openharmony/third_party_rust_nix
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Better type safety for mqueue

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On some platforms, mqd_t is a pointer.  That means code like the below
can trigger a segfault.  Fix it by defining a Newtype around mqd_t that
prevents use-after-free and dangling pointer scenarios.

```rust
fn invalid_mqd_t() {
    let mqd: libc::mqd_t = std::ptr::null_mut();
    mq_close(mqd).unwrap();
}
```

Also, get test coverage for mqueue in CI on FreeBSD.
This commit is contained in:
Alan Somers 2022-01-22 14:37:48 -07:00
parent c84316b7fc
commit 475da53d56
4 changed files with 70 additions and 28 deletions
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1
.cirrus.yml
View File

@ -40,6 +40,7 @@ task:
freebsd_instance:
image: freebsd-12-2-release-amd64
setup_script:
- kldload mqueuefs
- fetch https://sh.rustup.rs -o rustup.sh
- sh rustup.sh -y --profile=minimal --default-toolchain $TOOLCHAIN
- . $HOME/.cargo/env

5
CHANGELOG.md
View File

@ -39,6 +39,11 @@ This project adheres to [Semantic Versioning](https://semver.org/).
(#[1636](https://github.com/nix-rust/nix/pull/1636))
### Changed
- `mqueue` functions now operate on a distinct type, `nix::mqueue::MqdT`.
Accessors take this type by reference, not by value.
(#[1639](https://github.com/nix-rust/nix/pull/1639))
### Fixed
### Removed

70
src/mqueue.rs
View File

@ -1,12 +1,40 @@
//! Posix Message Queue functions
//!
//! # Example
//!
// no_run because a kernel module may be required.
//! ```no_run
//! # use std::ffi::CString;
//! # use nix::mqueue::*;
//! use nix::sys::stat::Mode;
//!
//! const MSG_SIZE: mq_attr_member_t = 32;
//! let mq_name= CString::new("/a_nix_test_queue").unwrap();
//!
//! let oflag0 = MQ_OFlag::O_CREAT | MQ_OFlag::O_WRONLY;
//! let mode = Mode::S_IWUSR | Mode::S_IRUSR | Mode::S_IRGRP | Mode::S_IROTH;
//! let mqd0 = mq_open(&mq_name, oflag0, mode, None).unwrap();
//! let msg_to_send = b"msg_1";
//! mq_send(&mqd0, msg_to_send, 1).unwrap();
//!
//! let oflag1 = MQ_OFlag::O_CREAT | MQ_OFlag::O_RDONLY;
//! let mqd1 = mq_open(&mq_name, oflag1, mode, None).unwrap();
//! let mut buf = [0u8; 32];
//! let mut prio = 0u32;
//! let len = mq_receive(&mqd1, &mut buf, &mut prio).unwrap();
//! assert_eq!(prio, 1);
//! assert_eq!(msg_to_send, &buf[0..len]);
//!
//! mq_close(mqd1).unwrap();
//! mq_close(mqd0).unwrap();
//! ```
//! [Further reading and details on the C API](https://man7.org/linux/man-pages/man7/mq_overview.7.html)
use crate::Result;
use crate::errno::Errno;
use libc::{self, c_char, mqd_t, size_t};
use std::ffi::CString;
use std::ffi::CStr;
use crate::sys::stat::Mode;
use std::mem;
@ -34,6 +62,14 @@ pub struct MqAttr {
mq_attr: libc::mq_attr,
}
/// Identifies an open POSIX Message Queue
// A safer wrapper around libc::mqd_t, which is a pointer on some platforms
// Deliberately is not Clone to prevent use-after-close scenarios
#[repr(transparent)]
#[derive(Debug)]
#[allow(missing_copy_implementations)]
pub struct MqdT(mqd_t);
// x32 compatibility
// See https://sourceware.org/bugzilla/show_bug.cgi?id=21279
#[cfg(all(target_arch = "x86_64", target_pointer_width = "32"))]
@ -87,11 +123,11 @@ impl MqAttr {
/// See also [`mq_open(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_open.html)
// The mode.bits cast is only lossless on some OSes
#[allow(clippy::cast_lossless)]
pub fn mq_open(name: &CString,
pub fn mq_open(name: &CStr,
oflag: MQ_OFlag,
mode: Mode,
attr: Option<&MqAttr>)
-> Result<mqd_t> {
-> Result<MqdT> {
let res = match attr {
Some(mq_attr) => unsafe {
libc::mq_open(name.as_ptr(),
@ -101,13 +137,13 @@ pub fn mq_open(name: &CString,
},
None => unsafe { libc::mq_open(name.as_ptr(), oflag.bits()) },
};
Errno::result(res)
Errno::result(res).map(MqdT)
}
/// Remove a message queue
///
/// See also [`mq_unlink(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_unlink.html)
pub fn mq_unlink(name: &CString) -> Result<()> {
pub fn mq_unlink(name: &CStr) -> Result<()> {
let res = unsafe { libc::mq_unlink(name.as_ptr()) };
Errno::result(res).map(drop)
}
@ -115,18 +151,18 @@ pub fn mq_unlink(name: &CString) -> Result<()> {
/// Close a message queue
///
/// See also [`mq_close(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_close.html)
pub fn mq_close(mqdes: mqd_t) -> Result<()> {
let res = unsafe { libc::mq_close(mqdes) };
pub fn mq_close(mqdes: MqdT) -> Result<()> {
let res = unsafe { libc::mq_close(mqdes.0) };
Errno::result(res).map(drop)
}
/// Receive a message from a message queue
///
/// See also [`mq_receive(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_receive.html)
pub fn mq_receive(mqdes: mqd_t, message: &mut [u8], msg_prio: &mut u32) -> Result<usize> {
pub fn mq_receive(mqdes: &MqdT, message: &mut [u8], msg_prio: &mut u32) -> Result<usize> {
let len = message.len() as size_t;
let res = unsafe {
libc::mq_receive(mqdes,
libc::mq_receive(mqdes.0,
message.as_mut_ptr() as *mut c_char,
len,
msg_prio as *mut u32)
@ -137,9 +173,9 @@ pub fn mq_receive(mqdes: mqd_t, message: &mut [u8], msg_prio: &mut u32) -> Resul
/// Send a message to a message queue
///
/// See also [`mq_send(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_send.html)
pub fn mq_send(mqdes: mqd_t, message: &[u8], msq_prio: u32) -> Result<()> {
pub fn mq_send(mqdes: &MqdT, message: &[u8], msq_prio: u32) -> Result<()> {
let res = unsafe {
libc::mq_send(mqdes,
libc::mq_send(mqdes.0,
message.as_ptr() as *const c_char,
message.len(),
msq_prio)
@ -150,9 +186,9 @@ pub fn mq_send(mqdes: mqd_t, message: &[u8], msq_prio: u32) -> Result<()> {
/// Get message queue attributes
///
/// See also [`mq_getattr(2)`](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_getattr.html)
pub fn mq_getattr(mqd: mqd_t) -> Result<MqAttr> {
pub fn mq_getattr(mqd: &MqdT) -> Result<MqAttr> {
let mut attr = mem::MaybeUninit::<libc::mq_attr>::uninit();
let res = unsafe { libc::mq_getattr(mqd, attr.as_mut_ptr()) };
let res = unsafe { libc::mq_getattr(mqd.0, attr.as_mut_ptr()) };
Errno::result(res).map(|_| unsafe{MqAttr { mq_attr: attr.assume_init() }})
}
@ -161,10 +197,10 @@ pub fn mq_getattr(mqd: mqd_t) -> Result<MqAttr> {
/// It is recommend to use the `mq_set_nonblock()` and `mq_remove_nonblock()` convenience functions as they are easier to use
///
/// [Further reading](https://pubs.opengroup.org/onlinepubs/9699919799/functions/mq_setattr.html)
pub fn mq_setattr(mqd: mqd_t, newattr: &MqAttr) -> Result<MqAttr> {
pub fn mq_setattr(mqd: &MqdT, newattr: &MqAttr) -> Result<MqAttr> {
let mut attr = mem::MaybeUninit::<libc::mq_attr>::uninit();
let res = unsafe {
libc::mq_setattr(mqd, &newattr.mq_attr as *const libc::mq_attr, attr.as_mut_ptr())
libc::mq_setattr(mqd.0, &newattr.mq_attr as *const libc::mq_attr, attr.as_mut_ptr())
};
Errno::result(res).map(|_| unsafe{ MqAttr { mq_attr: attr.assume_init() }})
}
@ -173,7 +209,7 @@ pub fn mq_setattr(mqd: mqd_t, newattr: &MqAttr) -> Result<MqAttr> {
/// Sets the `O_NONBLOCK` attribute for a given message queue descriptor
/// Returns the old attributes
#[allow(clippy::useless_conversion)] // Not useless on all OSes
pub fn mq_set_nonblock(mqd: mqd_t) -> Result<MqAttr> {
pub fn mq_set_nonblock(mqd: &MqdT) -> Result<MqAttr> {
let oldattr = mq_getattr(mqd)?;
let newattr = MqAttr::new(mq_attr_member_t::from(MQ_OFlag::O_NONBLOCK.bits()),
oldattr.mq_attr.mq_maxmsg,
@ -185,7 +221,7 @@ pub fn mq_set_nonblock(mqd: mqd_t) -> Result<MqAttr> {
/// Convenience function.
/// Removes `O_NONBLOCK` attribute for a given message queue descriptor
/// Returns the old attributes
pub fn mq_remove_nonblock(mqd: mqd_t) -> Result<MqAttr> {
pub fn mq_remove_nonblock(mqd: &MqdT) -> Result<MqAttr> {
let oldattr = mq_getattr(mqd)?;
let newattr = MqAttr::new(0,
oldattr.mq_attr.mq_maxmsg,

22
test/test_mq.rs
View File

@ -41,13 +41,13 @@ fn test_mq_send_and_receive() {
};
let mqd0 = r0.unwrap();
let msg_to_send = "msg_1";
mq_send(mqd0, msg_to_send.as_bytes(), 1).unwrap();
mq_send(&mqd0, msg_to_send.as_bytes(), 1).unwrap();
let oflag1 = MQ_OFlag::O_CREAT | MQ_OFlag::O_RDONLY;
let mqd1 = mq_open(mq_name, oflag1, mode, Some(&attr)).unwrap();
let mut buf = [0u8; 32];
let mut prio = 0u32;
let len = mq_receive(mqd1, &mut buf, &mut prio).unwrap();
let len = mq_receive(&mqd1, &mut buf, &mut prio).unwrap();
assert_eq!(prio, 1);
mq_close(mqd1).unwrap();
@ -71,7 +71,7 @@ fn test_mq_getattr() {
};
let mqd = r.unwrap();
let read_attr = mq_getattr(mqd).unwrap();
let read_attr = mq_getattr(&mqd).unwrap();
assert_attr_eq!(read_attr, initial_attr);
mq_close(mqd).unwrap();
}
@ -98,20 +98,20 @@ fn test_mq_setattr() {
let mqd = r.unwrap();
let new_attr = MqAttr::new(0, 20, MSG_SIZE * 2, 100);
let old_attr = mq_setattr(mqd, &new_attr).unwrap();
let old_attr = mq_setattr(&mqd, &new_attr).unwrap();
assert_attr_eq!(old_attr, initial_attr);
// No changes here because according to the Linux man page only
// O_NONBLOCK can be set (see tests below)
#[cfg(not(any(target_os = "dragonfly", target_os = "netbsd")))]
{
let new_attr_get = mq_getattr(mqd).unwrap();
let new_attr_get = mq_getattr(&mqd).unwrap();
assert_ne!(new_attr_get, new_attr);
}
let new_attr_non_blocking = MqAttr::new(MQ_OFlag::O_NONBLOCK.bits() as mq_attr_member_t, 10, MSG_SIZE, 0);
mq_setattr(mqd, &new_attr_non_blocking).unwrap();
let new_attr_get = mq_getattr(mqd).unwrap();
mq_setattr(&mqd, &new_attr_non_blocking).unwrap();
let new_attr_get = mq_getattr(&mqd).unwrap();
// now the O_NONBLOCK flag has been set
#[cfg(not(any(target_os = "dragonfly", target_os = "netbsd")))]
@ -142,12 +142,12 @@ fn test_mq_set_nonblocking() {
return;
};
let mqd = r.unwrap();
mq_set_nonblock(mqd).unwrap();
let new_attr = mq_getattr(mqd);
mq_set_nonblock(&mqd).unwrap();
let new_attr = mq_getattr(&mqd);
let o_nonblock_bits = MQ_OFlag::O_NONBLOCK.bits() as mq_attr_member_t;
assert_eq!(new_attr.unwrap().flags() & o_nonblock_bits, o_nonblock_bits);
mq_remove_nonblock(mqd).unwrap();
let new_attr = mq_getattr(mqd);
mq_remove_nonblock(&mqd).unwrap();
let new_attr = mq_getattr(&mqd);
assert_eq!(new_attr.unwrap().flags() & o_nonblock_bits, 0);
mq_close(mqd).unwrap();
}