diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 109 |
1 files changed, 90 insertions, 19 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index f79d9471cb76..659a8f39c61a 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -203,7 +203,8 @@ static struct mount *alloc_vfsmnt(const char *name) goto out_free_cache; if (name) { - mnt->mnt_devname = kstrdup_const(name, GFP_KERNEL); + mnt->mnt_devname = kstrdup_const(name, + GFP_KERNEL_ACCOUNT); if (!mnt->mnt_devname) goto out_free_id; } @@ -1715,18 +1716,14 @@ static inline bool may_mount(void) return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN); } -#ifdef CONFIG_MANDATORY_FILE_LOCKING -static inline bool may_mandlock(void) +static void warn_mandlock(void) { - return capable(CAP_SYS_ADMIN); + pr_warn_once("=======================================================\n" + "WARNING: The mand mount option has been deprecated and\n" + " and is ignored by this kernel. Remove the mand\n" + " option from the mount to silence this warning.\n" + "=======================================================\n"); } -#else -static inline bool may_mandlock(void) -{ - pr_warn("VFS: \"mand\" mount option not supported"); - return false; -} -#endif static int can_umount(const struct path *path, int flags) { @@ -2698,6 +2695,78 @@ out: return ret; } +static int do_set_group(struct path *from_path, struct path *to_path) +{ + struct mount *from, *to; + int err; + + from = real_mount(from_path->mnt); + to = real_mount(to_path->mnt); + + namespace_lock(); + + err = -EINVAL; + /* To and From must be mounted */ + if (!is_mounted(&from->mnt)) + goto out; + if (!is_mounted(&to->mnt)) + goto out; + + err = -EPERM; + /* We should be allowed to modify mount namespaces of both mounts */ + if (!ns_capable(from->mnt_ns->user_ns, CAP_SYS_ADMIN)) + goto out; + if (!ns_capable(to->mnt_ns->user_ns, CAP_SYS_ADMIN)) + goto out; + + err = -EINVAL; + /* To and From paths should be mount roots */ + if (from_path->dentry != from_path->mnt->mnt_root) + goto out; + if (to_path->dentry != to_path->mnt->mnt_root) + goto out; + + /* Setting sharing groups is only allowed across same superblock */ + if (from->mnt.mnt_sb != to->mnt.mnt_sb) + goto out; + + /* From mount root should be wider than To mount root */ + if (!is_subdir(to->mnt.mnt_root, from->mnt.mnt_root)) + goto out; + + /* From mount should not have locked children in place of To's root */ + if (has_locked_children(from, to->mnt.mnt_root)) + goto out; + + /* Setting sharing groups is only allowed on private mounts */ + if (IS_MNT_SHARED(to) || IS_MNT_SLAVE(to)) + goto out; + + /* From should not be private */ + if (!IS_MNT_SHARED(from) && !IS_MNT_SLAVE(from)) + goto out; + + if (IS_MNT_SLAVE(from)) { + struct mount *m = from->mnt_master; + + list_add(&to->mnt_slave, &m->mnt_slave_list); + to->mnt_master = m; + } + + if (IS_MNT_SHARED(from)) { + to->mnt_group_id = from->mnt_group_id; + list_add(&to->mnt_share, &from->mnt_share); + lock_mount_hash(); + set_mnt_shared(to); + unlock_mount_hash(); + } + + err = 0; +out: + namespace_unlock(); + return err; +} + static int do_move_mount(struct path *old_path, struct path *new_path) { struct mnt_namespace *ns; @@ -3193,8 +3262,8 @@ int path_mount(const char *dev_name, struct path *path, return ret; if (!may_mount()) return -EPERM; - if ((flags & SB_MANDLOCK) && !may_mandlock()) - return -EPERM; + if (flags & SB_MANDLOCK) + warn_mandlock(); /* Default to relatime unless overriden */ if (!(flags & MS_NOATIME)) @@ -3302,7 +3371,7 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool a if (!ucounts) return ERR_PTR(-ENOSPC); - new_ns = kzalloc(sizeof(struct mnt_namespace), GFP_KERNEL); + new_ns = kzalloc(sizeof(struct mnt_namespace), GFP_KERNEL_ACCOUNT); if (!new_ns) { dec_mnt_namespaces(ucounts); return ERR_PTR(-ENOMEM); @@ -3577,9 +3646,8 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, if (fc->phase != FS_CONTEXT_AWAITING_MOUNT) goto err_unlock; - ret = -EPERM; - if ((fc->sb_flags & SB_MANDLOCK) && !may_mandlock()) - goto err_unlock; + if (fc->sb_flags & SB_MANDLOCK) + warn_mandlock(); newmount.mnt = vfs_create_mount(fc); if (IS_ERR(newmount.mnt)) { @@ -3683,7 +3751,10 @@ SYSCALL_DEFINE5(move_mount, if (ret < 0) goto out_to; - ret = do_move_mount(&from_path, &to_path); + if (flags & MOVE_MOUNT_SET_GROUP) + ret = do_set_group(&from_path, &to_path); + else + ret = do_move_mount(&from_path, &to_path); out_to: path_put(&to_path); @@ -4236,7 +4307,7 @@ void __init mnt_init(void) int err; mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct mount), - 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); + 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL); mount_hashtable = alloc_large_system_hash("Mount-cache", sizeof(struct hlist_head), |