linux-kernel - Re: [PATCH v1] rust: cfi: only 64-bit arm and x86 support CFI

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: <20251003-viewing-residency-d4f849c6fbe6@spud>
Date: Fri, 3 Oct 2025 23:07:02 +0100
From: Conor Dooley <conor@...nel.org>
To: Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
Cc: linux-kernel@...r.kernel.org, Conor Dooley <conor.dooley@...rochip.com>,
	stable@...r.kernel.org, Paul Walmsley <paul.walmsley@...ive.com>,
	Palmer Dabbelt <palmer@...belt.com>,
	Alexandre Ghiti <alex@...ti.fr>, 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>,
	Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>,
	Danilo Krummrich <dakr@...nel.org>, Kees Cook <kees@...nel.org>,
	Sami Tolvanen <samitolvanen@...gle.com>,
	Matthew Maurer <mmaurer@...gle.com>,
	"Peter Zijlstra (Intel)" <peterz@...radead.org>,
	linux-riscv@...ts.infradead.org, rust-for-linux@...r.kernel.org
Subject: Re: [PATCH v1] rust: cfi: only 64-bit arm and x86 support CFI_CLANG

On Mon, Sep 08, 2025 at 04:36:09PM +0200, Miguel Ojeda wrote:
> On Mon, Sep 8, 2025 at 3:13 PM Conor Dooley <conor@...nel.org> wrote:
> >
> > From: Conor Dooley <conor.dooley@...rochip.com>
> >
> > The kernel uses the standard rustc targets for non-x86 targets, and out
> > of those only 64-bit arm's target has kcfi support enabled. For x86, the
> > custom 64-bit target enables kcfi.
> >
> > The HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC config option that allows
> > CFI_CLANG to be used in combination with RUST does not check whether the
> > rustc target supports kcfi. This breaks the build on riscv (and
> > presumably 32-bit arm) when CFI_CLANG and RUST are enabled at the same
> > time.
> >
> > Ordinarily, a rustc-option check would be used to detect target support
> > but unfortunately rustc-option filters out the target for reasons given
> > in commit 46e24a545cdb4 ("rust: kasan/kbuild: fix missing flags on first
> > build"). As a result, if the host supports kcfi but the target does not,
> > e.g. when building for riscv on x86_64, the build would remain broken.
> >
> > Instead, make HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC depend on the only
> > two architectures where the target used supports it to fix the build.
> >
> > CC: stable@...r.kernel.org
> > Fixes: ca627e636551e ("rust: cfi: add support for CFI_CLANG with Rust")
> > Signed-off-by: Conor Dooley <conor.dooley@...rochip.com>
> 
> If you are taking this through RISC-V:
> 
> Acked-by: Miguel Ojeda <ojeda@...nel.org>

Hopefully someone can take it! I was hoping it'd be 6.18 material, can
someone grab it for fixes please?

Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)