Feature #10098 ยป 0001-add-timing-safe-string-compare-method.patch
| configure.in | ||
|---|---|---|
| 2066 | 2066 |
AC_CHECK_FUNCS(utimes) |
| 2067 | 2067 |
AC_CHECK_FUNCS(wait4) |
| 2068 | 2068 |
AC_CHECK_FUNCS(waitpid) |
| 2069 |
AC_CHECK_FUNCS(consttime_memequal) |
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| 2070 |
AC_CHECK_FUNCS(timingsafe_memcmp) |
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| 2069 | 2071 | |
| 2070 | 2072 |
AS_IF([test "$ac_cv_func_getcwd" = yes], [ |
| 2071 | 2073 |
AC_CACHE_CHECK(if getcwd allocates buffer if NULL is given, [rb_cv_getcwd_malloc], |
| string.c | ||
|---|---|---|
| 2490 | 2490 |
return str_eql(str1, str2); |
| 2491 | 2491 |
} |
| 2492 | 2492 | |
| 2493 |
static inline int |
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| 2494 |
rb_consttime_memequal(const char *buf1, const char *buf2, long len) |
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{
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#if defined(HAVE_TIMINGSAFE_MEMCMP) |
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| 2497 |
return (timingsafe_memcmp(buf1, buf2, len) == 0); |
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| 2498 |
#elif defined(HAVE_CONSTTIME_MEMEQUAL) |
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| 2499 |
return (consttime_memequal(buf1, buf2, len) != 0); |
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#else |
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VALUE result; |
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long idx; |
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result = 0; |
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idx = 0; |
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if (UNALIGNED_WORD_ACCESS || !((VALUE)buf1 % sizeof(VALUE)) && !((VALUE)buf2 % sizeof(VALUE))) {
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| 2507 |
for (; idx < len; idx += sizeof(VALUE)) {
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result |= *(const VALUE *)(buf1+idx) ^ *(const VALUE *)(buf2+idx); |
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| 2509 |
} |
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| 2510 |
} |
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| 2511 | ||
| 2512 |
for (; idx < len; idx++) {
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| 2513 |
result |= buf1[idx] ^ buf2[idx]; |
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} |
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| 2515 | ||
| 2516 |
return (result == 0); |
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| 2517 |
#endif |
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| 2518 |
} |
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| 2519 | ||
| 2520 |
/* |
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| 2521 |
* call-seq: |
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* str.consttime_bytes_eq?(other) -> true or false |
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| 2523 |
* |
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| 2524 |
* Ignoring encoding, compares each byte of +str+ against +other+ in constant time. |
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| 2525 |
*/ |
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| 2526 | ||
| 2527 |
static VALUE |
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| 2528 |
rb_str_consttime_bytes_eq(VALUE str1, VALUE str2) |
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{
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long len; |
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| 2531 | ||
| 2532 |
str2 = StringValue(str2); |
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len = RSTRING_LEN(str1); |
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| 2534 | ||
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if (RSTRING_LEN(str2) != len) return Qfalse; |
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if (rb_consttime_memequal(RSTRING_PTR(str1), RSTRING_PTR(str2), len) != 0) return Qtrue; |
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| 2537 | ||
| 2538 |
return Qfalse; |
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| 2539 |
} |
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| 2540 | ||
| 2493 | 2541 |
/* |
| 2494 | 2542 |
* call-seq: |
| 2495 | 2543 |
* string <=> other_string -> -1, 0, +1 or nil |
| ... | ... | |
| 8761 | 8809 |
rb_define_method(rb_cString, "==", rb_str_equal, 1); |
| 8762 | 8810 |
rb_define_method(rb_cString, "===", rb_str_equal, 1); |
| 8763 | 8811 |
rb_define_method(rb_cString, "eql?", rb_str_eql, 1); |
| 8812 |
rb_define_method(rb_cString, "consttime_bytes_eq?", rb_str_consttime_bytes_eq, 1); |
|
| 8764 | 8813 |
rb_define_method(rb_cString, "hash", rb_str_hash_m, 0); |
| 8765 | 8814 |
rb_define_method(rb_cString, "casecmp", rb_str_casecmp, 1); |
| 8766 | 8815 |
rb_define_method(rb_cString, "+", rb_str_plus, 1); |
| test/ruby/test_string.rb | ||
|---|---|---|
| 1 | 1 |
require 'test/unit' |
| 2 | 2 |
require_relative 'envutil' |
| 3 |
require 'benchmark' |
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| 3 | 4 | |
| 4 | 5 |
# use of $= is deprecated after 1.7.1 |
| 5 | 6 |
def pre_1_7_1 |
| ... | ... | |
| 304 | 305 |
casetest(S("CaT"), S('cAt'), true) # find these in the case.
|
| 305 | 306 |
end |
| 306 | 307 | |
| 308 |
def test_consttime_bytes_eq # 'consttime_bytes_eq?' |
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assert_equal(true, S("foo").consttime_bytes_eq?(S("foo")))
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assert_equal(false, S("foo").consttime_bytes_eq?(S("foO")))
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assert_equal(true, S("f\x00oo").consttime_bytes_eq?(S("f\x00oo")))
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assert_equal(false, S("f\x00oo").consttime_bytes_eq?(S("f\x00oO")))
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| 313 |
end |
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| 314 | ||
| 315 |
def test_consttime_bytes_eq_timing |
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# ensure using consttime_bytes_eq? takes almost exactly the same amount of time to compare two |
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# different strings. |
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# NOTE: this test may be susceptible to noise if the system running the tests is otherwise under |
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| 319 |
# load. |
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| 320 |
a = "x"*1024_000 |
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| 321 |
b = a+"y" |
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c = "y"+a |
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a << "x" |
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| 324 | ||
| 325 |
def measure(&block) |
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| 326 |
Benchmark.measure(&block).real |
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| 327 |
end |
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| 328 | ||
| 329 |
n = 10_000 |
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| 330 |
a_b_time = measure { n.times { a.consttime_bytes_eq?(b) } }
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| 331 |
a_c_time = measure { n.times { a.consttime_bytes_eq?(c) } }
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| 332 |
assert_in_delta(a_b_time, a_c_time, 0.25, "consttime_bytes_eq? timing test failed") |
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| 333 |
end |
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| 334 | ||
| 307 | 335 |
def test_capitalize |
| 308 | 336 |
assert_equal(S("Hello"), S("hello").capitalize)
|
| 309 | 337 |
assert_equal(S("Hello"), S("hELLO").capitalize)
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| 310 |
- |
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