uprobes: remove redundant check

[platform/adaptation/renesas_rcar/renesas_kernel.git] / kernel / user_namespace.c

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index a946077..2b042c4 100644 (file)
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -58,6 +58,7 @@ int create_user_ns(struct cred *new)
        struct user_namespace *ns, *parent_ns = new->user_ns;
        kuid_t owner = new->euid;
        kgid_t group = new->egid;
+       int ret;
 
        /* The creator needs a mapping in the parent user namespace
         * or else we won't be able to reasonably tell userspace who
@@ -71,6 +72,12 @@ int create_user_ns(struct cred *new)
        if (!ns)
                return -ENOMEM;
 
+       ret = proc_alloc_inum(&ns->proc_inum);
+       if (ret) {
+               kmem_cache_free(user_ns_cachep, ns);
+               return ret;
+       }
+
        kref_init(&ns->kref);
        /* Leave the new->user_ns reference with the new user namespace. */
        ns->parent = parent_ns;
@@ -82,12 +89,28 @@ int create_user_ns(struct cred *new)
        return 0;
 }
 
+int unshare_userns(unsigned long unshare_flags, struct cred **new_cred)
+{
+       struct cred *cred;
+
+       if (!(unshare_flags & CLONE_NEWUSER))
+               return 0;
+
+       cred = prepare_creds();
+       if (!cred)
+               return -ENOMEM;
+
+       *new_cred = cred;
+       return create_user_ns(cred);
+}
+
 void free_user_ns(struct kref *kref)
 {
        struct user_namespace *parent, *ns =
                container_of(kref, struct user_namespace, kref);
 
        parent = ns->parent;
+       proc_free_inum(ns->proc_inum);
        kmem_cache_free(user_ns_cachep, ns);
        put_user_ns(parent);
 }
@@ -376,7 +399,7 @@ static int uid_m_show(struct seq_file *seq, void *v)
        struct user_namespace *lower_ns;
        uid_t lower;
 
-       lower_ns = current_user_ns();
+       lower_ns = seq_user_ns(seq);
        if ((lower_ns == ns) && lower_ns->parent)
                lower_ns = lower_ns->parent;
 
@@ -397,7 +420,7 @@ static int gid_m_show(struct seq_file *seq, void *v)
        struct user_namespace *lower_ns;
        gid_t lower;
 
-       lower_ns = current_user_ns();
+       lower_ns = seq_user_ns(seq);
        if ((lower_ns == ns) && lower_ns->parent)
                lower_ns = lower_ns->parent;
 
@@ -673,10 +696,14 @@ ssize_t proc_uid_map_write(struct file *file, const char __user *buf, size_t siz
 {
        struct seq_file *seq = file->private_data;
        struct user_namespace *ns = seq->private;
+       struct user_namespace *seq_ns = seq_user_ns(seq);
 
        if (!ns->parent)
                return -EPERM;
 
+       if ((seq_ns != ns) && (seq_ns != ns->parent))
+               return -EPERM;
+
        return map_write(file, buf, size, ppos, CAP_SETUID,
                         &ns->uid_map, &ns->parent->uid_map);
 }
@@ -685,10 +712,14 @@ ssize_t proc_gid_map_write(struct file *file, const char __user *buf, size_t siz
 {
        struct seq_file *seq = file->private_data;
        struct user_namespace *ns = seq->private;
+       struct user_namespace *seq_ns = seq_user_ns(seq);
 
        if (!ns->parent)
                return -EPERM;
 
+       if ((seq_ns != ns) && (seq_ns != ns->parent))
+               return -EPERM;
+
        return map_write(file, buf, size, ppos, CAP_SETGID,
                         &ns->gid_map, &ns->parent->gid_map);
 }
@@ -768,7 +799,7 @@ static int userns_install(struct nsproxy *nsproxy, void *ns)
        if (user_ns == current_user_ns())
                return -EINVAL;
 
-       /* Threaded many not enter a different user namespace */
+       /* Threaded processes may not enter a different user namespace */
        if (atomic_read(&current->mm->mm_users) > 1)
                return -EINVAL;
 
@@ -785,12 +816,19 @@ static int userns_install(struct nsproxy *nsproxy, void *ns)
        return commit_creds(cred);
 }
 
+static unsigned int userns_inum(void *ns)
+{
+       struct user_namespace *user_ns = ns;
+       return user_ns->proc_inum;
+}
+
 const struct proc_ns_operations userns_operations = {
        .name           = "user",
        .type           = CLONE_NEWUSER,
        .get            = userns_get,
        .put            = userns_put,
        .install        = userns_install,
+       .inum           = userns_inum,
 };
 
 static __init int user_namespaces_init(void)