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Index: sys/netinet6/ip6_id.c
===================================================================
--- sys/netinet6/ip6_id.c
+++ sys/netinet6/ip6_id.c
@@ -89,9 +89,12 @@
#include <sys/types.h>
#include <sys/param.h>
#include <sys/kernel.h>
+#include <sys/random.h>
#include <sys/socket.h>
#include <sys/libkern.h>
+#include <machine/cpu.h>
+
#include <net/if.h>
#include <net/route.h>
#include <net/vnet.h>
@@ -171,6 +174,25 @@
return (s);
}
+static inline uint32_t
+arc4random_wrapper(void)
+{
+ /*
+ * Is it sane to generate potentially non-random IPv6 flowids if random
+ * isn't seeded yet, rather than blocking indefinitely? Or do IPv6
+ * flowids really need to be unpredictable (and would prefer to block
+ * indefinitely until entropy is available)?
+ */
+
+ if (!is_random_seeded()) {
+ uint64_t cc;
+
+ cc = get_cyclecount();
+ return ((cc >> 32) ^ cc);
+ }
+ return (arc4random());
+}
+
/*
* Initializes the seed and chooses a suitable generator. Also toggles
* the msb flag. The msb flag is used to generate two distinct
@@ -185,20 +207,20 @@
u_int32_t j, i;
int noprime = 1;
- p->ru_x = arc4random() % p->ru_m;
+ p->ru_x = arc4random_wrapper() % p->ru_m;
/* (bits - 1) bits of random seed */
- p->ru_seed = arc4random() & (~0U >> (32 - p->ru_bits + 1));
- p->ru_seed2 = arc4random() & (~0U >> (32 - p->ru_bits + 1));
+ p->ru_seed = arc4random_wrapper() & (~0U >> (32 - p->ru_bits + 1));
+ p->ru_seed2 = arc4random_wrapper() & (~0U >> (32 - p->ru_bits + 1));
/* Determine the LCG we use */
- p->ru_b = (arc4random() & (~0U >> (32 - p->ru_bits))) | 1;
+ p->ru_b = (arc4random_wrapper() & (~0U >> (32 - p->ru_bits))) | 1;
p->ru_a = pmod(p->ru_agen,
- (arc4random() & (~0U >> (32 - p->ru_bits))) & (~1U), p->ru_m);
+ (arc4random_wrapper() & (~0U >> (32 - p->ru_bits))) & (~1U), p->ru_m);
while (p->ru_b % 3 == 0)
p->ru_b += 2;
- j = arc4random() % p->ru_n;
+ j = arc4random_wrapper() % p->ru_n;
/*
* Do a fast gcd(j, RU_N - 1), so we can find a j with
@@ -232,7 +254,7 @@
initid(p);
/* Skip a random number of ids */
- n = arc4random() & 0x3;
+ n = arc4random_wrapper() & 0x3;
if (p->ru_counter + n >= p->ru_max)
initid(p);

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