1 files changed, 20 insertions, 6 deletions

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index f71246bebfe4..a7ac78f8e67a 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -28,6 +28,7 @@ static int sysfs_do_create_link(struct kobject *kobj, struct kobject *target,
         struct sysfs_dirent *target_sd = NULL;
         struct sysfs_dirent *sd = NULL;
         struct sysfs_addrm_cxt acxt;
+        enum kobj_ns_type ns_type;
         int error;
 
         BUG_ON(!name);
@@ -58,16 +59,29 @@ static int sysfs_do_create_link(struct kobject *kobj, struct kobject *target,
         if (!sd)
                 goto out_put;
 
-        if (sysfs_ns_type(parent_sd))
+        ns_type = sysfs_ns_type(parent_sd);
+        if (ns_type)
                 sd->s_ns = target->ktype->namespace(target);
         sd->s_symlink.target_sd = target_sd;
         target_sd = NULL;       /* reference is now owned by the symlink */
 
         sysfs_addrm_start(&acxt, parent_sd);
-        if (warn)
-                error = sysfs_add_one(&acxt, sd);
-        else
-                error = __sysfs_add_one(&acxt, sd);
+        /* Symlinks must be between directories with the same ns_type */
+        if (!ns_type ||
+            (ns_type == sysfs_ns_type(sd->s_symlink.target_sd->s_parent))) {
+                if (warn)
+                        error = sysfs_add_one(&acxt, sd);
+                else
+                        error = __sysfs_add_one(&acxt, sd);
+        } else {
+                error = -EINVAL;
+                WARN(1, KERN_WARNING
+                        "sysfs: symlink across ns_types %s/%s -> %s/%s\n",
+                        parent_sd->s_name,
+                        sd->s_name,
+                        sd->s_symlink.target_sd->s_parent->s_name,
+                        sd->s_symlink.target_sd->s_name);
+        }
         sysfs_addrm_finish(&acxt);
 
         if (error)
@@ -122,7 +136,7 @@ void sysfs_delete_link(struct kobject *kobj, struct kobject *targ,
 {
         const void *ns = NULL;
         spin_lock(&sysfs_assoc_lock);
-        if (targ->sd)
+        if (targ->sd && sysfs_ns_type(kobj->sd))
                 ns = targ->sd->s_ns;
         spin_unlock(&sysfs_assoc_lock);
         sysfs_hash_and_remove(kobj->sd, ns, name);