Anton Livaja 9280fb8d6d | ||
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src | ||
.gitignore | ||
Cargo.lock | ||
Cargo.toml | ||
LICENSE | ||
Makefile | ||
README.md |
README.md
libfakerand
Introduction
libfakerand
intercepts various system calls that programs use to
retrieve entropy. It replaces the entropy which would otherwise be
used with the one supplied by the user. This means you can force
programs to use a fixed value instead of a random one.
libfakerand
overrides the following functions:
rand()
read()
function for/dev/urandom
and/dev/random
getrandom()
RAND_bytes()
Usage
You may use env variables LD_PRELOAD
and FAKERAND
along with a command:
LD_PRELOAD=./target/release/libfakerand.so FAKERAND=0 openssl rand -hex 16
Alternatively, set environment variables so that all programs running in that shell are effected:
export LD_PRELOAD=/usr/lib/fakerand/fakerand.so
export FAKERAND=42
If you will be using it this way, it may make sense to place the .so file in /usr/lib/fakerand
Notes
Statically linked libraries can't be overriden by LD_PRELOAD
. For
this reason, libfakerand
can't override cases such as:
FAKERAND=42 LD_PRELOAD=./target/release/libfakerand.so awk 'BEGIN{srand(); print rand()}' 2>/dev/null
This is because awk
is statically linked.