Merge branch 'prandom'

prandom fixes/improvements

====================
It would be great if you could still consider this series that fixes and
improves prandom for 3.13. We have sent it to netdev as prandom() originally
came from net/core/utils.c and networking is its main user. For a detailled
description, please see individual patches.

For patch 3 in this series, there will be a minor merge conflict with the
random tree that is for 3.13. See below how to resolve it.

====
Hannes says: on merge with the random tree I would suggest to resolve the
conflict in drivers/char/random.c like this:

if (r->entropy_total > 128) {
	r->initialized = 1;
	r->entropy_total = 0;
	if (r == &nonblocking_pool) {
		prandom_reseed_late();
		pr_notice("random: %s pool is initialized\n",
			  r->name);
	}
}

So it won't generate a warning if DEBUG_RANDOM_BOOT gets activated.
====

Patch 1 should probably also go to -stable.

Set tested on 32 and 64 bit machines.

Thanks a lot!

Ref. original discussion: http://patchwork.ozlabs.org/patch/289951/
====================

Signed-off-by: David S. Miller <[email protected]>

drivers/char/random.c

@@ -603,8 +603,11 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits)
 
 	if (!r->initialized && nbits > 0) {
 		r->entropy_total += nbits;
-		if (r->entropy_total > 128)
+		if (r->entropy_total > 128) {
 			r->initialized = 1;
+			if (r == &nonblocking_pool)
+				prandom_reseed_late();
+		}
 	}
 
 	trace_credit_entropy_bits(r->name, nbits, entropy_count,

include/linux/random.h

@@ -29,8 +29,13 @@ unsigned long randomize_range(unsigned long start, unsigned long end, unsigned l
 u32 prandom_u32(void);
 void prandom_bytes(void *buf, int nbytes);
 void prandom_seed(u32 seed);
+void prandom_reseed_late(void);
 
-u32 prandom_u32_state(struct rnd_state *);
+struct rnd_state {
+	__u32 s1, s2, s3, s4;
+};
+
+u32 prandom_u32_state(struct rnd_state *state);
 void prandom_bytes_state(struct rnd_state *state, void *buf, int nbytes);
 
 /*
@@ -50,9 +55,10 @@ static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
 {
 	u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
 
-	state->s1 = __seed(i, 1);
-	state->s2 = __seed(i, 7);
-	state->s3 = __seed(i, 15);
+	state->s1 = __seed(i,   2U);
+	state->s2 = __seed(i,   8U);
+	state->s3 = __seed(i,  16U);
+	state->s4 = __seed(i, 128U);
 }
 
 #ifdef CONFIG_ARCH_RANDOM

include/uapi/linux/random.h

@@ -40,11 +40,4 @@ struct rand_pool_info {
 	__u32	buf[0];
 };
 
-struct rnd_state {
-	__u32 s1, s2, s3;
-};
-
-/* Exported functions */
-
-
 #endif /* _UAPI_LINUX_RANDOM_H */

lib/Kconfig

@@ -189,6 +189,13 @@ config AUDIT_GENERIC
 	depends on AUDIT && !AUDIT_ARCH
 	default y
 
+config RANDOM32_SELFTEST
+	bool "PRNG perform self test on init"
+	default n
+	help
+	  This option enables the 32 bit PRNG library functions to perform a
+	  self test on initialization.
+
 #
 # compression support is select'ed if needed
 #