android_kernel_oneplus_msm8998/net/core
Alexei Starovoitov 28c486744e bpf: introduce BPF_JIT_ALWAYS_ON config
[ upstream commit 290af86629b25ffd1ed6232c4e9107da031705cb ]

The BPF interpreter has been used as part of the spectre 2 attack CVE-2017-5715.

A quote from goolge project zero blog:
"At this point, it would normally be necessary to locate gadgets in
the host kernel code that can be used to actually leak data by reading
from an attacker-controlled location, shifting and masking the result
appropriately and then using the result of that as offset to an
attacker-controlled address for a load. But piecing gadgets together
and figuring out which ones work in a speculation context seems annoying.
So instead, we decided to use the eBPF interpreter, which is built into
the host kernel - while there is no legitimate way to invoke it from inside
a VM, the presence of the code in the host kernel's text section is sufficient
to make it usable for the attack, just like with ordinary ROP gadgets."

To make attacker job harder introduce BPF_JIT_ALWAYS_ON config
option that removes interpreter from the kernel in favor of JIT-only mode.
So far eBPF JIT is supported by:
x64, arm64, arm32, sparc64, s390, powerpc64, mips64

The start of JITed program is randomized and code page is marked as read-only.
In addition "constant blinding" can be turned on with net.core.bpf_jit_harden

v2->v3:
- move __bpf_prog_ret0 under ifdef (Daniel)

v1->v2:
- fix init order, test_bpf and cBPF (Daniel's feedback)
- fix offloaded bpf (Jakub's feedback)
- add 'return 0' dummy in case something can invoke prog->bpf_func
- retarget bpf tree. For bpf-next the patch would need one extra hunk.
  It will be sent when the trees are merged back to net-next

Considered doing:
  int bpf_jit_enable __read_mostly = BPF_EBPF_JIT_DEFAULT;
but it seems better to land the patch as-is and in bpf-next remove
bpf_jit_enable global variable from all JITs, consolidate in one place
and remove this jit_init() function.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03 17:04:24 +01:00
..
datagram.c net: rename SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA 2015-12-01 15:45:05 -05:00
dev.c net: qdisc_pkt_len_init() should be more robust 2018-01-31 12:06:13 +01:00
dev_addr_lists.c net: fix spelling for synchronized 2014-11-18 15:26:32 -05:00
dev_ioctl.c net: Zero terminate ifr_name in dev_ifname(). 2017-08-11 09:08:52 -07:00
drop_monitor.c drop_monitor: consider inserted data in genlmsg_end 2017-01-15 13:41:35 +01:00
dst.c Fix an intermittent pr_emerg warning about lo becoming free. 2017-07-05 14:37:13 +02:00
ethtool.c ethtool: do not vzalloc(0) on registers dump 2017-06-17 06:39:36 +02:00
fib_rules.c fib_rules: fix fib rule dumps across multiple skbs 2015-09-24 15:21:54 -07:00
filter.c bpf: introduce BPF_JIT_ALWAYS_ON config 2018-02-03 17:04:24 +01:00
flow.c flow: Move __get_hash_from_flowi{4,6} into flow_dissector.c 2015-09-01 17:00:24 -07:00
flow_dissector.c flow_dissector: properly cap thoff field 2018-01-31 12:06:14 +01:00
gen_estimator.c net_sched: gen_estimator: extend pps limit 2015-07-08 13:59:20 -07:00
gen_stats.c gen_stats.c: Duplicate xstats buffer for later use 2015-02-19 15:45:53 -05:00
link_watch.c dev: introduce dev_get_iflink() 2015-04-02 14:04:59 -04:00
lwtunnel.c dst: Pass net into dst->output 2015-10-08 04:27:03 -07:00
Makefile lwtunnel: infrastructure for handling light weight tunnels like mpls 2015-07-21 10:39:03 -07:00
neighbour.c net: Allow neigh contructor functions ability to modify the primary_key 2018-01-31 12:06:14 +01:00
net-procfs.c rps: selective flow shedding during softnet overflow 2013-05-20 13:48:04 -07:00
net-sysfs.c switchdev: rename SWITCHDEV_ATTR_* enum values to SWITCHDEV_ATTR_ID_* 2015-10-03 04:49:37 -07:00
net-sysfs.h net: netdev_kobject_init: annotate with __init 2014-01-05 20:27:54 -05:00
net-traces.c net: FIB tracepoints 2015-08-29 13:05:16 -07:00
net_namespace.c net: Fix double free and memory corruption in get_net_ns_by_id() 2018-01-02 20:33:26 +01:00
netclassid_cgroup.c Merge branch 'master' into for-4.4-fixes 2015-12-07 10:09:03 -05:00
netevent.c netevent: remove automatic variable in register_netevent_notifier() 2015-05-31 00:03:21 -07:00
netpoll.c netpoll: Check for skb->queue_mapping 2017-05-02 21:19:53 -07:00
netprio_cgroup.c cgroup: fix handling of multi-destination migration from subtree_control enabling 2015-12-03 10:18:21 -05:00
pktgen.c net: pktgen: remove rcu locking in pktgen_change_name() 2016-11-15 07:46:38 +01:00
ptp_classifier.c ptp: Change ptp_class to a proper bitmask 2015-11-03 11:08:22 -05:00
request_sock.c tcp: restore fastopen operations 2015-10-05 03:19:06 -07:00
rtnetlink.c rtnetlink: allocate more memory for dev_set_mac_address() 2017-08-11 09:08:52 -07:00
scm.c unix: correctly track in-flight fds in sending process user_struct 2016-03-03 15:07:05 -08:00
secure_seq.c net: remove a sparse error in secure_dccpv6_sequence_number() 2015-05-25 22:55:37 -04:00
skbuff.c sock: free skb in skb_complete_tx_timestamp on error 2018-01-02 20:33:26 +01:00
sock.c net: Set sk_prot_creator when cloning sockets to the right proto 2017-10-21 17:09:03 +02:00
sock_diag.c net: core: fix module type in sock_diag_bind 2018-01-17 09:35:29 +01:00
stream.c net: fix sock_wake_async() rcu protection 2015-12-01 15:45:05 -05:00
sysctl_net_core.c bpf: introduce BPF_JIT_ALWAYS_ON config 2018-02-03 17:04:24 +01:00
timestamping.c net: skb_defer_rx_timestamp should check for phydev before setting up classify 2015-07-09 14:17:15 -07:00
tso.c net: tso: add support for IPv6 2015-10-26 22:24:22 -07:00
utils.c net: move net_get_random_once to lib 2015-10-08 05:26:35 -07:00