Commit Graph

1010 Commits

Author SHA1 Message Date
Linus Torvalds
8f49a658b4 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:
 "First batch of fixes in the new merge window:

   1) Double dst_cache free in act_tunnel_key, from Wenxu.

   2) Avoid NULL deref in IN_DEV_MFORWARD() by failing early in the
      ip_route_input_rcu() path, from Paolo Abeni.

   3) Fix appletalk compile regression, from Arnd Bergmann.

   4) If SLAB objects reach the TCP sendpage method we are in serious
      trouble, so put a debugging check there. From Vasily Averin.

   5) Memory leak in hsr layer, from Mao Wenan.

   6) Only test GSO type on GSO packets, from Willem de Bruijn.

   7) Fix crash in xsk_diag_put_umem(), from Eric Dumazet.

   8) Fix VNIC mailbox length in nfp, from Dirk van der Merwe.

   9) Fix race in ipv4 route exception handling, from Xin Long.

  10) Missing DMA memory barrier in hns3 driver, from Jian Shen.

  11) Use after free in __tcf_chain_put(), from Vlad Buslov.

  12) Handle inet_csk_reqsk_queue_add() failures, from Guillaume Nault.

  13) Return value correction when ip_mc_may_pull() fails, from Eric
      Dumazet.

  14) Use after free in x25_device_event(), also from Eric"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (72 commits)
  gro_cells: make sure device is up in gro_cells_receive()
  vxlan: test dev->flags & IFF_UP before calling gro_cells_receive()
  net/x25: fix use-after-free in x25_device_event()
  isdn: mISDNinfineon: fix potential NULL pointer dereference
  net: hns3: fix to stop multiple HNS reset due to the AER changes
  ip: fix ip_mc_may_pull() return value
  net: keep refcount warning in reqsk_free()
  net: stmmac: Avoid one more sometimes uninitialized Clang warning
  net: dsa: mv88e6xxx: Set correct interface mode for CPU/DSA ports
  rxrpc: Fix client call queueing, waiting for channel
  tcp: handle inet_csk_reqsk_queue_add() failures
  net: ethernet: sun: Zero initialize class in default case in niu_add_ethtool_tcam_entry
  8139too : Add support for U.S. Robotics USR997901A 10/100 Cardbus NIC
  fou, fou6: avoid uninit-value in gue_err() and gue6_err()
  net: sched: fix potential use-after-free in __tcf_chain_put()
  vhost: silence an unused-variable warning
  vsock/virtio: fix kernel panic from virtio_transport_reset_no_sock
  connector: fix unsafe usage of ->real_parent
  vxlan: do not need BH again in vxlan_cleanup()
  net: hns3: add dma_rmb() for rx description
  ...
2019-03-11 08:54:01 -07:00
Daniel Borkmann
20182390c4 bpf: fix replace_map_fd_with_map_ptr's ldimm64 second imm field
Non-zero imm value in the second part of the ldimm64 instruction for
BPF_PSEUDO_MAP_FD is invalid, and thus must be rejected. The map fd
only ever sits in the first instructions' imm field. None of the BPF
loaders known to us are using it, so risk of regression is minimal.
For clarity and consistency, the few insn->{src_reg,imm} occurrences
are rewritten into insn[0].{src_reg,imm}. Add a test case to the BPF
selftest suite as well.

Fixes: 0246e64d9a ("bpf: handle pseudo BPF_LD_IMM64 insn")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-03-07 08:47:13 -08:00
Linus Torvalds
203b6609e0 Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf updates from Ingo Molnar:
 "Lots of tooling updates - too many to list, here's a few highlights:

   - Various subcommand updates to 'perf trace', 'perf report', 'perf
     record', 'perf annotate', 'perf script', 'perf test', etc.

   - CPU and NUMA topology and affinity handling improvements,

   - HW tracing and HW support updates:
      - Intel PT updates
      - ARM CoreSight updates
      - vendor HW event updates

   - BPF updates

   - Tons of infrastructure updates, both on the build system and the
     library support side

   - Documentation updates.

   - ... and lots of other changes, see the changelog for details.

  Kernel side updates:

   - Tighten up kprobes blacklist handling, reduce the number of places
     where developers can install a kprobe and hang/crash the system.

   - Fix/enhance vma address filter handling.

   - Various PMU driver updates, small fixes and additions.

   - refcount_t conversions

   - BPF updates

   - error code propagation enhancements

   - misc other changes"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (238 commits)
  perf script python: Add Python3 support to syscall-counts-by-pid.py
  perf script python: Add Python3 support to syscall-counts.py
  perf script python: Add Python3 support to stat-cpi.py
  perf script python: Add Python3 support to stackcollapse.py
  perf script python: Add Python3 support to sctop.py
  perf script python: Add Python3 support to powerpc-hcalls.py
  perf script python: Add Python3 support to net_dropmonitor.py
  perf script python: Add Python3 support to mem-phys-addr.py
  perf script python: Add Python3 support to failed-syscalls-by-pid.py
  perf script python: Add Python3 support to netdev-times.py
  perf tools: Add perf_exe() helper to find perf binary
  perf script: Handle missing fields with -F +..
  perf data: Add perf_data__open_dir_data function
  perf data: Add perf_data__(create_dir|close_dir) functions
  perf data: Fail check_backup in case of error
  perf data: Make check_backup work over directories
  perf tools: Add rm_rf_perf_data function
  perf tools: Add pattern name checking to rm_rf
  perf tools: Add depth checking to rm_rf
  perf data: Add global path holder
  ...
2019-03-06 07:59:36 -08:00
David S. Miller
f7fb7c1a1c Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2019-03-04

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

The main changes are:

1) Add AF_XDP support to libbpf. Rationale is to facilitate writing
   AF_XDP applications by offering higher-level APIs that hide many
   of the details of the AF_XDP uapi. Sample programs are converted
   over to this new interface as well, from Magnus.

2) Introduce a new cant_sleep() macro for annotation of functions
   that cannot sleep and use it in BPF_PROG_RUN() to assert that
   BPF programs run under preemption disabled context, from Peter.

3) Introduce per BPF prog stats in order to monitor the usage
   of BPF; this is controlled by kernel.bpf_stats_enabled sysctl
   knob where monitoring tools can make use of this to efficiently
   determine the average cost of programs, from Alexei.

4) Split up BPF selftest's test_progs similarly as we already
   did with test_verifier. This allows to further reduce merge
   conflicts in future and to get more structure into our
   quickly growing BPF selftest suite, from Stanislav.

5) Fix a bug in BTF's dedup algorithm which can cause an infinite
   loop in some circumstances; also various BPF doc fixes and
   improvements, from Andrii.

6) Various BPF sample cleanups and migration to libbpf in order
   to further isolate the old sample loader code (so we can get
   rid of it at some point), from Jakub.

7) Add a new BPF helper for BPF cgroup skb progs that allows
   to set ECN CE code point and a Host Bandwidth Manager (HBM)
   sample program for limiting the bandwidth used by v2 cgroups,
   from Lawrence.

8) Enable write access to skb->queue_mapping from tc BPF egress
   programs in order to let BPF pick TX queue, from Jesper.

9) Fix a bug in BPF spinlock handling for map-in-map which did
   not propagate spin_lock_off to the meta map, from Yonghong.

10) Fix a bug in the new per-CPU BPF prog counters to properly
    initialize stats for each CPU, from Eric.

11) Add various BPF helper prototypes to selftest's bpf_helpers.h,
    from Willem.

12) Fix various BPF samples bugs in XDP and tracing progs,
    from Toke, Daniel and Yonghong.

13) Silence preemption splat in test_bpf after BPF_PROG_RUN()
    enforces it now everywhere, from Anders.

14) Fix a signedness bug in libbpf's btf_dedup_ref_type() to
    get error handling working, from Dan.

15) Fix bpftool documentation and auto-completion with regards
    to stream_{verdict,parser} attach types, from Alban.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-04 10:14:31 -08:00
David S. Miller
9eb359140c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-02 12:54:35 -08:00
Daniel Borkmann
3612af783c bpf: fix sanitation rewrite in case of non-pointers
Marek reported that he saw an issue with the below snippet in that
timing measurements where off when loaded as unpriv while results
were reasonable when loaded as privileged:

    [...]
    uint64_t a = bpf_ktime_get_ns();
    uint64_t b = bpf_ktime_get_ns();
    uint64_t delta = b - a;
    if ((int64_t)delta > 0) {
    [...]

Turns out there is a bug where a corner case is missing in the fix
d3bd7413e0 ("bpf: fix sanitation of alu op with pointer / scalar
type from different paths"), namely fixup_bpf_calls() only checks
whether aux has a non-zero alu_state, but it also needs to test for
the case of BPF_ALU_NON_POINTER since in both occasions we need to
skip the masking rewrite (as there is nothing to mask).

Fixes: d3bd7413e0 ("bpf: fix sanitation of alu op with pointer / scalar type from different paths")
Reported-by: Marek Majkowski <marek@cloudflare.com>
Reported-by: Arthur Fabre <afabre@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/netdev/CAJPywTJqP34cK20iLM5YmUMz9KXQOdu1-+BZrGMAGgLuBWz7fg@mail.gmail.com/T/
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-03-01 21:24:08 -08:00
Eric Dumazet
4b9113045b bpf: fix u64_stats_init() usage in bpf_prog_alloc()
We need to iterate through all possible cpus.

Fixes: 492ecee892 ("bpf: enable program stats")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-03-02 00:31:36 +01:00
Peng Sun
352d20d611 bpf: drop refcount if bpf_map_new_fd() fails in map_create()
In bpf/syscall.c, map_create() first set map->usercnt to 1, a file
descriptor is supposed to return to userspace. When bpf_map_new_fd()
fails, drop the refcount.

Fixes: bd5f5f4ecb ("bpf: Add BPF_MAP_GET_FD_BY_ID")
Signed-off-by: Peng Sun <sironhide0null@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-03-01 16:04:29 +01:00
Ingo Molnar
9ed8f1a6e7 Merge branch 'linus' into perf/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-28 08:27:17 +01:00
Yonghong Song
a115d0ed72 bpf: set inner_map_meta->spin_lock_off correctly
Commit d83525ca62 ("bpf: introduce bpf_spin_lock")
introduced bpf_spin_lock and the field spin_lock_off
in kernel internal structure bpf_map has the following
meaning:
  >=0 valid offset, <0 error

For every map created, the kernel will ensure
spin_lock_off has correct value.

Currently, bpf_map->spin_lock_off is not copied
from the inner map to the map_in_map inner_map_meta
during a map_in_map type map creation, so
inner_map_meta->spin_lock_off = 0.
This will give verifier wrong information that
inner_map has bpf_spin_lock and the bpf_spin_lock
is defined at offset 0. An access to offset 0
of a value pointer will trigger the following error:
   bpf_spin_lock cannot be accessed directly by load/store

This patch fixed the issue by copy inner map's spin_lock_off
value to inner_map_meta->spin_lock_off.

Fixes: d83525ca62 ("bpf: introduce bpf_spin_lock")
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-27 17:03:13 -08:00
Alexei Starovoitov
5f8f8b93ae bpf: expose program stats via bpf_prog_info
Return bpf program run_time_ns and run_cnt via bpf_prog_info

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-27 17:22:50 +01:00
Alexei Starovoitov
492ecee892 bpf: enable program stats
JITed BPF programs are indistinguishable from kernel functions, but unlike
kernel code BPF code can be changed often.
Typical approach of "perf record" + "perf report" profiling and tuning of
kernel code works just as well for BPF programs, but kernel code doesn't
need to be monitored whereas BPF programs do.
Users load and run large amount of BPF programs.
These BPF stats allow tools monitor the usage of BPF on the server.
The monitoring tools will turn sysctl kernel.bpf_stats_enabled
on and off for few seconds to sample average cost of the programs.
Aggregated data over hours and days will provide an insight into cost of BPF
and alarms can trigger in case given program suddenly gets more expensive.

The cost of two sched_clock() per program invocation adds ~20 nsec.
Fast BPF progs (like selftests/bpf/progs/test_pkt_access.c) will slow down
from ~10 nsec to ~30 nsec.
static_key minimizes the cost of the stats collection.
There is no measurable difference before/after this patch
with kernel.bpf_stats_enabled=0

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-27 17:22:50 +01:00
Peng Sun
781e62823c bpf: decrease usercnt if bpf_map_new_fd() fails in bpf_map_get_fd_by_id()
In bpf/syscall.c, bpf_map_get_fd_by_id() use bpf_map_inc_not_zero()
to increase the refcount, both map->refcnt and map->usercnt. Then, if
bpf_map_new_fd() fails, should handle map->usercnt too.

Fixes: bd5f5f4ecb ("bpf: Add BPF_MAP_GET_FD_BY_ID")
Signed-off-by: Peng Sun <sironhide0null@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-26 19:08:30 +01:00
David S. Miller
70f3522614 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Three conflicts, one of which, for marvell10g.c is non-trivial and
requires some follow-up from Heiner or someone else.

The issue is that Heiner converted the marvell10g driver over to
use the generic c45 code as much as possible.

However, in 'net' a bug fix appeared which makes sure that a new
local mask (MDIO_AN_10GBT_CTRL_ADV_NBT_MASK) with value 0x01e0
is cleared.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-24 12:06:19 -08:00
Alban Crequy
7c0cdf0b39 bpf, lpm: fix lookup bug in map_delete_elem
trie_delete_elem() was deleting an entry even though it was not matching
if the prefixlen was correct. This patch adds a check on matchlen.

Reproducer:

$ sudo bpftool map create /sys/fs/bpf/mylpm type lpm_trie key 8 value 1 entries 128 name mylpm flags 1
$ sudo bpftool map update pinned /sys/fs/bpf/mylpm key hex 10 00 00 00 aa bb cc dd value hex 01
$ sudo bpftool map dump pinned /sys/fs/bpf/mylpm
key: 10 00 00 00 aa bb cc dd  value: 01
Found 1 element
$ sudo bpftool map delete pinned /sys/fs/bpf/mylpm key hex 10 00 00 00 ff ff ff ff
$ echo $?
0
$ sudo bpftool map dump pinned /sys/fs/bpf/mylpm
Found 0 elements

A similar reproducer is added in the selftests.

Without the patch:

$ sudo ./tools/testing/selftests/bpf/test_lpm_map
test_lpm_map: test_lpm_map.c:485: test_lpm_delete: Assertion `bpf_map_delete_elem(map_fd, key) == -1 && errno == ENOENT' failed.
Aborted

With the patch: test_lpm_map runs without errors.

Fixes: e454cf5958 ("bpf: Implement map_delete_elem for BPF_MAP_TYPE_LPM_TRIE")
Cc: Craig Gallek <kraig@google.com>
Signed-off-by: Alban Crequy <alban@kinvolk.io>
Acked-by: Craig Gallek <kraig@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-22 16:17:53 +01:00
David S. Miller
375ca548f7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Two easily resolvable overlapping change conflicts, one in
TCP and one in the eBPF verifier.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-20 00:34:07 -08:00
David S. Miller
885e631959 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Alexei Starovoitov says:

====================
pull-request: bpf-next 2019-02-16

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

The main changes are:

1) numerous libbpf API improvements, from Andrii, Andrey, Yonghong.

2) test all bpf progs in alu32 mode, from Jiong.

3) skb->sk access and bpf_sk_fullsock(), bpf_tcp_sock() helpers, from Martin.

4) support for IP encap in lwt bpf progs, from Peter.

5) remove XDP_QUERY_XSK_UMEM dead code, from Jan.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-16 22:56:34 -08:00
Jakub Kicinski
dd27c2e3d0 bpf: offload: add priv field for drivers
Currently bpf_offload_dev does not have any priv pointer, forcing
the drivers to work backwards from the netdev in program metadata.
This is not great given programs are conceptually associated with
the offload device, and it means one or two unnecessary deferences.
Add a priv pointer to bpf_offload_dev.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-12 17:07:09 +01:00
Alexei Starovoitov
3defaf2f15 bpf: fix lockdep false positive in stackmap
Lockdep warns about false positive:
[   11.211460] ------------[ cut here ]------------
[   11.211936] DEBUG_LOCKS_WARN_ON(depth <= 0)
[   11.211985] WARNING: CPU: 0 PID: 141 at ../kernel/locking/lockdep.c:3592 lock_release+0x1ad/0x280
[   11.213134] Modules linked in:
[   11.214954] RIP: 0010:lock_release+0x1ad/0x280
[   11.223508] Call Trace:
[   11.223705]  <IRQ>
[   11.223874]  ? __local_bh_enable+0x7a/0x80
[   11.224199]  up_read+0x1c/0xa0
[   11.224446]  do_up_read+0x12/0x20
[   11.224713]  irq_work_run_list+0x43/0x70
[   11.225030]  irq_work_run+0x26/0x50
[   11.225310]  smp_irq_work_interrupt+0x57/0x1f0
[   11.225662]  irq_work_interrupt+0xf/0x20

since rw_semaphore is released in a different task vs task that locked the sema.
It is expected behavior.
Fix the warning with up_read_non_owner() and rwsem_release() annotation.

Fixes: bae77c5eb5 ("bpf: enable stackmap with build_id in nmi context")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-11 16:36:24 +01:00
Martin KaFai Lau
655a51e536 bpf: Add struct bpf_tcp_sock and BPF_FUNC_tcp_sock
This patch adds a helper function BPF_FUNC_tcp_sock and it
is currently available for cg_skb and sched_(cls|act):

struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk);

int cg_skb_foo(struct __sk_buff *skb) {
	struct bpf_tcp_sock *tp;
	struct bpf_sock *sk;
	__u32 snd_cwnd;

	sk = skb->sk;
	if (!sk)
		return 1;

	tp = bpf_tcp_sock(sk);
	if (!tp)
		return 1;

	snd_cwnd = tp->snd_cwnd;
	/* ... */

	return 1;
}

A 'struct bpf_tcp_sock' is also added to the uapi bpf.h to provide
read-only access.  bpf_tcp_sock has all the existing tcp_sock's fields
that has already been exposed by the bpf_sock_ops.
i.e. no new tcp_sock's fields are exposed in bpf.h.

This helper returns a pointer to the tcp_sock.  If it is not a tcp_sock
or it cannot be traced back to a tcp_sock by sk_to_full_sk(), it
returns NULL.  Hence, the caller needs to check for NULL before
accessing it.

The current use case is to expose members from tcp_sock
to allow a cg_skb_bpf_prog to provide per cgroup traffic
policing/shaping.

Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-10 19:46:17 -08:00
Martin KaFai Lau
46f8bc9275 bpf: Add a bpf_sock pointer to __sk_buff and a bpf_sk_fullsock helper
In kernel, it is common to check "skb->sk && sk_fullsock(skb->sk)"
before accessing the fields in sock.  For example, in __netdev_pick_tx:

static u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb,
			    struct net_device *sb_dev)
{
	/* ... */

	struct sock *sk = skb->sk;

		if (queue_index != new_index && sk &&
		    sk_fullsock(sk) &&
		    rcu_access_pointer(sk->sk_dst_cache))
			sk_tx_queue_set(sk, new_index);

	/* ... */

	return queue_index;
}

This patch adds a "struct bpf_sock *sk" pointer to the "struct __sk_buff"
where a few of the convert_ctx_access() in filter.c has already been
accessing the skb->sk sock_common's fields,
e.g. sock_ops_convert_ctx_access().

"__sk_buff->sk" is a PTR_TO_SOCK_COMMON_OR_NULL in the verifier.
Some of the fileds in "bpf_sock" will not be directly
accessible through the "__sk_buff->sk" pointer.  It is limited
by the new "bpf_sock_common_is_valid_access()".
e.g. The existing "type", "protocol", "mark" and "priority" in bpf_sock
     are not allowed.

The newly added "struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)"
can be used to get a sk with all accessible fields in "bpf_sock".
This helper is added to both cg_skb and sched_(cls|act).

int cg_skb_foo(struct __sk_buff *skb) {
	struct bpf_sock *sk;

	sk = skb->sk;
	if (!sk)
		return 1;

	sk = bpf_sk_fullsock(sk);
	if (!sk)
		return 1;

	if (sk->family != AF_INET6 || sk->protocol != IPPROTO_TCP)
		return 1;

	/* some_traffic_shaping(); */

	return 1;
}

(1) The sk is read only

(2) There is no new "struct bpf_sock_common" introduced.

(3) Future kernel sock's members could be added to bpf_sock only
    instead of repeatedly adding at multiple places like currently
    in bpf_sock_ops_md, bpf_sock_addr_md, sk_reuseport_md...etc.

(4) After "sk = skb->sk", the reg holding sk is in type
    PTR_TO_SOCK_COMMON_OR_NULL.

(5) After bpf_sk_fullsock(), the return type will be in type
    PTR_TO_SOCKET_OR_NULL which is the same as the return type of
    bpf_sk_lookup_xxx().

    However, bpf_sk_fullsock() does not take refcnt.  The
    acquire_reference_state() is only depending on the return type now.
    To avoid it, a new is_acquire_function() is checked before calling
    acquire_reference_state().

(6) The WARN_ON in "release_reference_state()" is no longer an
    internal verifier bug.

    When reg->id is not found in state->refs[], it means the
    bpf_prog does something wrong like
    "bpf_sk_release(bpf_sk_fullsock(skb->sk))" where reference has
    never been acquired by calling "bpf_sk_fullsock(skb->sk)".

    A -EINVAL and a verbose are done instead of WARN_ON.  A test is
    added to the test_verifier in a later patch.

    Since the WARN_ON in "release_reference_state()" is no longer
    needed, "__release_reference_state()" is folded into
    "release_reference_state()" also.

Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-10 19:46:17 -08:00
Martin KaFai Lau
5f4566498d bpf: Fix narrow load on a bpf_sock returned from sk_lookup()
By adding this test to test_verifier:
{
	"reference tracking: access sk->src_ip4 (narrow load)",
	.insns = {
	BPF_SK_LOOKUP,
	BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
	BPF_LDX_MEM(BPF_H, BPF_REG_2, BPF_REG_0, offsetof(struct bpf_sock, src_ip4) + 2),
	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
	BPF_EMIT_CALL(BPF_FUNC_sk_release),
	BPF_EXIT_INSN(),
	},
	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
	.result = ACCEPT,
},

The above test loads 2 bytes from sk->src_ip4 where
sk is obtained by bpf_sk_lookup_tcp().

It hits an internal verifier error from convert_ctx_accesses():
[root@arch-fb-vm1 bpf]# ./test_verifier 665 665
Failed to load prog 'Invalid argument'!
0: (b7) r2 = 0
1: (63) *(u32 *)(r10 -8) = r2
2: (7b) *(u64 *)(r10 -16) = r2
3: (7b) *(u64 *)(r10 -24) = r2
4: (7b) *(u64 *)(r10 -32) = r2
5: (7b) *(u64 *)(r10 -40) = r2
6: (7b) *(u64 *)(r10 -48) = r2
7: (bf) r2 = r10
8: (07) r2 += -48
9: (b7) r3 = 36
10: (b7) r4 = 0
11: (b7) r5 = 0
12: (85) call bpf_sk_lookup_tcp#84
13: (bf) r6 = r0
14: (15) if r0 == 0x0 goto pc+3
 R0=sock(id=1,off=0,imm=0) R6=sock(id=1,off=0,imm=0) R10=fp0,call_-1 fp-8=????0000 fp-16=0000mmmm fp-24=mmmmmmmm fp-32=mmmmmmmm fp-40=mmmmmmmm fp-48=mmmmmmmm refs=1
15: (69) r2 = *(u16 *)(r0 +26)
16: (bf) r1 = r6
17: (85) call bpf_sk_release#86
18: (95) exit

from 14 to 18: safe
processed 20 insns (limit 131072), stack depth 48
bpf verifier is misconfigured
Summary: 0 PASSED, 0 SKIPPED, 1 FAILED

The bpf_sock_is_valid_access() is expecting src_ip4 can be narrowly
loaded (meaning load any 1 or 2 bytes of the src_ip4) by
marking info->ctx_field_size.  However, this marked
ctx_field_size is not used.  This patch fixes it.

Due to the recent refactoring in test_verifier,
this new test will be added to the bpf-next branch
(together with the bpf_tcp_sock patchset)
to avoid merge conflict.

Fixes: c64b798328 ("bpf: Add PTR_TO_SOCKET verifier type")
Cc: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-10 19:37:41 -08:00
Martin KaFai Lau
d623876646 bpf: Fix narrow load on a bpf_sock returned from sk_lookup()
By adding this test to test_verifier:
{
	"reference tracking: access sk->src_ip4 (narrow load)",
	.insns = {
	BPF_SK_LOOKUP,
	BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
	BPF_LDX_MEM(BPF_H, BPF_REG_2, BPF_REG_0, offsetof(struct bpf_sock, src_ip4) + 2),
	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
	BPF_EMIT_CALL(BPF_FUNC_sk_release),
	BPF_EXIT_INSN(),
	},
	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
	.result = ACCEPT,
},

The above test loads 2 bytes from sk->src_ip4 where
sk is obtained by bpf_sk_lookup_tcp().

It hits an internal verifier error from convert_ctx_accesses():
[root@arch-fb-vm1 bpf]# ./test_verifier 665 665
Failed to load prog 'Invalid argument'!
0: (b7) r2 = 0
1: (63) *(u32 *)(r10 -8) = r2
2: (7b) *(u64 *)(r10 -16) = r2
3: (7b) *(u64 *)(r10 -24) = r2
4: (7b) *(u64 *)(r10 -32) = r2
5: (7b) *(u64 *)(r10 -40) = r2
6: (7b) *(u64 *)(r10 -48) = r2
7: (bf) r2 = r10
8: (07) r2 += -48
9: (b7) r3 = 36
10: (b7) r4 = 0
11: (b7) r5 = 0
12: (85) call bpf_sk_lookup_tcp#84
13: (bf) r6 = r0
14: (15) if r0 == 0x0 goto pc+3
 R0=sock(id=1,off=0,imm=0) R6=sock(id=1,off=0,imm=0) R10=fp0,call_-1 fp-8=????0000 fp-16=0000mmmm fp-24=mmmmmmmm fp-32=mmmmmmmm fp-40=mmmmmmmm fp-48=mmmmmmmm refs=1
15: (69) r2 = *(u16 *)(r0 +26)
16: (bf) r1 = r6
17: (85) call bpf_sk_release#86
18: (95) exit

from 14 to 18: safe
processed 20 insns (limit 131072), stack depth 48
bpf verifier is misconfigured
Summary: 0 PASSED, 0 SKIPPED, 1 FAILED

The bpf_sock_is_valid_access() is expecting src_ip4 can be narrowly
loaded (meaning load any 1 or 2 bytes of the src_ip4) by
marking info->ctx_field_size.  However, this marked
ctx_field_size is not used.  This patch fixes it.

Due to the recent refactoring in test_verifier,
this new test will be added to the bpf-next branch
(together with the bpf_tcp_sock patchset)
to avoid merge conflict.

Fixes: c64b798328 ("bpf: Add PTR_TO_SOCKET verifier type")
Cc: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-09 19:57:22 -08:00
David S. Miller
a655fe9f19 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
An ipvlan bug fix in 'net' conflicted with the abstraction away
of the IPV6 specific support in 'net-next'.

Similarly, a bug fix for mlx5 in 'net' conflicted with the flow
action conversion in 'net-next'.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-08 15:00:17 -08:00
Ingo Molnar
98cb621081 Merge branch 'perf/urgent' into perf/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-04 08:45:42 +01:00
Alexei Starovoitov
96049f3afd bpf: introduce BPF_F_LOCK flag
Introduce BPF_F_LOCK flag for map_lookup and map_update syscall commands
and for map_update() helper function.
In all these cases take a lock of existing element (which was provided
in BTF description) before copying (in or out) the rest of map value.

Implementation details that are part of uapi:

Array:
The array map takes the element lock for lookup/update.

Hash:
hash map also takes the lock for lookup/update and tries to avoid the bucket lock.
If old element exists it takes the element lock and updates the element in place.
If element doesn't exist it allocates new one and inserts into hash table
while holding the bucket lock.
In rare case the hashmap has to take both the bucket lock and the element lock
to update old value in place.

Cgroup local storage:
It is similar to array. update in place and lookup are done with lock taken.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-01 20:55:39 +01:00
Alexei Starovoitov
e16d2f1ab9 bpf: add support for bpf_spin_lock to cgroup local storage
Allow 'struct bpf_spin_lock' to reside inside cgroup local storage.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-01 20:55:38 +01:00
Alexei Starovoitov
d83525ca62 bpf: introduce bpf_spin_lock
Introduce 'struct bpf_spin_lock' and bpf_spin_lock/unlock() helpers to let
bpf program serialize access to other variables.

Example:
struct hash_elem {
    int cnt;
    struct bpf_spin_lock lock;
};
struct hash_elem * val = bpf_map_lookup_elem(&hash_map, &key);
if (val) {
    bpf_spin_lock(&val->lock);
    val->cnt++;
    bpf_spin_unlock(&val->lock);
}

Restrictions and safety checks:
- bpf_spin_lock is only allowed inside HASH and ARRAY maps.
- BTF description of the map is mandatory for safety analysis.
- bpf program can take one bpf_spin_lock at a time, since two or more can
  cause dead locks.
- only one 'struct bpf_spin_lock' is allowed per map element.
  It drastically simplifies implementation yet allows bpf program to use
  any number of bpf_spin_locks.
- when bpf_spin_lock is taken the calls (either bpf2bpf or helpers) are not allowed.
- bpf program must bpf_spin_unlock() before return.
- bpf program can access 'struct bpf_spin_lock' only via
  bpf_spin_lock()/bpf_spin_unlock() helpers.
- load/store into 'struct bpf_spin_lock lock;' field is not allowed.
- to use bpf_spin_lock() helper the BTF description of map value must be
  a struct and have 'struct bpf_spin_lock anyname;' field at the top level.
  Nested lock inside another struct is not allowed.
- syscall map_lookup doesn't copy bpf_spin_lock field to user space.
- syscall map_update and program map_update do not update bpf_spin_lock field.
- bpf_spin_lock cannot be on the stack or inside networking packet.
  bpf_spin_lock can only be inside HASH or ARRAY map value.
- bpf_spin_lock is available to root only and to all program types.
- bpf_spin_lock is not allowed in inner maps of map-in-map.
- ld_abs is not allowed inside spin_lock-ed region.
- tracing progs and socket filter progs cannot use bpf_spin_lock due to
  insufficient preemption checks

Implementation details:
- cgroup-bpf class of programs can nest with xdp/tc programs.
  Hence bpf_spin_lock is equivalent to spin_lock_irqsave.
  Other solutions to avoid nested bpf_spin_lock are possible.
  Like making sure that all networking progs run with softirq disabled.
  spin_lock_irqsave is the simplest and doesn't add overhead to the
  programs that don't use it.
- arch_spinlock_t is used when its implemented as queued_spin_lock
- archs can force their own arch_spinlock_t
- on architectures where queued_spin_lock is not available and
  sizeof(arch_spinlock_t) != sizeof(__u32) trivial lock is used.
- presence of bpf_spin_lock inside map value could have been indicated via
  extra flag during map_create, but specifying it via BTF is cleaner.
  It provides introspection for map key/value and reduces user mistakes.

Next steps:
- allow bpf_spin_lock in other map types (like cgroup local storage)
- introduce BPF_F_LOCK flag for bpf_map_update() syscall and helper
  to request kernel to grab bpf_spin_lock before rewriting the value.
  That will serialize access to map elements.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-01 20:55:38 +01:00
Martin KaFai Lau
7c4cd051ad bpf: Fix syscall's stackmap lookup potential deadlock
The map_lookup_elem used to not acquiring spinlock
in order to optimize the reader.

It was true until commit 557c0c6e7d ("bpf: convert stackmap to pre-allocation")
The syscall's map_lookup_elem(stackmap) calls bpf_stackmap_copy().
bpf_stackmap_copy() may find the elem no longer needed after the copy is done.
If that is the case, pcpu_freelist_push() saves this elem for reuse later.
This push requires a spinlock.

If a tracing bpf_prog got run in the middle of the syscall's
map_lookup_elem(stackmap) and this tracing bpf_prog is calling
bpf_get_stackid(stackmap) which also requires the same pcpu_freelist's
spinlock, it may end up with a dead lock situation as reported by
Eric Dumazet in https://patchwork.ozlabs.org/patch/1030266/

The situation is the same as the syscall's map_update_elem() which
needs to acquire the pcpu_freelist's spinlock and could race
with tracing bpf_prog.  Hence, this patch fixes it by protecting
bpf_stackmap_copy() with this_cpu_inc(bpf_prog_active)
to prevent tracing bpf_prog from running.

A later syscall's map_lookup_elem commit f1a2e44a3a ("bpf: add queue and stack maps")
also acquires a spinlock and races with tracing bpf_prog similarly.
Hence, this patch is forward looking and protects the majority
of the map lookups.  bpf_map_offload_lookup_elem() is the exception
since it is for network bpf_prog only (i.e. never called by tracing
bpf_prog).

Fixes: 557c0c6e7d ("bpf: convert stackmap to pre-allocation")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-31 23:18:21 +01:00
Alexei Starovoitov
a89fac57b5 bpf: fix lockdep false positive in percpu_freelist
Lockdep warns about false positive:
[   12.492084] 00000000e6b28347 (&head->lock){+...}, at: pcpu_freelist_push+0x2a/0x40
[   12.492696] but this lock was taken by another, HARDIRQ-safe lock in the past:
[   12.493275]  (&rq->lock){-.-.}
[   12.493276]
[   12.493276]
[   12.493276] and interrupts could create inverse lock ordering between them.
[   12.493276]
[   12.494435]
[   12.494435] other info that might help us debug this:
[   12.494979]  Possible interrupt unsafe locking scenario:
[   12.494979]
[   12.495518]        CPU0                    CPU1
[   12.495879]        ----                    ----
[   12.496243]   lock(&head->lock);
[   12.496502]                                local_irq_disable();
[   12.496969]                                lock(&rq->lock);
[   12.497431]                                lock(&head->lock);
[   12.497890]   <Interrupt>
[   12.498104]     lock(&rq->lock);
[   12.498368]
[   12.498368]  *** DEADLOCK ***
[   12.498368]
[   12.498837] 1 lock held by dd/276:
[   12.499110]  #0: 00000000c58cb2ee (rcu_read_lock){....}, at: trace_call_bpf+0x5e/0x240
[   12.499747]
[   12.499747] the shortest dependencies between 2nd lock and 1st lock:
[   12.500389]  -> (&rq->lock){-.-.} {
[   12.500669]     IN-HARDIRQ-W at:
[   12.500934]                       _raw_spin_lock+0x2f/0x40
[   12.501373]                       scheduler_tick+0x4c/0xf0
[   12.501812]                       update_process_times+0x40/0x50
[   12.502294]                       tick_periodic+0x27/0xb0
[   12.502723]                       tick_handle_periodic+0x1f/0x60
[   12.503203]                       timer_interrupt+0x11/0x20
[   12.503651]                       __handle_irq_event_percpu+0x43/0x2c0
[   12.504167]                       handle_irq_event_percpu+0x20/0x50
[   12.504674]                       handle_irq_event+0x37/0x60
[   12.505139]                       handle_level_irq+0xa7/0x120
[   12.505601]                       handle_irq+0xa1/0x150
[   12.506018]                       do_IRQ+0x77/0x140
[   12.506411]                       ret_from_intr+0x0/0x1d
[   12.506834]                       _raw_spin_unlock_irqrestore+0x53/0x60
[   12.507362]                       __setup_irq+0x481/0x730
[   12.507789]                       setup_irq+0x49/0x80
[   12.508195]                       hpet_time_init+0x21/0x32
[   12.508644]                       x86_late_time_init+0xb/0x16
[   12.509106]                       start_kernel+0x390/0x42a
[   12.509554]                       secondary_startup_64+0xa4/0xb0
[   12.510034]     IN-SOFTIRQ-W at:
[   12.510305]                       _raw_spin_lock+0x2f/0x40
[   12.510772]                       try_to_wake_up+0x1c7/0x4e0
[   12.511220]                       swake_up_locked+0x20/0x40
[   12.511657]                       swake_up_one+0x1a/0x30
[   12.512070]                       rcu_process_callbacks+0xc5/0x650
[   12.512553]                       __do_softirq+0xe6/0x47b
[   12.512978]                       irq_exit+0xc3/0xd0
[   12.513372]                       smp_apic_timer_interrupt+0xa9/0x250
[   12.513876]                       apic_timer_interrupt+0xf/0x20
[   12.514343]                       default_idle+0x1c/0x170
[   12.514765]                       do_idle+0x199/0x240
[   12.515159]                       cpu_startup_entry+0x19/0x20
[   12.515614]                       start_kernel+0x422/0x42a
[   12.516045]                       secondary_startup_64+0xa4/0xb0
[   12.516521]     INITIAL USE at:
[   12.516774]                      _raw_spin_lock_irqsave+0x38/0x50
[   12.517258]                      rq_attach_root+0x16/0xd0
[   12.517685]                      sched_init+0x2f2/0x3eb
[   12.518096]                      start_kernel+0x1fb/0x42a
[   12.518525]                      secondary_startup_64+0xa4/0xb0
[   12.518986]   }
[   12.519132]   ... key      at: [<ffffffff82b7bc28>] __key.71384+0x0/0x8
[   12.519649]   ... acquired at:
[   12.519892]    pcpu_freelist_pop+0x7b/0xd0
[   12.520221]    bpf_get_stackid+0x1d2/0x4d0
[   12.520563]    ___bpf_prog_run+0x8b4/0x11a0
[   12.520887]
[   12.521008] -> (&head->lock){+...} {
[   12.521292]    HARDIRQ-ON-W at:
[   12.521539]                     _raw_spin_lock+0x2f/0x40
[   12.521950]                     pcpu_freelist_push+0x2a/0x40
[   12.522396]                     bpf_get_stackid+0x494/0x4d0
[   12.522828]                     ___bpf_prog_run+0x8b4/0x11a0
[   12.523296]    INITIAL USE at:
[   12.523537]                    _raw_spin_lock+0x2f/0x40
[   12.523944]                    pcpu_freelist_populate+0xc0/0x120
[   12.524417]                    htab_map_alloc+0x405/0x500
[   12.524835]                    __do_sys_bpf+0x1a3/0x1a90
[   12.525253]                    do_syscall_64+0x4a/0x180
[   12.525659]                    entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   12.526167]  }
[   12.526311]  ... key      at: [<ffffffff838f7668>] __key.13130+0x0/0x8
[   12.526812]  ... acquired at:
[   12.527047]    __lock_acquire+0x521/0x1350
[   12.527371]    lock_acquire+0x98/0x190
[   12.527680]    _raw_spin_lock+0x2f/0x40
[   12.527994]    pcpu_freelist_push+0x2a/0x40
[   12.528325]    bpf_get_stackid+0x494/0x4d0
[   12.528645]    ___bpf_prog_run+0x8b4/0x11a0
[   12.528970]
[   12.529092]
[   12.529092] stack backtrace:
[   12.529444] CPU: 0 PID: 276 Comm: dd Not tainted 5.0.0-rc3-00018-g2fa53f892422 #475
[   12.530043] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
[   12.530750] Call Trace:
[   12.530948]  dump_stack+0x5f/0x8b
[   12.531248]  check_usage_backwards+0x10c/0x120
[   12.531598]  ? ___bpf_prog_run+0x8b4/0x11a0
[   12.531935]  ? mark_lock+0x382/0x560
[   12.532229]  mark_lock+0x382/0x560
[   12.532496]  ? print_shortest_lock_dependencies+0x180/0x180
[   12.532928]  __lock_acquire+0x521/0x1350
[   12.533271]  ? find_get_entry+0x17f/0x2e0
[   12.533586]  ? find_get_entry+0x19c/0x2e0
[   12.533902]  ? lock_acquire+0x98/0x190
[   12.534196]  lock_acquire+0x98/0x190
[   12.534482]  ? pcpu_freelist_push+0x2a/0x40
[   12.534810]  _raw_spin_lock+0x2f/0x40
[   12.535099]  ? pcpu_freelist_push+0x2a/0x40
[   12.535432]  pcpu_freelist_push+0x2a/0x40
[   12.535750]  bpf_get_stackid+0x494/0x4d0
[   12.536062]  ___bpf_prog_run+0x8b4/0x11a0

It has been explained that is a false positive here:
https://lkml.org/lkml/2018/7/25/756
Recap:
- stackmap uses pcpu_freelist
- The lock in pcpu_freelist is a percpu lock
- stackmap is only used by tracing bpf_prog
- A tracing bpf_prog cannot be run if another bpf_prog
  has already been running (ensured by the percpu bpf_prog_active counter).

Eric pointed out that this lockdep splats stops other
legit lockdep splats in selftests/bpf/test_progs.c.

Fix this by calling local_irq_save/restore for stackmap.

Another false positive had also been worked around by calling
local_irq_save in commit 89ad2fa3f0 ("bpf: fix lockdep splat").
That commit added unnecessary irq_save/restore to fast path of
bpf hash map. irqs are already disabled at that point, since htab
is holding per bucket spin_lock with irqsave.

Let's reduce overhead for htab by introducing __pcpu_freelist_push/pop
function w/o irqsave and convert pcpu_freelist_push/pop to irqsave
to be used elsewhere (right now only in stackmap).
It stops lockdep false positive in stackmap with a bit of acceptable overhead.

Fixes: 557c0c6e7d ("bpf: convert stackmap to pre-allocation")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-31 23:18:21 +01:00
Alexei Starovoitov
6cab5e90ab bpf: run bpf programs with preemption disabled
Disabled preemption is necessary for proper access to per-cpu maps
from BPF programs.

But the sender side of socket filters didn't have preemption disabled:
unix_dgram_sendmsg->sk_filter->sk_filter_trim_cap->bpf_prog_run_save_cb->BPF_PROG_RUN

and a combination of af_packet with tun device didn't disable either:
tpacket_snd->packet_direct_xmit->packet_pick_tx_queue->ndo_select_queue->
  tun_select_queue->tun_ebpf_select_queue->bpf_prog_run_clear_cb->BPF_PROG_RUN

Disable preemption before executing BPF programs (both classic and extended).

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-31 23:14:55 +01:00
Valdis Kletnieks
1832f4ef58 bpf, cgroups: clean up kerneldoc warnings
Building with W=1 reveals some bitrot:

  CC      kernel/bpf/cgroup.o
kernel/bpf/cgroup.c:238: warning: Function parameter or member 'flags' not described in '__cgroup_bpf_attach'
kernel/bpf/cgroup.c:367: warning: Function parameter or member 'unused_flags' not described in '__cgroup_bpf_detach'

Add a kerneldoc line for 'flags'.

Fixing the warning for 'unused_flags' is best approached by
removing the unused parameter on the function call.

Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-31 10:32:01 +01:00
Valdis Kletnieks
de1da68d9c bpf: fix bitrotted kerneldoc
Over the years, the function signature has changed, but the
kerneldoc block hasn't.

Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-31 10:31:44 +01:00
Yonghong Song
81f5c6f5db bpf: btf: allow typedef func_proto
Current implementation does not allow typedef func_proto.
But it is actually allowed.
  -bash-4.4$ cat t.c
  typedef int (f) (int);
  f *g;
  -bash-4.4$ clang -O2 -g -c -target bpf t.c -Xclang -target-feature -Xclang +dwarfris
  -bash-4.4$ pahole -JV t.o
  File t.o:
  [1] PTR (anon) type_id=2
  [2] TYPEDEF f type_id=3
  [3] FUNC_PROTO (anon) return=4 args=(4 (anon))
  [4] INT int size=4 bit_offset=0 nr_bits=32 encoding=SIGNED
  -bash-4.4$

This patch related btf verifier to allow such (typedef func_proto)
patterns.

Fixes: 2667a2626f ("bpf: btf: Add BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO")
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-29 19:15:32 -08:00
David S. Miller
ec7146db15 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2019-01-29

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

The main changes are:

1) Teach verifier dead code removal, this also allows for optimizing /
   removing conditional branches around dead code and to shrink the
   resulting image. Code store constrained architectures like nfp would
   have hard time doing this at JIT level, from Jakub.

2) Add JMP32 instructions to BPF ISA in order to allow for optimizing
   code generation for 32-bit sub-registers. Evaluation shows that this
   can result in code reduction of ~5-20% compared to 64 bit-only code
   generation. Also add implementation for most JITs, from Jiong.

3) Add support for __int128 types in BTF which is also needed for
   vmlinux's BTF conversion to work, from Yonghong.

4) Add a new command to bpftool in order to dump a list of BPF-related
   parameters from the system or for a specific network device e.g. in
   terms of available prog/map types or helper functions, from Quentin.

5) Add AF_XDP sock_diag interface for querying sockets from user
   space which provides information about the RX/TX/fill/completion
   rings, umem, memory usage etc, from Björn.

6) Add skb context access for skb_shared_info->gso_segs field, from Eric.

7) Add support for testing flow dissector BPF programs by extending
   existing BPF_PROG_TEST_RUN infrastructure, from Stanislav.

8) Split BPF kselftest's test_verifier into various subgroups of tests
   in order better deal with merge conflicts in this area, from Jakub.

9) Add support for queue/stack manipulations in bpftool, from Stanislav.

10) Document BTF, from Yonghong.

11) Dump supported ELF section names in libbpf on program load
    failure, from Taeung.

12) Silence a false positive compiler warning in verifier's BTF
    handling, from Peter.

13) Fix help string in bpftool's feature probing, from Prashant.

14) Remove duplicate includes in BPF kselftests, from Yue.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-28 19:38:33 -08:00
Jiong Wang
a7b76c8857 bpf: JIT blinds support JMP32
This patch adds JIT blinds support for JMP32.

Like BPF_JMP_REG/IMM, JMP32 version are needed for building raw bpf insn.
They are added to both include/linux/filter.h and
tools/include/linux/filter.h.

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-26 13:33:01 -08:00
Jiong Wang
503a8865a4 bpf: interpreter support for JMP32
This patch implements interpreting new JMP32 instructions.

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-26 13:33:01 -08:00
Jiong Wang
56cbd82ef0 bpf: disassembler support JMP32
This patch teaches disassembler about JMP32. There are two places to
update:

  - Class 0x6 now used by BPF_JMP32, not "unused".

  - BPF_JMP32 need to show comparison operands properly.
    The disassemble format is to add an extra "(32)" before the operands if
    it is a sub-register. A better disassemble format for both JMP32 and
    ALU32 just show the register prefix as "w" instead of "r", this is the
    format using by LLVM assembler.

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-26 13:33:01 -08:00
Jiong Wang
092ed0968b bpf: verifier support JMP32
This patch teach verifier about the new BPF_JMP32 instruction class.
Verifier need to treat it similar as the existing BPF_JMP class.
A BPF_JMP32 insn needs to go through all checks that have been done on
BPF_JMP.

Also, verifier is doing runtime optimizations based on the extra info
conditional jump instruction could offer, especially when the comparison is
between constant and register that the value range of the register could be
improved based on the comparison results. These code are updated
accordingly.

Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-26 13:33:01 -08:00
Jiong Wang
a72dafafbd bpf: refactor verifier min/max code for condition jump
The current min/max code does both signed and unsigned comparisons against
the input argument "val" which is "u64" and there is explicit type casting
when the comparison is signed.

As we will need slightly more complexer type casting when JMP32 introduced,
it is better to host the signed type casting. This makes the code more
clean with ignorable runtime overhead.

Also, code for J*GE/GT/LT/LE and JEQ/JNE are very similar, this patch
combine them.

The main purpose for this refactor is to make sure the min/max code will
still be readable and with minimum code duplication after JMP32 introduced.

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-26 13:33:01 -08:00
Jakub Kicinski
08ca90afba bpf: notify offload JITs about optimizations
Let offload JITs know when instructions are replaced and optimized
out, so they can update their state appropriately.  The optimizations
are best effort, if JIT returns an error from any callback verifier
will stop notifying it as state may now be out of sync, but the
verifier continues making progress.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-23 17:35:32 -08:00
Jakub Kicinski
9e4c24e7ee bpf: verifier: record original instruction index
The communication between the verifier and advanced JITs is based
on instruction indexes.  We have to keep them stable throughout
the optimizations otherwise referring to a particular instruction
gets messy quickly.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-23 17:35:32 -08:00
Jakub Kicinski
a1b14abc00 bpf: verifier: remove unconditional branches by 0
Unconditional branches by 0 instructions are basically noops
but they can result from earlier optimizations, e.g. a conditional
jumps which would never be taken or a conditional jump around
dead code.

Remove those branches.

v0.2:
 - s/opt_remove_dead_branches/opt_remove_nops/ (Jiong).

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-23 17:35:32 -08:00
Jakub Kicinski
52875a04f4 bpf: verifier: remove dead code
Instead of overwriting dead code with jmp -1 instructions
remove it completely for root.  Adjust verifier state and
line info appropriately.

v2:
 - adjust func_info (Alexei);
 - make sure first instruction retains line info (Alexei).
v4: (Yonghong)
 - remove unnecessary if (!insn to remove) checks;
 - always keep last line info if first live instruction lacks one.
v5: (Martin Lau)
 - improve and clarify comments.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-23 17:35:31 -08:00
Jakub Kicinski
e2ae4ca266 bpf: verifier: hard wire branches to dead code
Loading programs with dead code becomes more and more
common, as people begin to patch constants at load time.
Turn conditional jumps to unconditional ones, to avoid
potential branch misprediction penalty.

This optimization is enabled for privileged users only.

For branches which just fall through we could just mark
them as not seen and have dead code removal take care of
them, but that seems less clean.

v0.2:
 - don't call capable(CAP_SYS_ADMIN) twice (Jiong).
v3:
 - fix GCC warning;

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-23 17:35:31 -08:00
Jakub Kicinski
2cbd95a5c4 bpf: change parameters of call/branch offset adjustment
In preparation for code removal change parameters to branch
and call adjustment functions to be more universal.  The
current parameters assume we are patching a single instruction
with a longer set.

A diagram may help reading the change, this is for the patch
single case, patching instruction 1 with a replacement of 4:
   ____
0 |____|
1 |____| <-- pos                ^
2 |    | <-- end old  ^         |
3 |    |              |  delta  |  len
4 |____|              |         |  (patch region)
5 |    | <-- end new  v         v
6 |____|

end_old = pos + 1
end_new = pos + delta + 1

If we are before the patch region - curr variable and the target
are fully in old coordinates (hence comparing against end_old).
If we are after the region curr is in new coordinates (hence
the comparison to end_new) but target is in mixed coordinates,
so we just check if it falls before end_new, and if so it needs
the adjustment.

Note that we will not fix up branches which land in removed region
in case of removal, which should be okay, as we are only going to
remove dead code.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-23 17:35:31 -08:00
Song Liu
6ee52e2a3f perf, bpf: Introduce PERF_RECORD_BPF_EVENT
For better performance analysis of BPF programs, this patch introduces
PERF_RECORD_BPF_EVENT, a new perf_event_type that exposes BPF program
load/unload information to user space.

Each BPF program may contain up to BPF_MAX_SUBPROGS (256) sub programs.
The following example shows kernel symbols for a BPF program with 7 sub
programs:

    ffffffffa0257cf9 t bpf_prog_b07ccb89267cf242_F
    ffffffffa02592e1 t bpf_prog_2dcecc18072623fc_F
    ffffffffa025b0e9 t bpf_prog_bb7a405ebaec5d5c_F
    ffffffffa025dd2c t bpf_prog_a7540d4a39ec1fc7_F
    ffffffffa025fcca t bpf_prog_05762d4ade0e3737_F
    ffffffffa026108f t bpf_prog_db4bd11e35df90d4_F
    ffffffffa0263f00 t bpf_prog_89d64e4abf0f0126_F
    ffffffffa0257cf9 t bpf_prog_ae31629322c4b018__dummy_tracepoi

When a bpf program is loaded, PERF_RECORD_KSYMBOL is generated for each
of these sub programs. Therefore, PERF_RECORD_BPF_EVENT is not needed
for simple profiling.

For annotation, user space need to listen to PERF_RECORD_BPF_EVENT and
gather more information about these (sub) programs via sys_bpf.

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradeaed.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20190117161521.1341602-4-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-01-21 17:00:57 -03:00
Daniel Borkmann
9d5564ddcf bpf: fix inner map masking to prevent oob under speculation
During review I noticed that inner meta map setup for map in
map is buggy in that it does not propagate all needed data
from the reference map which the verifier is later accessing.

In particular one such case is index masking to prevent out of
bounds access under speculative execution due to missing the
map's unpriv_array/index_mask field propagation. Fix this such
that the verifier is generating the correct code for inlined
lookups in case of unpriviledged use.

Before patch (test_verifier's 'map in map access' dump):

  # bpftool prog dump xla id 3
     0: (62) *(u32 *)(r10 -4) = 0
     1: (bf) r2 = r10
     2: (07) r2 += -4
     3: (18) r1 = map[id:4]
     5: (07) r1 += 272                |
     6: (61) r0 = *(u32 *)(r2 +0)     |
     7: (35) if r0 >= 0x1 goto pc+6   | Inlined map in map lookup
     8: (54) (u32) r0 &= (u32) 0      | with index masking for
     9: (67) r0 <<= 3                 | map->unpriv_array.
    10: (0f) r0 += r1                 |
    11: (79) r0 = *(u64 *)(r0 +0)     |
    12: (15) if r0 == 0x0 goto pc+1   |
    13: (05) goto pc+1                |
    14: (b7) r0 = 0                   |
    15: (15) if r0 == 0x0 goto pc+11
    16: (62) *(u32 *)(r10 -4) = 0
    17: (bf) r2 = r10
    18: (07) r2 += -4
    19: (bf) r1 = r0
    20: (07) r1 += 272                |
    21: (61) r0 = *(u32 *)(r2 +0)     | Index masking missing (!)
    22: (35) if r0 >= 0x1 goto pc+3   | for inner map despite
    23: (67) r0 <<= 3                 | map->unpriv_array set.
    24: (0f) r0 += r1                 |
    25: (05) goto pc+1                |
    26: (b7) r0 = 0                   |
    27: (b7) r0 = 0
    28: (95) exit

After patch:

  # bpftool prog dump xla id 1
     0: (62) *(u32 *)(r10 -4) = 0
     1: (bf) r2 = r10
     2: (07) r2 += -4
     3: (18) r1 = map[id:2]
     5: (07) r1 += 272                |
     6: (61) r0 = *(u32 *)(r2 +0)     |
     7: (35) if r0 >= 0x1 goto pc+6   | Same inlined map in map lookup
     8: (54) (u32) r0 &= (u32) 0      | with index masking due to
     9: (67) r0 <<= 3                 | map->unpriv_array.
    10: (0f) r0 += r1                 |
    11: (79) r0 = *(u64 *)(r0 +0)     |
    12: (15) if r0 == 0x0 goto pc+1   |
    13: (05) goto pc+1                |
    14: (b7) r0 = 0                   |
    15: (15) if r0 == 0x0 goto pc+12
    16: (62) *(u32 *)(r10 -4) = 0
    17: (bf) r2 = r10
    18: (07) r2 += -4
    19: (bf) r1 = r0
    20: (07) r1 += 272                |
    21: (61) r0 = *(u32 *)(r2 +0)     |
    22: (35) if r0 >= 0x1 goto pc+4   | Now fixed inlined inner map
    23: (54) (u32) r0 &= (u32) 0      | lookup with proper index masking
    24: (67) r0 <<= 3                 | for map->unpriv_array.
    25: (0f) r0 += r1                 |
    26: (05) goto pc+1                |
    27: (b7) r0 = 0                   |
    28: (b7) r0 = 0
    29: (95) exit

Fixes: b2157399cc ("bpf: prevent out-of-bounds speculation")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-18 15:19:56 -08:00
Mathieu Malaterre
c8dc79806e bpf: Annotate implicit fall through in cgroup_dev_func_proto
There is a plan to build the kernel with -Wimplicit-fallthrough
and this place in the code produced a warnings (W=1).

This commit removes the following warning:

  kernel/bpf/cgroup.c:719:6: warning: this statement may fall through [-Wimplicit-fallthrough=]

Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-17 16:52:23 +01:00
Mathieu Malaterre
583c531853 bpf: Make function btf_name_offset_valid static
Initially in commit 69b693f0ae ("bpf: btf: Introduce BPF Type Format
(BTF)") the function 'btf_name_offset_valid' was introduced as static
function it was later on changed to a non-static one, and then finally
in commit 23127b33ec ("bpf: Create a new btf_name_by_offset() for
non type name use case") the function prototype was removed.

Revert back to original implementation and make the function static.
Remove warning triggered with W=1:

  kernel/bpf/btf.c:470:6: warning: no previous prototype for 'btf_name_offset_valid' [-Wmissing-prototypes]

Fixes: 23127b33ec ("bpf: Create a new btf_name_by_offset() for non type name use case")
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-17 16:47:05 +01:00