@@ -17,6 +17,12 @@ void prandom_bytes(void *buf, size_t nbytes);
void prandom_seed(u32 seed);
void prandom_reseed_late(void);
+DECLARE_PER_CPU(unsigned long, net_rand_noise);
+
+#define PRANDOM_ADD_NOISE(a, b, c, d) \
+ prandom_u32_add_noise((unsigned long)(a), (unsigned long)(b), \
+ (unsigned long)(c), (unsigned long)(d))
+
#if BITS_PER_LONG == 64
/*
* The core SipHash round function. Each line can be executed in
@@ -41,6 +47,18 @@ void prandom_reseed_late(void);
#error Unsupported BITS_PER_LONG
#endif
+static inline void prandom_u32_add_noise(unsigned long a, unsigned long b,
+ unsigned long c, unsigned long d)
+{
+ /*
+ * This is not used cryptographically; it's just
+ * a convenient 4-word hash function. (3 xor, 2 add, 2 rol)
+ */
+ a ^= raw_cpu_read(net_rand_noise);
+ PRND_SIPROUND(a, b, c, d);
+ raw_cpu_write(net_rand_noise, d);
+}
+
struct rnd_state {
__u32 s1, s2, s3, s4;
};
@@ -90,6 +108,7 @@ static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
state->s2 = __seed(i, 8U);
state->s3 = __seed(i, 16U);
state->s4 = __seed(i, 128U);
+ PRANDOM_ADD_NOISE(state, i, 0, 0);
}
/* Pseudo random number generator from numerical recipes. */
@@ -1734,6 +1734,8 @@ void update_process_times(int user_tick)
{
struct task_struct *p = current;
+ PRANDOM_ADD_NOISE(jiffies, user_tick, p, 0);
+
/* Note: this timer irq context must be accounted for as well. */
account_process_tick(p, user_tick);
run_local_timers();
@@ -339,6 +339,8 @@ struct siprand_state {
};
static DEFINE_PER_CPU(struct siprand_state, net_rand_state) __latent_entropy;
+DEFINE_PER_CPU(unsigned long, net_rand_noise);
+EXPORT_PER_CPU_SYMBOL(net_rand_noise);
/*
* This is the core CPRNG function. As "pseudorandom", this is not used
@@ -362,9 +364,12 @@ static DEFINE_PER_CPU(struct siprand_state, net_rand_state) __latent_entropy;
static inline u32 siprand_u32(struct siprand_state *s)
{
unsigned long v0 = s->v0, v1 = s->v1, v2 = s->v2, v3 = s->v3;
+ unsigned long n = raw_cpu_read(net_rand_noise);
+ v3 ^= n;
PRND_SIPROUND(v0, v1, v2, v3);
PRND_SIPROUND(v0, v1, v2, v3);
+ v0 ^= n;
s->v0 = v0; s->v1 = v1; s->v2 = v2; s->v3 = v3;
return v1 + v3;
}
@@ -143,6 +143,7 @@
#include <linux/net_namespace.h>
#include <linux/indirect_call_wrapper.h>
#include <net/devlink.h>
+#include <linux/prandom.h>
#include "net-sysfs.h"
@@ -3204,6 +3205,7 @@ static int xmit_one(struct sk_buff *skb, struct net_device *dev,
dev_queue_xmit_nit(skb, dev);
len = skb->len;
+ PRANDOM_ADD_NOISE(skb, dev, txq, len + jiffies);
trace_net_dev_start_xmit(skb, dev);
rc = netdev_start_xmit(skb, dev, txq, more);
trace_net_dev_xmit(skb, rc, dev, len);
@@ -3782,6 +3784,7 @@ static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
if (!skb)
goto out;
+ PRANDOM_ADD_NOISE(skb, dev, txq, jiffies);
HARD_TX_LOCK(dev, txq, cpu);
if (!netif_xmit_stopped(txq)) {
@@ -3847,6 +3850,7 @@ int dev_direct_xmit(struct sk_buff *skb, u16 queue_id)
skb_set_queue_mapping(skb, queue_id);
txq = skb_get_tx_queue(dev, skb);
+ PRANDOM_ADD_NOISE(skb, dev, txq, jiffies);
local_bh_disable();