linux/io_uring/xattr.c
Stefan Metzmacher f2ccb5aed7 io_uring: make io_kiocb_to_cmd() typesafe
We need to make sure (at build time) that struct io_cmd_data is not
casted to a structure that's larger.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Link: https://lore.kernel.org/r/c024cdf25ae19fc0319d4180e2298bade8ed17b8.1660201408.git.metze@samba.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-08-12 17:01:00 -06:00

259 lines
5.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/io_uring.h>
#include <linux/xattr.h>
#include <uapi/linux/io_uring.h>
#include "../fs/internal.h"
#include "io_uring.h"
#include "xattr.h"
struct io_xattr {
struct file *file;
struct xattr_ctx ctx;
struct filename *filename;
};
void io_xattr_cleanup(struct io_kiocb *req)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
if (ix->filename)
putname(ix->filename);
kfree(ix->ctx.kname);
kvfree(ix->ctx.kvalue);
}
static void io_xattr_finish(struct io_kiocb *req, int ret)
{
req->flags &= ~REQ_F_NEED_CLEANUP;
io_xattr_cleanup(req);
io_req_set_res(req, ret, 0);
}
static int __io_getxattr_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
const char __user *name;
int ret;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
ix->filename = NULL;
ix->ctx.kvalue = NULL;
name = u64_to_user_ptr(READ_ONCE(sqe->addr));
ix->ctx.cvalue = u64_to_user_ptr(READ_ONCE(sqe->addr2));
ix->ctx.size = READ_ONCE(sqe->len);
ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
if (ix->ctx.flags)
return -EINVAL;
ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
if (!ix->ctx.kname)
return -ENOMEM;
ret = strncpy_from_user(ix->ctx.kname->name, name,
sizeof(ix->ctx.kname->name));
if (!ret || ret == sizeof(ix->ctx.kname->name))
ret = -ERANGE;
if (ret < 0) {
kfree(ix->ctx.kname);
return ret;
}
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}
int io_fgetxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return __io_getxattr_prep(req, sqe);
}
int io_getxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
const char __user *path;
int ret;
ret = __io_getxattr_prep(req, sqe);
if (ret)
return ret;
path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
if (IS_ERR(ix->filename)) {
ret = PTR_ERR(ix->filename);
ix->filename = NULL;
}
return ret;
}
int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
int ret;
if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
ret = do_getxattr(mnt_user_ns(req->file->f_path.mnt),
req->file->f_path.dentry,
&ix->ctx);
io_xattr_finish(req, ret);
return IOU_OK;
}
int io_getxattr(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
unsigned int lookup_flags = LOOKUP_FOLLOW;
struct path path;
int ret;
if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
retry:
ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
if (!ret) {
ret = do_getxattr(mnt_user_ns(path.mnt),
path.dentry,
&ix->ctx);
path_put(&path);
if (retry_estale(ret, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
}
io_xattr_finish(req, ret);
return IOU_OK;
}
static int __io_setxattr_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
const char __user *name;
int ret;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
ix->filename = NULL;
name = u64_to_user_ptr(READ_ONCE(sqe->addr));
ix->ctx.cvalue = u64_to_user_ptr(READ_ONCE(sqe->addr2));
ix->ctx.kvalue = NULL;
ix->ctx.size = READ_ONCE(sqe->len);
ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
ix->ctx.kname = kmalloc(sizeof(*ix->ctx.kname), GFP_KERNEL);
if (!ix->ctx.kname)
return -ENOMEM;
ret = setxattr_copy(name, &ix->ctx);
if (ret) {
kfree(ix->ctx.kname);
return ret;
}
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}
int io_setxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
const char __user *path;
int ret;
ret = __io_setxattr_prep(req, sqe);
if (ret)
return ret;
path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
ix->filename = getname_flags(path, LOOKUP_FOLLOW, NULL);
if (IS_ERR(ix->filename)) {
ret = PTR_ERR(ix->filename);
ix->filename = NULL;
}
return ret;
}
int io_fsetxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return __io_setxattr_prep(req, sqe);
}
static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
struct path *path)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
int ret;
ret = mnt_want_write(path->mnt);
if (!ret) {
ret = do_setxattr(mnt_user_ns(path->mnt), path->dentry, &ix->ctx);
mnt_drop_write(path->mnt);
}
return ret;
}
int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
{
int ret;
if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
ret = __io_setxattr(req, issue_flags, &req->file->f_path);
io_xattr_finish(req, ret);
return IOU_OK;
}
int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
unsigned int lookup_flags = LOOKUP_FOLLOW;
struct path path;
int ret;
if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
retry:
ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
if (!ret) {
ret = __io_setxattr(req, issue_flags, &path);
path_put(&path);
if (retry_estale(ret, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
}
io_xattr_finish(req, ret);
return IOU_OK;
}