As per 15d83c4d ("bpf: Allow loading of a bpf_iter program") we only
allow a range of [0,1] for return codes. Therefore BPF_TRACE_ITER relies
on the default tnum_range(0, 1) which is set in range var. On recent merge
of net into net-next commit e92888c7 ("bpf: Enforce returning 0 for
fentry/fexit progs") got pulled in and caused a merge conflict with the
changes from 15d83c4d. The resolution had a snall hiccup in that it
removed the [0,1] range restriction again so that BPF_TRACE_ITER would
have no enforcement. Fix it by adding it back.

Fixes: da07f52d ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>

Move the bpf verifier trace check into the new switch statement in
HEAD.

Resolve the overlapping changes in hinic, where bug fixes overlap
the addition of VF support.
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull networking fixes from David Miller:

 1) Fix sk_psock reference count leak on receive, from Xiyu Yang.

 2) CONFIG_HNS should be invisible, from Geert Uytterhoeven.

 3) Don't allow locking route MTUs in ipv6, RFCs actually forbid this,
    from Maciej Żenczykowski.

 4) ipv4 route redirect backoff wasn't actually enforced, from Paolo
    Abeni.

 5) Fix netprio cgroup v2 leak, from Zefan Li.

 6) Fix infinite loop on rmmod in conntrack, from Florian Westphal.

 7) Fix tcp SO_RCVLOWAT hangs, from Eric Dumazet.

 8) Various bpf probe handling fixes, from Daniel Borkmann.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (68 commits)
  selftests: mptcp: pm: rm the right tmp file
  dpaa2-eth: properly handle buffer size restrictions
  bpf: Restrict bpf_trace_printk()'s %s usage and add %pks, %pus specifier
  bpf: Add bpf_probe_read_{user, kernel}_str() to do_refine_retval_range
  bpf: Restrict bpf_probe_read{, str}() only to archs where they work
  MAINTAINERS: Mark networking drivers as Maintained.
  ipmr: Add lockdep expression to ipmr_for_each_table macro
  ipmr: Fix RCU list debugging warning
  drivers: net: hamradio: Fix suspicious RCU usage warning in bpqether.c
  net: phy: broadcom: fix BCM54XX_SHD_SCR3_TRDDAPD value for BCM54810
  tcp: fix error recovery in tcp_zerocopy_receive()
  MAINTAINERS: Add Jakub to networking drivers.
  MAINTAINERS: another add of Karsten Graul for S390 networking
  drivers: ipa: fix typos for ipa_smp2p structure doc
  pppoe: only process PADT targeted at local interfaces
  selftests/bpf: Enforce returning 0 for fentry/fexit programs
  bpf: Enforce returning 0 for fentry/fexit progs
  net: stmmac: fix num_por initialization
  security: Fix the default value of secid_to_secctx hook
  libbpf: Fix register naming in PT_REGS s390 macros
  ...

Pull rdma fixes from Jason Gunthorpe:
 "A few minor bug fixes for user visible defects, and one regression:

   - Various bugs from static checkers and syzkaller

   - Add missing error checking in mlx4

   - Prevent RTNL lock recursion in i40iw

   - Fix segfault in cxgb4 in peer abort cases

   - Fix a regression added in 5.7 where the IB_EVENT_DEVICE_FATAL could
     be lost, and wasn't delivered to all the FDs"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  RDMA/uverbs: Move IB_EVENT_DEVICE_FATAL to destroy_uobj
  RDMA/uverbs: Do not discard the IB_EVENT_DEVICE_FATAL event
  RDMA/iw_cxgb4: Fix incorrect function parameters
  RDMA/core: Fix double put of resource
  IB/core: Fix potential NULL pointer dereference in pkey cache
  IB/hfi1: Fix another case where pq is left on waitlist
  IB/i40iw: Remove bogus call to netdev_master_upper_dev_get()
  IB/mlx4: Test return value of calls to ib_get_cached_pkey
  RDMA/rxe: Always return ERR_PTR from rxe_create_mmap_info()
  i40iw: Fix error handling in i40iw_manage_arp_cache()

Merge tag 'linux-kselftest-5.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull kselftest fixes from Shuah Khan:

 - lkdtm runner fixes to prevent dmesg clearing and shellcheck errors

 - ftrace test handling when test module doesn't exist

 - nsfs test fix to replace zero-length array with flexible-array

 - dmabuf-heaps test fix to return clear error value

* tag 'linux-kselftest-5.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  selftests/lkdtm: Use grep -E instead of egrep
  selftests/lkdtm: Don't clear dmesg when running tests
  selftests/ftrace: mark irqsoff_tracer.tc test as unresolved if the test module does not exist
  tools/testing: Replace zero-length array with flexible-array
  kselftests: dmabuf-heaps: Fix confused return value on expected error testing

Pull RISC-V fixes from Palmer Dabbelt:
 "A handful of build fixes, all found by Huawei's autobuilder.

  None of these patches should have any functional impact on kernels
  that build, and they're mostly related to various features
  intermingling with !MMU.

  While some of these might be better hoisted to generic code, it seems
  better to have the simple fixes in the meanwhile.

  As far as I know these are the only outstanding patches for 5.7"

* tag 'riscv-for-linus-5.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: mmiowb: Fix implicit declaration of function 'smp_processor_id'
  riscv: pgtable: Fix __kernel_map_pages build error if NOMMU
  riscv: Make SYS_SUPPORTS_HUGETLBFS depends on MMU
  riscv: Disable ARCH_HAS_DEBUG_VIRTUAL if NOMMU
  riscv: Add pgprot_writecombine/device and PAGE_SHARED defination if NOMMU
  riscv: stacktrace: Fix undefined reference to `walk_stackframe'
  riscv: Fix unmet direct dependencies built based on SOC_VIRT
  riscv: perf: RISCV_BASE_PMU should be independent
  riscv: perf_event: Make some funciton static

Paolo Abeni says:

====================
mptcp: fix MP_JOIN failure handling

Currently if we hit an MP_JOIN failure on the third ack, the child socket is
closed with reset, but the request socket is not deleted, causing weird
behaviors.

The main problem is that MPTCP's MP_JOIN code needs to plug it's own
'valid 3rd ack' checks and the current TCP callbacks do not allow that.

This series tries to address the above shortcoming introducing a new MPTCP
specific bit in a 'struct tcp_request_sock' hole, and leveraging that to allow
tcp_check_req releasing the request socket when needed.

The above allows cleaning-up a bit current MPTCP hooking in tcp_check_req().

An alternative solution, possibly cleaner but more invasive, would be
changing the 'bool *own_req' syn_recv_sock() argument into 'int *req_status'
and let MPTCP set it to 'REQ_DROP'.

v1 -> v2:
 - be more conservative about drop_req initialization

RFC -> v1:
 - move the drop_req bit inside tcp_request_sock (Eric)
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently, on MP_JOIN failure we reset the child
socket, but leave the request socket untouched.

tcp_check_req will deal with it according to the
'tcp_abort_on_overflow' sysctl value - by default the
req socket will stay alive.

The above leads to inconsistent behavior on MP JOIN
failure, and bad listener overflow accounting.

This patch addresses the issue leveraging the infrastructure
just introduced to ask the TCP stack to drop the req on
failure.

The child socket is not freed anymore by subflow_syn_recv_sock(),
instead it's moved to a dead state and will be disposed by the
next sock_put done by the TCP stack, so that listener overflow
accounting is not affected by MP JOIN failure.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Move the steps to prepare an inet_connection_sock for
forced disposal inside a separate helper. No functional
changes inteded, this will just simplify the next patch.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MP_JOIN subflows must not land into the accept queue.
Currently tcp_check_req() calls an mptcp specific helper
to detect such scenario.

Such helper leverages the subflow context to check for
MP_JOIN subflows. We need to deal also with MP JOIN
failures, even when the subflow context is not available
due allocation failure.

A possible solution would be changing the syn_recv_sock()
signature to allow returning a more descriptive action/
error code and deal with that in tcp_check_req().

Since the above need is MPTCP specific, this patch instead
uses a TCP request socket hole to add a MPTCP specific flag.
Such flag is used by the MPTCP syn_recv_sock() to tell
tcp_check_req() how to deal with the request socket.

This change is a no-op for !MPTCP build, and makes the
MPTCP code simpler. It allows also the next patch to deal
correctly with MP JOIN failure.

v1 -> v2:
 - be more conservative on drop_req initialization (Mat)

RFC -> v1:
 - move the drop_req bit inside tcp_request_sock (Eric)
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull arm64 fix from Catalin Marinas:
 "Fix flush_icache_range() second argument in machine_kexec() to be an
  address rather than size"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: fix the flush_icache_range arguments in machine_kexec

A typical 100Base-T1 link should be always connected. If the link is in
a shot or open state, it is a failure. In most cases, we won't be able
to automatically handle this issue, but we need to log it or notify user
(if possible).

With this patch, the cable will be tested on "ip l s dev .. up" attempt
and send ethnl notification to the user space.

This patch was tested with TJA1102 PHY and "ethtool --monitor" command.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Alexei Starovoitov says:

====================
pull-request: bpf 2020-05-15

The following pull-request contains BPF updates for your *net* tree.

We've added 9 non-merge commits during the last 2 day(s) which contain
a total of 14 files changed, 137 insertions(+), 43 deletions(-).

The main changes are:

1) Fix secid_to_secctx LSM hook default value, from Anders.

2) Fix bug in mmap of bpf array, from Andrii.

3) Restrict bpf_probe_read to archs where they work, from Daniel.

4) Enforce returning 0 for fentry/fexit progs, from Yonghong.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The BCM54811 PHY shares many similarities with the already supported BCM54810
PHY but additionally requires some semi-unique configuration.
Signed-off-by: Kevin Lo <kevlo@kevlo.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Rahul Lakkireddy says:

====================
cxgb4: improve and tune TC-MQPRIO offload

Patch 1 improves the Tx path's credit request and recovery mechanism
when running under heavy load.

Patch 2 adds ability to tune the burst buffer sizes of all traffic
classes to improve performance for <= 1500 MTU, under heavy load.

Patch 3 adds support to track EOTIDs and dump software queue
contexts used by TC-MQPRIO offload.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Rework and add support for dumping EOTID software context used by
TC-MQPRIO. Also track number of EOTIDs in use.
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

For each traffic class, firmware handles up to 4 * MTU amount of data
per burst cycle. Under heavy load, this small buffer size is a
bottleneck when buffering large TSO packets in <= 1500 MTU case.
Increase the burst buffer size to 8 * MTU when supported.

Also, keep the driver's traffic class configuration API similar to
the firmware API counterpart.
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Request credit update for every half credits consumed, including
the current request. Also, avoid re-trying to post packets when there
are no credits left. The credit update reply via interrupt will
eventually restore the credits and will invoke the Tx path again.
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-05-15

The following pull-request contains BPF updates for your *net-next* tree.

We've added 37 non-merge commits during the last 1 day(s) which contain
a total of 67 files changed, 741 insertions(+), 252 deletions(-).

The main changes are:

1) bpf_xdp_adjust_tail() now allows to grow the tail as well, from Jesper.

2) bpftool can probe CONFIG_HZ, from Daniel.

3) CAP_BPF is introduced to isolate user processes that use BPF infra and
   to secure BPF networking services by dropping CAP_SYS_ADMIN requirement
   in certain cases, from Alexei.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Allow DSA to add VLAN entries even if VLAN filtering is disabled, so
enabling it will not block the traffic of existent ports in the bridge
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Vlad Buslov says:

====================
Implement classifier-action terse dump mode

Output rate of current upstream kernel TC filter dump implementation if
relatively low (~100k rules/sec depending on configuration). This
constraint impacts performance of software switch implementation that
rely on TC for their datapath implementation and periodically call TC
filter dump to update rules stats. Moreover, TC filter dump output a lot
of static data that don't change during the filter lifecycle (filter
key, specific action details, etc.) which constitutes significant
portion of payload on resulting netlink packets and increases amount of
syscalls necessary to dump all filters on particular Qdisc. In order to
significantly improve filter dump rate this patch sets implement new
mode of TC filter dump operation named "terse dump" mode. In this mode
only parameters necessary to identify the filter (handle, action cookie,
etc.) and data that can change during filter lifecycle (filter flags,
action stats, etc.) are preserved in dump output while everything else
is omitted.

Userspace API is implemented using new TCA_DUMP_FLAGS tlv with only
available flag value TCA_DUMP_FLAGS_TERSE. Internally, new API requires
individual classifier support (new tcf_proto_ops->terse_dump()
callback). Support for action terse dump is implemented in act API and
don't require changing individual action implementations.

The following table provides performance comparison between regular
filter dump and new terse dump mode for two classifier-action profiles:
one minimal config with L2 flower classifier and single gact action and
another heavier config with L2+5tuple flower classifier with
tunnel_key+mirred actions.

 Classifier-action type      |        dump |  terse dump | X improvement
                             | (rules/sec) | (rules/sec) |
-----------------------------+-------------+-------------+---------------
 L2 with gact                |       141.8 |       293.2 |          2.07
 L2+5tuple tunnel_key+mirred |        76.4 |       198.8 |          2.60

Benchmark details: to measure the rate tc filter dump and terse dump
commands are invoked on ingress Qdisc that have one million filters
configured using following commands.

> time sudo tc -s filter show dev ens1f0 ingress >/dev/null

> time sudo tc -s filter show terse dev ens1f0 ingress >/dev/null

Value in results table is calculated by dividing 1000000 total rules by
"real" time reported by time command.

Setup details: 2x Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz, 32GB memory
====================
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

"$err" is a variable pointing to a temp file. "$out" is not: only used
as a local variable in "check()" and representing the output of a
command line.

Fixes: eedbc685 (selftests: add PM netlink functional tests)
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Depending on the WRIOP version, the buffer size on the RX path must by a
multiple of 64 or 256. Handle this restriction properly by aligning down
the buffer size to the necessary value. Also, use the new buffer size
dynamically computed instead of the compile time one.

Fixes: 27c87486 ("dpaa2-eth: Use a single page per Rx buffer")
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Implement two basic tests to verify terse dump functionality of flower
classifier:

- Test that verifies that terse dump works.

- Test that verifies that terse dump doesn't print filter key.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Implement tcf_proto_ops->terse_dump() callback for flower classifier. Only
dump handle, flags and action data in terse mode.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Extend tcf_action_dump() with boolean argument 'terse' that is used to
request terse-mode action dump. In terse mode only essential data needed to
identify particular action (action kind, cookie, etc.) and its stats is put
to resulting skb and everything else is omitted. Implement
tcf_exts_terse_dump() helper in cls API that is intended to be used to
request terse dump of all exts (actions) attached to the filter.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add new TCA_DUMP_FLAGS attribute and use it in cls API to request terse
filter output from classifiers with TCA_DUMP_FLAGS_TERSE flag. This option
is intended to be used to improve performance of TC filter dump when
userland only needs to obtain stats and not the whole classifier/action
data. Extend struct tcf_proto_ops with new terse_dump() callback that must
be defined by supporting classifier implementations.

Support of the options in specific classifiers and actions is
implemented in following patches in the series.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The assumption that a device node is associated either with the
netdev's device, or the parent of that device, does not hold for all
drivers. E.g. Freescale's DPAA has two layers of platform devices
above the netdev. Instead, recursively walk up the tree from the
netdev, allowing any parent to match against the sought after node.
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'hwmon-for-v5.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:

 - Fix ADC access synchronization problem with da9052 driver

 - Fix temperature limit and status reporting in nct7904 driver

 - Fix drivetemp temperature reporting if SCT is supported but SCT data
   tables are not.

* tag 'hwmon-for-v5.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (da9052) Synchronize access with mfd
  hwmon: (nct7904) Fix incorrect range of temperature limit registers
  hwmon: (nct7904) Read all SMI status registers in probe function
  hwmon: (drivetemp) Fix SCT support if SCT data tables are not supported

Pull sound fixes from Takashi Iwai:
 "Things look good and calming down; the only change to ALSA core is the
  fix for racy rawmidi buffer accesses spotted by syzkaller, and the
  rest are all small device-specific quirks for HD-audio and USB-audio
  devices"

* tag 'sound-5.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda/realtek - Limit int mic boost for Thinkpad T530
  ALSA: hda/realtek - Add COEF workaround for ASUS ZenBook UX431DA
  ALSA: hda/realtek: Enable headset mic of ASUS UX581LV with ALC295
  ALSA: hda/realtek - Enable headset mic of ASUS UX550GE with ALC295
  ALSA: hda/realtek - Enable headset mic of ASUS GL503VM with ALC295
  ALSA: hda/realtek: Add quirk for Samsung Notebook
  ALSA: rawmidi: Fix racy buffer resize under concurrent accesses
  ALSA: usb-audio: add mapping for ASRock TRX40 Creator
  ALSA: hda/realtek - Fix S3 pop noise on Dell Wyse
  Revert "ALSA: hda/realtek: Fix pop noise on ALC225"
  ALSA: firewire-lib: fix 'function sizeof not defined' error of tracepoints format
  ALSA: usb-audio: Add control message quirk delay for Kingston HyperX headset

Pull drm fixes from Dave Airlie:
 "As mentioned last week an i915 PR came in late, but I left it, so the
  i915 bits of this cover 2 weeks, which is why it's likely a bit larger
  than usual.

  Otherwise it's mostly amdgpu fixes, one tegra fix, one meson fix.

  i915:
   - Handle idling during i915_gem_evict_something busy loops (Chris)
   - Mark current submissions with a weak-dependency (Chris)
   - Propagate error from completed fences (Chris)
   - Fixes on execlist to avoid GPU hang situation (Chris)
   - Fixes couple deadlocks (Chris)
   - Timeslice preemption fixes (Chris)
   - Fix Display Port interrupt handling on Tiger Lake (Imre)
   - Reduce debug noise around Frame Buffer Compression (Peter)
   - Fix logic around IPC W/a for Coffee Lake and Kaby Lake (Sultan)
   - Avoid dereferencing a dead context (Chris)

  tegra:
   - tegra120/4 smmu fixes

  amdgpu:
   - Clockgating fixes
   - Fix fbdev with scatter/gather display
   - S4 fix for navi
   - Soft recovery for gfx10
   - Freesync fixes
   - Atomic check cursor fix
   - Add a gfxoff quirk
   - MST fix

  amdkfd:
   - Fix GEM reference counting

  meson:
   - error code propogation fix"

* tag 'drm-fixes-2020-05-15' of git://anongit.freedesktop.org/drm/drm: (29 commits)
  drm/i915: Handle idling during i915_gem_evict_something busy loops
  drm/meson: pm resume add return errno branch
  drm/amd/amdgpu: Update update_config() logic
  drm/amd/amdgpu: add raven1 part to the gfxoff quirk list
  drm/i915: Mark concurrent submissions with a weak-dependency
  drm/i915: Propagate error from completed fences
  drm/i915/gvt: Fix kernel oops for 3-level ppgtt guest
  drm/i915/gvt: Init DPLL/DDI vreg for virtual display instead of inheritance.
  drm/amd/display: add basic atomic check for cursor plane
  drm/amd/display: Fix vblank and pageflip event handling for FreeSync
  drm/amdgpu: implement soft_recovery for gfx10
  drm/amdgpu: enable hibernate support on Navi1X
  drm/amdgpu: Use GEM obj reference for KFD BOs
  drm/amdgpu: force fbdev into vram
  drm/amd/powerplay: perform PG ungate prior to CG ungate
  drm/amdgpu: drop unnecessary cancel_delayed_work_sync on PG ungate
  drm/amdgpu: disable MGCG/MGLS also on gfx CG ungate
  drm/i915/execlists: Track inflight CCID
  drm/i915/execlists: Avoid reusing the same logical CCID
  drm/i915/gem: Remove object_is_locked assertion from unpin_from_display_plane
  ...

Alexei Starovoitov says:

====================
v6->v7:
- permit SK_REUSEPORT program type under CAP_BPF as suggested by Marek Majkowski.
  It's equivalent to SOCKET_FILTER which is unpriv.

v5->v6:
- split allow_ptr_leaks into four flags.
- retain bpf_jit_limit under cap_sys_admin.
- fixed few other issues spotted by Daniel.

v4->v5:

Split BPF operations that are allowed under CAP_SYS_ADMIN into combination of
CAP_BPF, CAP_PERFMON, CAP_NET_ADMIN and keep some of them under CAP_SYS_ADMIN.

The user process has to have
- CAP_BPF to create maps, do other sys_bpf() commands and load SK_REUSEPORT progs.
  Note: dev_map, sock_hash, sock_map map types still require CAP_NET_ADMIN.
  That could be relaxed in the future.
- CAP_BPF and CAP_PERFMON to load tracing programs.
- CAP_BPF and CAP_NET_ADMIN to load networking programs.
(or CAP_SYS_ADMIN for backward compatibility).

CAP_BPF solves three main goals:
1. provides isolation to user space processes that drop CAP_SYS_ADMIN and switch to CAP_BPF.
   More on this below. This is the major difference vs v4 set back from Sep 2019.
2. makes networking BPF progs more secure, since CAP_BPF + CAP_NET_ADMIN
   prevents pointer leaks and arbitrary kernel memory access.
3. enables fuzzers to exercise all of the verifier logic. Eventually finding bugs
   and making BPF infra more secure. Currently fuzzers run in unpriv.
   They will be able to run with CAP_BPF.

The patchset is long overdue follow-up from the last plumbers conference.
Comparing to what was discussed at LPC the CAP* checks at attach time are gone.
For tracing progs the CAP_SYS_ADMIN check was done at load time only. There was
no check at attach time. For networking and cgroup progs CAP_SYS_ADMIN was
required at load time and CAP_NET_ADMIN at attach time, but there are several
ways to bypass CAP_NET_ADMIN:
- if networking prog is using tail_call writing FD into prog_array will
  effectively attach it, but bpf_map_update_elem is an unprivileged operation.
- freplace prog with CAP_SYS_ADMIN can replace networking prog

Consolidating all CAP checks at load time makes security model similar to
open() syscall. Once the user got an FD it can do everything with it.
read/write/poll don't check permissions. The same way when bpf_prog_load
command returns an FD the user can do everything (including attaching,
detaching, and bpf_test_run).

The important design decision is to allow ID->FD transition for
CAP_SYS_ADMIN only. What it means that user processes can run
with CAP_BPF and CAP_NET_ADMIN and they will not be able to affect each
other unless they pass FDs via scm_rights or via pinning in bpffs.
ID->FD is a mechanism for human override and introspection.
An admin can do 'sudo bpftool prog ...'. It's possible to enforce via LSM that
only bpftool binary does bpf syscall with CAP_SYS_ADMIN and the rest of user
space processes do bpf syscall with CAP_BPF isolating bpf objects (progs, maps,
links) that are owned by such processes from each other.

Another significant change from LPC is that the verifier checks are split into
four flags. The allow_ptr_leaks flag allows pointer manipulations. The
bpf_capable flag enables all modern verifier features like bpf-to-bpf calls,
BTF, bounded loops, dead code elimination, etc. All the goodness. The
bypass_spec_v1 flag enables indirect stack access from bpf programs and
disables speculative analysis and bpf array mitigations. The bypass_spec_v4
flag disables store sanitation. That allows networking progs with CAP_BPF +
CAP_NET_ADMIN enjoy modern verifier features while being more secure.

Some networking progs may need CAP_BPF + CAP_NET_ADMIN + CAP_PERFMON,
since subtracting pointers (like skb->data_end - skb->data) is a pointer leak,
but the verifier may get smarter in the future.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Make all test_verifier test exercise CAP_BPF and CAP_PERFMON
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200513230355.7858-4-alexei.starovoitov@gmail.com

Implement permissions as stated in uapi/linux/capability.h
In order to do that the verifier allow_ptr_leaks flag is split
into four flags and they are set as:
  env->allow_ptr_leaks = bpf_allow_ptr_leaks();
  env->bypass_spec_v1 = bpf_bypass_spec_v1();
  env->bypass_spec_v4 = bpf_bypass_spec_v4();
  env->bpf_capable = bpf_capable();

The first three currently equivalent to perfmon_capable(), since leaking kernel
pointers and reading kernel memory via side channel attacks is roughly
equivalent to reading kernel memory with cap_perfmon.

'bpf_capable' enables bounded loops, precision tracking, bpf to bpf calls and
other verifier features. 'allow_ptr_leaks' enable ptr leaks, ptr conversions,
subtraction of pointers. 'bypass_spec_v1' disables speculative analysis in the
verifier, run time mitigations in bpf array, and enables indirect variable
access in bpf programs. 'bypass_spec_v4' disables emission of sanitation code
by the verifier.

That means that the networking BPF program loaded with CAP_BPF + CAP_NET_ADMIN
will have speculative checks done by the verifier and other spectre mitigation
applied. Such networking BPF program will not be able to leak kernel pointers
and will not be able to access arbitrary kernel memory.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200513230355.7858-3-alexei.starovoitov@gmail.com

Split BPF operations that are allowed under CAP_SYS_ADMIN into
combination of CAP_BPF, CAP_PERFMON, CAP_NET_ADMIN.
For backward compatibility include them in CAP_SYS_ADMIN as well.

The end result provides simple safety model for applications that use BPF:
- to load tracing program types
  BPF_PROG_TYPE_{KPROBE, TRACEPOINT, PERF_EVENT, RAW_TRACEPOINT, etc}
  use CAP_BPF and CAP_PERFMON
- to load networking program types
  BPF_PROG_TYPE_{SCHED_CLS, XDP, SK_SKB, etc}
  use CAP_BPF and CAP_NET_ADMIN

There are few exceptions from this rule:
- bpf_trace_printk() is allowed in networking programs, but it's using
  tracing mechanism, hence this helper needs additional CAP_PERFMON
  if networking program is using this helper.
- BPF_F_ZERO_SEED flag for hash/lru map is allowed under CAP_SYS_ADMIN only
  to discourage production use.
- BPF HW offload is allowed under CAP_SYS_ADMIN.
- bpf_probe_write_user() is allowed under CAP_SYS_ADMIN only.

CAPs are not checked at attach/detach time with two exceptions:
- loading BPF_PROG_TYPE_CGROUP_SKB is allowed for unprivileged users,
  hence CAP_NET_ADMIN is required at attach time.
- flow_dissector detach doesn't check prog FD at detach,
  hence CAP_NET_ADMIN is required at detach time.

CAP_SYS_ADMIN is required to iterate BPF objects (progs, maps, links) via get_next_id
command and convert them to file descriptor via GET_FD_BY_ID command.
This restriction guarantees that mutliple tasks with CAP_BPF are not able to
affect each other. That leads to clean isolation of tasks. For example:
task A with CAP_BPF and CAP_NET_ADMIN loads and attaches a firewall via bpf_link.
task B with the same capabilities cannot detach that firewall unless
task A explicitly passed link FD to task B via scm_rights or bpffs.
CAP_SYS_ADMIN can still detach/unload everything.

Two networking user apps with CAP_SYS_ADMIN and CAP_NET_ADMIN can
accidentely mess with each other programs and maps.
Two networking user apps with CAP_NET_ADMIN and CAP_BPF cannot affect each other.

CAP_NET_ADMIN + CAP_BPF allows networking programs access only packet data.
Such networking progs cannot access arbitrary kernel memory or leak pointers.

bpftool, bpftrace, bcc tools binaries should NOT be installed with
CAP_BPF and CAP_PERFMON, since unpriv users will be able to read kernel secrets.
But users with these two permissions will be able to use these tracing tools.

CAP_PERFMON is least secure, since it allows kprobes and kernel memory access.
CAP_NET_ADMIN can stop network traffic via iproute2.
CAP_BPF is the safest from security point of view and harmless on its own.

Having CAP_BPF and/or CAP_NET_ADMIN is not enough to write into arbitrary map
and if that map is used by firewall-like bpf prog.
CAP_BPF allows many bpf prog_load commands in parallel. The verifier
may consume large amount of memory and significantly slow down the system.

Existing unprivileged BPF operations are not affected.
In particular unprivileged users are allowed to load socket_filter and cg_skb
program types and to create array, hash, prog_array, map-in-map map types.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200513230355.7858-2-alexei.starovoitov@gmail.com

In Cilium we've recently switched to make use of bpf_jiffies64() for
parts of our tc and XDP datapath since bpf_ktime_get_ns() is more
expensive and high-precision is not needed for our timeouts we have
anyway. Our agent has a probe manager which picks up the json of
bpftool's feature probe and we also use the macro output in our C
programs e.g. to have workarounds when helpers are not available on
older kernels.

Extend the kernel config info dump to also include the kernel's
CONFIG_HZ, and rework the probe_kernel_image_config() for allowing a
macro dump such that CONFIG_HZ can be propagated to BPF C code as a
simple define if available via config. Latter allows to have _compile-
time_ resolution of jiffies <-> sec conversion in our code since all
are propagated as known constants.

Given we cannot generally assume availability of kconfig everywhere,
we also have a kernel hz probe [0] as a fallback. Potentially, bpftool
could have an integrated probe fallback as well, although to derive it,
we might need to place it under 'bpftool feature probe full' or similar
given it would slow down the probing process overall. Yet 'full' doesn't
fit either for us since we don't want to pollute the kernel log with
warning messages from bpf_probe_write_user() and bpf_trace_printk() on
agent startup; I've left it out for the time being.

  [0] https://github.com/cilium/cilium/blob/master/bpf/cilium-probe-kernel-hz.cSigned-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200513075849.20868-1-daniel@iogearbox.net

Daniel Borkmann says:

====================
Small set of fixes in order to restrict BPF helpers for tracing which are
broken on archs with overlapping address ranges as per discussion in [0].
I've targetted this for -bpf tree so they can be routed as fixes. Thanks!

v1 -> v2:
  - switch to reusable %pks, %pus format specifiers (Yonghong)
    - fixate %s on kernel_ds probing for archs with overlapping addr space

      [0] https://lore.kernel.org/bpf/CAHk-=wjJKo0GVixYLmqPn-Q22WFu0xHaBSjKEo7e7Yw72y5SPQ@mail.gmail.com/T/
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Usage of plain %s conversion specifier in bpf_trace_printk() suffers from the
very same issue as bpf_probe_read{,str}() helpers, that is, it is broken on
archs with overlapping address ranges.

While the helpers have been addressed through work in 6ae08ae3 ("bpf: Add
probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers"), we need
an option for bpf_trace_printk() as well to fix it.

Similarly as with the helpers, force users to make an explicit choice by adding
%pks and %pus specifier to bpf_trace_printk() which will then pick the corresponding
strncpy_from_unsafe*() variant to perform the access under KERNEL_DS or USER_DS.
The %pk* (kernel specifier) and %pu* (user specifier) can later also be extended
for other objects aside strings that are probed and printed under tracing, and
reused out of other facilities like bpf_seq_printf() or BTF based type printing.

Existing behavior of %s for current users is still kept working for archs where it
is not broken and therefore gated through CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE.
For archs not having this property we fall-back to pick probing under KERNEL_DS as
a sensible default.

Fixes: 8d3b7dce ("bpf: add support for %s specifier to bpf_trace_printk()")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Link: https://lore.kernel.org/bpf/20200515101118.6508-4-daniel@iogearbox.net

Given bpf_probe_read{,str}() BPF helpers are now only available under
CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE, we need to add the drop-in
replacements of bpf_probe_read_{kernel,user}_str() to do_refine_retval_range()
as well to avoid hitting the same issue as in 849fa506 ("bpf/verifier:
refine retval R0 state for bpf_get_stack helper").
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200515101118.6508-3-daniel@iogearbox.net

Given the legacy bpf_probe_read{,str}() BPF helpers are broken on archs
with overlapping address ranges, we should really take the next step to
disable them from BPF use there.

To generally fix the situation, we've recently added new helper variants
bpf_probe_read_{user,kernel}() and bpf_probe_read_{user,kernel}_str().
For details on them, see 6ae08ae3 ("bpf: Add probe_read_{user, kernel}
and probe_read_{user,kernel}_str helpers").

Given bpf_probe_read{,str}() have been around for ~5 years by now, there
are plenty of users at least on x86 still relying on them today, so we
cannot remove them entirely w/o breaking the BPF tracing ecosystem.

However, their use should be restricted to archs with non-overlapping
address ranges where they are working in their current form. Therefore,
move this behind a CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE and
have x86, arm64, arm select it (other archs supporting it can follow-up
on it as well).

For the remaining archs, they can workaround easily by relying on the
feature probe from bpftool which spills out defines that can be used out
of BPF C code to implement the drop-in replacement for old/new kernels
via: bpftool feature probe macro
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/bpf/20200515101118.6508-2-daniel@iogearbox.net