linux-kernel - Re: [PATCH 1/5] rust: transmute: add `from_bytes

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

Message-ID: <CAH5fLgiXYj0f0UEPCTjDgykjX3mFo4hf9SUswRYwHzh6Vznwtg@mail.gmail.com>
Date: Fri, 22 Aug 2025 14:52:32 +0200
From: Alice Ryhl <aliceryhl@...gle.com>
To: Alexandre Courbot <acourbot@...dia.com>
Cc: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>, 
	Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>, 
	Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
	Benno Lossin <lossin@...nel.org>, Andreas Hindborg <a.hindborg@...nel.org>, 
	Trevor Gross <tmgross@...ch.edu>, Danilo Krummrich <dakr@...nel.org>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, rust-for-linux@...r.kernel.org, 
	linux-kernel@...r.kernel.org, nouveau@...ts.freedesktop.org, 
	dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH 1/5] rust: transmute: add `from_bytes_copy` method to
 `FromBytes` trait

On Fri, Aug 22, 2025 at 2:47 PM Alexandre Courbot <acourbot@...dia.com> wrote:
>
> `FromBytes::from_bytes` comes with a few practical limitations:
>
> - It requires the bytes slice to have the same alignment as the returned
>   type, which might not be guaranteed in the case of a byte stream,
> - It returns a reference, requiring the returned type to implement
>   `Clone` if one wants to keep the value for longer than the lifetime of
>   the slice.
>
> To overcome these when needed, add a `from_bytes_copy` with a default
> implementation in the trait. `from_bytes_copy` returns an owned value
> that is populated using an unaligned read, removing the lifetime
> constraint and making it usable even on non-aligned byte slices.
>
> Signed-off-by: Alexandre Courbot <acourbot@...dia.com>

Reviewed-by: Alice Ryhl <aliceryhl@...gle.com>