Commit 7640ead93924 ("bpf: verifier: make sure callees don't prune
with caller differences") connected up parentage chains of all
frames of the stack.  It didn't, however, ensure propagate_liveness()
propagates all liveness information along those chains.

This means pruning happening in the callee may generate explored
states with incomplete liveness for the chains in lower frames
of the stack.

The included selftest is similar to the prior one from commit
7640ead93924 ("bpf: verifier: make sure callees don't prune with
caller differences"), where callee would prune regardless of the
difference in r8 state.

Now we also initialize r9 to 0 or 1 based on a result from get_random().
r9 is never read so the walk with r9 = 0 gets pruned (correctly) after
the walk with r9 = 1 completes.

The selftest is so arranged that the pruning will happen in the
callee.  Since callee does not propagate read marks of r8, the
explored state at the pruning point prior to the callee will
now ignore r8.

Propagate liveness on all frames of the stack when pruning.

Fixes: f4d7e40a5b71 ("bpf: introduce function calls (verification)")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Syzkaller hit 'KASAN: use-after-free Write in sanitize_ptr_alu' bug.

Call trace:

  dump_stack+0xbf/0x12e
  print_address_description+0x6a/0x280
  kasan_report+0x237/0x360
  sanitize_ptr_alu+0x85a/0x8d0
  adjust_ptr_min_max_vals+0x8f2/0x1ca0
  adjust_reg_min_max_vals+0x8ed/0x22e0
  do_check+0x1ca6/0x5d00
  bpf_check+0x9ca/0x2570
  bpf_prog_load+0xc91/0x1030
  __se_sys_bpf+0x61e/0x1f00
  do_syscall_64+0xc8/0x550
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fault injection trace:

  kfree+0xea/0x290
  free_func_state+0x4a/0x60
  free_verifier_state+0x61/0xe0
  push_stack+0x216/0x2f0	          <- inject failslab
  sanitize_ptr_alu+0x2b1/0x8d0
  adjust_ptr_min_max_vals+0x8f2/0x1ca0
  adjust_reg_min_max_vals+0x8ed/0x22e0
  do_check+0x1ca6/0x5d00
  bpf_check+0x9ca/0x2570
  bpf_prog_load+0xc91/0x1030
  __se_sys_bpf+0x61e/0x1f00
  do_syscall_64+0xc8/0x550
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

When kzalloc() fails in push_stack(), free_verifier_state() will free
current verifier state. As push_stack() returns, dst_reg was restored
if ptr_is_dst_reg is false. However, as member of the cur_state,
dst_reg is also freed, and error occurs when dereferencing dst_reg.
Simply fix it by testing ret of push_stack() before restoring dst_reg.

Fixes: 979d63d50c0c ("bpf: prevent out of bounds speculation on pointer arithmetic")
Signed-off-by: Xu Yu <xuyu@linux.alibaba.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Naresh reported that test_align fails because of the mismatch at the
verbose printout of the register states.  The reason is due to the newly
added ref_obj_id.

ref_obj_id is only useful for refcounted reg.  Thus, this patch fixes it
by only printing ref_obj_id for refcounted reg.  While at it, it also uses
comma instead of space to separate between "id" and "ref_obj_id".

Fixes: 1b986589680a ("bpf: Fix bpf_tcp_sock and bpf_sk_fullsock issue related to bpf_sk_release")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

It has been observed that sometimes a higher order memory allocation
for BPF maps fails when there is no obvious memory pressure in a system.
E.g. the map (BPF_MAP_TYPE_LRU_HASH, key=38, value=56, max_elems=524288)
could not be created due to vmalloc unable to allocate 75497472B,
when the system's memory consumption (in MB) was the following:

    Total: 3942 Used: 837 (21.24%) Free: 138 Buffers: 239 Cached: 2727

Later analysis [1] by Michal Hocko showed that the vmalloc was not trying
to reclaim memory from the page cache and was failing prematurely due to
__GFP_NORETRY.

Considering dcda9b0471 ("mm, tree wide: replace __GFP_REPEAT by
__GFP_RETRY_MAYFAIL with more useful semantic") and [1], we can replace
__GFP_NORETRY with __GFP_RETRY_MAYFAIL, as it won't invoke OOM killer
and will try harder to fulfil allocation requests.

Unfortunately, replacing the body of the BPF map memory allocation
function with the kvmalloc_node helper function is not an option at
this point in time, given 1) kmalloc is non-optional for higher order
allocations, and 2) passing __GFP_RETRY_MAYFAIL to the kmalloc would
stress the slab allocator too much for large requests.

The change has been tested with the workloads mentioned above and by
observing oom_kill value from /proc/vmstat.

[1]: https://lore.kernel.org/bpf/20190310071318.GW5232@dhcp22.suse.cz/

Signed-off-by: Martynas Pumputis <m@lambda.lt>
Acked-by: Yonghong Song <yhs@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20190318153940.GL8924@dhcp22.suse.cz/

Daniel Borkmann says:

====================
pull-request: bpf 2019-03-16

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

The main changes are:

1) Fix a umem memory leak on cleanup in AF_XDP, from Björn.

2) Fix BTF to properly resolve forward-declared enums into their corresponding
   full enum definition types during deduplication, from Andrii.

3) Fix libbpf to reject invalid flags in xsk_socket__create(), from Magnus.

4) Fix accessing invalid pointer returned from bpf_tcp_sock() and
   bpf_sk_fullsock() after bpf_sk_release() was called, from Martin.

5) Fix generation of load/store DW instructions in PPC JIT, from Naveen.

6) Various fixes in BPF helper function documentation in bpf.h UAPI header
   used to bpf-helpers(7) man page, from Quentin.

7) Fix segfault in BPF test_progs when prog loading failed, from Yonghong.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Lorenz Bauer [thanks!] reported that a ptr returned by bpf_tcp_sock(sk)
can still be accessed after bpf_sk_release(sk).
Both bpf_tcp_sock() and bpf_sk_fullsock() have the same issue.
This patch addresses them together.

A simple reproducer looks like this:

	sk = bpf_sk_lookup_tcp();
	/* if (!sk) ... */
	tp = bpf_tcp_sock(sk);
	/* if (!tp) ... */
	bpf_sk_release(sk);
	snd_cwnd = tp->snd_cwnd; /* oops! The verifier does not complain. */

The problem is the verifier did not scrub the register's states of
the tcp_sock ptr (tp) after bpf_sk_release(sk).

[ Note that when calling bpf_tcp_sock(sk), the sk is not always
  refcount-acquired. e.g. bpf_tcp_sock(skb->sk). The verifier works
  fine for this case. ]

Currently, the verifier does not track if a helper's return ptr (in REG_0)
is "carry"-ing one of its argument's refcount status. To carry this info,
the reg1->id needs to be stored in reg0.

One approach was tried, like "reg0->id = reg1->id", when calling
"bpf_tcp_sock()".  The main idea was to avoid adding another "ref_obj_id"
for the same reg.  However, overlapping the NULL marking and ref
tracking purpose in one "id" does not work well:

	ref_sk = bpf_sk_lookup_tcp();
	fullsock = bpf_sk_fullsock(ref_sk);
	tp = bpf_tcp_sock(ref_sk);
	if (!fullsock) {
	     bpf_sk_release(ref_sk);
	     return 0;
	}
	/* fullsock_reg->id is marked for NOT-NULL.
	 * Same for tp_reg->id because they have the same id.
	 */

	/* oops. verifier did not complain about the missing !tp check */
	snd_cwnd = tp->snd_cwnd;

Hence, a new "ref_obj_id" is needed in "struct bpf_reg_state".
With a new ref_obj_id, when bpf_sk_release(sk) is called, the verifier can
scrub all reg states which has a ref_obj_id match.  It is done with the
changes in release_reg_references() in this patch.

While fixing it, sk_to_full_sk() is removed from bpf_tcp_sock() and
bpf_sk_fullsock() to avoid these helpers from returning
another ptr. It will make bpf_sk_release(tp) possible:

	sk = bpf_sk_lookup_tcp();
	/* if (!sk) ... */
	tp = bpf_tcp_sock(sk);
	/* if (!tp) ... */
	bpf_sk_release(tp);

A separate helper "bpf_get_listener_sock()" will be added in a later
patch to do sk_to_full_sk().

Misc change notes:
- To allow bpf_sk_release(tp), the arg of bpf_sk_release() is changed
  from ARG_PTR_TO_SOCKET to ARG_PTR_TO_SOCK_COMMON.  ARG_PTR_TO_SOCKET
  is removed from bpf.h since no helper is using it.

- arg_type_is_refcounted() is renamed to arg_type_may_be_refcounted()
  because ARG_PTR_TO_SOCK_COMMON is the only one and skb->sk is not
  refcounted.  All bpf_sk_release(), bpf_sk_fullsock() and bpf_tcp_sock()
  take ARG_PTR_TO_SOCK_COMMON.

- check_refcount_ok() ensures is_acquire_function() cannot take
  arg_type_may_be_refcounted() as its argument.

- The check_func_arg() can only allow one refcount-ed arg.  It is
  guaranteed by check_refcount_ok() which ensures at most one arg can be
  refcounted.  Hence, it is a verifier internal error if >1 refcount arg
  found in check_func_arg().

- In release_reference(), release_reference_state() is called
  first to ensure a match on "reg->ref_obj_id" can be found before
  scrubbing the reg states with release_reg_references().

- reg_is_refcounted() is no longer needed.
  1. In mark_ptr_or_null_regs(), its usage is replaced by
     "ref_obj_id && ref_obj_id == id" because,
     when is_null == true, release_reference_state() should only be
     called on the ref_obj_id obtained by a acquire helper (i.e.
     is_acquire_function() == true).  Otherwise, the following
     would happen:

	sk = bpf_sk_lookup_tcp();
	/* if (!sk) { ... } */
	fullsock = bpf_sk_fullsock(sk);
	if (!fullsock) {
		/*
		 * release_reference_state(fullsock_reg->ref_obj_id)
		 * where fullsock_reg->ref_obj_id == sk_reg->ref_obj_id.
		 *
		 * Hence, the following bpf_sk_release(sk) will fail
		 * because the ref state has already been released in the
		 * earlier release_reference_state(fullsock_reg->ref_obj_id).
		 */
		bpf_sk_release(sk);
	}

  2. In release_reg_references(), the current reg_is_refcounted() call
     is unnecessary because the id check is enough.

- The type_is_refcounted() and type_is_refcounted_or_null()
  are no longer needed also because reg_is_refcounted() is removed.

Fixes: 655a51e536c0 ("bpf: Add struct bpf_tcp_sock and BPF_FUNC_tcp_sock")
Reported-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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
  ...

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: 0246e64d9a5f ("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>

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
  ...

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>