From: Florian Weimer <fw@deneb.enyo.de>
To: Siddhesh Poyarekar via Libc-alpha <libc-alpha@sourceware.org>
Cc: Siddhesh Poyarekar <siddhesh@sourceware.org>
Subject: Re: [PATCH] manual: Document __wur usage under _FORTIFY_SOURCE
Date: Fri, 24 Mar 2023 16:15:45 +0100 [thread overview]
Message-ID: <877cv62na6.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <20230324144005.26782-1-siddhesh@sourceware.org> (Siddhesh Poyarekar via Libc-alpha's message of "Fri, 24 Mar 2023 10:40:05 -0400")
* Siddhesh Poyarekar via Libc-alpha:
> The __warn_unused_result__ attribute is only enabled when fortification
> is enabled. Mention that in the document. The rationale for this is
> essentially to mitigate against CWE-252:
>
> [1] https://cwe.mitre.org/data/definitions/252.html
>
> Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
> ---
> manual/maint.texi | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/manual/maint.texi b/manual/maint.texi
> index 76d4a1a147..ae651c2a4a 100644
> --- a/manual/maint.texi
> +++ b/manual/maint.texi
> @@ -206,7 +206,10 @@ to the function call are safe, the call may be replaced by a call to its
> hardened variant that does additional safety checks at runtime. Some
> hardened variants need the size of the buffer to perform access
> validation and this is provided by the @code{__builtin_object_size} or
> -the @code{__builtin_dynamic_object_size} builtin functions.
> +the @code{__builtin_dynamic_object_size} builtin functions. The macro
> +also enables additional compile time diagnostics, such as unchecked
> +return values from some functions, to encourage developers to add error
> +checking for those functions.
Maybe repeat _FORTIFY_SOURCE it's been a while since it's been
mentioned?
Note that now that GCC supports [[nodiscard]] (with the standard way
to suppress it), we could apply that to functions even outside
_FORTIFY_SOURCE, I think. That's a separate matter, of course.
next prev parent reply other threads:[~2023-03-24 15:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-24 14:40 Siddhesh Poyarekar
2023-03-24 15:15 ` Florian Weimer [this message]
2023-03-24 15:23 ` Siddhesh Poyarekar
2023-03-24 15:25 ` [PATCH v2] " Siddhesh Poyarekar
2023-04-03 13:54 ` Florian Weimer
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