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Make numerous improvements

Browse source 
- Python static hello world now 1.8mb
- Python static fully loaded now 10mb
- Python HTTPS client now uses MbedTLS
- Python REPL now completes import stmts
- Increase stack size for Python for now
- Begin synthesizing posixpath and ntpath
- Restore Python \N{UNICODE NAME} support
- Restore Python NFKD symbol normalization
- Add optimized code path for Intel SHA-NI
- Get more Python unit tests passing faster
- Get Python help() pagination working on NT
- Python hashlib now supports MbedTLS PBKDF2
- Make memcpy/memmove/memcmp/bcmp/etc. faster
- Add Mersenne Twister and Vigna to LIBC_RAND
- Provide privileged __printf() for error code
- Fix zipos opendir() so that it reports ENOTDIR
- Add basic chmod() implementation for Windows NT
- Add Cosmo's best functions to Python cosmo module
- Pin function trace indent depth to that of caller
- Show memory diagram on invalid access in MODE=dbg
- Differentiate stack overflow on crash in MODE=dbg
- Add stb_truetype and tools for analyzing font files
- Upgrade to UNICODE 13 and reduce its binary footprint
- COMPILE.COM now logs resource usage of build commands
- Start implementing basic poll() support on bare metal
- Set getauxval(AT_EXECFN) to GetModuleFileName() on NT
- Add descriptions to strerror() in non-TINY build modes
- Add COUNTBRANCH() macro to help with micro-optimizations
- Make error / backtrace / asan / memory code more unbreakable
- Add fast perfect C implementation of μ-Law and a-Law audio codecs
- Make strtol() functions consistent with other libc implementations
- Improve Linenoise implementation (see also github.com/jart/bestline)
- COMPILE.COM now suppresses stdout/stderr of successful build commands
This commit is contained in:
Justine Tunney 2021-09-27 22:58:51 -07:00
parent fa7b4f5bd1
commit 39bf41f4eb
806 changed files with 77494 additions and 63859 deletions
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50
libc/str/timingsafe_memcmp.c
View file

@ -24,20 +24,62 @@ Copyright 2014 Google Inc.\"");
asm(".include \"libc/disclaimer.inc\"");
/**
* Lexicographically compares the first len bytes in b1 and b2.
* Lexicographically compares the first 𝑛 bytes in 𝑝 and 𝑞.
*
* The following expression:
*
* timingsafe_memcmp(p, q, n)
*
* Is functionally equivalent to:
*
* MAX(-1, MIN(1, memcmp(p, q, n)))
*
* Running time is independent of the byte sequences compared, making
* this safe to use for comparing secret values such as cryptographic
* MACs. In contrast, memcmp() may short-circuit after finding the first
* differing byte.
*
* timingsafe_memcmp n=0 661 picoseconds
* timingsafe_memcmp n=1 1 ns/byte 590 mb/s
* timingsafe_memcmp n=2 1 ns/byte 738 mb/s
* timingsafe_memcmp n=3 1 ns/byte 805 mb/s
* timingsafe_memcmp n=4 1 ns/byte 843 mb/s
* timingsafe_memcmp n=5 1 ns/byte 922 mb/s
* timingsafe_memcmp n=6 1 ns/byte 932 mb/s
* timingsafe_memcmp n=7 1 ns/byte 939 mb/s
* timingsafe_memcmp n=8 992 ps/byte 984 mb/s
* timingsafe_memcmp n=9 992 ps/byte 984 mb/s
* timingsafe_memcmp n=15 926 ps/byte 1,054 mb/s
* timingsafe_memcmp n=16 950 ps/byte 1,026 mb/s
* timingsafe_memcmp n=17 933 ps/byte 1,045 mb/s
* timingsafe_memcmp n=31 896 ps/byte 1,089 mb/s
* timingsafe_memcmp n=32 888 ps/byte 1,098 mb/s
* timingsafe_memcmp n=33 972 ps/byte 1,004 mb/s
* timingsafe_memcmp n=80 913 ps/byte 1,068 mb/s
* timingsafe_memcmp n=128 891 ps/byte 1,095 mb/s
* timingsafe_memcmp n=256 873 ps/byte 1,118 mb/s
* timingsafe_memcmp n=16384 858 ps/byte 1,138 mb/s
* timingsafe_memcmp n=32768 856 ps/byte 1,140 mb/s
* timingsafe_memcmp n=131072 857 ps/byte 1,138 mb/s
* bcmp ne n=256 3 ps/byte 246 gb/s
* bcmp eq n=256 32 ps/byte 30,233 mb/s
* memcmp ne n=256 3 ps/byte 246 gb/s
* memcmp eq n=256 31 ps/byte 31,493 mb/s
* timingsafe_bcmp ne n=256 27 ps/byte 35,992 mb/s
* timingsafe_bcmp eq n=256 27 ps/byte 35,992 mb/s
* timingsafe_memcmp ne n=256 877 ps/byte 1,113 mb/s
* timingsafe_memcmp eq n=256 883 ps/byte 1,105 mb/s
*
* @note each byte is interpreted as unsigned char
* @return -1, 0, or 1 based on comparison
* @see timingsafe_bcmp() it's 100x faster
* @asyncsignalsafe
*/
int timingsafe_memcmp(const void *b1, const void *b2, size_t len) {
const unsigned char *p1 = b1, *p2 = b2;
int timingsafe_memcmp(const void *p, const void *q, size_t n) {
const unsigned char *p1 = p, *p2 = q;
size_t i;
int res = 0, done = 0;
for (i = 0; i < len; i++) {
for (i = 0; i < n; i++) {
/* lt is -1 if p1[i] < p2[i]; else 0. */
int lt = (p1[i] - p2[i]) >> CHAR_BIT;
/* gt is -1 if p1[i] > p2[i]; else 0. */