}
/* Don't allow unprivileged users to reveal what is under a mount */
- if ((flag & CL_UNPRIVILEGED) && list_empty(&old->mnt_expire))
+ if ((flag & CL_UNPRIVILEGED) &&
+ (!(flag & CL_EXPIRE) || list_empty(&old->mnt_expire)))
mnt->mnt.mnt_flags |= MNT_LOCKED;
atomic_inc(&sb->s_active);
goto dput_and_out;
if (mnt->mnt.mnt_flags & MNT_LOCKED)
goto dput_and_out;
+ retval = -EPERM;
+ if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN))
+ goto dput_and_out;
retval = do_umount(mnt, flags);
dput_and_out:
static bool is_mnt_ns_file(struct dentry *dentry)
{
/* Is this a proxy for a mount namespace? */
- struct inode *inode = dentry->d_inode;
- struct proc_ns *ei;
-
- if (!proc_ns_inode(inode))
- return false;
-
- ei = get_proc_ns(inode);
- if (ei->ns_ops != &mntns_operations)
- return false;
+ return dentry->d_op == &ns_dentry_operations &&
+ dentry->d_fsdata == &mntns_operations;
+}
- return true;
+struct mnt_namespace *to_mnt_ns(struct ns_common *ns)
+{
+ return container_of(ns, struct mnt_namespace, ns);
}
static bool mnt_ns_loop(struct dentry *dentry)
if (!is_mnt_ns_file(dentry))
return false;
- mnt_ns = get_proc_ns(dentry->d_inode)->ns;
+ mnt_ns = to_mnt_ns(get_proc_ns(dentry->d_inode));
return current->nsproxy->mnt_ns->seq >= mnt_ns->seq;
}
if (IS_ERR(q))
return q;
- q->mnt.mnt_flags &= ~MNT_LOCKED;
q->mnt_mountpoint = mnt->mnt_mountpoint;
p = mnt;
if (IS_MNT_UNBINDABLE(old))
goto out2;
- if (!check_mnt(parent) || !check_mnt(old))
+ if (!check_mnt(parent))
+ goto out2;
+
+ if (!check_mnt(old) && old_path.dentry->d_op != &ns_dentry_operations)
goto out2;
if (!recurse && has_locked_children(old, old_path.dentry))
}
if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) &&
!(mnt_flags & MNT_NODEV)) {
- return -EPERM;
+ /* Was the nodev implicitly added in mount? */
+ if ((mnt->mnt_ns->user_ns != &init_user_ns) &&
+ !(sb->s_type->fs_flags & FS_USERNS_DEV_MOUNT)) {
+ mnt_flags |= MNT_NODEV;
+ } else {
+ return -EPERM;
+ }
}
if ((mnt->mnt.mnt_flags & MNT_LOCK_NOSUID) &&
!(mnt_flags & MNT_NOSUID)) {
static void free_mnt_ns(struct mnt_namespace *ns)
{
- proc_free_inum(ns->proc_inum);
+ ns_free_inum(&ns->ns);
put_user_ns(ns->user_ns);
kfree(ns);
}
new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
if (!new_ns)
return ERR_PTR(-ENOMEM);
- ret = proc_alloc_inum(&new_ns->proc_inum);
+ ret = ns_alloc_inum(&new_ns->ns);
if (ret) {
kfree(new_ns);
return ERR_PTR(ret);
}
+ new_ns->ns.ops = &mntns_operations;
new_ns->seq = atomic64_add_return(1, &mnt_ns_seq);
atomic_set(&new_ns->count, 1);
new_ns->root = NULL;
/* mount new_root on / */
attach_mnt(new_mnt, real_mount(root_parent.mnt), root_mp);
touch_mnt_namespace(current->nsproxy->mnt_ns);
+ /* A moved mount should not expire automatically */
+ list_del_init(&new_mnt->mnt_expire);
unlock_mount_hash();
chroot_fs_refs(&root, &new);
put_mountpoint(root_mp);
root.mnt = mnt;
root.dentry = mnt->mnt_root;
+ mnt->mnt_flags |= MNT_LOCKED;
set_fs_pwd(current->fs, &root);
set_fs_root(current->fs, &root);
return visible;
}
-static void *mntns_get(struct task_struct *task)
+static struct ns_common *mntns_get(struct task_struct *task)
{
- struct mnt_namespace *ns = NULL;
+ struct ns_common *ns = NULL;
struct nsproxy *nsproxy;
task_lock(task);
nsproxy = task->nsproxy;
if (nsproxy) {
- ns = nsproxy->mnt_ns;
- get_mnt_ns(ns);
+ ns = &nsproxy->mnt_ns->ns;
+ get_mnt_ns(to_mnt_ns(ns));
}
task_unlock(task);
return ns;
}
-static void mntns_put(void *ns)
+static void mntns_put(struct ns_common *ns)
{
- put_mnt_ns(ns);
+ put_mnt_ns(to_mnt_ns(ns));
}
-static int mntns_install(struct nsproxy *nsproxy, void *ns)
+static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns)
{
struct fs_struct *fs = current->fs;
- struct mnt_namespace *mnt_ns = ns;
+ struct mnt_namespace *mnt_ns = to_mnt_ns(ns);
struct path root;
if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) ||
return 0;
}
-static unsigned int mntns_inum(void *ns)
-{
- struct mnt_namespace *mnt_ns = ns;
- return mnt_ns->proc_inum;
-}
-
const struct proc_ns_operations mntns_operations = {
.name = "mnt",
.type = CLONE_NEWNS,
.get = mntns_get,
.put = mntns_put,
.install = mntns_install,
- .inum = mntns_inum,
};
.llseek = seq_lseek,
.release = proc_id_map_release,
};
+
+ static int proc_setgroups_open(struct inode *inode, struct file *file)
+ {
+ struct user_namespace *ns = NULL;
+ struct task_struct *task;
+ int ret;
+
+ ret = -ESRCH;
+ task = get_proc_task(inode);
+ if (task) {
+ rcu_read_lock();
+ ns = get_user_ns(task_cred_xxx(task, user_ns));
+ rcu_read_unlock();
+ put_task_struct(task);
+ }
+ if (!ns)
+ goto err;
+
+ if (file->f_mode & FMODE_WRITE) {
+ ret = -EACCES;
+ if (!ns_capable(ns, CAP_SYS_ADMIN))
+ goto err_put_ns;
+ }
+
+ ret = single_open(file, &proc_setgroups_show, ns);
+ if (ret)
+ goto err_put_ns;
+
+ return 0;
+ err_put_ns:
+ put_user_ns(ns);
+ err:
+ return ret;
+ }
+
+ static int proc_setgroups_release(struct inode *inode, struct file *file)
+ {
+ struct seq_file *seq = file->private_data;
+ struct user_namespace *ns = seq->private;
+ int ret = single_release(inode, file);
+ put_user_ns(ns);
+ return ret;
+ }
+
+ static const struct file_operations proc_setgroups_operations = {
+ .open = proc_setgroups_open,
+ .write = proc_setgroups_write,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = proc_setgroups_release,
+ };
#endif /* CONFIG_USER_NS */
static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
REG("uid_map", S_IRUGO|S_IWUSR, proc_uid_map_operations),
REG("gid_map", S_IRUGO|S_IWUSR, proc_gid_map_operations),
REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
+ REG("setgroups", S_IRUGO|S_IWUSR, proc_setgroups_operations),
#endif
#ifdef CONFIG_CHECKPOINT_RESTORE
REG("timers", S_IRUGO, proc_timers_operations),
dput(dentry);
}
+ if (pid == tgid)
+ return;
+
name.name = buf;
name.len = snprintf(buf, sizeof(buf), "%d", tgid);
leader = d_hash_and_lookup(mnt->mnt_root, &name);
int proc_pid_readdir(struct file *file, struct dir_context *ctx)
{
struct tgid_iter iter;
- struct pid_namespace *ns = file->f_dentry->d_sb->s_fs_info;
+ struct pid_namespace *ns = file_inode(file)->i_sb->s_fs_info;
loff_t pos = ctx->pos;
if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
REG("uid_map", S_IRUGO|S_IWUSR, proc_uid_map_operations),
REG("gid_map", S_IRUGO|S_IWUSR, proc_gid_map_operations),
REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
+ REG("setgroups", S_IRUGO|S_IWUSR, proc_setgroups_operations),
#endif
};
/* f_version caches the tgid value that the last readdir call couldn't
* return. lseek aka telldir automagically resets f_version to 0.
*/
- ns = file->f_dentry->d_sb->s_fs_info;
+ ns = inode->i_sb->s_fs_info;
tid = (int)file->f_version;
file->f_version = 0;
for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
#include <linux/kref.h>
#include <linux/nsproxy.h>
+#include <linux/ns_common.h>
#include <linux/sched.h>
#include <linux/err.h>
} extent[UID_GID_MAP_MAX_EXTENTS];
};
+ #define USERNS_SETGROUPS_ALLOWED 1UL
+
+ #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
+
struct user_namespace {
struct uid_gid_map uid_map;
struct uid_gid_map gid_map;
int level;
kuid_t owner;
kgid_t group;
- unsigned int proc_inum;
+ struct ns_common ns;
+ unsigned long flags;
/* Register of per-UID persistent keyrings for this namespace */
#ifdef CONFIG_PERSISTENT_KEYRINGS
extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
+ extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
+ extern int proc_setgroups_show(struct seq_file *m, void *v);
+ extern bool userns_may_setgroups(const struct user_namespace *ns);
#else
static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
{
}
+ static inline bool userns_may_setgroups(const struct user_namespace *ns)
+ {
+ return true;
+ }
#endif
#endif /* _LINUX_USER_H */
.count = ATOMIC_INIT(3),
.owner = GLOBAL_ROOT_UID,
.group = GLOBAL_ROOT_GID,
- .proc_inum = PROC_USER_INIT_INO,
+ .ns.inum = PROC_USER_INIT_INO,
+#ifdef CONFIG_USER_NS
+ .ns.ops = &userns_operations,
+#endif
+ .flags = USERNS_INIT_FLAGS,
#ifdef CONFIG_PERSISTENT_KEYRINGS
.persistent_keyring_register_sem =
__RWSEM_INITIALIZER(init_user_ns.persistent_keyring_register_sem),
#include <linux/fs_struct.h>
static struct kmem_cache *user_ns_cachep __read_mostly;
+ static DEFINE_MUTEX(userns_state_mutex);
static bool new_idmap_permitted(const struct file *file,
struct user_namespace *ns, int cap_setid,
if (!ns)
return -ENOMEM;
- ret = proc_alloc_inum(&ns->proc_inum);
+ ret = ns_alloc_inum(&ns->ns);
if (ret) {
kmem_cache_free(user_ns_cachep, ns);
return ret;
}
+ ns->ns.ops = &userns_operations;
atomic_set(&ns->count, 1);
/* Leave the new->user_ns reference with the new user namespace. */
ns->owner = owner;
ns->group = group;
+ /* Inherit USERNS_SETGROUPS_ALLOWED from our parent */
+ mutex_lock(&userns_state_mutex);
+ ns->flags = parent_ns->flags;
+ mutex_unlock(&userns_state_mutex);
+
set_cred_user_ns(new, ns);
#ifdef CONFIG_PERSISTENT_KEYRINGS
#ifdef CONFIG_PERSISTENT_KEYRINGS
key_put(ns->persistent_keyring_register);
#endif
- proc_free_inum(ns->proc_inum);
+ ns_free_inum(&ns->ns);
kmem_cache_free(user_ns_cachep, ns);
ns = parent;
} while (atomic_dec_and_test(&parent->count));
return false;
}
-
- static DEFINE_MUTEX(id_map_mutex);
-
static ssize_t map_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos,
int cap_setid,
ssize_t ret = -EINVAL;
/*
- * The id_map_mutex serializes all writes to any given map.
+ * The userns_state_mutex serializes all writes to any given map.
*
* Any map is only ever written once.
*
* order and smp_rmb() is guaranteed that we don't have crazy
* architectures returning stale data.
*/
- mutex_lock(&id_map_mutex);
+ mutex_lock(&userns_state_mutex);
ret = -EPERM;
/* Only allow one successful write to the map */
if (!page)
goto out;
- /* Only allow <= page size writes at the beginning of the file */
+ /* Only allow < page size writes at the beginning of the file */
ret = -EINVAL;
if ((*ppos != 0) || (count >= PAGE_SIZE))
goto out;
*ppos = count;
ret = count;
out:
- mutex_unlock(&id_map_mutex);
+ mutex_unlock(&userns_state_mutex);
if (page)
free_page(page);
return ret;
struct user_namespace *ns, int cap_setid,
struct uid_gid_map *new_map)
{
- /* Allow mapping to your own filesystem ids */
- if ((new_map->nr_extents == 1) && (new_map->extent[0].count == 1)) {
+ const struct cred *cred = file->f_cred;
+ /* Don't allow mappings that would allow anything that wouldn't
+ * be allowed without the establishment of unprivileged mappings.
+ */
+ if ((new_map->nr_extents == 1) && (new_map->extent[0].count == 1) &&
+ uid_eq(ns->owner, cred->euid)) {
u32 id = new_map->extent[0].lower_first;
if (cap_setid == CAP_SETUID) {
kuid_t uid = make_kuid(ns->parent, id);
- if (uid_eq(uid, file->f_cred->fsuid))
+ if (uid_eq(uid, cred->euid))
return true;
} else if (cap_setid == CAP_SETGID) {
kgid_t gid = make_kgid(ns->parent, id);
- if (gid_eq(gid, file->f_cred->fsgid))
+ if (!(ns->flags & USERNS_SETGROUPS_ALLOWED) &&
+ gid_eq(gid, cred->egid))
return true;
}
}
return false;
}
-static void *userns_get(struct task_struct *task)
+ int proc_setgroups_show(struct seq_file *seq, void *v)
+ {
+ struct user_namespace *ns = seq->private;
+ unsigned long userns_flags = ACCESS_ONCE(ns->flags);
+
+ seq_printf(seq, "%s\n",
+ (userns_flags & USERNS_SETGROUPS_ALLOWED) ?
+ "allow" : "deny");
+ return 0;
+ }
+
+ ssize_t proc_setgroups_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+ {
+ struct seq_file *seq = file->private_data;
+ struct user_namespace *ns = seq->private;
+ char kbuf[8], *pos;
+ bool setgroups_allowed;
+ ssize_t ret;
+
+ /* Only allow a very narrow range of strings to be written */
+ ret = -EINVAL;
+ if ((*ppos != 0) || (count >= sizeof(kbuf)))
+ goto out;
+
+ /* What was written? */
+ ret = -EFAULT;
+ if (copy_from_user(kbuf, buf, count))
+ goto out;
+ kbuf[count] = '\0';
+ pos = kbuf;
+
+ /* What is being requested? */
+ ret = -EINVAL;
+ if (strncmp(pos, "allow", 5) == 0) {
+ pos += 5;
+ setgroups_allowed = true;
+ }
+ else if (strncmp(pos, "deny", 4) == 0) {
+ pos += 4;
+ setgroups_allowed = false;
+ }
+ else
+ goto out;
+
+ /* Verify there is not trailing junk on the line */
+ pos = skip_spaces(pos);
+ if (*pos != '\0')
+ goto out;
+
+ ret = -EPERM;
+ mutex_lock(&userns_state_mutex);
+ if (setgroups_allowed) {
+ /* Enabling setgroups after setgroups has been disabled
+ * is not allowed.
+ */
+ if (!(ns->flags & USERNS_SETGROUPS_ALLOWED))
+ goto out_unlock;
+ } else {
+ /* Permanently disabling setgroups after setgroups has
+ * been enabled by writing the gid_map is not allowed.
+ */
+ if (ns->gid_map.nr_extents != 0)
+ goto out_unlock;
+ ns->flags &= ~USERNS_SETGROUPS_ALLOWED;
+ }
+ mutex_unlock(&userns_state_mutex);
+
+ /* Report a successful write */
+ *ppos = count;
+ ret = count;
+ out:
+ return ret;
+ out_unlock:
+ mutex_unlock(&userns_state_mutex);
+ goto out;
+ }
+
+ bool userns_may_setgroups(const struct user_namespace *ns)
+ {
+ bool allowed;
+
+ mutex_lock(&userns_state_mutex);
+ /* It is not safe to use setgroups until a gid mapping in
+ * the user namespace has been established.
+ */
+ allowed = ns->gid_map.nr_extents != 0;
+ /* Is setgroups allowed? */
+ allowed = allowed && (ns->flags & USERNS_SETGROUPS_ALLOWED);
+ mutex_unlock(&userns_state_mutex);
+
+ return allowed;
+ }
+
+static inline struct user_namespace *to_user_ns(struct ns_common *ns)
+{
+ return container_of(ns, struct user_namespace, ns);
+}
+
+static struct ns_common *userns_get(struct task_struct *task)
{
struct user_namespace *user_ns;
user_ns = get_user_ns(__task_cred(task)->user_ns);
rcu_read_unlock();
- return user_ns;
+ return user_ns ? &user_ns->ns : NULL;
}
-static void userns_put(void *ns)
+static void userns_put(struct ns_common *ns)
{
- put_user_ns(ns);
+ put_user_ns(to_user_ns(ns));
}
-static int userns_install(struct nsproxy *nsproxy, void *ns)
+static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns)
{
- struct user_namespace *user_ns = ns;
+ struct user_namespace *user_ns = to_user_ns(ns);
struct cred *cred;
/* Don't allow gaining capabilities by reentering
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)
projects / cascardo / linux.git / commitdiff