115 lines
2.6 KiB
C
115 lines
2.6 KiB
C
/*
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* FUSE: Filesystem in Userspace
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* Copyright (C) 2016 Canonical Ltd. <seth.forshee@canonical.com>
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*
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* This program can be distributed under the terms of the GNU GPL.
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* See the file COPYING.
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*/
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#include "fuse_i.h"
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#include <linux/posix_acl.h>
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#include <linux/posix_acl_xattr.h>
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struct posix_acl *fuse_get_acl(struct inode *inode, int type, bool rcu)
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{
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struct fuse_conn *fc = get_fuse_conn(inode);
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int size;
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const char *name;
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void *value = NULL;
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struct posix_acl *acl;
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if (rcu)
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return ERR_PTR(-ECHILD);
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if (fuse_is_bad(inode))
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return ERR_PTR(-EIO);
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if (!fc->posix_acl || fc->no_getxattr)
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return NULL;
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if (type == ACL_TYPE_ACCESS)
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name = XATTR_NAME_POSIX_ACL_ACCESS;
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else if (type == ACL_TYPE_DEFAULT)
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name = XATTR_NAME_POSIX_ACL_DEFAULT;
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else
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return ERR_PTR(-EOPNOTSUPP);
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value = kmalloc(PAGE_SIZE, GFP_KERNEL);
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if (!value)
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return ERR_PTR(-ENOMEM);
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size = fuse_getxattr(inode, name, value, PAGE_SIZE);
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if (size > 0)
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acl = posix_acl_from_xattr(fc->user_ns, value, size);
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else if ((size == 0) || (size == -ENODATA) ||
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(size == -EOPNOTSUPP && fc->no_getxattr))
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acl = NULL;
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else if (size == -ERANGE)
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acl = ERR_PTR(-E2BIG);
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else
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acl = ERR_PTR(size);
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kfree(value);
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return acl;
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}
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int fuse_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
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struct posix_acl *acl, int type)
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{
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struct fuse_conn *fc = get_fuse_conn(inode);
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const char *name;
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int ret;
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if (fuse_is_bad(inode))
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return -EIO;
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if (!fc->posix_acl || fc->no_setxattr)
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return -EOPNOTSUPP;
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if (type == ACL_TYPE_ACCESS)
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name = XATTR_NAME_POSIX_ACL_ACCESS;
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else if (type == ACL_TYPE_DEFAULT)
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name = XATTR_NAME_POSIX_ACL_DEFAULT;
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else
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return -EINVAL;
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if (acl) {
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unsigned int extra_flags = 0;
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/*
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* Fuse userspace is responsible for updating access
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* permissions in the inode, if needed. fuse_setxattr
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* invalidates the inode attributes, which will force
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* them to be refreshed the next time they are used,
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* and it also updates i_ctime.
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*/
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size_t size = posix_acl_xattr_size(acl->a_count);
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void *value;
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if (size > PAGE_SIZE)
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return -E2BIG;
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value = kmalloc(size, GFP_KERNEL);
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if (!value)
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return -ENOMEM;
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ret = posix_acl_to_xattr(fc->user_ns, acl, value, size);
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if (ret < 0) {
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kfree(value);
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return ret;
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}
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if (!in_group_p(i_gid_into_mnt(&init_user_ns, inode)) &&
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!capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID))
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extra_flags |= FUSE_SETXATTR_ACL_KILL_SGID;
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ret = fuse_setxattr(inode, name, value, size, 0, extra_flags);
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kfree(value);
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} else {
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ret = fuse_removexattr(inode, name);
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}
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forget_all_cached_acls(inode);
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fuse_invalidate_attr(inode);
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return ret;
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}
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