From ce9d26a8fbad590aa685db707e93ed6aa9278068 Mon Sep 17 00:00:00 2001
From: tg <tg@mirbsd.org>
Date: Tue, 27 Apr 2004 19:59:57 +0000
Subject: [PATCH] * mirbsdksh and mirosksh != rksh * use arc4random familiy for
 randomness, if exists * feed back randomness on reseed and variable
 assignments

---
 ksh.1tbl |  9 ++++++++-
 main.c   | 20 ++++++++++++++------
 proto.h  |  4 +++-
 var.c    | 40 ++++++++++++++++++++++++++++++++++++----
 4 files changed, 61 insertions(+), 12 deletions(-)

diff --git a/ksh.1tbl b/ksh.1tbl
index f37a037..b25f537 100644
--- a/ksh.1tbl
+++ b/ksh.1tbl
@@ -1,4 +1,4 @@
-.\" $MirBSD: ksh.1tbl,v 1.21 2004/04/26 18:38:19 tg Exp $
+.\" $MirBSD: ksh.1tbl,v 1.22 2004/04/27 19:59:55 tg Exp $
 .\" $OpenBSD: ksh.1tbl,v 1.65 2004/01/23 23:08:45 jmc Exp $
 .\"
 .\" Copyright (c) 1980, 1990, 1993
@@ -1565,6 +1565,13 @@ The point in the series can be set by assigning a number to
 .Ev RANDOM
 (see
 .Xr rand 3 ) .
+.Pp
+On systems which provide the
+.Xr arc4random 3
+function, the random value is seeded on start by the arcfour
+random number generator.
+If a feedback function is provided, changed values are propagated
+back to the arcfour random number generator.
 .It Ev REPLY
 Default parameter for the
 .Ic read
diff --git a/main.c b/main.c
index b9e6ec4..73c0561 100644
--- a/main.c
+++ b/main.c
@@ -1,5 +1,5 @@
-/*	$MirBSD: main.c,v 1.5 2004/04/26 18:38:20 tg Exp $	*/
-/*	$OpenBSD: main.c,v 1.26 2004/01/08 05:43:14 jmc Exp $	*/
+/* $MirBSD: main.c,v 1.6 2004/04/27 19:59:56 tg Exp $	*/
+/* $OpenBSD: main.c,v 1.26 2004/01/08 05:43:14 jmc Exp $	*/
 
 /*
  * startup, main loop, environments and error handling
@@ -94,6 +94,9 @@ main(int argc, char *argv[])
 	char **wp;
 	struct env env;
 	pid_t ppid;
+#ifdef	KSH
+	long trnd;
+#endif
 
 #ifdef MEM_DEBUG
 	chmem_set_defaults("ct", 1);
@@ -115,6 +118,9 @@ main(int argc, char *argv[])
 		argc = 1;
 	}
 	kshname = *argv;
+#ifdef	KSH
+	trnd = *((long *)kshname);
+#endif
 
 	ainit(&aperm);		/* initialize permanent Area */
 
@@ -255,9 +261,10 @@ main(int argc, char *argv[])
 	}
 	ppid = getppid();
 	setint(global("PPID"), (long) ppid);
-#ifdef KSH
-	setint(global("RANDOM"), (long) (time((time_t *)0) * kshpid * ppid));
-#endif /* KSH */
+#ifdef	KSH
+	trnd ^= ((long) (time((time_t *)0) * kshpid * ppid));
+	setint(global("RANDOM"), prng_seed(trnd));
+#endif	/* KSH */
 	/* setstr can't fail here */
 	setstr(global(version_param), ksh_version, KSH_RETURN_ERROR);
 
@@ -848,7 +855,8 @@ is_restricted(name)
 	if ((p = ksh_strrchr_dirsep(name)))
 		name = p;
 	/* accepts rsh, rksh, rpdksh, pdrksh, etc. */
-	return (p = strchr(name, 'r')) && strstr(p, "sh");
+	return (p = strchr(name, 'r')) && strstr(p, "sh")
+	    && !strstr(p-2, "mirbsdksh") && !strstr(p-2, "mirosksh");
 }
 
 void
diff --git a/proto.h b/proto.h
index d0b7e8a..aa41f3c 100644
--- a/proto.h
+++ b/proto.h
@@ -1,4 +1,5 @@
-/*	$OpenBSD: proto.h,v 1.11 2003/05/16 19:58:57 jsyn Exp $	*/
+/* $MirBSD: proto.h,v 1.2 2004/04/27 19:59:57 tg Exp $ */
+/* $OpenBSD: proto.h,v 1.11 2003/05/16 19:58:57 jsyn Exp $	*/
 
 /*
  * prototypes for PD-KSH
@@ -275,6 +276,7 @@ void	change_random	ARGS((void));
 int	array_ref_len	ARGS((const char *cp));
 char *	arrayname	ARGS((const char *str));
 void    set_array	ARGS((const char *var, int reset, char **vals));
+long	prng_seed	ARGS((long));
 /* version.c */
 /* vi.c: see edit.h */
 
diff --git a/var.c b/var.c
index dc2577b..7b5d4a4 100644
--- a/var.c
+++ b/var.c
@@ -1,5 +1,5 @@
-/*	$MirBSD: var.c,v 1.2 2004/04/17 00:47:20 tg Exp $	*/
-/*	$OpenBSD: var.c,v 1.16 2003/08/05 20:52:27 millert Exp $	*/
+/* $MirBSD: var.c,v 1.3 2004/04/27 19:59:57 tg Exp $	*/
+/* $OpenBSD: var.c,v 1.16 2003/08/05 20:52:27 millert Exp $	*/
 
 #include "sh.h"
 #include "ksh_time.h"
@@ -891,7 +891,7 @@ makenv()
 void
 change_random()
 {
-    rand();
+    prng_seed(rand());
 }
 
 /*
@@ -1046,7 +1046,8 @@ setspec(vp)
 		break;
 	  case V_RANDOM:
 		vp->flag &= ~SPECIAL;
-		srand((unsigned int)intval(vp));
+		srand(prng_seed(((unsigned int)intval(vp))
+		    ^ ((unsigned long)rand() << 24)));
 		vp->flag |= SPECIAL;
 		break;
 	  case V_SECONDS:
@@ -1237,3 +1238,34 @@ set_array(var, reset, vals)
 		setstr(vq, vals[i], KSH_RETURN_ERROR);
 	}
 }
+
+/* Return a seed PRNG value, and feed one back to arc4random */
+long
+prng_seed(val)
+	long val;
+{
+	unsigned long i, j;
+
+#ifdef	HAVE_ARC4RANDOM
+	i = arc4random();
+#else
+	i = ((long) (time((time_t *)0) * getpid()));
+#endif
+	j = (rand() << 16) | rand();
+
+	i ^= val;
+	j ^= val;
+
+#if defined(HAVE_ARC4RANDOM_PUSH)
+	arc4random_push(j);
+#elif defined(HAVE_ARC4RANDOM_ADDRANDOM)
+	arc4random_addrandom(&j, sizeof (j));
+#else
+	while (j) {
+		rand();
+		j >>= 1;
+	}
+#endif
+
+	return i;
+}