Also, do not test for locking errors: on Linux, they do not happen.
function old new delta
.rodata 104900 104878 -22
seedrng_main 1022 994 -28
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
gcc in fact detects this and does this transformation
when generating code - no object code changes.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
We do not expect /dev/[u]random to be not openable/readable.
If they are, just bail out (something is obviously very wrong).
function old new delta
seedrng_main 1077 1076 -1
.rodata 104939 104929 -10
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Remove redundant includes.
We have platform specific handling in libbb.h and platform.h so we can
handle quirks in a central place.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Since we're passing 0 as the timeout, we don't need safe_poll. Remove
cleanup at end of program, since OS does that, which lets us simplify
control flow. Factor repeated function calls into ternary loop.
function old new delta
seedrng_main 1061 1459 +398
seed_from_file_if_exists 468 - -468
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/0 up/down: 398/-468) Total: -70 bytes
text data bss dec hex filename
1052781 16515 1816 1071112 105808 busybox_old
1052711 16515 1816 1071042 1057c2 busybox_unstripped
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
- Avoid an xstrdup call with seed_dir.
- Compress format strings with %s arguments.
- Open /dev/urandom for add entropy ioctl rather than /dev/random, so that
/dev/random is only used for the already-sightly-flawed poll() check for
creditability.
function old new delta
seedrng_main 948 958 +10
seed_from_file_if_exists 410 417 +7
.rodata 108338 108206 -132
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 17/-132) Total: -115 bytes
text data bss dec hex filename
975829 4227 1816 981872 efb70 busybox_old
975714 4227 1816 981757 efafd busybox_unstripped
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
- Use predefined strings where possible.
- Open /dev/random with O_RDONLY for ioctl().
function old new delta
seed_from_file_if_exists 413 410 -3
.rodata 108407 108350 -57
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-60) Total: -60 bytes
text data bss dec hex filename
975979 4227 1816 982022 efc06 busybox_old
975919 4227 1816 981962 efbca busybox_unstripped
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
- Remove all games with errno to further reduce code size.
- Combine error messages that don't benefit from being separated.
- Lock directory fd instead of separate file.
function old new delta
static.longopts 38 26 -12
seed_from_file_if_exists 426 413 -13
packed_usage 34519 34480 -39
.rodata 108484 108407 -77
seedrng_main 1088 1000 -88
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/5 up/down: 0/-229) Total: -229 bytes
text data bss dec hex filename
976208 4227 1816 982251 efceb busybox_old
975979 4227 1816 982022 efc06 busybox_unstripped
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
- Remove global variables and pass dfd by value, opened once instead of
twice, which shaves off some more bytes.
function old new delta
seedrng_main 1086 1088 +2
seed_dir 8 - -8
non_creditable_seed 8 - -8
lock_file 8 - -8
creditable_seed 8 - -8
seed_from_file_if_exists 456 426 -30
------------------------------------------------------------------------------
(add/remove: 0/4 grow/shrink: 1/1 up/down: 2/-62) Total: -60 bytes
text data bss dec hex filename
976236 4227 1848 982311 efd27 busybox_old
976208 4227 1816 982251 efceb busybox_unstripped
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
- 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>
