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Ensure the first random number is non-zero when fuzzing

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In fuzzing mode, `isc_random` uses a fixed seed for reproducibility.
The particular seed chosen happened to produce zero as its first
number, however commit bd251de0 introduced an initialization check in
`random_test` that required it to be non-zero. This change adjusts the
seed to avoid spurious test failures.

Also, remove the temporary variable that was used for initialization
because it did not match the type of the thread-local seed array.
This commit is contained in:
Tony Finch
2022-09-21 12:21:32 +01:00
parent 2ee16067c5
commit 4b9af22830
1 changed files with 5 additions and 6 deletions
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11
lib/isc/random.c
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@@ -90,17 +90,16 @@ next(void) {
} }
void void
isc__random_initialize(void) { isc__random_initialize(void) {
int useed[4] = { 0, 0, 0, 1 };
#if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION #if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
/* /*
* Set a constant seed to help in problem reproduction should fuzzing * A fixed seed helps with problem reproduction when fuzzing. It must be
* find a crash or a hang. The seed array must be non-zero else * non-zero else xoshiro128starstar will generate only zeroes, and the
* xoshiro128starstar will generate an infinite series of zeroes. * first result needs to be non-zero as expected by random_test.c
*/ */
seed[0] = 1;
#else /* if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */ #else /* if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */
isc_entropy_get(useed, sizeof(useed)); isc_entropy_get(seed, sizeof(seed));
#endif /* if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */ #endif /* if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */
memmove(seed, useed, sizeof(seed));
} }
uint8_t uint8_t