From: "Theodore Ts'o" <tytso@mit.edu>
To: David Laight <david.laight.linux@gmail.com>
Cc: Kees Cook <kees@kernel.org>,
Ethan Carter Edwards <ethan@ethancedwards.com>,
Andreas Dilger <adilger.kernel@dilger.ca>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2] ext4: replace strcpy() with '.' assignment
Date: Fri, 23 May 2025 10:24:49 -0400 [thread overview]
Message-ID: <20250523142449.GB1414791@mit.edu> (raw)
In-Reply-To: <20250523133100.1b023a6e@pumpkin>
On Fri, May 23, 2025 at 01:31:00PM +0100, David Laight wrote:
>
> The compiler (or headers files) can also allow strcpy() of constant
> length strings into arrays (known size). Erroring requests that are too long.
> The strcpy() is then converted to a memcpy() which can then be optimised
> into writes of constants.
>
> So using strcpy() under those conditions 'isn't all bad' and can generate
> better (and less bug prone) code than trying to hand-optimise it.
>
> So even through strcpy() is usually a bad idea, there is not need to
> remove the calls that the compiler can validate as safe.
I assume that what the hardening folks want to do is to assert that
strcpy is always evil(tm) so they can detect potential security bugs
by doing "git grep strcpy".
- Ted
next prev parent reply other threads:[~2025-05-23 14:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-19 3:54 [PATCH v2] ext4: replace strcpy() with '.' assignment Ethan Carter Edwards
2025-05-19 5:58 ` kernel test robot
2025-05-19 13:56 ` Theodore Ts'o
2025-05-19 5:58 ` kernel test robot
2025-05-19 13:52 ` Kees Cook
2025-05-19 14:59 ` Theodore Ts'o
2025-05-23 12:31 ` David Laight
2025-05-23 14:24 ` Theodore Ts'o [this message]
2025-05-23 17:14 ` Kees Cook
2025-05-23 22:07 ` Theodore Ts'o
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