This code was filling a 64K buffer from /dev/urandom in order to
compute a CRC over (on average half of) it by two different methods,
comparing the CRCs, and repeating.
This is not a remotely security-critical application, so use the far
faster and cheaper prandom_u32() generator.
And, while we're at it, only fill as much of the buffer as we plan to use.
Signed-off-by: George Spelvin <l...@sdf.org>
Cc: Daniel Axtens <d...@axtens.net>
Cc: Herbert Xu <herb...@gondor.apana.org.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Michael Ellerman <m...@ellerman.id.au>
---
arch/powerpc/crypto/crc-vpmsum_test.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/crypto/crc-vpmsum_test.c
b/arch/powerpc/crypto/crc-vpmsum_test.c
index 0153a9c6f4af..98ea4f4d3dde 100644
--- a/arch/powerpc/crypto/crc-vpmsum_test.c
+++ b/arch/powerpc/crypto/crc-vpmsum_test.c
@@ -78,16 +78,12 @@ static int __init crc_test_init(void)
pr_info("crc-vpmsum_test begins, %lu iterations\n", iterations);
for (i=0; i<iterations; i++) {
- size_t len, offset;
+ size_t offset = prandom_u32_max(16);
+ size_t len = prandom_u32_max(MAX_CRC_LENGTH);
- get_random_bytes(data, MAX_CRC_LENGTH);
- get_random_bytes(&len, sizeof(len));
- get_random_bytes(&offset, sizeof(offset));
-
- len %= MAX_CRC_LENGTH;
- offset &= 15;
if (len <= offset)
continue;
+ prandom_bytes(data, len);
len -= offset;
crypto_shash_update(crct10dif_shash, data+offset, len);
--
2.20.1
