mailing list of musl libc
 help / color / mirror / code / Atom feed
From: Pablo Correa Gomez <ablocorrea@hotmail.com>
To: musl@lists.openwall.com
Subject: [musl] newlocale: Segmentation fault when locale input is NULL
Date: Wed, 06 Oct 2021 11:31:29 +0200	[thread overview]
Message-ID: <AM5P192MB00812237500EA1FEBEB2C7ABC7B09@AM5P192MB0081.EURP192.PROD.OUTLOOK.COM> (raw)

Dear musl maintainers,

While doing some work in GNOME control center for postmarketos, we
bumped into a segmentation fault which is also present in GNOME in
Alpine[1].

After doing some degugging, I figured out that the reason is that,
through GNOME desktop[2], there is a call to newlocale, where they end
up calling it with a NULL argument.

newlocale(LC_CTYPE, NULL, (locale_t)0);

In this case, "name" is passed to __get_locale in
src/locale/newlocale.c:27 and then dereferenced in
src/locale/locale_map.c:43, causing a segmentation fault.

In the case of glibc, this is not an issue, as per the documentation[3]
they consider it an error:

       EINVAL locale is NULL.

Unfortunately, this is a difference in the implementation between glibc
and musl, maybe due to the fact that the standard[4] in not clear in
this point:


The newlocale() function may fail if:

[EINVAL]
    The locale argument is not a valid string pointer. 


My personal believe is that adding a NULL pointer check in musl is very
simple and might help not only GNOME desktop, but maybe also other
projects in the future. This is the reason why I brought the issue here
first instead of directly patching GNOME desktop. If you believe that
musl behaviour should remain the way it is, please let me know and I
will send MRs for upstream and Alpine's GNOME desktop. I am not
subscribed to the mailing list, so I would appreciate if I am CC'ed in
any response.

Best regards,
Pablo Correa Gómez.


[1] 
https://gitlab.com/postmarketOS/pmaports/-/merge_requests/2552#note_686956660
[2] https://gitlab.gnome.org/GNOME/gnome-desktop
[3] https://man7.org/linux/man-pages/man3/newlocale.3.html
[4] 
https://pubs.opengroup.org/onlinepubs/9699919799/functions/newlocale.html


             reply	other threads:[~2021-10-06 10:23 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-06  9:31 Pablo Correa Gomez [this message]
2021-10-06 12:29 ` Rich Felker
2021-10-06 12:57   ` Pablo Correa Gomez
2021-10-06 12:31 ` Quentin Rameau

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=AM5P192MB00812237500EA1FEBEB2C7ABC7B09@AM5P192MB0081.EURP192.PROD.OUTLOOK.COM \
    --to=ablocorrea@hotmail.com \
    --cc=musl@lists.openwall.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.
Code repositories for project(s) associated with this public inbox

	https://git.vuxu.org/mirror/musl/

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).