Explicitly clear temporary stack buffers in tls_prf_sha1_md5()

The local buffers may contain information used to generate parts of the
derived key, so clear these explicitly to minimize amount of unnecessary
private key-related material in memory.

Signed-off-by: Jouni Malinen <j@w1.fi>

diff --git a/src/crypto/sha1-tlsprf.c b/src/crypto/sha1-tlsprf.c
index 0effd9b..f9bc0eb 100644 (file)
--- a/src/crypto/sha1-tlsprf.c
+++ b/src/crypto/sha1-tlsprf.c
@@ -95,5 +95,10 @@ int tls_prf_sha1_md5(const u8 *secret, size_t secret_len, const char *label,
                SHA1_pos++;
        }
 
+       os_memset(A_MD5, 0, MD5_MAC_LEN);
+       os_memset(P_MD5, 0, MD5_MAC_LEN);
+       os_memset(A_SHA1, 0, SHA1_MAC_LEN);
+       os_memset(P_SHA1, 0, SHA1_MAC_LEN);
+
        return 0;
 }