Situation occur where bootloader cannot supply kernel with early

random data. But a new source of entropy arrived a few months ago
-- KARL generates highly disturbed images for some kernels (well,
not for bsd.rd)
This assumes the tail of text (just before etext[]) is readable.
We are trying to use a portable symbol name, and also avoid reading
a locore0 which has been unmapped...
ok mortimer

diff --git a/sys/dev/rnd.c b/sys/dev/rnd.c
index 48ae1af..e33cb5f 100644 (file)
--- a/sys/dev/rnd.c
+++ b/sys/dev/rnd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: rnd.c,v 1.197 2018/02/08 10:01:12 mortimer Exp $      */
+/*     $OpenBSD: rnd.c,v 1.198 2018/02/09 03:01:24 deraadt Exp $       */
 
 /*
  * Copyright (c) 2011 Theo de Raadt.
@@ -747,6 +747,8 @@ arc4_reinit(void *v)
 void
 random_start(void)
 {
+       extern char etext[];
+
 #if !defined(NO_PROPOLICE)
        extern long __guard_local;
 
@@ -761,6 +763,8 @@ random_start(void)
        if (msgbufp->msg_magic == MSG_MAGIC)
                add_entropy_words((u_int32_t *)msgbufp->msg_bufc,
                    msgbufp->msg_bufs / sizeof(u_int32_t));
+       add_entropy_words((u_int32_t *)etext - 32*1024,
+           8192/sizeof(u_int32_t));
 
        dequeue_randomness(NULL);
        arc4_init(NULL);