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authorLinus Torvalds <torvalds@linux-foundation.org>2020-10-25 10:40:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-25 10:40:08 -0700
commit91f28da8c9a054286d6917ce191349455c479478 (patch)
treee095a831ada79f835d1d9310df529007665a498e /drivers
parentd76913908102044f14381df865bb74df17a538cb (diff)
parentc6e169bc146a76d5ccbf4d3825f705414352bd03 (diff)
Merge tag '20201024-v4-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/prandom
Pull random32 updates from Willy Tarreau: "Make prandom_u32() less predictable. This is the cleanup of the latest series of prandom_u32 experimentations consisting in using SipHash instead of Tausworthe to produce the randoms used by the network stack. The changes to the files were kept minimal, and the controversial commit that used to take noise from the fast_pool (f227e3ec3b5c) was reverted. Instead, a dedicated "net_rand_noise" per_cpu variable is fed from various sources of activities (networking, scheduling) to perturb the SipHash state using fast, non-trivially predictable data, instead of keeping it fully deterministic. The goal is essentially to make any occasional memory leakage or brute-force attempt useless. The resulting code was verified to be very slightly faster on x86_64 than what is was with the controversial commit above, though this remains barely above measurement noise. It was also tested on i386 and arm, and build- tested only on arm64" Link: https://lore.kernel.org/netdev/20200808152628.GA27941@SDF.ORG/ * tag '20201024-v4-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/prandom: random32: add a selftest for the prandom32 code random32: add noise from network and scheduling activity random32: make prandom_u32() output unpredictable
Diffstat (limited to 'drivers')
-rw-r--r--drivers/char/random.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index d20ba1b104ca..2a41b21623ae 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1277,7 +1277,6 @@ void add_interrupt_randomness(int irq, int irq_flags)
fast_mix(fast_pool);
add_interrupt_bench(cycles);
- this_cpu_add(net_rand_state.s1, fast_pool->pool[cycles & 3]);
if (unlikely(crng_init == 0)) {
if ((fast_pool->count >= 64) &&