Author: ache
Date: Fri Apr 26 01:56:58 2013
New Revision: 249915
URL: http://svnweb.freebsd.org/changeset/base/249915
Log:
MFC r249631
Attempt to mitigate poor initialization of arc4 by one-shot
reinitialization from yarrow right after good entropy is harvested.
Approved by: secteam (delphij)
Modified:
stable/9/sys/dev/random/randomdev_soft.c
stable/9/sys/libkern/arc4random.c
stable/9/sys/sys/libkern.h
Directory Properties:
stable/9/sys/ (props changed)
stable/9/sys/dev/ (props changed)
stable/9/sys/sys/ (props changed)
Modified: stable/9/sys/dev/random/randomdev_soft.c
==============================================================================
--- stable/9/sys/dev/random/randomdev_soft.c Fri Apr 26 00:53:34 2013
(r249914)
+++ stable/9/sys/dev/random/randomdev_soft.c Fri Apr 26 01:56:58 2013
(r249915)
@@ -366,6 +366,8 @@ random_yarrow_unblock(void)
selwakeuppri(&random_systat.rsel, PUSER);
wakeup(&random_systat);
}
+ (void)atomic_cmpset_int(&arc4rand_iniseed_state, ARC4_ENTR_NONE,
+ ARC4_ENTR_HAVE);
}
static int
Modified: stable/9/sys/libkern/arc4random.c
==============================================================================
--- stable/9/sys/libkern/arc4random.c Fri Apr 26 00:53:34 2013
(r249914)
+++ stable/9/sys/libkern/arc4random.c Fri Apr 26 01:56:58 2013
(r249915)
@@ -24,6 +24,8 @@ __FBSDID("$FreeBSD$");
#define ARC4_RESEED_SECONDS 300
#define ARC4_KEYBYTES (256 / 8)
+int arc4rand_iniseed_state = ARC4_ENTR_NONE;
+
static u_int8_t arc4_i, arc4_j;
static int arc4_numruns = 0;
static u_int8_t arc4_sbox[256];
@@ -130,7 +132,8 @@ arc4rand(void *ptr, u_int len, int resee
struct timeval tv;
getmicrouptime(&tv);
- if (reseed ||
+ if (atomic_cmpset_int(&arc4rand_iniseed_state, ARC4_ENTR_HAVE,
+ ARC4_ENTR_SEED) || reseed ||
(arc4_numruns > ARC4_RESEED_BYTES) ||
(tv.tv_sec > arc4_t_reseed))
arc4_randomstir();
Modified: stable/9/sys/sys/libkern.h
==============================================================================
--- stable/9/sys/sys/libkern.h Fri Apr 26 00:53:34 2013 (r249914)
+++ stable/9/sys/sys/libkern.h Fri Apr 26 01:56:58 2013 (r249915)
@@ -70,6 +70,11 @@ static __inline int abs(int a) { return
static __inline long labs(long a) { return (a < 0 ? -a : a); }
static __inline quad_t qabs(quad_t a) { return (a < 0 ? -a : a); }
+#define ARC4_ENTR_NONE 0 /* Don't have entropy yet. */
+#define ARC4_ENTR_HAVE 1 /* Have entropy. */
+#define ARC4_ENTR_SEED 2 /* Reseeding. */
+extern int arc4rand_iniseed_state;
+
/* Prototypes for non-quad routines. */
struct malloc_type;
uint32_t arc4random(void);
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