//! namespace. So with the checking here, they may fail, but they won't be able
//! to succeed with bogus results.
-use crate::fd::{AsFd, BorrowedFd};
+use crate::fd::{AsFd, BorrowedFd, OwnedFd};
use crate::ffi::CStr;
use crate::fs::{
cwd, fstat, fstatfs, major, openat, renameat, Dir, FileType, Mode, OFlags, Stat,
PROC_SUPER_MAGIC,
};
-use crate::io::{self, OwnedFd};
+use crate::io;
use crate::path::DecInt;
-use crate::process::{getgid, getpid, getuid, Gid, RawGid, RawUid, Uid};
+use crate::process::getpid;
#[cfg(feature = "rustc-dep-of-std")]
use core::lazy::OnceCell;
#[cfg(not(feature = "rustc-dep-of-std"))]
kind: Kind,
entry: BorrowedFd<'_>,
proc_stat: Option<&Stat>,
- uid: RawUid,
- gid: RawGid,
) -> io::Result<Stat> {
let entry_stat = fstat(entry)?;
- check_proc_entry_with_stat(kind, entry, entry_stat, proc_stat, uid, gid)
+ check_proc_entry_with_stat(kind, entry, entry_stat, proc_stat)
}
/// Check a subdirectory of "/proc" for anomalies, using the provided `Stat`.
entry: BorrowedFd<'_>,
entry_stat: Stat,
proc_stat: Option<&Stat>,
- uid: RawUid,
- gid: RawGid,
) -> io::Result<Stat> {
// Check the filesystem magic.
check_procfs(entry)?;
Kind::File => check_proc_file(&entry_stat, proc_stat)?,
}
- // Check the ownership of the directory. We can't do that for the toplevel
- // "/proc" though, because in e.g. a user namespace scenario, root outside
- // the container may be mapped to another uid like `nobody`.
- if !matches!(kind, Kind::Proc) && (entry_stat.st_uid, entry_stat.st_gid) != (uid, gid) {
- return Err(io::Errno::NOTSUP);
- }
-
// "/proc" directories are typically mounted r-xr-xr-x.
// "/proc/self/fd" is r-x------. Allow them to have fewer permissions, but
// not more.
/// Open a directory in `/proc`, mapping all errors to `io::Errno::NOTSUP`.
fn proc_opendirat<P: crate::path::Arg, Fd: AsFd>(dirfd: Fd, path: P) -> io::Result<OwnedFd> {
// We could add `PATH`|`NOATIME` here but Linux 2.6.32 doesn't support it.
+ // Also for `NOATIME` see the comment in `open_and_check_file`.
let oflags = OFlags::NOFOLLOW | OFlags::DIRECTORY | OFlags::CLOEXEC | OFlags::NOCTTY;
openat(dirfd, path, oflags, Mode::empty()).map_err(|_err| io::Errno::NOTSUP)
}
PROC.get_or_try_init(|| {
// Open "/proc".
let proc = proc_opendirat(cwd(), cstr!("/proc"))?;
- let proc_stat = check_proc_entry(
- Kind::Proc,
- proc.as_fd(),
- None,
- Uid::ROOT.as_raw(),
- Gid::ROOT.as_raw(),
- )
- .map_err(|_err| io::Errno::NOTSUP)?;
+ let proc_stat =
+ check_proc_entry(Kind::Proc, proc.as_fd(), None).map_err(|_err| io::Errno::NOTSUP)?;
Ok(new_static_fd(proc, proc_stat))
})
.get_or_try_init(|| {
let (proc, proc_stat) = proc()?;
- let (uid, gid, pid) = (getuid(), getgid(), getpid());
+ let pid = getpid();
// Open "/proc/self". Use our pid to compute the name rather than literally
// using "self", as "self" is a symlink.
let proc_self = proc_opendirat(proc, DecInt::new(pid.as_raw_nonzero().get()))?;
- let proc_self_stat = check_proc_entry(
- Kind::Pid,
- proc_self.as_fd(),
- Some(proc_stat),
- uid.as_raw(),
- gid.as_raw(),
- )
- .map_err(|_err| io::Errno::NOTSUP)?;
+ let proc_self_stat = check_proc_entry(Kind::Pid, proc_self.as_fd(), Some(proc_stat))
+ .map_err(|_err| io::Errno::NOTSUP)?;
Ok(new_static_fd(proc_self, proc_self_stat))
})
.get_or_try_init(|| {
let (_, proc_stat) = proc()?;
- let (proc_self, proc_self_stat) = proc_self()?;
+ let (proc_self, _proc_self_stat) = proc_self()?;
// Open "/proc/self/fd".
let proc_self_fd = proc_opendirat(proc_self, cstr!("fd"))?;
- let proc_self_fd_stat = check_proc_entry(
- Kind::Fd,
- proc_self_fd.as_fd(),
- Some(proc_stat),
- proc_self_stat.st_uid,
- proc_self_stat.st_gid,
- )
- .map_err(|_err| io::Errno::NOTSUP)?;
+ let proc_self_fd_stat =
+ check_proc_entry(Kind::Fd, proc_self_fd.as_fd(), Some(proc_stat))
+ .map_err(|_err| io::Errno::NOTSUP)?;
Ok(new_static_fd(proc_self_fd, proc_self_fd_stat))
})
///
/// [Linux]: https://man7.org/linux/man-pages/man5/proc.5.html
fn proc_self_fdinfo() -> io::Result<(BorrowedFd<'static>, &'static Stat)> {
- static PROC_SELF_FDINFO: OnceCell<(OwnedFd, Stat)> = OnceCell::new();
+ static PROC_SELF_FDINFO: StaticFd = StaticFd::new();
PROC_SELF_FDINFO
.get_or_try_init(|| {
let (_, proc_stat) = proc()?;
- let (proc_self, proc_self_stat) = proc_self()?;
+ let (proc_self, _proc_self_stat) = proc_self()?;
// Open "/proc/self/fdinfo".
let proc_self_fdinfo = proc_opendirat(proc_self, cstr!("fdinfo"))?;
- let proc_self_fdinfo_stat = check_proc_entry(
- Kind::Fd,
- proc_self_fdinfo.as_fd(),
- Some(proc_stat),
- proc_self_stat.st_uid,
- proc_self_stat.st_gid,
- )
- .map_err(|_err| io::Errno::NOTSUP)?;
+ let proc_self_fdinfo_stat =
+ check_proc_entry(Kind::Fd, proc_self_fdinfo.as_fd(), Some(proc_stat))
+ .map_err(|_err| io::Errno::NOTSUP)?;
Ok((proc_self_fdinfo, proc_self_fdinfo_stat))
})
proc_self_file(cstr!("maps"))
}
+/// Returns a handle to a Linux `/proc/self/status` file.
+///
+/// This ensures that `/proc/self/status` is `procfs`, that nothing is
+/// mounted on top of it, and that it looks normal.
+///
+/// # References
+/// - [Linux]
+///
+/// [Linux]: https://man7.org/linux/man-pages/man5/proc.5.html
+#[inline]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "procfs")))]
+pub fn proc_self_status() -> io::Result<OwnedFd> {
+ proc_self_file(cstr!("status"))
+}
+
/// Open a file under `/proc/self`.
fn proc_self_file(name: &CStr) -> io::Result<OwnedFd> {
let (proc_self, proc_self_stat) = proc_self()?;
fn open_and_check_file(dir: BorrowedFd, dir_stat: &Stat, name: &CStr) -> io::Result<OwnedFd> {
let (_, proc_stat) = proc()?;
- let oflags =
- OFlags::RDONLY | OFlags::CLOEXEC | OFlags::NOFOLLOW | OFlags::NOCTTY | OFlags::NOATIME;
- let file = openat(&dir, name, oflags, Mode::empty()).map_err(|_err| io::Errno::NOTSUP)?;
+ // Don't use `NOATIME`, because it [requires us to own the file], and when
+ // a process sets itself non-dumpable Linux changes the user:group of its
+ // `/proc/<pid>` files [to root:root].
+ //
+ // [requires us to own the file]: https://man7.org/linux/man-pages/man2/openat.2.html
+ // [to root:root]: https://man7.org/linux/man-pages/man5/proc.5.html
+ let oflags = OFlags::RDONLY | OFlags::CLOEXEC | OFlags::NOFOLLOW | OFlags::NOCTTY;
+ let file = openat(dir, name, oflags, Mode::empty()).map_err(|_err| io::Errno::NOTSUP)?;
let file_stat = fstat(&file)?;
// `is_mountpoint` only works on directory mount points, not file mount
&& entry.file_name() == name
{
// We found the file. Proceed to check the file handle.
- let _ = check_proc_entry_with_stat(
- Kind::File,
- file.as_fd(),
- file_stat,
- Some(proc_stat),
- dir_stat.st_uid,
- dir_stat.st_gid,
- )?;
+ let _ =
+ check_proc_entry_with_stat(Kind::File, file.as_fd(), file_stat, Some(proc_stat))?;
found_file = true;
} else if entry.ino() == dir_stat.st_ino
projects / rustc.git / blobdiff