linux-kernel - Re: [PATCH] poll: rust: allow poll

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAH5fLgh7n75Q4Txi29CxFG4nfkxzceqh=bMBDyYj01G_KC0vwg@mail.gmail.com>
Date: Fri, 20 Jun 2025 15:19:22 +0200
From: Alice Ryhl <aliceryhl@...gle.com>
To: Benno Lossin <lossin@...nel.org>
Cc: Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>, 
	Miguel Ojeda <ojeda@...nel.org>, Christian Brauner <brauner@...nel.org>, Boqun Feng <boqun.feng@...il.com>, 
	Gary Guo <gary@...yguo.net>, Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
	Andreas Hindborg <a.hindborg@...nel.org>, Trevor Gross <tmgross@...ch.edu>, 
	Danilo Krummrich <dakr@...nel.org>, linux-kernel@...r.kernel.org, 
	rust-for-linux@...r.kernel.org
Subject: Re: [PATCH] poll: rust: allow poll_table ptrs to be null

On Fri, Jun 20, 2025 at 2:31 PM Benno Lossin <lossin@...nel.org> wrote:
>
> On Fri Jun 20, 2025 at 1:49 PM CEST, Alice Ryhl wrote:
> >      ///
> >      /// # Safety
> >      ///
> > -    /// The caller must ensure that for the duration of `'a`, the pointer will point at a valid poll
> > -    /// table (as defined in the type invariants).
> > -    ///
> > -    /// The caller must also ensure that the `poll_table` is only accessed via the returned
> > -    /// reference for the duration of `'a`.
> > -    pub unsafe fn from_ptr<'a>(ptr: *mut bindings::poll_table) -> &'a mut PollTable {
>
> Returning `Option<&'a mut PollTable>` is not an option? I'd like to
> avoid wrapping raw pointers...

You're going to make people handle the Option by early-returning if
you do that, but that's wrong. You're supposed to treat null and
non-null the same.

Alice