Bug#1039092: linux: Braille keyboards broken with Linux 6.3 with disabled TIOCSTI

[Samuel Thibault]

Source: linux
Version: 6.3.7-1
Severity: important
Tags: a11y upstream
Forwarded: https://lkml.org/lkml/2022/12/27/719

Hello,

This is an upstream issue, but I am reporting it here so it gets
documented.

With version 6.3, Linux disabled TIOCSTI by default, for security
reasons. This basically broke Braille keyboards: brltty needs that
interface to properly simulate keypresses. I had proposed upstream on
https://lkml.org/lkml/2022/12/27/719 some solutions, without any answer.
Now that we actually have a regression and people start complaining
on debian-accessibility, perhaps they'll listen? We really need to do
something about it, anyway.

A workaround is to set dev.tty.legacy_tiocsti=1 in /etc/sysctl.conf, but
that basically re-exposes the security issues.

Samuel

-- System Information:
Debian Release: trixie/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable-debug'), (500, 'testing-debug'), (500, 'stable-security'), (500, 'stable-debug'), (500, 'oldstable-proposed-updates-debug'), (500, 'oldstable-proposed-updates'), (500, 'oldoldstable-proposed-updates'), (500, 'oldoldstable'), (500, 'buildd-unstable'), (500, 'unstable'), (500, 'stable'), (500, 'oldstable'), (1, 'experimental-debug'), (1, 'buildd-experimental'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386, arm64

Kernel: Linux 6.3.0 (SMP w/8 CPU threads; PREEMPT)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

-- 
Samuel
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