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 for Android: free password hash cracker in your pocket

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

Message-ID: <87tt8iy3fe.fsf@kernel.org>
Date: Tue, 25 Feb 2025 06:54:45 +0100
From: Andreas Hindborg <a.hindborg@...nel.org>
To: "Janne Grunau" <j@...nau.net>
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

"Janne Grunau" <j@...nau.net> writes:

> 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).

Thanks for reporting! I will have to find a better way to fix this issue
then.


Best regards,
Andreas Hindborg