libgcrypt/SOURCES/libgcrypt-1.8.3-fips-enttest.patch
2021-10-08 12:41:06 +00:00

31 lines
1.0 KiB
Diff

diff -up libgcrypt-1.8.3/random/random-drbg.c.fips-enttest libgcrypt-1.8.3/random/random-drbg.c
--- libgcrypt-1.8.3/random/random-drbg.c.fips-enttest 2017-11-23 19:16:58.000000000 +0100
+++ libgcrypt-1.8.3/random/random-drbg.c 2019-06-03 13:19:44.035516400 +0200
@@ -610,6 +610,8 @@ drbg_get_entropy (drbg_state_t drbg, uns
size_t len)
{
int rc = 0;
+ static unsigned char oldhash[64] = { 0 };
+ unsigned char newhash[64];
/* Perform testing as defined in 11.3.2 */
if (drbg->test_data && drbg->test_data->fail_seed_source)
@@ -634,6 +636,17 @@ drbg_get_entropy (drbg_state_t drbg, uns
#else
rc = -1;
#endif
+
+ /* to avoid storing the actual entropy obtained for indefinite
+ time, we just store the SHA-512 hash of the entropy gathered
+ */
+ _gcry_md_hash_buffer (GCRY_MD_SHA512, newhash, buffer, len);
+
+ if (memcmp (newhash, oldhash, sizeof (oldhash)) == 0)
+ return -1; /* continous entropy test failed */
+
+ memcpy (oldhash, newhash, sizeof (oldhash));
+
return rc;
}