| /* |
| * (C) 2005 Andreas Gruenbacher <agruen@suse.de> |
| * |
| * This file is released under the GPL. |
| * |
| * Generic ACL support for in-memory filesystems. |
| */ |
| |
| #include <linux/sched.h> |
| #include <linux/gfp.h> |
| #include <linux/fs.h> |
| #include <linux/generic_acl.h> |
| #include <linux/posix_acl.h> |
| #include <linux/posix_acl_xattr.h> |
| |
| |
| static size_t |
| generic_acl_list(struct dentry *dentry, char *list, size_t list_size, |
| const char *name, size_t name_len, int type) |
| { |
| struct posix_acl *acl; |
| const char *xname; |
| size_t size; |
| |
| acl = get_cached_acl(dentry->d_inode, type); |
| if (!acl) |
| return 0; |
| posix_acl_release(acl); |
| |
| switch (type) { |
| case ACL_TYPE_ACCESS: |
| xname = POSIX_ACL_XATTR_ACCESS; |
| break; |
| case ACL_TYPE_DEFAULT: |
| xname = POSIX_ACL_XATTR_DEFAULT; |
| break; |
| default: |
| return 0; |
| } |
| size = strlen(xname) + 1; |
| if (list && size <= list_size) |
| memcpy(list, xname, size); |
| return size; |
| } |
| |
| static int |
| generic_acl_get(struct dentry *dentry, const char *name, void *buffer, |
| size_t size, int type) |
| { |
| struct posix_acl *acl; |
| int error; |
| |
| if (strcmp(name, "") != 0) |
| return -EINVAL; |
| |
| acl = get_cached_acl(dentry->d_inode, type); |
| if (!acl) |
| return -ENODATA; |
| error = posix_acl_to_xattr(acl, buffer, size); |
| posix_acl_release(acl); |
| |
| return error; |
| } |
| |
| static int |
| generic_acl_set(struct dentry *dentry, const char *name, const void *value, |
| size_t size, int flags, int type) |
| { |
| struct inode *inode = dentry->d_inode; |
| struct posix_acl *acl = NULL; |
| int error; |
| |
| if (strcmp(name, "") != 0) |
| return -EINVAL; |
| if (S_ISLNK(inode->i_mode)) |
| return -EOPNOTSUPP; |
| if (!inode_owner_or_capable(inode)) |
| return -EPERM; |
| if (value) { |
| acl = posix_acl_from_xattr(value, size); |
| if (IS_ERR(acl)) |
| return PTR_ERR(acl); |
| } |
| if (acl) { |
| mode_t mode; |
| |
| error = posix_acl_valid(acl); |
| if (error) |
| goto failed; |
| switch (type) { |
| case ACL_TYPE_ACCESS: |
| mode = inode->i_mode; |
| error = posix_acl_equiv_mode(acl, &mode); |
| if (error < 0) |
| goto failed; |
| inode->i_mode = mode; |
| inode->i_ctime = CURRENT_TIME; |
| if (error == 0) { |
| posix_acl_release(acl); |
| acl = NULL; |
| } |
| break; |
| case ACL_TYPE_DEFAULT: |
| if (!S_ISDIR(inode->i_mode)) { |
| error = -EINVAL; |
| goto failed; |
| } |
| break; |
| } |
| } |
| set_cached_acl(inode, type, acl); |
| error = 0; |
| failed: |
| posix_acl_release(acl); |
| return error; |
| } |
| |
| /** |
| * generic_acl_init - Take care of acl inheritance at @inode create time |
| * |
| * Files created inside a directory with a default ACL inherit the |
| * directory's default ACL. |
| */ |
| int |
| generic_acl_init(struct inode *inode, struct inode *dir) |
| { |
| struct posix_acl *acl = NULL; |
| mode_t mode = inode->i_mode; |
| int error; |
| |
| inode->i_mode = mode & ~current_umask(); |
| if (!S_ISLNK(inode->i_mode)) |
| acl = get_cached_acl(dir, ACL_TYPE_DEFAULT); |
| if (acl) { |
| struct posix_acl *clone; |
| |
| if (S_ISDIR(inode->i_mode)) { |
| clone = posix_acl_clone(acl, GFP_KERNEL); |
| error = -ENOMEM; |
| if (!clone) |
| goto cleanup; |
| set_cached_acl(inode, ACL_TYPE_DEFAULT, clone); |
| posix_acl_release(clone); |
| } |
| clone = posix_acl_clone(acl, GFP_KERNEL); |
| error = -ENOMEM; |
| if (!clone) |
| goto cleanup; |
| error = posix_acl_create_masq(clone, &mode); |
| if (error >= 0) { |
| inode->i_mode = mode; |
| if (error > 0) |
| set_cached_acl(inode, ACL_TYPE_ACCESS, clone); |
| } |
| posix_acl_release(clone); |
| } |
| error = 0; |
| |
| cleanup: |
| posix_acl_release(acl); |
| return error; |
| } |
| |
| /** |
| * generic_acl_chmod - change the access acl of @inode upon chmod() |
| * |
| * A chmod also changes the permissions of the owner, group/mask, and |
| * other ACL entries. |
| */ |
| int |
| generic_acl_chmod(struct inode *inode) |
| { |
| struct posix_acl *acl; |
| int error = 0; |
| |
| if (S_ISLNK(inode->i_mode)) |
| return -EOPNOTSUPP; |
| acl = get_cached_acl(inode, ACL_TYPE_ACCESS); |
| if (acl) { |
| error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode); |
| if (error) |
| return error; |
| set_cached_acl(inode, ACL_TYPE_ACCESS, acl); |
| posix_acl_release(acl); |
| } |
| return error; |
| } |
| |
| int |
| generic_check_acl(struct inode *inode, int mask) |
| { |
| struct posix_acl *acl; |
| |
| acl = get_cached_acl(inode, ACL_TYPE_ACCESS); |
| if (acl) { |
| int error = posix_acl_permission(inode, acl, mask); |
| posix_acl_release(acl); |
| return error; |
| } |
| return -EAGAIN; |
| } |
| |
| const struct xattr_handler generic_acl_access_handler = { |
| .prefix = POSIX_ACL_XATTR_ACCESS, |
| .flags = ACL_TYPE_ACCESS, |
| .list = generic_acl_list, |
| .get = generic_acl_get, |
| .set = generic_acl_set, |
| }; |
| |
| const struct xattr_handler generic_acl_default_handler = { |
| .prefix = POSIX_ACL_XATTR_DEFAULT, |
| .flags = ACL_TYPE_DEFAULT, |
| .list = generic_acl_list, |
| .get = generic_acl_get, |
| .set = generic_acl_set, |
| }; |