diff options
| author | Dominik Maier <domenukk@gmail.com> | 2020-08-26 05:28:33 +0200 |
|---|---|---|
| committer | Dominik Maier <domenukk@gmail.com> | 2020-08-26 05:28:33 +0200 |
| commit | 96ef7083c84cbd1892233cc36bcc139f77515a19 (patch) | |
| tree | e62dba157e334bd9585d6ff83187ed59967a8ac8 /include | |
| parent | 78eaa6b2038bee5d36f4da5c95f019437b627dd0 (diff) | |
| download | AFLplusplus-96ef7083c84cbd1892233cc36bcc139f77515a19.tar.gz | |
using unbiased rand_below
Diffstat (limited to 'include')
| -rw-r--r-- | include/afl-fuzz.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/include/afl-fuzz.h b/include/afl-fuzz.h index 24e8ca9b..5c391049 100644 --- a/include/afl-fuzz.h +++ b/include/afl-fuzz.h @@ -1027,7 +1027,12 @@ static inline u32 rand_below(afl_state_t *afl, u32 limit) { } - return rand_next(afl) % limit; + /* Modulo is biased - we don't want our fuzzing to be biased so let's do it right. */ + u64 unbiased_rnd; + do { + unbiased_rnd = rand_next(afl); + } while (unbiased_rnd >= (UINT64_MAX - (UINT64_MAX % limit))); + return unbiased_rnd % limit; } |