = mkdir(buf, mode);
+            ret = make_dir(buf, mode);
             if (ret && errno != EEXIST)
                 return ret;
         }
     }
-    ret = mkdir(pathname, mode);
+    ret = make_dir(pathname, mode);
     if (ret && errno != EEXIST)
         return ret;
     return 0;
@@ -451,3 +451,52 @@ void import_kernel_cmdline(int in_qemu,
         ptr = x;
     }
 }
+
+int make_dir(const char *path, mode_t mode)
+{
+    int rc;
+
+#ifdef HAVE_SELINUX
+    char *secontext = NULL;
+
+    if (sehandle) {
+        selabel_lookup(sehandle, &secontext, path, mode);
+        setfscreatecon(secontext);
+    }
+#endif
+
+    rc = mkdir(path, mode);
+
+#ifdef HAVE_SELINUX
+    if (secontext) {
+        int save_errno = errno;
+        freecon(secontext);
+        setfscreatecon(NULL);
+        errno = save_errno;
+    }
+#endif
+    return rc;
+}
+
+int restorecon(const char *pathname)
+{
+#ifdef HAVE_SELINUX
+    char *secontext = NULL;
+    struct stat sb;
+    int i;
+
+    if (is_selinux_enabled() <= 0 || !sehandle)
+        return 0;
+
+    if (lstat(pathname, &sb) < 0)
+        return -errno;
+    if (selabel_lookup(sehandle, &secontext, pathname, sb.st_mode) < 0)
+        return -errno;
+    if (lsetfilecon(pathname, secontext) < 0) {
+        freecon(secontext);
+        return -errno;
+    }
+    freecon(secontext);
+#endif
+    return 0;
+}

init/util.h

@@ -39,4 +39,6 @@ int wait_for_file(const char *filename, int timeout);
 void open_devnull_stdio(void);
 void get_hardware_name(char *hardware, unsigned int *revision);
 void import_kernel_cmdline(int in_qemu, void (*import_kernel_nv)(char *name, int in_qemu));
+int make_dir(const char *path, mode_t mode);
+int restorecon(const char *pathname);
 #endif