/* * (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, *clone; int error = 0; if (S_ISLNK(inode->i_mode)) return -EOPNOTSUPP; acl = get_cached_acl(inode, ACL_TYPE_ACCESS); if (acl) { clone = posix_acl_clone(acl, GFP_KERNEL); posix_acl_release(acl); if (!clone) return -ENOMEM; error = posix_acl_chmod_masq(clone, inode->i_mode); if (!error) set_cached_acl(inode, ACL_TYPE_ACCESS, clone); posix_acl_release(clone); } return error; } int generic_check_acl(struct inode *inode, int mask) { if (mask & MAY_NOT_BLOCK) { if (!negative_cached_acl(inode, ACL_TYPE_ACCESS)) return -ECHILD; } else { 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, };