Attachment 313529 Details for Bug 458016 – Upstream patch for this issue

[patch] Upstream patch for this issue

0001-random32-seeding-improvement.patch (text/plain), 2.86 KB, created by Eugene Teo (Security Response) on 2008-08-06 06:22:51 UTC

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Creator: Eugene Teo (Security Response)

Created: 2008-08-06 06:22:51 UTC

Size: 2.86 KB

patch

obsolete

>From 697f8d0348a652593d195a13dd1067d9df911a82 Mon Sep 17 00:00:00 2001
>From: Stephen Hemminger <shemminger@vyatta.com>
>Date: Wed, 30 Jul 2008 16:29:19 -0700
>Subject: [PATCH] random32: seeding improvement
>
>The rationale is:
>   * use u32 consistently
>   * no need to do LCG on values from (better) get_random_bytes
>   * use more data from get_random_bytes for secondary seeding
>   * don't reduce state space on srandom32()
>   * enforce state variable initialization restrictions
>
>Note: the second paper has a version of random32() with even longer period
>and a version of random64() if needed.
>
>Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>---
> lib/random32.c |   48 +++++++++++++++++++++++++++---------------------
> 1 files changed, 27 insertions(+), 21 deletions(-)
>
>diff --git a/lib/random32.c b/lib/random32.c
>index ca87d86..217d5c4 100644
>--- a/lib/random32.c
>+++ b/lib/random32.c
>@@ -56,23 +56,12 @@ static u32 __random32(struct rnd_state *state)
> 	return (state->s1 ^ state->s2 ^ state->s3);
> }
> 
>-static void __set_random32(struct rnd_state *state, unsigned long s)
>+/*
>+ * Handle minimum values for seeds
>+ */
>+static inline u32 __seed(u32 x, u32 m)
> {
>-	if (s == 0)
>-		s = 1;      /* default seed is 1 */
>-
>-#define LCG(n) (69069 * n)
>-	state->s1 = LCG(s);
>-	state->s2 = LCG(state->s1);
>-	state->s3 = LCG(state->s2);
>-
>-	/* "warm it up" */
>-	__random32(state);
>-	__random32(state);
>-	__random32(state);
>-	__random32(state);
>-	__random32(state);
>-	__random32(state);
>+	return (x < m) ? x + m : x;
> }
> 
> /**
>@@ -107,7 +96,7 @@ void srandom32(u32 entropy)
> 	 */
> 	for_each_possible_cpu (i) {
> 		struct rnd_state *state = &per_cpu(net_rand_state, i);
>-		__set_random32(state, state->s1 ^ entropy);
>+		state->s1 = __seed(state->s1 ^ entropy, 1);
> 	}
> }
> EXPORT_SYMBOL(srandom32);
>@@ -122,7 +111,19 @@ static int __init random32_init(void)
> 
> 	for_each_possible_cpu(i) {
> 		struct rnd_state *state = &per_cpu(net_rand_state,i);
>-		__set_random32(state, i + jiffies);
>+
>+#define LCG(x)	((x) * 69069)	/* super-duper LCG */
>+		state->s1 = __seed(LCG(i + jiffies), 1);
>+		state->s2 = __seed(LCG(state->s1), 7);
>+		state->s3 = __seed(LCG(state->s2), 15);
>+
>+		/* "warm it up" */
>+		__random32(state);
>+		__random32(state);
>+		__random32(state);
>+		__random32(state);
>+		__random32(state);
>+		__random32(state);
> 	}
> 	return 0;
> }
>@@ -135,13 +136,18 @@ core_initcall(random32_init);
> static int __init random32_reseed(void)
> {
> 	int i;
>-	unsigned long seed;
> 
> 	for_each_possible_cpu(i) {
> 		struct rnd_state *state = &per_cpu(net_rand_state,i);
>+		u32 seeds[3];
>+
>+		get_random_bytes(&seeds, sizeof(seeds));
>+		state->s1 = __seed(seeds[0], 1);
>+		state->s2 = __seed(seeds[1], 7);
>+		state->s3 = __seed(seeds[2], 15);
> 
>-		get_random_bytes(&seed, sizeof(seed));
>-		__set_random32(state, seed);
>+		/* mix it in */
>+		__random32(state);
> 	}
> 	return 0;
> }
>-- 
>1.5.5.1
>

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Attachments on bug 458016: 313529