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SAK.txt: standardize document format 

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- mark document title;
- use :Author: and :Date: for authorship;
- adjust notation for literals and bold;
- mark literal blocks;
- adjust identation.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Mauro Carvalho Chehab 2017-05-17 07:45:57 -03:00 committed by Jonathan Corbet
parent af3137f132
commit 2273194d1e
1 changed files with 34 additions and 31 deletions
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33
Documentation/SAK.txt
View File

@ -1,5 +1,9 @@
Linux 2.4.2 Secure Attention Key (SAK) handling
18 March 2001, Andrew Morton
=========================================
Linux Secure Attention Key (SAK) handling
=========================================
:Date: 18 March 2001
:Author: Andrew Morton
An operating system's Secure Attention Key is a security tool which is
provided as protection against trojan password capturing programs. It
@ -13,7 +17,7 @@ this sequence. It is only available if the kernel was compiled with
sysrq support.
The proper way of generating a SAK is to define the key sequence using
`loadkeys'. This will work whether or not sysrq support is compiled
``loadkeys``. This will work whether or not sysrq support is compiled
into the kernel.
SAK works correctly when the keyboard is in raw mode. This means that
@ -25,22 +29,21 @@ What key sequence should you use? Well, CTRL-ALT-DEL is used to reboot
the machine. CTRL-ALT-BACKSPACE is magical to the X server. We'll
choose CTRL-ALT-PAUSE.
In your rc.sysinit (or rc.local) file, add the command
In your rc.sysinit (or rc.local) file, add the command::
echo "control alt keycode 101 = SAK" | /bin/loadkeys
And that's it! Only the superuser may reprogram the SAK key.
NOTES
=====
.. note::
1: Linux SAK is said to be not a "true SAK" as is required by
1. Linux SAK is said to be not a "true SAK" as is required by
systems which implement C2 level security. This author does not
know why.
2: On the PC keyboard, SAK kills all applications which have
2. On the PC keyboard, SAK kills all applications which have
/dev/console opened.
Unfortunately this includes a number of things which you don't
@ -49,38 +52,38 @@ NOTES
Linux distributor about this!
You can identify processes which will be killed by SAK with the
command
command::
# ls -l /proc/[0-9]*/fd/* | grep console
l-wx------ 1 root root 64 Mar 18 00:46 /proc/579/fd/0 -> /dev/console
Then:
Then::
# ps aux|grep 579
root 579 0.0 0.1 1088 436 ? S 00:43 0:00 gpm -t ps/2
So `gpm' will be killed by SAK. This is a bug in gpm. It should
So ``gpm`` will be killed by SAK. This is a bug in gpm. It should
be closing standard input. You can work around this by finding the
initscript which launches gpm and changing it thusly:
Old:
Old::
daemon gpm
New:
New::
daemon gpm < /dev/null
Vixie cron also seems to have this problem, and needs the same treatment.
Also, one prominent Linux distribution has the following three
lines in its rc.sysinit and rc scripts:
lines in its rc.sysinit and rc scripts::
exec 3<&0
exec 4>&1
exec 5>&2
These commands cause *all* daemons which are launched by the
These commands cause **all** daemons which are launched by the
initscripts to have file descriptors 3, 4 and 5 attached to
/dev/console. So SAK kills them all. A workaround is to simply
delete these lines, but this may cause system management