- Hoist bb_strtoul out of min/max to prevent quadruple evaluation.
- Don't use separate variables for boottime/realtime.
- Make use of ENABLE_FEATURE_CLEAN_UP where appropriate.
- Order hash initialization after lock taking per Bernhard's taste.
- Add comment description of theory of operation.
function old new delta
seed_from_file_if_exists 533 456 -77
seedrng_main 1218 1086 -132
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-209) Total: -209 bytes
text data bss dec hex filename
976445 4227 1848 982520 efdf8 busybox_old
976236 4227 1848 982311 efd27 busybox_unstripped
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
- Make extensive use of libbb.h functions, which simplify a lot of code
and reduce binary size considerably.
- Use the already existing PID_FILE_PATH variable.
function old new delta
seed_from_file_if_exists 697 533 -164
.rodata 108665 108484 -181
seedrng_main 1463 1218 -245
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-590) Total: -590 bytes
text data bss dec hex filename
977035 4227 1848 983110 f0046 busybox_old
976445 4227 1848 982520 efdf8 busybox_unstripped
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
The RNG can't actually be seeded from a shell script, due to the
reliance on ioctls and the fact that entropy written into the
unprivileged /dev/urandom device is not immediately mixed in, making
subsequent seed reads dangerous. For this reason, the seedrng project
provides a basic "C script" meant to be copy and pasted into projects
like Busybox and tweaked as needed: <https://git.zx2c4.com/seedrng/about/>.
The SeedRNG construction has been part of systemd's seeder since
January, and recently was added to Android, OpenRC, and Void's Runit,
with more integrations on their way depending on context. Virtually
every single Busybox-based distro I have seen seeds things in wrong,
incomplete, or otherwise dangerous way. For example, fixing this issue
in Buildroot requires first for Busybox to have this fix.
This commit imports it into Busybox and wires up the basic config. The
utility itself is tiny, and unlike the example code from the SeedRNG
project, we can re-use libbb's existing hash functions, rather than
having to ship a standalone BLAKE2s, which makes this even smaller.
function old new delta
seedrng_main - 1463 +1463
.rodata 107858 108665 +807
seed_from_file_if_exists - 697 +697
packed_usage 34414 34519 +105
static.longopts - 38 +38
static.seedrng_prefix - 26 +26
seed_dir - 8 +8
non_creditable_seed - 8 +8
lock_file - 8 +8
creditable_seed - 8 +8
applet_names 2747 2755 +8
applet_main 3192 3200 +8
------------------------------------------------------------------------------
(add/remove: 9/0 grow/shrink: 4/0 up/down: 3184/0) Total: 3184 bytes
text data bss dec hex filename
973776 4219 1816 979811 ef363 busybox_old
977035 4227 1848 983110 f0046 busybox_unstripped
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
