| xj | b04a402 | 2021-11-25 15:01:52 +0800 | [diff] [blame] | 1 | /* |
| 2 | * FUSE: Filesystem in Userspace |
| 3 | * Copyright (C) 2016 Canonical Ltd. <seth.forshee@canonical.com> |
| 4 | * |
| 5 | * This program can be distributed under the terms of the GNU GPL. |
| 6 | * See the file COPYING. |
| 7 | */ |
| 8 | |
| 9 | #include "fuse_i.h" |
| 10 | |
| 11 | #include <linux/posix_acl.h> |
| 12 | #include <linux/posix_acl_xattr.h> |
| 13 | |
| 14 | struct posix_acl *fuse_get_acl(struct inode *inode, int type) |
| 15 | { |
| 16 | struct fuse_conn *fc = get_fuse_conn(inode); |
| 17 | int size; |
| 18 | const char *name; |
| 19 | void *value = NULL; |
| 20 | struct posix_acl *acl; |
| 21 | |
| 22 | if (!fc->posix_acl || fc->no_getxattr) |
| 23 | return NULL; |
| 24 | |
| 25 | if (type == ACL_TYPE_ACCESS) |
| 26 | name = XATTR_NAME_POSIX_ACL_ACCESS; |
| 27 | else if (type == ACL_TYPE_DEFAULT) |
| 28 | name = XATTR_NAME_POSIX_ACL_DEFAULT; |
| 29 | else |
| 30 | return ERR_PTR(-EOPNOTSUPP); |
| 31 | |
| 32 | value = kmalloc(PAGE_SIZE, GFP_KERNEL); |
| 33 | if (!value) |
| 34 | return ERR_PTR(-ENOMEM); |
| 35 | size = fuse_getxattr(inode, name, value, PAGE_SIZE); |
| 36 | if (size > 0) |
| 37 | acl = posix_acl_from_xattr(fc->user_ns, value, size); |
| 38 | else if ((size == 0) || (size == -ENODATA) || |
| 39 | (size == -EOPNOTSUPP && fc->no_getxattr)) |
| 40 | acl = NULL; |
| 41 | else if (size == -ERANGE) |
| 42 | acl = ERR_PTR(-E2BIG); |
| 43 | else |
| 44 | acl = ERR_PTR(size); |
| 45 | |
| 46 | kfree(value); |
| 47 | return acl; |
| 48 | } |
| 49 | |
| 50 | int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type) |
| 51 | { |
| 52 | struct fuse_conn *fc = get_fuse_conn(inode); |
| 53 | const char *name; |
| 54 | int ret; |
| 55 | |
| 56 | if (!fc->posix_acl || fc->no_setxattr) |
| 57 | return -EOPNOTSUPP; |
| 58 | |
| 59 | if (type == ACL_TYPE_ACCESS) |
| 60 | name = XATTR_NAME_POSIX_ACL_ACCESS; |
| 61 | else if (type == ACL_TYPE_DEFAULT) |
| 62 | name = XATTR_NAME_POSIX_ACL_DEFAULT; |
| 63 | else |
| 64 | return -EINVAL; |
| 65 | |
| 66 | if (acl) { |
| 67 | /* |
| 68 | * Fuse userspace is responsible for updating access |
| 69 | * permissions in the inode, if needed. fuse_setxattr |
| 70 | * invalidates the inode attributes, which will force |
| 71 | * them to be refreshed the next time they are used, |
| 72 | * and it also updates i_ctime. |
| 73 | */ |
| 74 | size_t size = posix_acl_xattr_size(acl->a_count); |
| 75 | void *value; |
| 76 | |
| 77 | if (size > PAGE_SIZE) |
| 78 | return -E2BIG; |
| 79 | |
| 80 | value = kmalloc(size, GFP_KERNEL); |
| 81 | if (!value) |
| 82 | return -ENOMEM; |
| 83 | |
| 84 | ret = posix_acl_to_xattr(fc->user_ns, acl, value, size); |
| 85 | if (ret < 0) { |
| 86 | kfree(value); |
| 87 | return ret; |
| 88 | } |
| 89 | |
| 90 | ret = fuse_setxattr(inode, name, value, size, 0); |
| 91 | kfree(value); |
| 92 | } else { |
| 93 | ret = fuse_removexattr(inode, name); |
| 94 | } |
| 95 | forget_all_cached_acls(inode); |
| 96 | fuse_invalidate_attr(inode); |
| 97 | |
| 98 | return ret; |
| 99 | } |