diff options
Diffstat (limited to 'fs/super.c')
| -rw-r--r-- | fs/super.c | 148 |
1 files changed, 44 insertions, 104 deletions
diff --git a/fs/super.c b/fs/super.c index 2739f57515f8..113c58f19425 100644 --- a/fs/super.c +++ b/fs/super.c @@ -476,6 +476,17 @@ void generic_shutdown_super(struct super_block *sb) EXPORT_SYMBOL(generic_shutdown_super); +bool mount_capable(struct fs_context *fc) +{ + struct user_namespace *user_ns = fc->global ? &init_user_ns + : fc->user_ns; + + if (!(fc->fs_type->fs_flags & FS_USERNS_MOUNT)) + return capable(CAP_SYS_ADMIN); + else + return ns_capable(user_ns, CAP_SYS_ADMIN); +} + /** * sget_fc - Find or create a superblock * @fc: Filesystem context. @@ -503,20 +514,6 @@ struct super_block *sget_fc(struct fs_context *fc, struct user_namespace *user_ns = fc->global ? &init_user_ns : fc->user_ns; int err; - if (!(fc->sb_flags & SB_KERNMOUNT) && - fc->purpose != FS_CONTEXT_FOR_SUBMOUNT) { - /* Don't allow mounting unless the caller has CAP_SYS_ADMIN - * over the namespace. - */ - if (!(fc->fs_type->fs_flags & FS_USERNS_MOUNT)) { - if (!capable(CAP_SYS_ADMIN)) - return ERR_PTR(-EPERM); - } else { - if (!ns_capable(fc->user_ns, CAP_SYS_ADMIN)) - return ERR_PTR(-EPERM); - } - } - retry: spin_lock(&sb_lock); if (test) { @@ -543,6 +540,7 @@ retry: } fc->s_fs_info = NULL; s->s_type = fc->fs_type; + s->s_iflags |= fc->s_iflags; strlcpy(s->s_id, s->s_type->name, sizeof(s->s_id)); list_add_tail(&s->s_list, &super_blocks); hlist_add_head(&s->s_instances, &s->s_type->fs_supers); @@ -565,28 +563,31 @@ share_extant_sb: EXPORT_SYMBOL(sget_fc); /** - * sget_userns - find or create a superblock - * @type: filesystem type superblock should belong to - * @test: comparison callback - * @set: setup callback - * @flags: mount flags - * @user_ns: User namespace for the super_block - * @data: argument to each of them + * sget - find or create a superblock + * @type: filesystem type superblock should belong to + * @test: comparison callback + * @set: setup callback + * @flags: mount flags + * @data: argument to each of them */ -struct super_block *sget_userns(struct file_system_type *type, +struct super_block *sget(struct file_system_type *type, int (*test)(struct super_block *,void *), int (*set)(struct super_block *,void *), - int flags, struct user_namespace *user_ns, + int flags, void *data) { + struct user_namespace *user_ns = current_user_ns(); struct super_block *s = NULL; struct super_block *old; int err; - if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) && - !(type->fs_flags & FS_USERNS_MOUNT) && - !capable(CAP_SYS_ADMIN)) - return ERR_PTR(-EPERM); + /* We don't yet pass the user namespace of the parent + * mount through to here so always use &init_user_ns + * until that changes. + */ + if (flags & SB_SUBMOUNT) + user_ns = &init_user_ns; + retry: spin_lock(&sb_lock); if (test) { @@ -627,39 +628,6 @@ retry: register_shrinker_prepared(&s->s_shrink); return s; } - -EXPORT_SYMBOL(sget_userns); - -/** - * sget - find or create a superblock - * @type: filesystem type superblock should belong to - * @test: comparison callback - * @set: setup callback - * @flags: mount flags - * @data: argument to each of them - */ -struct super_block *sget(struct file_system_type *type, - int (*test)(struct super_block *,void *), - int (*set)(struct super_block *,void *), - int flags, - void *data) -{ - struct user_namespace *user_ns = current_user_ns(); - - /* We don't yet pass the user namespace of the parent - * mount through to here so always use &init_user_ns - * until that changes. - */ - if (flags & SB_SUBMOUNT) - user_ns = &init_user_ns; - - /* Ensure the requestor has permissions over the target filesystem */ - if (!(flags & (SB_KERNMOUNT|SB_SUBMOUNT)) && !ns_capable(user_ns, CAP_SYS_ADMIN)) - return ERR_PTR(-EPERM); - - return sget_userns(type, test, set, flags, user_ns, data); -} - EXPORT_SYMBOL(sget); void drop_super(struct super_block *sb) @@ -1147,50 +1115,6 @@ void kill_litter_super(struct super_block *sb) } EXPORT_SYMBOL(kill_litter_super); -static int ns_test_super(struct super_block *sb, void *data) -{ - return sb->s_fs_info == data; -} - -static int ns_set_super(struct super_block *sb, void *data) -{ - sb->s_fs_info = data; - return set_anon_super(sb, NULL); -} - -struct dentry *mount_ns(struct file_system_type *fs_type, - int flags, void *data, void *ns, struct user_namespace *user_ns, - int (*fill_super)(struct super_block *, void *, int)) -{ - struct super_block *sb; - - /* Don't allow mounting unless the caller has CAP_SYS_ADMIN - * over the namespace. - */ - if (!(flags & SB_KERNMOUNT) && !ns_capable(user_ns, CAP_SYS_ADMIN)) - return ERR_PTR(-EPERM); - - sb = sget_userns(fs_type, ns_test_super, ns_set_super, flags, - user_ns, ns); - if (IS_ERR(sb)) - return ERR_CAST(sb); - - if (!sb->s_root) { - int err; - err = fill_super(sb, data, flags & SB_SILENT ? 1 : 0); - if (err) { - deactivate_locked_super(sb); - return ERR_PTR(err); - } - - sb->s_flags |= SB_ACTIVE; - } - - return dget(sb->s_root); -} - -EXPORT_SYMBOL(mount_ns); - int set_anon_super_fc(struct super_block *sb, struct fs_context *fc) { return set_anon_super(sb, NULL); @@ -1274,6 +1198,22 @@ int vfs_get_super(struct fs_context *fc, } EXPORT_SYMBOL(vfs_get_super); +int get_tree_nodev(struct fs_context *fc, + int (*fill_super)(struct super_block *sb, + struct fs_context *fc)) +{ + return vfs_get_super(fc, vfs_get_independent_super, fill_super); +} +EXPORT_SYMBOL(get_tree_nodev); + +int get_tree_single(struct fs_context *fc, + int (*fill_super)(struct super_block *sb, + struct fs_context *fc)) +{ + return vfs_get_super(fc, vfs_get_single_super, fill_super); +} +EXPORT_SYMBOL(get_tree_single); + #ifdef CONFIG_BLOCK static int set_bdev_super(struct super_block *s, void *data) { |