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random: Clean up implementation of PCG's and Xoshiro's constructor #13106

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Merged
TimWolla merged 2 commits into from
Jan 11, 2024
Merged

random: Clean up implementation of PCG's and Xoshiro's constructor #13106

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random: Reduce variable scope in Random\Engine\PcgOneseq128XslRr64::_…
TimWolla Jan 9, 2024
88c83c2
random: Dynamically calculate the state size when seeding with CSPRNG
TimWolla Jan 9, 2024
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11 changes: 6 additions & 5 deletions ext/random/engine_pcgoneseq128xslrr64.c
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Original file line number Diff line number Diff line change
Expand Up @@ -146,30 +146,31 @@ PHP_METHOD(Random_Engine_PcgOneseq128XslRr64, __construct)
zend_string *str_seed = NULL;
zend_long int_seed = 0;
bool seed_is_null = true;
uint32_t i, j;
uint64_t t[2];

ZEND_PARSE_PARAMETERS_START(0, 1)
Z_PARAM_OPTIONAL;
Z_PARAM_STR_OR_LONG_OR_NULL(str_seed, int_seed, seed_is_null);
ZEND_PARSE_PARAMETERS_END();

if (seed_is_null) {
if (php_random_bytes_throw(&state->state, sizeof(php_random_uint128_t)) == FAILURE) {
if (php_random_bytes_throw(&state->state, sizeof(state->state)) == FAILURE) {
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@Girgias Girgias Jan 9, 2024

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I'm assuming this is determined at compile time because the compiler knows the struct field type.

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@TimWolla TimWolla Jan 10, 2024

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sizeof is always compile time.

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@Girgias Girgias Jan 10, 2024

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That is technically incorrect sizeof of a VLA is a runtime construct. :)

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@TimWolla TimWolla Jan 10, 2024

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TIL, but VLA are terrible anyway 😄

zend_throw_exception(random_ce_Random_RandomException, "Failed to generate a random seed", 0);
RETURN_THROWS();
}
} else {
if (str_seed) {
/* char (byte: 8 bit) * 16 = 128 bits */
if (ZSTR_LEN(str_seed) == 16) {
uint64_t t[2];

/* Endianness safe copy */
for (i = 0; i < 2; i++) {
for (uint32_t i = 0; i < 2; i++) {
t[i] = 0;
for (j = 0; j < 8; j++) {
for (uint32_t j = 0; j < 8; j++) {
t[i] += ((uint64_t) (unsigned char) ZSTR_VAL(str_seed)[(i * 8) + j]) << (j * 8);
}
}

seed128(engine->status, php_random_uint128_constant(t[0], t[1]));
} else {
zend_argument_value_error(1, "must be a 16 byte (128 bit) string");
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2 changes: 1 addition & 1 deletion ext/random/engine_xoshiro256starstar.c
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Expand Up @@ -213,7 +213,7 @@ PHP_METHOD(Random_Engine_Xoshiro256StarStar, __construct)

if (seed_is_null) {
do {
if (php_random_bytes_throw(&state->state, 32) == FAILURE) {
if (php_random_bytes_throw(&state->state, sizeof(state->state)) == FAILURE) {
zend_throw_exception(random_ce_Random_RandomException, "Failed to generate a random seed", 0);
RETURN_THROWS();
}
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