Commit graph

4 commits

Author SHA1 Message Date
Justine Tunney
ead3fc2b31 Fix Landlock Make so it can read pattern rule vars
It turned out that specifying all SRCS and INCS as dependencies on the
pattern rules for all headers, caused `make` memory usage to skyrocket
from 40mb ot 160mb. This change also reduces the build graph another 4%.
2022-08-13 17:23:05 -07:00
Justine Tunney
05b8f82371 Fold LIBC_BITS into LIBC_INTRIN 2022-08-11 12:13:18 -07:00
Justine Tunney
226aaf3547 Improve memory safety
This commit makes numerous refinements to cosmopolitan memory handling.

The default stack size has been reduced from 2mb to 128kb. A new macro
is now provided so you can easily reconfigure the stack size to be any
value you want. Work around the breaking change by adding to your main:

    STATIC_STACK_SIZE(0x00200000);  // 2mb stack

If you're not sure how much stack you need, then you can use:

    STATIC_YOINK("stack_usage_logging");

After which you can `sort -nr o/$MODE/stack.log`. Based on the unit test
suite, nothing in the Cosmopolitan repository (except for Python) needs
a stack size greater than 30kb. There are also new macros for detecting
the size and address of the stack at runtime, e.g. GetStackAddr(). We
also now support sigaltstack() so if you want to see nice looking crash
reports whenever a stack overflow happens, you can put this in main():

    ShowCrashReports();

Under `make MODE=dbg` and `make MODE=asan` the unit testing framework
will now automatically print backtraces of memory allocations when
things like memory leaks happen. Bugs are now fixed in ASAN global
variable overrun detection. The memtrack and asan runtimes also handle
edge cases now. The new tools helped to identify a few memory leaks,
which are fixed by this change.

This change should fix an issue reported in #288 with ARG_MAX limits.
Fixing this doubled the performance of MKDEPS.COM and AR.COM yet again.
2021-10-13 17:27:13 -07:00
Justine Tunney
ea83cc0ad0 Make stronger crypto nearly as fast
One of the disadvantages of x25519 and ℘256 is it only provides 126 bits
of security, so that seems like a weak link in the chain, if we're using
ECDHE-ECDSA-AES256-GCM-SHA384. The U.S. government wants classified data
to be encrypted using a curve at least as strong as ℘384, which provides
192 bits of security, but if you read the consensus of stack exchange it
would give you the impression that ℘384 is three times slower.

This change (as well as the previous one) makes ℘384 three times as fast
by tuning its modulus and multiplication subroutines with new tests that
should convincingly show: the optimized code behaves the same way as the
old code. Some of the diff noise from the previous change is now removed
too, so that our vendored fork can be more easily compared with upstream
sources. So you can now have stronger cryptography without compromises.

℘384 modulus Justine                        l:         28𝑐          9𝑛𝑠
℘384 modulus MbedTLS NIST                   l:        127𝑐         41𝑛𝑠
℘384 modulus MbedTLS MPI                    l:      1,850𝑐        597𝑛𝑠

The benchmarks above show the improvements made by secp384r1() which is
an important function since it needs to be called 13,000 times whenever
someone establishes a connection to your web server. The same's true of
Mul6x6Adx() which is able to multiply 384-bit numbers in 73 cycles, but
only if your CPU was purchased after 2014 when Broadwell was introduced
2021-07-26 16:19:45 -07:00