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实现了对用户空间传入指针抽象的UserBufferReader/Writer，来检验用户空间指针地址并提供一定的功能抽象 (#326)
* 构建了 Userbuffer 对用户空间传入的指针进行了抽象，并提供了读写操作 * 分成了Reader和Writer，增加了从地址读和写入到指定地址的功能 * 删除了多余的注释 * 增加了直接获取BufferWriter切片的函数 * 通过 where 的一个 Trick 实现了 const generic 和后续功能 * 替换为了 core::slice::align_to 实现&[u8}转&[T] * 移除了 userbuffer.rs * 提供了独立获取缓冲区中不同偏移量位置的数据的函数 * 替换了部分系统调用(还未测试 * 简化了代码 * 修复内存越界的bug --------- Co-authored-by: longjin <longjin@RinGoTek.cn>
This commit is contained in:
Chiichen
GitHub
parent
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commit
4537ffb7e9
@ -25,6 +25,8 @@ use crate::{
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},
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};
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use self::user_access::UserBufferWriter;
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pub mod user_access;
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#[repr(i32)]
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@ -651,18 +653,18 @@ impl Syscall {
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SYS_CLOCK => Self::clock(),
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SYS_PIPE => {
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let pipefd = args[0] as *mut c_int;
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let virt_pipefd = VirtAddr::new(pipefd as usize);
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if from_user
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&& verify_area(virt_pipefd, core::mem::size_of::<[c_int; 2]>() as usize)
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.is_err()
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{
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Err(SystemError::EFAULT)
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} else if pipefd.is_null() {
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Err(SystemError::EFAULT)
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} else {
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let pipefd = unsafe { core::slice::from_raw_parts_mut(pipefd, 2) };
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Self::pipe(pipefd)
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match UserBufferWriter::new(
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pipefd,
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core::mem::size_of::<[c_int; 2]>() as usize,
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from_user,
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) {
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Err(e) => Err(e),
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Ok(mut user_buffer) => match user_buffer.buffer::<i32>(0) {
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Err(e) => Err(e),
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Ok(pipefd) => Self::pipe(pipefd),
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},
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}
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}
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SYS_UNLINK_AT => {
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@ -853,27 +855,21 @@ impl Syscall {
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SYS_RECVMSG => {
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let msg = args[1] as *mut crate::net::syscall::MsgHdr;
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let flags = args[2] as u32;
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let virt_msg = VirtAddr::new(msg as usize);
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let security_check = || {
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// 验证msg的地址是否合法
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if verify_area(
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virt_msg,
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core::mem::size_of::<crate::net::syscall::MsgHdr>() as usize,
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)
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.is_err()
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{
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// 地址空间超出了用户空间的范围，不合法
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return Err(SystemError::EFAULT);
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match UserBufferWriter::new(
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msg,
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core::mem::size_of::<crate::net::syscall::MsgHdr>(),
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true,
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) {
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Err(e) => Err(e),
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Ok(mut user_buffer_writer) => {
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match user_buffer_writer.buffer::<crate::net::syscall::MsgHdr>(0) {
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Err(e) => Err(e),
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Ok(buffer) => {
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let msg = &mut buffer[0];
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Self::recvmsg(args[0], msg, flags)
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}
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}
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}
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let msg = unsafe { msg.as_mut() }.ok_or(SystemError::EFAULT)?;
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return Ok(msg);
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};
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let r = security_check();
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if r.is_err() {
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Err(r.unwrap_err())
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} else {
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let msg = r.unwrap();
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Self::recvmsg(args[0], msg, flags)
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}
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}
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@ -889,32 +885,23 @@ impl Syscall {
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SYS_GETTIMEOFDAY => {
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let timeval = args[0] as *mut PosixTimeval;
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let timezone_ptr = args[1] as *mut PosixTimeZone;
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let virt_timeval = VirtAddr::new(timeval as usize);
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let virt_timezone_ptr = VirtAddr::new(timezone_ptr as usize);
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let security_check = || {
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if verify_area(virt_timeval, core::mem::size_of::<PosixTimeval>() as usize)
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.is_err()
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{
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return Err(SystemError::EFAULT);
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}
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if verify_area(
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virt_timezone_ptr,
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core::mem::size_of::<PosixTimeZone>() as usize,
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)
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.is_err()
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{
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return Err(SystemError::EFAULT);
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}
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return Ok(());
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};
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let r = security_check();
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if r.is_err() {
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Err(r.unwrap_err())
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} else {
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if !timeval.is_null() {
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Self::gettimeofday(timeval, timezone_ptr)
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} else {
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Err(SystemError::EFAULT)
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match UserBufferWriter::new(timeval, core::mem::size_of::<PosixTimeval>(), true) {
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Err(e) => Err(e),
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Ok(_) => {
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match UserBufferWriter::new(
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timezone_ptr,
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core::mem::size_of::<PosixTimeZone>(),
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true,
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) {
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Err(e) => Err(e),
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Ok(_) => {
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if !timeval.is_null() {
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Self::gettimeofday(timeval, timezone_ptr)
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} else {
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Err(SystemError::EFAULT)
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}
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}
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}
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}
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}
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}
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@ -1,5 +1,9 @@
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//! 这个文件用于放置一些内核态访问用户态数据的函数
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use core::mem::size_of;
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use core::{
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mem::size_of,
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slice::{from_raw_parts, from_raw_parts_mut},
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};
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use alloc::{string::String, vec::Vec};
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@ -139,3 +143,199 @@ pub fn check_and_clone_cstr_array(user: *const *const u8) -> Result<Vec<String>,
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return Ok(buffer);
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}
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}
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#[derive(Debug)]
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pub struct UserBufferWriter<'a> {
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buffer: &'a mut [u8],
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}
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#[derive(Debug)]
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pub struct UserBufferReader<'a> {
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buffer: &'a [u8],
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}
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#[allow(dead_code)]
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impl<'a> UserBufferReader<'a> {
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/// 构造一个指向用户空间位置的BufferReader，为了兼容类似传入 *const u8 的情况，使用单独的泛型来进行初始化
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///
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/// @param addr 用户空间指针
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/// @param len 缓冲区的字节长度
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/// @param frm_user 代表是否要检验地址来自用户空间
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/// @return 构造成功返回UserbufferReader实例，否则返回错误码
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///
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pub fn new<U>(addr: *const U, len: usize, from_user: bool) -> Result<Self, SystemError> {
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if from_user && verify_area(VirtAddr::new(addr as usize), len).is_err() {
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return Err(SystemError::EFAULT);
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}
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return Ok(Self {
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buffer: unsafe { core::slice::from_raw_parts(addr as *const u8, len) },
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});
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}
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/// 从用户空间读取数据(到变量中)
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///
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/// @param offset 字节偏移量
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/// @return 返回用户空间数据的切片(对单个结构体就返回长度为一的切片)
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///
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pub fn read_from_user<T>(&self, offset: usize) -> Result<&[T], SystemError> {
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return self.convert_with_offset(&self.buffer, offset);
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}
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/// 从用户空间读取一个指定偏移量的数据(到变量中)
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///
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/// @param offset 字节偏移量
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/// @return 返回用户空间数据的引用
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///
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pub fn read_one_from_user<T>(&self, offset: usize) -> Result<&T, SystemError> {
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return self.convert_one_with_offset(&self.buffer, offset);
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}
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/// 从用户空间拷贝数据(到指定地址中)
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///
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/// @param dst 目标地址指针
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/// @return 拷贝成功的话返回拷贝的元素数量
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///
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pub fn copy_from_user<T: core::marker::Copy>(
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&self,
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dst: &mut [T],
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offset: usize,
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) -> Result<usize, SystemError> {
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let data = self.convert_with_offset(&self.buffer, offset)?;
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dst.copy_from_slice(data);
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return Ok(dst.len());
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}
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/// 从用户空间拷贝数据(到指定地址中)
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///
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/// @param dst 目标地址指针
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/// @return 拷贝成功的话返回拷贝的元素数量
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///
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pub fn copy_one_from_user<T: core::marker::Copy>(
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&self,
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dst: &mut T,
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offset: usize,
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) -> Result<(), SystemError> {
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let data = self.convert_one_with_offset::<T>(&self.buffer, offset)?;
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dst.clone_from(data);
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return Ok(());
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}
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fn convert_with_offset<T>(&self, src: &[u8], offset: usize) -> Result<&[T], SystemError> {
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if offset >= src.len() {
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return Err(SystemError::EINVAL);
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}
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let byte_buffer: &[u8] = &src[offset..];
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if byte_buffer.len() % core::mem::size_of::<T>() != 0 || byte_buffer.is_empty() {
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return Err(SystemError::EINVAL);
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}
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let chunks = unsafe {
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from_raw_parts(
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byte_buffer.as_ptr() as *const T,
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byte_buffer.len() / core::mem::size_of::<T>(),
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)
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};
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return Ok(chunks);
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}
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fn convert_one_with_offset<T>(&self, src: &[u8], offset: usize) -> Result<&T, SystemError> {
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if offset + core::mem::size_of::<T>() > src.len() {
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return Err(SystemError::EINVAL);
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}
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let byte_buffer: &[u8] = &src[offset..offset + core::mem::size_of::<T>()];
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let chunks = unsafe { from_raw_parts(byte_buffer.as_ptr() as *const T, 1) };
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let data = &chunks[0];
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return Ok(data);
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}
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}
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#[allow(dead_code)]
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impl<'a> UserBufferWriter<'a> {
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/// 构造一个指向用户空间位置的BufferWriter
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///
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/// @param addr 用户空间指针
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/// @param len 缓冲区的字节长度
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/// @return 构造成功返回UserbufferWriter实例，否则返回错误码
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///
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pub fn new<U>(addr: *mut U, len: usize, from_user: bool) -> Result<Self, SystemError> {
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if from_user
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&& verify_area(
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VirtAddr::new(addr as usize),
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(len * core::mem::size_of::<U>()) as usize,
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)
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.is_err()
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{
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return Err(SystemError::EFAULT);
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}
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return Ok(Self {
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buffer: unsafe {
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core::slice::from_raw_parts_mut(addr as *mut u8, len * core::mem::size_of::<U>())
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},
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});
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}
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/// 从指定地址写入数据到用户空间
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///
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/// @param data 要写入的数据地址
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/// @param offset 在UserBuffer中的字节偏移量
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/// @return 返回写入元素的数量
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///
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pub fn copy_to_user<T: core::marker::Copy>(
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&'a mut self,
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src: &'a [T],
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offset: usize,
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) -> Result<usize, SystemError> {
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let dst = Self::convert_with_offset(self.buffer, offset)?;
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dst.copy_from_slice(&src);
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return Ok(src.len());
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}
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/// 从指定地址写入一个数据到用户空间
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///
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/// @param data 要写入的数据地址
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/// @param offset 在UserBuffer中的字节偏移量
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/// @return 返回写入元素的数量
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///
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pub fn copy_one_to_user<T: core::marker::Copy>(
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&'a mut self,
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src: &'a T,
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offset: usize,
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) -> Result<(), SystemError> {
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let dst = Self::convert_one_with_offset::<T>(self.buffer, offset)?;
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dst.clone_from(src);
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return Ok(());
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}
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pub fn buffer<T>(&'a mut self, offset: usize) -> Result<&mut [T], SystemError> {
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Ok(Self::convert_with_offset::<T>(self.buffer, offset).map_err(|_| SystemError::EINVAL)?)
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}
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fn convert_with_offset<T>(src: &mut [u8], offset: usize) -> Result<&mut [T], SystemError> {
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if offset >= src.len() {
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return Err(SystemError::EINVAL);
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}
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let byte_buffer: &mut [u8] = &mut src[offset..];
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if byte_buffer.len() % core::mem::size_of::<T>() != 0 || byte_buffer.is_empty() {
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return Err(SystemError::EINVAL);
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}
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let chunks = unsafe {
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from_raw_parts_mut(
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byte_buffer.as_mut_ptr() as *mut T,
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byte_buffer.len() / core::mem::size_of::<T>(),
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)
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};
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return Ok(chunks);
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}
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fn convert_one_with_offset<T>(src: &mut [u8], offset: usize) -> Result<&mut T, SystemError> {
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if offset + core::mem::size_of::<T>() > src.len() {
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return Err(SystemError::EINVAL);
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}
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let byte_buffer: &mut [u8] = &mut src[offset..offset + core::mem::size_of::<T>()];
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let chunks = unsafe { from_raw_parts_mut(byte_buffer.as_mut_ptr() as *mut T, 1) };
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let data = &mut chunks[0];
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return Ok(data);
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}
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}
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