e67fe63341
Convert to struct mnt_idmap.
Remove legacy file_mnt_user_ns() and mnt_user_ns().
Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
116 lines
2.7 KiB
C
116 lines
2.7 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 mnt_idmap *idmap, struct dentry *dentry,
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struct posix_acl *acl, int type)
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{
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struct inode *inode = d_inode(dentry);
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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 (!vfsgid_in_group_p(i_gid_into_vfsgid(&nop_mnt_idmap, inode)) &&
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!capable_wrt_inode_uidgid(&nop_mnt_idmap, 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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