From: Stephan Mueller <smueller@chronox.de>
Date: Thu, 31 Jul 2014 19:47:33 +0000 (+0200)
Subject: crypto: drbg - fix failure of generating multiple of 2**16 bytes
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ce5481d01f67ad304908ec2113515440c0fa86eb;p=linux-beck.git

crypto: drbg - fix failure of generating multiple of 2**16 bytes

The function drbg_generate_long slices the request into 2**16 byte
or smaller chunks. However, the loop, however invokes the random number
generation function with zero bytes when the request size is a multiple
of 2**16 bytes. The fix prevents zero bytes requests.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

diff --git a/crypto/drbg.c b/crypto/drbg.c
index ff975d9e0c2a..7894db9ca90b 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -1500,7 +1500,7 @@ static int drbg_generate_long(struct drbg_state *drbg,
 		if (0 >= tmplen)
 			return tmplen;
 		len += tmplen;
-	} while (slice > 0);
+	} while (slice > 0 && (len < buflen));
 	return len;
 }