Daniel Borkmann says:

====================
This set adds probe_read_{user,kernel}(), probe_read_str_{user,kernel}()
helpers, fixes probe_write_user() helper and selftests. For details please
see individual patches.

Thanks!

v2 -> v3:
  - noticed two more things that are fixed in here:
   - bpf uapi helper description used 'int size' for *_str helpers, now u32
   - we need TASK_SIZE_MAX + guard page on x86-64 in patch 2 otherwise
     we'll trigger the 00c42373 warn as well, so full range covered now
v1 -> v2:
  - standardize unsafe_ptr terminology in uapi header comment (Andrii)
  - probe_read_{user,kernel}[_str] naming scheme (Andrii)
  - use global data in last test case, remove relaxed_maps (Andrii)
  - add strict non-pagefault kernel read funcs to avoid warning in
    kernel probe read helpers (Alexei)
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Tested on x86-64 and Ilya was also kind enough to give it a spin on
s390x, both passing with probe_user:OK there. The test is using the
newly added bpf_probe_read_user() to dump sockaddr from connect call
into .bss BPF map and overrides the user buffer via bpf_probe_write_user():

  # ./test_progs
  [...]
  #17 pkt_md_access:OK
  #18 probe_user:OK
  #19 prog_run_xattr:OK
  [...]
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/90f449d8af25354e05080e82fc6e2d3179da30ea.1572649915.git.daniel@iogearbox.net

Use probe read *_{kernel,user}{,_str}() helpers instead of bpf_probe_read()
or bpf_probe_read_user_str() for program tests where appropriate.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/4a61d4b71ce3765587d8ef5cb93afa18515e5b3e.1572649915.git.daniel@iogearbox.net

Use bpf_probe_read_user() helper instead of bpf_probe_read() for samples that
attach to kprobes probing on user addresses.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/5b0144b3f8e031ec5e2438bd7de8d7877e63bf2f.1572649915.git.daniel@iogearbox.net

Commit 2a02759e ("bpf: Add support for BTF pointers to interpreter")
explicitly states that the pointer to BTF object is a pointer to a kernel
object or NULL. Therefore we should also switch to using the strict kernel
probe helper which is restricted to kernel addresses only when architectures
have non-overlapping address spaces.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/d2b90827837685424a4b8008dfe0460558abfada.1572649915.git.daniel@iogearbox.net

The current bpf_probe_read() and bpf_probe_read_str() helpers are broken
in that they assume they can be used for probing memory access for kernel
space addresses /as well as/ user space addresses.

However, plain use of probe_kernel_read() for both cases will attempt to
always access kernel space address space given access is performed under
KERNEL_DS and some archs in-fact have overlapping address spaces where a
kernel pointer and user pointer would have the /same/ address value and
therefore accessing application memory via bpf_probe_read{,_str}() would
read garbage values.

Lets fix BPF side by making use of recently added 3d708182 ("uaccess:
Add non-pagefault user-space read functions"). Unfortunately, the only way
to fix this status quo is to add dedicated bpf_probe_read_{user,kernel}()
and bpf_probe_read_{user,kernel}_str() helpers. The bpf_probe_read{,_str}()
helpers are kept as-is to retain their current behavior.

The two *_user() variants attempt the access always under USER_DS set, the
two *_kernel() variants will -EFAULT when accessing user memory if the
underlying architecture has non-overlapping address ranges, also avoiding
throwing the kernel warning via 00c42373 ("x86-64: add warning for
non-canonical user access address dereferences").

Fixes: a5e8c070 ("bpf: add bpf_probe_read_str helper")
Fixes: 2541517c ("tracing, perf: Implement BPF programs attached to kprobes")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/796ee46e948bc808d54891a1108435f8652c6ca4.1572649915.git.daniel@iogearbox.net

Convert the bpf_probe_write_user() helper to probe_user_write() such that
writes are not attempted under KERNEL_DS anymore which is buggy as kernel
and user space pointers can have overlapping addresses. Also, given we have
the access_ok() check inside probe_user_write(), the helper doesn't need
to do it twice.

Fixes: 96ae5227 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/841c461781874c07a0ee404a454c3bc0459eed30.1572649915.git.daniel@iogearbox.net

Add two new probe_kernel_read_strict() and strncpy_from_unsafe_strict()
helpers which by default alias to the __probe_kernel_read() and the
__strncpy_from_unsafe(), respectively, but can be overridden by archs
which have non-overlapping address ranges for kernel space and user
space in order to bail out with -EFAULT when attempting to probe user
memory including non-canonical user access addresses [0]:

  4-level page tables:
    user-space mem: 0x0000000000000000 - 0x00007fffffffffff
    non-canonical:  0x0000800000000000 - 0xffff7fffffffffff

  5-level page tables:
    user-space mem: 0x0000000000000000 - 0x00ffffffffffffff
    non-canonical:  0x0100000000000000 - 0xfeffffffffffffff

The idea is that these helpers are complementary to the probe_user_read()
and strncpy_from_unsafe_user() which probe user-only memory. Both added
helpers here do the same, but for kernel-only addresses.

Both set of helpers are going to be used for BPF tracing. They also
explicitly avoid throwing the splat for non-canonical user addresses from
00c42373 ("x86-64: add warning for non-canonical user access address
dereferences").

For compat, the current probe_kernel_read() and strncpy_from_unsafe() are
left as-is.

  [0] Documentation/x86/x86_64/mm.txt
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: x86@kernel.org
Link: https://lore.kernel.org/bpf/eefeefd769aa5a013531f491a71f0936779e916b.1572649915.git.daniel@iogearbox.net

Commit 3d708182 ("uaccess: Add non-pagefault user-space read functions")
missed to add probe write function, therefore factor out a probe_write_common()
helper with most logic of probe_kernel_write() except setting KERNEL_DS, and
add a new probe_user_write() helper so it can be used from BPF side.

Again, on some archs, the user address space and kernel address space can
co-exist and be overlapping, so in such case, setting KERNEL_DS would mean
that the given address is treated as being in kernel address space.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/bpf/9df2542e68141bfa3addde631441ee45503856a8.1572649915.git.daniel@iogearbox.net

Toke Høiland-Jørgensen says:

====================
This series adds support to libbpf for reading 'pinning' settings from BTF-based
map definitions. It introduces a new open option which can set the pinning path;
if no path is set, /sys/fs/bpf is used as the default. Callers can customise the
pinning between open and load by setting the pin path per map, and still get the
automatic reuse feature.

The semantics of the pinning is similar to the iproute2 "PIN_GLOBAL" setting,
and the eventual goal is to move the iproute2 implementation to be based on
libbpf and the functions introduced in this series.

Changelog:

v6:
  - Fix leak of struct bpf_object in selftest
  - Make struct bpf_map arg const in bpf_map__is_pinned() and bpf_map__get_pin_path()

v5:
  - Don't pin maps with pinning set, but with a value of LIBBPF_PIN_NONE
  - Add a few more selftests:
    - Should not pin map with pinning set, but value LIBBPF_PIN_NONE
    - Should fail to load a map with an invalid pinning value
    - Should fail to re-use maps with parameter mismatch
  - Alphabetise libbpf.map
  - Whitespace and typo fixes

v4:
  - Don't check key_type_id and value_type_id when checking for map reuse
    compatibility.
  - Move building of map->pin_path into init_user_btf_map()
  - Get rid of 'pinning' attribute in struct bpf_map
  - Make sure we also create parent directory on auto-pin (new patch 3).
  - Abort the selftest on error instead of attempting to continue.
  - Support unpinning all pinned maps with bpf_object__unpin_maps(obj, NULL)
  - Support pinning at map->pin_path with bpf_object__pin_maps(obj, NULL)
  - Make re-pinning a map at the same path a noop
  - Rename the open option to pin_root_path
  - Add a bunch more self-tests for pin_maps(NULL) and unpin_maps(NULL)
  - Fix a couple of smaller nits

v3:
  - Drop bpf_object__pin_maps_opts() and just use an open option to customise
    the pin path; also don't touch bpf_object__{un,}pin_maps()
  - Integrate pinning and reuse into bpf_object__create_maps() instead of having
    multiple loops though the map structure
  - Make errors in map reuse and pinning fatal to the load procedure
  - Add selftest to exercise pinning feature
  - Rebase series to latest bpf-next

v2:
  - Drop patch that adds mounting of bpffs
  - Only support a single value of the pinning attribute
  - Add patch to fixup error handling in reuse_fd()
  - Implement the full automatic pinning and map reuse logic on load
====================
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

This adds a new BPF selftest to exercise the new automatic map pinning
code.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157269298209.394725.15420085139296213182.stgit@toke.dk

This adds support to libbpf for setting map pinning information as part of
the BTF map declaration, to get automatic map pinning (and reuse) on load.
The pinning type currently only supports a single PIN_BY_NAME mode, where
each map will be pinned by its name in a path that can be overridden, but
defaults to /sys/fs/bpf.

Since auto-pinning only does something if any maps actually have a
'pinning' BTF attribute set, we default the new option to enabled, on the
assumption that seamless pinning is what most callers want.

When a map has a pin_path set at load time, libbpf will compare the map
pinned at that location (if any), and if the attributes match, will re-use
that map instead of creating a new one. If no existing map is found, the
newly created map will instead be pinned at the location.

Programs wanting to customise the pinning can override the pinning paths
using bpf_map__set_pin_path() before calling bpf_object__load() (including
setting it to NULL to disable pinning of a particular map).
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157269298092.394725.3966306029218559681.stgit@toke.dk

The existing pin_*() functions all try to create the parent directory
before pinning. Move this check into the per-object _pin() functions
instead. This ensures consistent behaviour when auto-pinning is
added (which doesn't go through the top-level pin_maps() function), at the
cost of a few more calls to mkdir().
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157269297985.394725.5882630952992598610.stgit@toke.dk

Support storing and setting a pin path in struct bpf_map, which can be used
for automatic pinning. Also store the pin status so we can avoid attempts
to re-pin a map that has already been pinned (or reused from a previous
pinning).

The behaviour of bpf_object__{un,}pin_maps() is changed so that if it is
called with a NULL path argument (which was previously illegal), it will
(un)pin only those maps that have a pin_path set.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157269297876.394725.14782206533681896279.stgit@toke.dk

bpf_map__reuse_fd() was calling close() in the error path before returning
an error value based on errno. However, close can change errno, so that can
lead to potentially misleading error messages. Instead, explicitly store
errno in the err variable before each goto.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/157269297769.394725.12634985106772698611.stgit@toke.dk

Björn Töpel says:

====================
This set consists of three patches from Maciej and myself which are
optimizing the XSKMAP lookups.  In the first patch, the sockets are
moved to be stored at the tail of the struct xsk_map. The second
patch, Maciej implements map_gen_lookup() for XSKMAP. The third patch,
introduced in this revision, moves various XSKMAP functions, to permit
the compiler to do more aggressive inlining.

Based on the XDP program from tools/lib/bpf/xsk.c where
bpf_map_lookup_elem() is explicitly called, this work yields a 5%
improvement for xdpsock's rxdrop scenario. The last patch yields 2%
improvement.

Jonathan's Acked-by: for patch 1 and 2 was carried on. Note that the
overflow checks are done in the bpf_map_area_alloc() and
bpf_map_charge_init() functions, which was fixed in commit
ff1c08e1 ("bpf: Change size to u64 for bpf_map_{area_alloc,
charge_init}()").

  [1] https://patchwork.ozlabs.org/patch/1186170/

v1->v2: * Change size/cost to size_t and use {struct, array}_size
          where appropriate. (Jakub)
v2->v3: * Proper commit message for patch 2.
v3->v4: * Change size_t to u64 to handle 32-bit overflows. (Jakub)
        * Introduced patch 3.
v4->v5: * Use BPF_SIZEOF size, instead of BPF_DW, for correct
          pointer-sized loads. (Daniel)
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

In this commit the XSKMAP entry lookup function used by the XDP
redirect code is moved from the xskmap.c file to the xdp_sock.h
header, so the lookup can be inlined from, e.g., the
bpf_xdp_redirect_map() function.

Further the __xsk_map_redirect() and __xsk_map_flush() is moved to the
xsk.c, which lets the compiler inline the xsk_rcv() and xsk_flush()
functions.

Finally, all the XDP socket functions were moved from linux/bpf.h to
net/xdp_sock.h, where most of the XDP sockets functions are anyway.

This yields a ~2% performance boost for the xdpsock "rx_drop"
scenario.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191101110346.15004-4-bjorn.topel@gmail.com

Inline the xsk_map_lookup_elem() via implementing the map_gen_lookup()
callback. This results in emitting the bpf instructions in place of
bpf_map_lookup_elem() helper call and better performance of bpf
programs.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/bpf/20191101110346.15004-3-bjorn.topel@gmail.com

Prior this commit, the array storing XDP socket instances were stored
in a separate allocated array of the XSKMAP. Now, we store the sockets
as a flexible array member in a similar fashion as the arraymap. Doing
so, we do less pointer chasing in the lookup.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/bpf/20191101110346.15004-2-bjorn.topel@gmail.com

This reverts commit 5bc60de5 ("selftests: bpf: Don't try to read
files without read permission").

Quoted commit does not work at all, and was never tested.
Script requires root permissions (and tests for them)
and os.access() will always return true for root.

The correct fix is needed in the bpf tree, so let's just
revert and save ourselves the merge conflict.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Pirko <jiri@resnulli.us>
Link: https://lore.kernel.org/bpf/20191101005127.1355-1-jakub.kicinski@netronome.com

Alexei Starovoitov says:

====================
v1->v2: addressed Andrii's feedback

When BTF-enabled raw_tp were introduced the plan was to follow up
with BTF-enabled kprobe and kretprobe reusing PROG_RAW_TRACEPOINT
and PROG_KPROBE types. But k[ret]probe expect pt_regs while
BTF-enabled program ctx will be the same as raw_tp.
kretprobe is indistinguishable from kprobe while BTF-enabled
kretprobe will have access to retval while kprobe will not.
Hence PROG_KPROBE type is not reusable and reusing
PROG_RAW_TRACEPOINT no longer fits well.
Hence introduce 'umbrella' prog type BPF_PROG_TYPE_TRACING
that will cover different BTF-enabled tracing attach points.
The changes make libbpf side cleaner as well.
check_attach_btf_id() is cleaner too.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Cleanup libbpf from expected_attach_type == attach_btf_id hack
and introduce BPF_PROG_TYPE_TRACING.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191030223212.953010-3-ast@kernel.org

The bpf program type raw_tp together with 'expected_attach_type'
was the most appropriate api to indicate BTF-enabled raw_tp programs.
But during development it became apparent that 'expected_attach_type'
cannot be used and new 'attach_btf_id' field had to be introduced.
Which means that the information is duplicated in two fields where
one of them is ignored.
Clean it up by introducing new program type where both
'expected_attach_type' and 'attach_btf_id' fields have
specific meaning.
In the future 'expected_attach_type' will be extended
with other attach points that have similar semantics to raw_tp.
This patch is replacing BTF-enabled BPF_PROG_TYPE_RAW_TRACEPOINT with
prog_type = BPF_RPOG_TYPE_TRACING
expected_attach_type = BPF_TRACE_RAW_TP
attach_btf_id = btf_id of raw tracepoint inside the kernel
Future patches will add
expected_attach_type = BPF_TRACE_FENTRY or BPF_TRACE_FEXIT
where programs have the same input context and the same helpers,
but different attach points.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191030223212.953010-2-ast@kernel.org

Jiri reported crash when JIT is on, but net.core.bpf_jit_kallsyms is off.
bpf_prog_kallsyms_find() was skipping addr->bpf_prog resolution
logic in oops and stack traces. That's incorrect.
It should only skip addr->name resolution for 'cat /proc/kallsyms'.
That's what bpf_jit_kallsyms and bpf_jit_harden protect.

Fixes: 3dec541b ("bpf: Add support for BTF pointers to x86 JIT")
Reported-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191030233019.1187404-1-ast@kernel.org

Following reports of skb_segment() hitting a BUG_ON when working on
GROed skbs which have their gso_size mangled (e.g. after a
bpf_skb_change_proto call), add a reproducer test that mimics the
input skbs that lead to the mentioned BUG_ON as in [1] and validates the
fix submitted in [2].

[1] https://lists.openwall.net/netdev/2019/08/26/110
[2] commit 3dcbdb13 ("net: gso: Fix skb_segment splat when splitting gso_size mangled skb having linear-headed frag_list")
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191025134223.2761-3-shmulik.ladkani@gmail.com

Currently, test_skb_segment() builds a single test skb and runs
skb_segment() on it.

Extend test_skb_segment() so it processes an array of numerous
skb/feature pairs to test.
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191025134223.2761-2-shmulik.ladkani@gmail.com

This commits adds a document that explains how to test BPF in an s390
QEMU guest.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191029172916.36528-1-iii@linux.ibm.com

There are tests for full and narrows loads from bpf_sysctl.file_pos, but
for bpf_sysctl.write only full load is tested. Add the missing test.
Suggested-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrey Ignatov <rdna@fb.com>
Link: https://lore.kernel.org/bpf/20191029143027.28681-1-iii@linux.ibm.com

The return value of raw_tp programs is ignored by __bpf_trace_run()
that calls them. The verifier also allows any value to be returned.
For BTF-enabled raw_tp lets enforce 'return 0', so that return value
can be used for something in the future.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191029032426.1206762-1-ast@kernel.org

u32 is a kernel-side typedef. User-space library is supposed to use __u32.
This breaks Github's projection of libbpf. Do u32 -> __u32 fix.

Fixes: 94ff9ebb ("libbpf: Fix compatibility for kernels without need_wakeup")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20191029055953.2461336-1-andriin@fb.com

libbpf's bpf_object__elf_collect() does simple sanity check after iterating
over all ELF sections, if checks that .strtab index is correct. Unfortunately,
due to section indices being 1-based, the check breaks for cases when .strtab
ends up being the very last section in ELF.

Fixes: 77ba9a5b ("tools lib bpf: Fetch map names from correct strtab")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191028233727.1286699-1-andriin@fb.com

When the need_wakeup flag was added to AF_XDP, the format of the
XDP_MMAP_OFFSETS getsockopt was extended. Code was added to the
kernel to take care of compatibility issues arrising from running
applications using any of the two formats. However, libbpf was
not extended to take care of the case when the application/libbpf
uses the new format but the kernel only supports the old
format. This patch adds support in libbpf for parsing the old
format, before the need_wakeup flag was added, and emulating a
set of static need_wakeup flags that will always work for the
application.

v2 -> v3:
* Incorporated code improvements suggested by Jonathan Lemon

v1 -> v2:
* Rebased to bpf-next
* Rewrote the code as the previous version made you blind

Fixes: a4500432 ("libbpf: add support for need_wakeup flag in AF_XDP part")
Reported-by: Eloy Degen <degeneloy@gmail.com>
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/bpf/1571995035-21889-1-git-send-email-magnus.karlsson@intel.com

`make O=/linux-build kselftest TARGETS=bpf` fails with

	make[3]: *** No rule to make target '/linux-build/bpf/test_stub.o', needed by '/linux-build/bpf/test_verifier'

The same command without the O= part works, presumably thanks to the
implicit rule.

Fix by restoring the explicit $(OUTPUT)/test_stub.o rule.

Fixes: 74b5a596 ("selftests/bpf: Replace test_progs and test_maps w/ general rule")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191028102110.7545-1-iii@linux.ibm.com

When cross-compiling tests from x86 to s390, the resulting BPF objects
fail to load due to endianness mismatch.

Fix by using BPF-GCC endianness check for clang as well.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191028102049.7489-1-iii@linux.ibm.com

Daniel Borkmann says:

====================
pull-request: bpf-next 2019-10-27

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

We've added 52 non-merge commits during the last 11 day(s) which contain
a total of 65 files changed, 2604 insertions(+), 1100 deletions(-).

The main changes are:

 1) Revolutionize BPF tracing by using in-kernel BTF to type check BPF
    assembly code. The work here teaches BPF verifier to recognize
    kfree_skb()'s first argument as 'struct sk_buff *' in tracepoints
    such that verifier allows direct use of bpf_skb_event_output() helper
    used in tc BPF et al (w/o probing memory access) that dumps skb data
    into perf ring buffer. Also add direct loads to probe memory in order
    to speed up/replace bpf_probe_read() calls, from Alexei Starovoitov.

 2) Big batch of changes to improve libbpf and BPF kselftests. Besides
    others: generalization of libbpf's CO-RE relocation support to now
    also include field existence relocations, revamp the BPF kselftest
    Makefile to add test runner concept allowing to exercise various
    ways to build BPF programs, and teach bpf_object__open() and friends
    to automatically derive BPF program type/expected attach type from
    section names to ease their use, from Andrii Nakryiko.

 3) Fix deadlock in stackmap's build-id lookup on rq_lock(), from Song Liu.

 4) Allow to read BTF as raw data from bpftool. Most notable use case
    is to dump /sys/kernel/btf/vmlinux through this, from Jiri Olsa.

 5) Use bpf_redirect_map() helper in libbpf's AF_XDP helper prog which
    manages to improve "rx_drop" performance by ~4%., from Björn Töpel.

 6) Fix to restore the flow dissector after reattach BPF test and also
    fix error handling in bpf_helper_defs.h generation, from Jakub Sitnicki.

 7) Improve verifier's BTF ctx access for use outside of raw_tp, from
    Martin KaFai Lau.

 8) Improve documentation for AF_XDP with new sections and to reflect
    latest features, from Magnus Karlsson.

 9) Add back 'version' section parsing to libbpf for old kernels, from
    John Fastabend.

10) Fix strncat bounds error in libbpf's libbpf_prog_type_by_name(),
    from KP Singh.

11) Turn on -mattr=+alu32 in LLVM by default for BPF kselftests in order
    to improve insn coverage for built BPF progs, from Yonghong Song.

12) Misc minor cleanups and fixes, from various others.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Updated config with required kernel options for conntrac TC action,
so that tdc can run the tests.
Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pablo Neira Ayuso says:

====================
Netfilter/IPVS updates for net-next

The following patchset contains Netfilter/IPVS updates for net-next,
more specifically:

* Updates for ipset:

1) Coding style fix for ipset comment extension, from Jeremy Sowden.

2) De-inline many functions in ipset, from Jeremy Sowden.

3) Move ipset function definition from header to source file.

4) Move ip_set_put_flags() to source, export it as a symbol, remove
   inline.

5) Move range_to_mask() to the source file where this is used.

6) Move ip_set_get_ip_port() to the source file where this is used.

* IPVS selftests and netns improvements:

7) Two patches to speedup ipvs netns dismantle, from Haishuang Yan.

8) Three patches to add selftest script for ipvs, also from
   Haishuang Yan.

* Conntrack updates and new nf_hook_slow_list() function:

9) Document ct ecache extension, from Florian Westphal.

10) Skip ct extensions from ctnetlink dump, from Florian.

11) Free ct extension immediately, from Florian.

12) Skip access to ecache extension from nf_ct_deliver_cached_events()
    this is not correct as reported by Syzbot.

13) Add and use nf_hook_slow_list(), from Florian.

* Flowtable infrastructure updates:

14) Move priority to nf_flowtable definition.

15) Dynamic allocation of per-device hooks in flowtables.

16) Allow to include netdevice only once in flowtable definitions.

17) Rise maximum number of devices per flowtable.

* Netfilter hardware offload infrastructure updates:

18) Add nft_flow_block_chain() helper function.

19) Pass callback list to nft_setup_cb_call().

20) Add nft_flow_cls_offload_setup() helper function.

21) Remove rules for the unregistered device via netdevice event.

22) Support for multiple devices in a basechain definition at the
    ingress hook.

22) Add nft_chain_offload_cmd() helper function.

23) Add nft_flow_block_offload_init() helper function.

24) Rewind in case of failing to bind multiple devices to hook.

25) Typo in IPv6 tproxy module description, from Norman Rasmussen.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Igor Russkikh says:

====================
net: aquantia: ptp followup fixes

Here are two sparse warnings, third patch is a fix for
scaled_ppm_to_ppb missing. Eventually I reworked this
to exclude ptp module from build. Please consider it instead
of this patch: https://patchwork.ozlabs.org/patch/1184171/
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

We do disable aq_ptp module build using inline
stubs when CONFIG_PTP_1588_CLOCK is not declared.

This reduces module size and removes unnecessary code.
Reported-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

fixes to remove sparse warnings:
sparse: sparse: cast to restricted __be64

Fixes: 04a18399 ("net: aquantia: implement data PTP datapath")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>