Import change 40eebf235370b6fe6353784ccf01ab92eed062a5 from upstream wpa:

From: Jouni Malinen <j@w1.fi>
  Date: Fri, 15 Jul 2011 13:42:06 +0300
  Subject: [PATCH] MD5: Fix clearing of temporary stack memory to use correct length

  sizeof of the structure instead of the pointer was supposed to be used
  here. Fix this to clear the full structure at the end of MD5Final().

Found by:	clang ToT
Reviewed by:	rpaulo
MFC after:	3 days

contrib/wpa/src/crypto/md5-internal.c

@@ -188,7 +188,7 @@ void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
     MD5Transform(ctx->buf, (u32 *) ctx->in);
     byteReverse((unsigned char *) ctx->buf, 4);
     os_memcpy(digest, ctx->buf, 16);
-    os_memset(ctx, 0, sizeof(ctx));	/* In case it's sensitive */
+    os_memset(ctx, 0, sizeof(*ctx));	/* In case it's sensitive */
 }
 
 /* The four core functions - F1 is optimized somewhat */