random: make get_random_int() more random

[firefly-linux-kernel-4.4.55.git] / drivers / char / random.c

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 7c43ae782b26e385e1b0c96efacd7e82846b794b..b2ced39d76b227a064d383f55aeca78ac2bf380a 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1488,7 +1488,8 @@ static void rekey_seq_generator(struct work_struct *work)
        keyptr->count = (ip_cnt & COUNT_MASK) << HASH_BITS;
        smp_wmb();
        ip_cnt++;
-       schedule_delayed_work(&rekey_work, REKEY_INTERVAL);
+       schedule_delayed_work(&rekey_work,
+                             round_jiffies_relative(REKEY_INTERVAL));
 }
 
 static inline struct keydata *get_keyptr(void)
@@ -1664,15 +1665,20 @@ EXPORT_SYMBOL(secure_dccp_sequence_number);
  * value is not cryptographically secure but for several uses the cost of
  * depleting entropy is too high
  */
+DEFINE_PER_CPU(__u32 [4], get_random_int_hash);
 unsigned int get_random_int(void)
 {
-       /*
-        * Use IP's RNG. It suits our purpose perfectly: it re-keys itself
-        * every second, from the entropy pool (and thus creates a limited
-        * drain on it), and uses halfMD4Transform within the second. We
-        * also mix it with jiffies and the PID:
-        */
-       return secure_ip_id((__force __be32)(current->pid + jiffies));
+       struct keydata *keyptr;
+       __u32 *hash = get_cpu_var(get_random_int_hash);
+       int ret;
+
+       keyptr = get_keyptr();
+       hash[0] += current->pid + jiffies + get_cycles() + (int)(long)&ret;
+
+       ret = half_md4_transform(hash, keyptr->secret);
+       put_cpu_var(get_random_int_hash);
+
+       return ret;
 }
 
 /*