crypto: testmgr - generate power-of-2 lengths more often
Subsystems (2)
PATCH 1/1 crypto: testmgr - generate power-of-2 lengths more often
From: Eric Biggers <[email protected]>
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.
---
This is the same as
https://lore.kernel.org/linux-crypto/[email protected]/,
just resent as a standalone patch.
crypto/testmgr.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
crypto/testmgr.c +12 -4
@@ -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 )
base-commit: 95c0f5c3b8bb7acdc5c4f04bc6a7d3f40d319e9e
Signature · 1 line
2.45.2
Herbert Xu
maintainerQuoted 14 lines · Eric Biggers
From: Eric Biggers <[email protected]>
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 <[email protected]>Acked-by Ard Biesheuvel <[email protected]>Signed-off-by Eric Biggers <[email protected]>
Quoted 8 lines
---
This is the same as
https://lore.kernel.org/linux-crypto/[email protected]/,
just resent as a standalone patch.
crypto/testmgr.c| 16 ++++++++++++----1 file changed, 12 insertions(+), 4 deletions(-)
Patch applied. Thanks.
Signature · 3 lines
Email: Herbert Xu <[email protected]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt