The first test case, for pointer null checks, is equivalent to the
following pseudo-code.  It checks that the verifier does not complain on
line 6 and recognizes that ptr isn't null.

1: ptr = bpf_map_lookup_elem(map, &key);
2: ret = subprog(ptr) {
3:   return ptr != NULL;
4: }
5: if (ret)
6:   value = *ptr;

The second test case, for packet bound checks, is equivalent to the
following pseudo-code.  It checks that the verifier does not complain on
line 7 and recognizes that the packet is at least 1 byte long.

1: pkt_end = ctx.pkt_end;
2: ptr = ctx.pkt + 8;
3: ret = subprog(ptr, pkt_end) {
4:   return ptr <= pkt_end;
5: }
6: if (ret)
7:   value = *(u8 *)ctx.pkt;

Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This is a preparation for the next commit that would prohibit access to
the most fields of __sk_buff from the BPF programs.

Instead of requiring BPF flow dissector programs to look into skb,
pass all input data in the flow_keys.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

When we tail call PROG(VLAN) from parse_eth_proto we don't need to peek
back to handle vlan proto because we didn't adjust nhoff/thoff yet. Use
flow_keys->n_proto, that we set in parse_eth_proto instead and
properly increment nhoff as well.

Also, always use skb->protocol and don't look at skb->vlan_present.
skb->vlan_present indicates that vlan information is stored out-of-band
in skb->vlan_{tci,proto} and vlan header is already pulled from skb.
That means, skb->vlan_present == true is not relevant for BPF flow
dissector.

Add simple test cases with VLAN tagged frames:
  * single vlan for ipv4
  * double vlan for ipv6

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

This patch adds specific test exposing bug in btf_dedup_is_equiv() when
comparing candidate VOID type to a non-VOID canonical type. It's
important for canonical type to be anonymous, otherwise name equality
check will do the right thing and will exit early.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This patch adds a test case with an excessive number of call stack frames
in dead code.

Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
Tested-by: Xiao Han <xiao.han@orange.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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>

This patch adds test verifying new btf_dedup logic of resolving
forward-declared enums.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This patch adds an example in using the new helper
bpf_get_listener_sock().

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Adding verifier tests to ensure the ptr returned from bpf_tcp_sock() and
bpf_sk_fullsock() cannot be accessed after bpf_sk_release() is called.
A few of the tests are derived from a reproducer test by Lorenz Bauer.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

The test_progs subtests, test_spin_lock() and test_map_lock(),
requires BTF present to run successfully.
Currently, when BTF failed to load, test_progs will segfault,
  $ ./test_progs
  ...
  12: (bf) r1 = r8
  13: (85) call bpf_spin_lock#93
  map 'hash_map' has to have BTF in order to use bpf_spin_lock

  libbpf: -- END LOG --
  libbpf: failed to load program 'map_lock_demo'
  libbpf: failed to load object './test_map_lock.o'
  test_map_lock:bpf_prog_load errno 13
  Segmentation fault

The segfault is caused by uninitialized variable "obj", which
is used in bpf_object__close(obj), when bpf prog failed to load.

Initializing variable "obj" to NULL in two occasions fixed the problem.
  $ ./test_progs
  ...
  Summary: 219 PASSED, 2 FAILED

Fixes: b4d4556c3266 ("selftests/bpf: add bpf_spin_lock verifier tests")
Fixes: ba72a7b4badb ("selftests/bpf: test for BPF_F_LOCK")
Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>