Willy Tarreau 3744741ada random32: add noise from network and scheduling activity ... With the removal of the interrupt perturbations in previous random32 change (random32: make prandom_u32() output unpredictable), the PRNG has become 100% deterministic again. While SipHash is expected to be way more robust against brute force than the previous Tausworthe LFSR, there's still the risk that whoever has even one temporary access to the PRNG's internal state is able to predict all subsequent draws till the next reseed (roughly every minute). This may happen through a side channel attack or any data leak. This patch restores the spirit of commit f227e3ec3b ("random32: update the net random state on interrupt and activity") in that it will perturb the internal PRNG's statee using externally collected noise, except that it will not pick that noise from the random pool's bits nor upon interrupt, but will rather combine a few elements along the Tx path that are collectively hard to predict, such as dev, skb and txq pointers, packet length and jiffies values. These ones are combined using a single round of SipHash into a single long variable that is mixed with the net_rand_state upon each invocation. The operation was inlined because it produces very small and efficient code, typically 3 xor, 2 add and 2 rol. The performance was measured to be the same (even very slightly better) than before the switch to SipHash; on a 6-core 12-thread Core i7-8700k equipped with a 40G NIC (i40e), the connection rate dropped from 556k/s to 555k/s while the SYN cookie rate grew from 5.38 Mpps to 5.45 Mpps. Link: https://lore.kernel.org/netdev/20200808152628.GA27941@SDF.ORG/ Cc: George Spelvin <lkml@sdf.org> Cc: Amit Klein <aksecurity@gmail.com> Cc: Eric Dumazet <edumazet@google.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: tytso@mit.edu Cc: Florian Westphal <fw@strlen.de> Cc: Marc Plumb <lkml.mplumb@gmail.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Willy Tarreau <w@1wt.eu>		2020-10-24 20:21:57 +02:00
..
bpf_sk_storage.c	bpf: Change bpf_sk_storage_*() to accept ARG_PTR_TO_BTF_ID_SOCK_COMMON	2020-09-25 13:58:01 -07:00
datagram.c	net: zerocopy: combine pages in zerocopy_sg_from_iter()	2020-08-20 16:12:50 -07:00
datagram.h
dev.c	random32: add noise from network and scheduling activity	2020-10-24 20:21:57 +02:00
dev_addr_lists.c	net: core: add nested_level variable in net_device	2020-09-28 15:00:15 -07:00
dev_ioctl.c	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
devlink.c	devlink: Add enable_remote_dev_reset generic parameter	2020-10-09 12:06:53 -07:00
drop_monitor.c	genetlink: move to smaller ops wherever possible	2020-10-02 19:11:11 -07:00
dst.c	net: Correct the comment of dst_dev_put()	2020-09-10 13:28:57 -07:00
dst_cache.c
failover.c
fib_notifier.c
fib_rules.c	fib: fix fib_rule_ops indirect call wrappers when CONFIG_IPV6=m	2020-09-08 20:09:08 -07:00
filter.c	net: Properly typecast int values to set sk_max_pacing_rate	2020-10-22 12:18:25 -07:00
flow_dissector.c	net: flow_dissector: avoid indirect call to DSA .flow_dissect for generic case	2020-09-26 14:17:59 -07:00
flow_offload.c
gen_estimator.c
gen_stats.c
gro_cells.c
hwbm.c
link_watch.c
lwt_bpf.c
lwtunnel.c
Makefile
neighbour.c
net-procfs.c	net-sysfs: add backlog len and CPU id to softnet data	2020-09-21 13:56:37 -07:00
net-sysfs.c	net-sysfs: Fix inconsistent of format with argument type in net-sysfs.c	2020-10-01 18:45:23 -07:00
net-sysfs.h
net-traces.c
net_namespace.c	bpf, net: Rework cookie generator as per-cpu one	2020-09-30 11:50:35 -07:00
netclassid_cgroup.c
netevent.c
netpoll.c	net: make sure napi_list is safe for RCU traversal	2020-09-10 13:08:46 -07:00
netprio_cgroup.c
page_pool.c
pktgen.c	pktgen: Fix inconsistent of format with argument type in pktgen.c	2020-10-01 18:45:23 -07:00
ptp_classifier.c	ptp: Add generic ptp v2 header parsing function	2020-08-19 16:07:49 -07:00
request_sock.c
rtnetlink.c	rtnetlink: fix data overflow in rtnl_calcit()	2020-10-21 18:24:08 -07:00
scm.c
secure_seq.c
skbuff.c	networking changes for the 5.10 merge window	2020-10-15 18:42:13 -07:00
skmsg.c	bpf, sockmap: Allow skipping sk_skb parser program	2020-10-11 18:09:44 -07:00
sock.c	net: Properly typecast int values to set sk_max_pacing_rate	2020-10-22 12:18:25 -07:00
sock_diag.c	bpf, net: Rework cookie generator as per-cpu one	2020-09-30 11:50:35 -07:00
sock_map.c	net, sockmap: Don't call bpf_prog_put() on NULL pointer	2020-10-15 21:05:23 +02:00
sock_reuseport.c
stream.c
sysctl_net_core.c	net: add option to not create fall-back tunnels in root-ns as well	2020-08-28 06:52:44 -07:00
timestamping.c
tso.c
utils.c
xdp.c