[src/trunk]: src/lib/libc/gen Fix bug in previous: don't reinitialize on ever...

[tls <tls%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3720e2ff1913
branches:  trunk
changeset: 777778:3720e2ff1913
user:      tls <tls%NetBSD.org@localhost>
date:      Sun Mar 04 00:36:43 2012 +0000

description:
Fix bug in previous: don't reinitialize on every call!  Fix arc4random_buf so it actually ever initializes -- a security problem with revisions 1.9 and 1.10.

diffstat:

 lib/libc/gen/arc4random.c |  36 +++++++++++++++++++++++-------------
 1 files changed, 23 insertions(+), 13 deletions(-)

diffs (105 lines):

diff -r b1d7e54cd495 -r 3720e2ff1913 lib/libc/gen/arc4random.c
--- a/lib/libc/gen/arc4random.c Sun Mar 04 00:21:20 2012 +0000
+++ b/lib/libc/gen/arc4random.c Sun Mar 04 00:36:43 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: arc4random.c,v 1.11 2012/02/27 04:25:12 tls Exp $      */
+/*     $NetBSD: arc4random.c,v 1.12 2012/03/04 00:36:43 tls Exp $      */
 /*     $OpenBSD: arc4random.c,v 1.6 2001/06/05 05:05:38 pvalchev Exp $ */
 
 /*
@@ -27,7 +27,7 @@
 
 #include <sys/cdefs.h>
 #if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: arc4random.c,v 1.11 2012/02/27 04:25:12 tls Exp $");
+__RCSID("$NetBSD: arc4random.c,v 1.12 2012/03/04 00:36:43 tls Exp $");
 #endif /* LIBC_SCCS and not lint */
 
 #include "namespace.h"
@@ -46,12 +46,12 @@
 
 struct arc4_stream {
        mutex_t mtx;
+       int initialized;
        uint8_t i;
        uint8_t j;
        uint8_t s[256];
 };
 
-static int rs_initialized;
 /* XXX lint explodes with an internal error if only mtx is initialized! */
 static struct arc4_stream rs = { .i = 0, .mtx = MUTEX_INITIALIZER };
 
@@ -70,6 +70,9 @@
                as->s[n] = n;
        as->i = 0;
        as->j = 0;
+
+       as->initialized = 1;
+       arc4_stir(as);
 }
 
 static inline void
@@ -155,11 +158,11 @@
 static inline void
 _arc4random_stir_unlocked(void)
 {
-       if (!rs_initialized) {
-               arc4_init(&rs);
-               rs_initialized = 1;
+       if (__predict_false(!rs.initialized)) {
+               arc4_init(&rs);                         /* stirs */
+       } else {
+               arc4_stir(&rs);
        }
-       arc4_stir(&rs);
 }
 
 void
@@ -179,8 +182,9 @@
 static inline void
 _arc4random_addrandom_unlocked(u_char *dat, int datlen)
 {
-       if (!rs_initialized)
-               arc4_stir(&rs);
+       if (__predict_false(rs.initialized)) {
+               arc4_init(&rs);
+       }
        arc4_addrandom(&rs, dat, datlen);
 }
 
@@ -201,8 +205,9 @@
 static inline uint32_t
 _arc4random_unlocked(void)
 {
-       if (!rs_initialized)
-               arc4_stir(&rs);
+       if (__predict_false(!rs.initialized)) {
+               arc4_init(&rs);
+       }
        return arc4_getword(&rs);
 }
 
@@ -228,6 +233,10 @@
        uint8_t *bp = buf;
        uint8_t *ep = bp + len;
 
+       if (__predict_false(!rs.initialized)) {
+               arc4_init(&rs);
+       }
+
        bp[0] = arc4_getbyte(&rs) % 3;
        while (bp[0]--)
                (void)arc4_getbyte(&rs);
@@ -292,8 +301,9 @@
         * number inside the range we need, so it should rarely need
         * to re-roll (at all).
         */
-       if (!rs_initialized)
-               arc4_stir(&rs);
+       if (__predict_false(!rs.initialized)) {
+               arc4_init(&rs);
+       }
        if (arc4_getbyte(&rs) & 1)
                (void)arc4_getbyte(&rs);
        do