From: Cyril Hrubis <chrubis@suse.cz>
To: Tudor Cretu <tudor.cretu@arm.com>
Cc: ltp@lists.linux.it
Subject: Re: [LTP] [PATCH 0/3] safe_macros: Fix undefined behaviour in vararg handling
Date: Tue, 29 Nov 2022 12:48:21 +0100 [thread overview]
Message-ID: <Y4XxhXsTrD2AA+WS@yuki> (raw)
In-Reply-To: <20221123144746.590890-1-tudor.cretu@arm.com>
Hi!
> Accessing elements in an empty va_list results in undefined behaviour[0]
> that can include accessing arbitrary stack memory. While typically this
> doesn't raise a fault, some new more security-oriented architectures
> (e.g. CHERI[1] or Morello[2]) don't allow it.
Looking at how glibc handles this, the code looks like:
int mode = 0;
if (__OPEN_NEEDS_MODE(oflag)) {
..
mode = va_arg(arg, int);
..
}
That sounds much easier than messing with the macros and should avoid
undefined behavior.
--
Cyril Hrubis
chrubis@suse.cz
--
Mailing list info: https://lists.linux.it/listinfo/ltp
prev parent reply other threads:[~2022-11-29 11:47 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-23 14:47 [LTP] [PATCH 0/3] safe_macros: Fix undefined behaviour in vararg handling Tudor Cretu
2022-11-23 14:47 ` [LTP] [PATCH 1/3] safe_open: " Tudor Cretu
2022-11-23 14:47 ` [LTP] [PATCH 2/3] safe_openat: " Tudor Cretu
2022-11-23 14:47 ` [LTP] [PATCH 3/3] safe_semctl: " Tudor Cretu
2022-11-29 11:01 ` [LTP] [PATCH 0/3] safe_macros: " Petr Vorel
2022-11-29 11:06 ` Petr Vorel
2022-11-29 11:11 ` Richard Palethorpe
2022-11-29 11:27 ` Richard Palethorpe
2022-11-29 11:32 ` Petr Vorel
2022-11-29 11:46 ` Tudor Cretu
2022-11-29 12:01 ` Richard Palethorpe
2022-11-29 11:45 ` Tudor Cretu
2022-11-29 11:48 ` Cyril Hrubis [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Y4XxhXsTrD2AA+WS@yuki \
--to=chrubis@suse.cz \
--cc=ltp@lists.linux.it \
--cc=tudor.cretu@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox