qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
From: "Christian Ehrhardt " <1749393@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1749393] Re: sbrk() not working under qemu-user with a PIE-compiled binary?
Date: Fri, 01 May 2020 06:47:12 -0000	[thread overview]
Message-ID: <158831563276.13979.12202053518555221631.malone@gac.canonical.com> (raw)
In-Reply-To: 151859702399.9461.6832978283203997178.malonedeb@chaenomeles.canonical.com

Will be merged in 20.10 with qemu >=5.0 where this came upstream.

** Tags added: qemu-20.10

** Changed in: qemu (Ubuntu)
       Status: Confirmed => Triaged

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1749393

Title:
  sbrk() not working under qemu-user with a PIE-compiled binary?

Status in QEMU:
  Fix Released
Status in qemu package in Ubuntu:
  Triaged

Bug description:
  In Debian unstable, we recently switched bash to be a PIE-compiled
  binary (for hardening). Unfortunately this resulted in bash being
  broken when run under qemu-user (for all target architectures, host
  being amd64 for me).

  $ sudo chroot /srv/chroots/sid-i386/ qemu-i386-static /bin/bash
  bash: xmalloc: .././shell.c:1709: cannot allocate 10 bytes (0 bytes allocated)

  bash has its own malloc implementation based on sbrk():
  https://git.savannah.gnu.org/cgit/bash.git/tree/lib/malloc/malloc.c

  When we disable this internal implementation and rely on glibc's
  malloc, then everything is fine. But it might be that glibc has a
  fallback when sbrk() is not working properly and it might hide the
  underlying problem in qemu-user.

  This issue has also been reported to the bash upstream author and he suggested that the issue might be in qemu-user so I'm opening a ticket here. Here's the discussion with the bash upstream author:
  https://lists.gnu.org/archive/html/bug-bash/2018-02/threads.html#00080

  You can find the problematic bash binary in that .deb file:
  http://snapshot.debian.org/archive/debian/20180206T154716Z/pool/main/b/bash/bash_4.4.18-1_i386.deb

  The version of qemu I have been using is 2.11 (Debian package qemu-
  user-static version 1:2.11+dfsg-1) but I have had reports that the
  problem is reproducible with older versions (back to 2.8 at least).

  Here are the related Debian bug reports:
  https://bugs.debian.org/889869
  https://bugs.debian.org/865599

  It's worth noting that bash used to have this problem (when compiled as a PIE binary) even when run directly but then something got fixed in the kernel and now the problem only appears when run under qemu-user:
  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1518483

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1749393/+subscriptions


  parent reply	other threads:[~2020-05-01  6:57 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-14  8:30 [Qemu-devel] [Bug 1749393] [NEW] sbrk() not working under qemu-user with a PIE-compiled binary? Raphaël Hertzog
2018-02-14 15:46 ` [Qemu-devel] [Bug 1749393] " Gérard Vidal
2018-03-01 19:15 ` Peter Ogden
2018-03-15 11:39 ` Peter Maydell
2018-03-15 15:27 ` Matthias Klose
2018-03-15 16:17 ` Peter Maydell
2018-03-15 17:56 ` Peter Ogden
2018-03-22 21:45 ` Launchpad Bug Tracker
2018-04-04 16:16 ` Matthias Klose
2020-01-17 23:52 ` Richard Henderson
2020-03-10  9:07 ` Laurent Vivier
2020-04-30 13:34 ` Laurent Vivier
2020-05-01  6:47 ` Christian Ehrhardt  [this message]
2020-06-17  7:52 ` Christian Ehrhardt 
2020-08-01  5:05 ` Launchpad Bug Tracker
2021-04-19 23:03 ` Robie Basak
2021-04-26  9:12 ` Launchpad Bug Tracker
2021-04-26  9:17 ` Christian Ehrhardt 
2021-04-26  9:30 ` Christian Ehrhardt 
2021-05-21  0:53 ` Yasuhiro Horimoto
2021-09-17  4:33 ` Sebastian Unger
2021-09-20  9:58 ` Christian Ehrhardt 
2021-11-30  8:44 ` Christian Ehrhardt 
2021-11-30  9:20 ` Christian Ehrhardt 
2021-11-30  9:25 ` Christian Ehrhardt 
2021-11-30 10:10 ` Christian Ehrhardt 
2021-11-30 19:28 ` Brian Murray
2021-12-01  7:46 ` Christian Ehrhardt 
2021-12-16  7:53 ` Christian Ehrhardt 
2021-12-26 12:21 ` frank
2022-01-03 11:42 ` Christian Ehrhardt 
2022-01-04 17:38 ` Launchpad Bug Tracker
2022-01-04 17:39 ` [Bug 1749393] Update Released Brian Murray

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=158831563276.13979.12202053518555221631.malone@gac.canonical.com \
    --to=1749393@bugs.launchpad.net \
    --cc=qemu-devel@nongnu.org \
    /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;
as well as URLs for NNTP newsgroup(s).