Make sure to explicitly clear memory that is used for password input. memset
is often optimized out by the compiler.
Brought to attention by the OpenBSD community, see:
https://marc.info/?t=146989502600003&r=1&w=2
Thread subject: x11/slock: clear passwords with explicit_bzero
Changes:
- explicit_bzero.c import from libressl-portable.
- Makefile: add COMPATSRC for compatibility src.
- config.mk: add separate *BSD section in config.mk to simply uncomment it on
these platforms.
This reverts most of commit a6dc051e37 and fixes
some related stuff:
- keep spelling fixes from original commit
- make -h and -v also work when followed by more arguments
- any unknown flag prints usage
- fix output of -v to display "slock: version 1.3" instead of "slock: slock-1.3"
There are 2 arguments why -v and -h are broken:
1) if you are running off git, -v will show the last stable
release, effectively making this option useless.
people running stable versions leave open an attack surface
this way in case there are vulnerabilities found.
99% of the people are also using package managers to keep
their software up to date, instead of running $TOOL -v to
check how old it is.
2) -h is a sad excuse for not just looking at the manual page
(man 1 slock). Given we accept a post_lock_command, we can't
be as liberal and just intercept certain flags.
I changed the manpage to reflect this change.
There really is no need to source a defined variable from a linux
header. The OOM-rank ranges from -1000 to 1000, so we can safely
hardcode -1000, which is a sane thing to do given slock is suid and
we don't want to play around too much here anyway.
On another notice, let's not forget that this still is a shitty
heuristic. The OOM-killer still can kill us (thus I also changed
the wording in the error-message. We do not disable the OOM-killer,
we're just hiding.
- Adds another color in config.def.h, COLOR_INIT
- Renames the colours from numerical ones to ones with meaningful names;
COLOR_INPUT for when there is content in the input buffer and COLOR_EMPTY
for when the input buffer has been cleared (backspaced or a failed attempt).
- Ensures XFreeColors frees the right number of colours. This is now derived
from the size of `Lock->colors` rather than being an integer literal.
- Makes slock exhibit the behaviour described by Markus
The default colours are the same as the ones slock currently uses, with the
exception of the new color, which I have set to red, as it indicates someone
has either failed an attempt to unlock, or that they have entered input and
erased it all.
Hiltjo Posthuma
Markus Teich
FRIGN
David Phillips
Nick Currier
Anselm R Garbe
sin
Anselm R Garbe
anselm@garbe.us