linux-kernel - Re: [PATCH v7 5/6] rust: str: add radix prefixed integer parsing functions

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: <20250224223032.GA615664@robin.jannau.net>
Date: Mon, 24 Feb 2025 23:30:32 +0100
From: Janne Grunau <j@...nau.net>
To: Andreas Hindborg <a.hindborg@...nel.org>
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 <benno.lossin@...ton.me>,
	Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>,
	Masahiro Yamada <masahiroy@...nel.org>,
	Nathan Chancellor <nathan@...nel.org>,
	Nicolas Schier <nicolas@...sle.eu>,
	Luis Chamberlain <mcgrof@...nel.org>,
	rust-for-linux@...r.kernel.org, linux-kernel@...r.kernel.org,
	Adam Bratschi-Kaye <ark.email@...il.com>,
	linux-kbuild@...r.kernel.org, Petr Pavlu <petr.pavlu@...e.com>,
	Sami Tolvanen <samitolvanen@...gle.com>,
	Daniel Gomez <da.gomez@...sung.com>,
	Simona Vetter <simona.vetter@...ll.ch>,
	Greg KH <gregkh@...uxfoundation.org>, linux-modules@...r.kernel.org
Subject: Re: [PATCH v7 5/6] rust: str: add radix prefixed integer parsing
 functions

On Tue, Feb 18, 2025 at 02:00:47PM +0100, Andreas Hindborg wrote:
> Add the trait `ParseInt` for parsing string representations of integers
> where the string representations are optionally prefixed by a radix
> specifier. Implement the trait for the primitive integer types.
> 
> Signed-off-by: Andreas Hindborg <a.hindborg@...nel.org>
> ---
>  rust/kernel/str.rs | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 118 insertions(+)
> 
> diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
> index db272d2198fcc..8b0d814b47f52 100644
> --- a/rust/kernel/str.rs
> +++ b/rust/kernel/str.rs
> @@ -945,3 +945,121 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {

[...]

> +    pub trait ParseInt: FromStrRadix + TryFrom<i128> {
> +        /// Parse a string according to the description in [`Self`].
> +        fn from_str(src: &BStr) -> Result<Self> {
> +            match src.deref() {
> +                [b'-', rest @ ..] => {
> +                    let (radix, digits) = strip_radix(rest.as_ref());
> +                    // 2's complement values range from -2^(b-1) to 2^(b-1)-1.
> +                    // So if we want to parse negative numbers as positive and
> +                    // later multiply by -1, we have to parse into a larger
> +                    // integer. We choose i128 as sufficiently large.
> +                    let val = i128::from_str_radix(

The usage of i128 causes here following link errors on arm64 with
"rustc 1.84.1 (e71f9a9a9 2025-01-27) (Fedora 1.84.1-1.fc41)"

| ld: rust/kernel.o: in function `<i128>::from_str_radix':
| /usr/lib/rustlib/src/rust/library/core/src/num/mod.rs:1563:(.text+0x3bc): undefined reference to `__muloti4'
| ld: /usr/lib/rustlib/src/rust/library/core/src/num/mod.rs:1563:(.text+0x440): undefined reference to `__muloti4'
| ld: rust/kernel.o: in function `<i128>::overflowing_mul':
| /usr/lib/rustlib/src/rust/library/core/src/num/int_macros.rs:2517:(.text+0x4b4): undefined reference to `__muloti4'
| ld: /usr/lib/rustlib/src/rust/library/core/src/num/int_macros.rs:2517:(.text+0x534): undefined reference to `__muloti4'

The errors go away after exchanging i128 with i64 (while breaking the
parsing for large values).

ciao Janne