Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random

Pull /dev/random updates from Ted Ts'o:
 "This adds a memzero_explicit() call which is guaranteed not to be
  optimized away by GCC.  This is important when we are wiping
  cryptographically sensitive material"

* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
  crypto: memzero_explicit - make sure to clear out sensitive data
  random: add and use memzero_explicit() for clearing data

1 files changed, 2 insertions, 3 deletions

diff --git a/crypto/sha256_generic.c b/crypto/sha256_generic.c
index 0bb558344699..65e7b76b057f 100644
--- a/crypto/sha256_generic.c
+++ b/crypto/sha256_generic.c
@@ -211,10 +211,9 @@ static void sha256_transform(u32 *state, const u8 *input)
 
         /* clear any sensitive info... */
         a = b = c = d = e = f = g = h = t1 = t2 = 0;
-        memset(W, 0, 64 * sizeof(u32));
+        memzero_explicit(W, 64 * sizeof(u32));
 }
 
-
 static int sha224_init(struct shash_desc *desc)
 {
         struct sha256_state *sctx = shash_desc_ctx(desc);
@@ -317,7 +316,7 @@ static int sha224_final(struct shash_desc *desc, u8 *hash)
         sha256_final(desc, D);
 
         memcpy(hash, D, SHA224_DIGEST_SIZE);
-        memset(D, 0, SHA256_DIGEST_SIZE);
+        memzero_explicit(D, SHA256_DIGEST_SIZE);
 
         return 0;
 }