1 files changed, 28 insertions, 21 deletions

diff --git a/lib/random32.c b/lib/random32.c
index fa5da61ce7ad..c9b6bf3afe0c 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -40,6 +40,10 @@
 
 #ifdef CONFIG_RANDOM32_SELFTEST
 static void __init prandom_state_selftest(void);
+#else
+static inline void prandom_state_selftest(void)
+{
+}
 #endif
 
 static DEFINE_PER_CPU(struct rnd_state, net_rand_state);
@@ -53,8 +57,7 @@ static DEFINE_PER_CPU(struct rnd_state, net_rand_state);
  */
 u32 prandom_u32_state(struct rnd_state *state)
 {
-#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
-
+#define TAUSWORTHE(s, a, b, c, d) ((s & c) << d) ^ (((s << a) ^ s) >> b)
         state->s1 = TAUSWORTHE(state->s1,  6U, 13U, 4294967294U, 18U);
         state->s2 = TAUSWORTHE(state->s2,  2U, 27U, 4294967288U,  2U);
         state->s3 = TAUSWORTHE(state->s3, 13U, 21U, 4294967280U,  7U);
@@ -147,21 +150,25 @@ static void prandom_warmup(struct rnd_state *state)
         prandom_u32_state(state);
 }
 
-static void prandom_seed_very_weak(struct rnd_state *state, u32 seed)
+static u32 __extract_hwseed(void)
 {
-        /* Note: This sort of seeding is ONLY used in test cases and
-         * during boot at the time from core_initcall until late_initcall
-         * as we don't have a stronger entropy source available yet.
-         * After late_initcall, we reseed entire state, we have to (!),
-         * otherwise an attacker just needs to search 32 bit space to
-         * probe for our internal 128 bit state if he knows a couple
-         * of prandom32 outputs!
-         */
-#define LCG(x)  ((x) * 69069U)  /* super-duper LCG */
-        state->s1 = __seed(LCG(seed),        2U);
-        state->s2 = __seed(LCG(state->s1),   8U);
-        state->s3 = __seed(LCG(state->s2),  16U);
-        state->s4 = __seed(LCG(state->s3), 128U);
+        u32 val = 0;
+
+        (void)(arch_get_random_seed_int(&val) ||
+               arch_get_random_int(&val));
+
+        return val;
+}
+
+static void prandom_seed_early(struct rnd_state *state, u32 seed,
+                               bool mix_with_hwseed)
+{
+#define LCG(x)   ((x) * 69069U) /* super-duper LCG */
+#define HWSEED() (mix_with_hwseed ? __extract_hwseed() : 0)
+        state->s1 = __seed(HWSEED() ^ LCG(seed),        2U);
+        state->s2 = __seed(HWSEED() ^ LCG(state->s1),   8U);
+        state->s3 = __seed(HWSEED() ^ LCG(state->s2),  16U);
+        state->s4 = __seed(HWSEED() ^ LCG(state->s3), 128U);
 }
 
 /**
@@ -194,14 +201,13 @@ static int __init prandom_init(void)
 {
         int i;
 
-#ifdef CONFIG_RANDOM32_SELFTEST
         prandom_state_selftest();
-#endif
 
         for_each_possible_cpu(i) {
                 struct rnd_state *state = &per_cpu(net_rand_state,i);
+                u32 weak_seed = (i + jiffies) ^ random_get_entropy();
 
-                prandom_seed_very_weak(state, (i + jiffies) ^ random_get_entropy());
+                prandom_seed_early(state, weak_seed, true);
                 prandom_warmup(state);
         }
 
@@ -210,6 +216,7 @@ static int __init prandom_init(void)
 core_initcall(prandom_init);
 
 static void __prandom_timer(unsigned long dontcare);
+
 static DEFINE_TIMER(seed_timer, __prandom_timer, 0, 0);
 
 static void __prandom_timer(unsigned long dontcare)
@@ -419,7 +426,7 @@ static void __init prandom_state_selftest(void)
         for (i = 0; i < ARRAY_SIZE(test1); i++) {
                 struct rnd_state state;
 
-                prandom_seed_very_weak(&state, test1[i].seed);
+                prandom_seed_early(&state, test1[i].seed, false);
                 prandom_warmup(&state);
 
                 if (test1[i].result != prandom_u32_state(&state))
@@ -434,7 +441,7 @@ static void __init prandom_state_selftest(void)
         for (i = 0; i < ARRAY_SIZE(test2); i++) {
                 struct rnd_state state;
 
-                prandom_seed_very_weak(&state, test2[i].seed);
+                prandom_seed_early(&state, test2[i].seed, false);
                 prandom_warmup(&state);
 
                 for (j = 0; j < test2[i].iteration - 1; j++)