crypto: drbg - HMAC-SHA1 DRBG has crypto strength of 128 bits

smuellerDD · herbertx · commit 5b635e280efc · 2014-07-08T21:18:25.000+08:00
The patch corrects the security strength of the HMAC-SHA1 DRBG to 128
bits. This strength defines the size of the seed required for the DRBG.
Thus, the patch lowers the seeding requirement from 256 bits to 128 bits
for HMAC-SHA1.

Signed-off-by: Stephan Mueller &lt;smueller@chronox.de&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
diff --git a/crypto/drbg.c b/crypto/drbg.c
@@ -184,7 +184,7 @@ static const struct drbg_core drbg_cores[] = {
 #endif /* CONFIG_CRYPTO_DRBG_HASH */
 #ifdef CONFIG_CRYPTO_DRBG_HMAC
 	{
-		.flags = DRBG_HMAC | DRBG_STRENGTH256,
+		.flags = DRBG_HMAC | DRBG_STRENGTH128,
 		.statelen = 20, /* block length of cipher */
 		.max_addtllen = 35,
 		.max_bits = 19,

Original file line number	Diff line number	Diff line change
`@@ -184,7 +184,7 @@ static const struct drbg_core drbg_cores[] = {`
`184`	`184`	`#endif /* CONFIG_CRYPTO_DRBG_HASH */`
`185`	`185`	`#ifdef CONFIG_CRYPTO_DRBG_HMAC`
`186`	`186`	`{`
`187`		`- .flags = DRBG_HMAC \| DRBG_STRENGTH256,`
	`187`	`+ .flags = DRBG_HMAC \| DRBG_STRENGTH128,`
`188`	`188`	`.statelen = 20, /* block length of cipher */`
`189`	`189`	`.max_addtllen = 35,`
`190`	`190`	`.max_bits = 19,`