Add ctrl for SHA1 and SSLv3

Add SSLv3 ctrl to EVP_sha1() this is only needed if SSLv3 client
authentication is used with DSA/ECDSA.
Reviewed-by: NTim Hudson <tjh@openssl.org>

crypto/evp/m_sha1.c

@@ -81,6 +81,60 @@ static int final(EVP_MD_CTX *ctx, unsigned char *md)
     return SHA1_Final(md, ctx->md_data);
 }
 
+static int ctrl(EVP_MD_CTX *ctx, int cmd, int mslen, void *ms)
+{
+    unsigned char padtmp[40];
+    unsigned char sha1tmp[SHA_DIGEST_LENGTH];
+
+    SHA_CTX *sha1 = ctx->md_data;
+
+    if (cmd != EVP_CTRL_SSL3_MASTER_SECRET)
+        return 0;
+
+    /* SSLv3 client auth handling: see RFC-6101 5.6.8 */
+    if (mslen != 48)
+        return 0;
+
+    /* At this point hash contains all handshake messages, update
+     * with master secret and pad_1.
+     */
+
+    if (SHA1_Update(sha1, ms, mslen) <= 0)
+        return 0;
+
+    /* Set padtmp to pad_1 value */
+    memset(padtmp, 0x36, sizeof(padtmp));
+
+    if (!SHA1_Update(sha1, padtmp, sizeof(padtmp)))
+        return 0;
+
+    if (!SHA1_Final(sha1tmp, sha1))
+        return 0;
+
+    /* Reinitialise context */
+
+    if (!SHA1_Init(sha1))
+        return 0;
+
+    if (SHA1_Update(sha1, ms, mslen) <= 0)
+        return 0;
+
+    /* Set padtmp to pad_2 value */
+    memset(padtmp, 0x5c, sizeof(padtmp));
+
+    if (!SHA1_Update(sha1, padtmp, sizeof(padtmp)))
+        return 0;
+
+    if (!SHA1_Update(sha1, sha1tmp, sizeof(sha1tmp)))
+        return 0;
+
+    /* Now when ctx is finalised it will return the SSL v3 hash value */
+    OPENSSL_cleanse(sha1tmp, sizeof(sha1tmp));
+
+    return 1;
+
+}
+
 static const EVP_MD sha1_md = {
     NID_sha1,
     NID_sha1WithRSAEncryption,
@@ -94,6 +148,7 @@ static const EVP_MD sha1_md = {
     EVP_PKEY_NULL_method,
     SHA_CBLOCK,
     sizeof(EVP_MD *) + sizeof(SHA_CTX),
+    ctrl
 };
 
 const EVP_MD *EVP_sha1(void)