linux-kernel - Re: [PATCH] cfi: rust: pass -Zpatchable-function-entry on all architectures

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: <CABCJKuf83gywnbtkJ3d2VfDRH9f6kcf1Bn1Zau5re=4YoV6E8g@mail.gmail.com>
Date: Wed, 9 Oct 2024 09:48:03 -0700
From: Sami Tolvanen <samitolvanen@...gle.com>
To: Alice Ryhl <aliceryhl@...gle.com>
Cc: Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
	Huacai Chen <chenhuacai@...nel.org>, WANG Xuerui <kernel@...0n.name>, 
	Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>, 
	Albert Ou <aou@...s.berkeley.edu>, 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 <benno.lossin@...ton.me>, Andreas Hindborg <a.hindborg@...nel.org>, 
	Trevor Gross <tmgross@...ch.edu>, Kees Cook <kees@...nel.org>, Matthew Maurer <mmaurer@...gle.com>, 
	"Peter Zijlstra (Intel)" <peterz@...radead.org>, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, loongarch@...ts.linux.dev, 
	linux-riscv@...ts.infradead.org, rust-for-linux@...r.kernel.org
Subject: Re: [PATCH] cfi: rust: pass -Zpatchable-function-entry on all architectures

On Tue, Oct 8, 2024 at 10:37 AM Alice Ryhl <aliceryhl@...gle.com> wrote:
>
> The KCFI sanitizer stores the CFI tag of a function just before its
> machine code. However, the patchable-function-entry flag can be used to
> introduce additional nop instructions before the machine code, taking up
> the space that normally holds the CFI tag. In this case, a backwards
> offset is applied to the CFI tag to move them out of the way of the nop
> instructions. To ensure that C and Rust agree on the offset used by CFI
> tags, pass the -Zpatchable-function-entry to rustc whenever it is passed
> to the C compiler.
>
> The required rustc version is bumped to 1.81.0 to ensure that the
> -Zpatchable-function-entry flag is available when CFI is used.
>
> Fixes: ca627e636551 ("rust: cfi: add support for CFI_CLANG with Rust")
> Signed-off-by: Alice Ryhl <aliceryhl@...gle.com>

Reviewed-by: Sami Tolvanen <samitolvanen@...gle.com>

Sami