| Message ID | 20240703190431.6513-1-ebiggers@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | crypto: testmgr - generate power-of-2 lengths more often | expand |
Eric Biggers <ebiggers@kernel.org> wrote: > From: Eric Biggers <ebiggers@google.com> > > Implementations of hash functions often have special cases when lengths > are a multiple of the hash function's internal block size (e.g. 64 for > SHA-256, 128 for SHA-512). Currently, when the fuzz testing code > generates lengths, it doesn't prefer any length mod 64 over any other. > This limits the coverage of these special cases. > > Therefore, this patch updates the fuzz testing code to generate > power-of-2 lengths and divide messages exactly in half a bit more often. > > Reviewed-by: Sami Tolvanen <samitolvanen@google.com> > Acked-by: Ard Biesheuvel <ardb@kernel.org> > Signed-off-by: Eric Biggers <ebiggers@google.com> > --- > > This is the same as > https://lore.kernel.org/linux-crypto/20240621165922.77672-3-ebiggers@kernel.org/, > just resent as a standalone patch. > > crypto/testmgr.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) Patch applied. Thanks.
diff --git a/crypto/testmgr.c b/crypto/testmgr.c index a780b615f8c6..f02cb075bd68 100644 --- a/crypto/testmgr.c +++ b/crypto/testmgr.c @@ -914,18 +914,24 @@ static unsigned int generate_random_length(struct rnd_state *rng, { unsigned int len = prandom_u32_below(rng, max_len + 1); switch (prandom_u32_below(rng, 4)) { case 0: - return len % 64; + len %= 64; + break; case 1: - return len % 256; + len %= 256; + break; case 2: - return len % 1024; + len %= 1024; + break; default: - return len; + break; } + if (len && prandom_u32_below(rng, 4) == 0) + len = rounddown_pow_of_two(len); + return len; } /* Flip a random bit in the given nonempty data buffer */ static void flip_random_bit(struct rnd_state *rng, u8 *buf, size_t size) { @@ -1017,10 +1023,12 @@ static char *generate_random_sgl_divisions(struct rnd_state *rng, unsigned int this_len; const char *flushtype_str; if (div == &divs[max_divs - 1] || prandom_bool(rng)) this_len = remaining; + else if (prandom_u32_below(rng, 4) == 0) + this_len = (remaining + 1) / 2; else this_len = prandom_u32_inclusive(rng, 1, remaining); div->proportion_of_total = this_len; if (prandom_u32_below(rng, 4) == 0)