Commit Graph

159 Commits

Author SHA1 Message Date
Dave Marchevsky
391145ba2a bpf: Add __bpf_kfunc_{start,end}_defs macros
BPF kfuncs are meant to be called from BPF programs. Accordingly, most
kfuncs are not called from anywhere in the kernel, which the
-Wmissing-prototypes warning is unhappy about. We've peppered
__diag_ignore_all("-Wmissing-prototypes", ... everywhere kfuncs are
defined in the codebase to suppress this warning.

This patch adds two macros meant to bound one or many kfunc definitions.
All existing kfunc definitions which use these __diag calls to suppress
-Wmissing-prototypes are migrated to use the newly-introduced macros.
A new __diag_ignore_all - for "-Wmissing-declarations" - is added to the
__bpf_kfunc_start_defs macro based on feedback from Andrii on an earlier
version of this patch [0] and another recent mailing list thread [1].

In the future we might need to ignore different warnings or do other
kfunc-specific things. This change will make it easier to make such
modifications for all kfunc defs.

  [0]: https://lore.kernel.org/bpf/CAEf4BzaE5dRWtK6RPLnjTW-MW9sx9K3Fn6uwqCTChK2Dcb1Xig@mail.gmail.com/
  [1]: https://lore.kernel.org/bpf/ZT+2qCc%2FaXep0%2FLf@krava/

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20231031215625.2343848-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-11-01 22:33:53 -07:00
Yonghong Song
32337c0a28 bpf: Prevent inlining of bpf_fentry_test7()
With latest clang18, I hit test_progs failures for the following test:

  #13/2    bpf_cookie/multi_kprobe_link_api:FAIL
  #13/3    bpf_cookie/multi_kprobe_attach_api:FAIL
  #13      bpf_cookie:FAIL
  #75      fentry_fexit:FAIL
  #76/1    fentry_test/fentry:FAIL
  #76      fentry_test:FAIL
  #80/1    fexit_test/fexit:FAIL
  #80      fexit_test:FAIL
  #110/1   kprobe_multi_test/skel_api:FAIL
  #110/2   kprobe_multi_test/link_api_addrs:FAIL
  #110/3   kprobe_multi_test/link_api_syms:FAIL
  #110/4   kprobe_multi_test/attach_api_pattern:FAIL
  #110/5   kprobe_multi_test/attach_api_addrs:FAIL
  #110/6   kprobe_multi_test/attach_api_syms:FAIL
  #110     kprobe_multi_test:FAIL

For example, for #13/2, the error messages are:

  [...]
  kprobe_multi_test_run:FAIL:kprobe_test7_result unexpected kprobe_test7_result: actual 0 != expected 1
  [...]
  kprobe_multi_test_run:FAIL:kretprobe_test7_result unexpected kretprobe_test7_result: actual 0 != expected 1

clang17 does not have this issue.

Further investigation shows that kernel func bpf_fentry_test7(), used in
the above tests, is inlined by the compiler although it is marked as
noinline.

  int noinline bpf_fentry_test7(struct bpf_fentry_test_t *arg)
  {
        return (long)arg;
  }

It is known that for simple functions like the above (e.g. just returning
a constant or an input argument), the clang compiler may still do inlining
for a noinline function. Adding 'asm volatile ("")' in the beginning of the
bpf_fentry_test7() can prevent inlining.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20230826200843.2210074-1-yonghong.song@linux.dev
2023-08-30 08:36:17 +02:00
Yunsheng Lin
a9ca9f9cef page_pool: split types and declarations from page_pool.h
Split types and pure function declarations from page_pool.h
and add them in page_page/types.h, so that C sources can
include page_pool.h and headers should generally only include
page_pool/types.h as suggested by jakub.
Rename page_pool.h to page_pool/helpers.h to have both in
one place.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Link: https://lore.kernel.org/r/20230804180529.2483231-2-aleksander.lobakin@intel.com
[Jakub: change microsoft/mana, fix kdoc paths in Documentation]
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-07 13:05:19 -07:00
Jakub Kicinski
49e47a5b61 net: move struct netdev_rx_queue out of netdevice.h
struct netdev_rx_queue is touched in only a few places
and having it defined in netdevice.h brings in the dependency
on xdp.h, because struct xdp_rxq_info gets embedded in
struct netdev_rx_queue.

In prep for removal of xdp.h from netdevice.h move all
the netdev_rx_queue stuff to a new header.

We could technically break the new header up to avoid
the sysfs.h include but it's so rarely included it
doesn't seem to be worth it at this point.

Reviewed-by: Amritha Nambiar <amritha.nambiar@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Link: https://lore.kernel.org/r/20230803010230.1755386-3-kuba@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-08-03 08:38:07 -07:00
Menglong Dong
5e9cf77d81 selftests/bpf: add testcase for TRACING with 6+ arguments
Add fentry_many_args.c and fexit_many_args.c to test the fentry/fexit
with 7/11 arguments. As this feature is not supported by arm64 yet, we
disable these testcases for arm64 in DENYLIST.aarch64. We can combine
them with fentry_test.c/fexit_test.c when arm64 is supported too.

Correspondingly, add bpf_testmod_fentry_test7() and
bpf_testmod_fentry_test11() to bpf_testmod.c

Meanwhile, add bpf_modify_return_test2() to test_run.c to test the
MODIFY_RETURN with 7 arguments.

Add bpf_testmod_test_struct_arg_7/bpf_testmod_test_struct_arg_7 in
bpf_testmod.c to test the struct in the arguments.

And the testcases passed on x86_64:

./test_progs -t fexit
Summary: 5/14 PASSED, 0 SKIPPED, 0 FAILED

./test_progs -t fentry
Summary: 3/2 PASSED, 0 SKIPPED, 0 FAILED

./test_progs -t modify_return
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

./test_progs -t tracing_struct
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230713040738.1789742-4-imagedong@tencent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-13 16:04:56 -07:00
Stanislav Fomichev
2597a25cb8 selftests/bpf: Add test to exercise typedef walking
Add new bpf_fentry_test_sinfo with skb_shared_info argument and try to
access frags.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230626212522.2414485-2-sdf@google.com
2023-06-30 10:36:08 +02:00
Jiri Olsa
65eb006d85 bpf: Move kernel test kfuncs to bpf_testmod
Moving kernel test kfuncs into bpf_testmod kernel module, and adding
necessary init calls and BTF IDs records.

We need to keep following structs in kernel:
  struct prog_test_ref_kfunc
  struct prog_test_member (embedded in prog_test_ref_kfunc)

The reason is because they need to be marked as rcu safe (check test
prog mark_ref_as_untrusted_or_null) and such objects are being required
to be defined only in kernel at the moment (see rcu_safe_kptr check
in kernel).

We need to keep also dtor functions for both objects in kernel:
  bpf_kfunc_call_test_release
  bpf_kfunc_call_memb_release

We also keep the copy of these struct in bpf_testmod_kfunc.h, because
other test functions use them. This is unfortunate, but this is just
temporary solution until we are able to these structs them to bpf_testmod
completely.

As suggested by David adding bpf_testmod.ko make dependency for
bpf programs, so they are rebuilt if we change the bpf_testmod.ko
module.

Also adding missing __bpf_kfunc to bpf_kfunc_call_test4 functions.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230515133756.1658301-11-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-05-16 22:09:24 -07:00
Yunsheng Lin
b51f4113eb net: introduce and use skb_frag_fill_page_desc()
Most users use __skb_frag_set_page()/skb_frag_off_set()/
skb_frag_size_set() to fill the page desc for a skb frag.

Introduce skb_frag_fill_page_desc() to do that.

net/bpf/test_run.c does not call skb_frag_off_set() to
set the offset, "copy_from_user(page_address(page), ...)"
and 'shinfo' being part of the 'data' kzalloced in
bpf_test_init() suggest that it is assuming offset to be
initialized as zero, so call skb_frag_fill_page_desc()
with offset being zero for this case.

Also, skb_frag_set_page() is not used anymore, so remove
it.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-05-13 19:47:56 +01:00
Florian Westphal
2b99ef22e0 bpf: add test_run support for netfilter program type
add glue code so a bpf program can be run using userspace-provided
netfilter state and packet/skb.

Default is to use ipv4:output hook point, but this can be overridden by
userspace.  Userspace provided netfilter state is restricted, only hook and
protocol families can be overridden and only to ipv4/ipv6.

Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230421170300.24115-7-fw@strlen.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-04-21 11:34:50 -07:00
David Vernet
09b501d905 bpf: Remove bpf_kfunc_call_test_kptr_get() test kfunc
We've managed to improve the UX for kptrs significantly over the last 9
months. All of the prior main use cases, struct bpf_cpumask *, struct
task_struct *, and struct cgroup *, have all been updated to be
synchronized mainly using RCU. In other words, their KF_ACQUIRE kfunc
calls are all KF_RCU, and the pointers themselves are MEM_RCU and can be
accessed in an RCU read region in BPF.

In a follow-on change, we'll be removing the KF_KPTR_GET kfunc flag.
This patch prepares for that by removing the
bpf_kfunc_call_test_kptr_get() kfunc, and all associated selftests.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230416084928.326135-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-04-16 08:51:24 -07:00
Jakub Kicinski
c2865b1122 bpf-next-for-netdev
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Daniel Borkmann says:

====================
pull-request: bpf-next 2023-04-13

We've added 260 non-merge commits during the last 36 day(s) which contain
a total of 356 files changed, 21786 insertions(+), 11275 deletions(-).

The main changes are:

1) Rework BPF verifier log behavior and implement it as a rotating log
   by default with the option to retain old-style fixed log behavior,
   from Andrii Nakryiko.

2) Adds support for using {FOU,GUE} encap with an ipip device operating
   in collect_md mode and add a set of BPF kfuncs for controlling encap
   params, from Christian Ehrig.

3) Allow BPF programs to detect at load time whether a particular kfunc
   exists or not, and also add support for this in light skeleton,
   from Alexei Starovoitov.

4) Optimize hashmap lookups when key size is multiple of 4,
   from Anton Protopopov.

5) Enable RCU semantics for task BPF kptrs and allow referenced kptr
   tasks to be stored in BPF maps, from David Vernet.

6) Add support for stashing local BPF kptr into a map value via
   bpf_kptr_xchg(). This is useful e.g. for rbtree node creation
   for new cgroups, from Dave Marchevsky.

7) Fix BTF handling of is_int_ptr to skip modifiers to work around
   tracing issues where a program cannot be attached, from Feng Zhou.

8) Migrate a big portion of test_verifier unit tests over to
   test_progs -a verifier_* via inline asm to ease {read,debug}ability,
   from Eduard Zingerman.

9) Several updates to the instruction-set.rst documentation
   which is subject to future IETF standardization
   (https://lwn.net/Articles/926882/), from Dave Thaler.

10) Fix BPF verifier in the __reg_bound_offset's 64->32 tnum sub-register
    known bits information propagation, from Daniel Borkmann.

11) Add skb bitfield compaction work related to BPF with the overall goal
    to make more of the sk_buff bits optional, from Jakub Kicinski.

12) BPF selftest cleanups for build id extraction which stand on its own
    from the upcoming integration work of build id into struct file object,
    from Jiri Olsa.

13) Add fixes and optimizations for xsk descriptor validation and several
    selftest improvements for xsk sockets, from Kal Conley.

14) Add BPF links for struct_ops and enable switching implementations
    of BPF TCP cong-ctls under a given name by replacing backing
    struct_ops map, from Kui-Feng Lee.

15) Remove a misleading BPF verifier env->bypass_spec_v1 check on variable
    offset stack read as earlier Spectre checks cover this,
    from Luis Gerhorst.

16) Fix issues in copy_from_user_nofault() for BPF and other tracers
    to resemble copy_from_user_nmi() from safety PoV, from Florian Lehner
    and Alexei Starovoitov.

17) Add --json-summary option to test_progs in order for CI tooling to
    ease parsing of test results, from Manu Bretelle.

18) Batch of improvements and refactoring to prep for upcoming
    bpf_local_storage conversion to bpf_mem_cache_{alloc,free} allocator,
    from Martin KaFai Lau.

19) Improve bpftool's visual program dump which produces the control
    flow graph in a DOT format by adding C source inline annotations,
    from Quentin Monnet.

20) Fix attaching fentry/fexit/fmod_ret/lsm to modules by extracting
    the module name from BTF of the target and searching kallsyms of
    the correct module, from Viktor Malik.

21) Improve BPF verifier handling of '<const> <cond> <non_const>'
    to better detect whether in particular jmp32 branches are taken,
    from Yonghong Song.

22) Allow BPF TCP cong-ctls to write app_limited of struct tcp_sock.
    A built-in cc or one from a kernel module is already able to write
    to app_limited, from Yixin Shen.

Conflicts:

Documentation/bpf/bpf_devel_QA.rst
  b7abcd9c65 ("bpf, doc: Link to submitting-patches.rst for general patch submission info")
  0f10f647f4 ("bpf, docs: Use internal linking for link to netdev subsystem doc")
https://lore.kernel.org/all/20230307095812.236eb1be@canb.auug.org.au/

include/net/ip_tunnels.h
  bc9d003dc4 ("ip_tunnel: Preserve pointer const in ip_tunnel_info_opts")
  ac931d4cde ("ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices")
https://lore.kernel.org/all/20230413161235.4093777-1-broonie@kernel.org/

net/bpf/test_run.c
  e5995bc7e2 ("bpf, test_run: fix crashes due to XDP frame overwriting/corruption")
  294635a816 ("bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES")
https://lore.kernel.org/all/20230320102619.05b80a98@canb.auug.org.au/
====================

Link: https://lore.kernel.org/r/20230413191525.7295-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-04-13 16:43:38 -07:00
Feng Zhou
75dcef8d36 selftests/bpf: Add test to access u32 ptr argument in tracing program
Adding verifier test for accessing u32 pointer argument in
tracing programs.

The test program loads 1nd argument of bpf_fentry_test9 function
which is u32 pointer and checks that verifier allows that.

Co-developed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230410085908.98493-3-zhoufeng.zf@bytedance.com
2023-04-11 20:29:49 +02:00
Alexei Starovoitov
b7e852a9ec bpf: Remove unused arguments from btf_struct_access().
Remove unused arguments from btf_struct_access() callback.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230404045029.82870-3-alexei.starovoitov@gmail.com
2023-04-04 16:57:10 -07:00
Alexei Starovoitov
7d64c51328 bpf: Invoke btf_struct_access() callback only for writes.
Remove duplicated if (atype == BPF_READ) btf_struct_access() from
btf_struct_access() callback and invoke it only for writes. This is
possible to do because currently btf_struct_access() custom callback
always delegates to generic btf_struct_access() helper for BPF_READ
accesses.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230404045029.82870-2-alexei.starovoitov@gmail.com
2023-04-04 16:57:03 -07:00
David Vernet
6c831c4684 bpf: Treat KF_RELEASE kfuncs as KF_TRUSTED_ARGS
KF_RELEASE kfuncs are not currently treated as having KF_TRUSTED_ARGS,
even though they have a superset of the requirements of KF_TRUSTED_ARGS.
Like KF_TRUSTED_ARGS, KF_RELEASE kfuncs require a 0-offset argument, and
don't allow NULL-able arguments. Unlike KF_TRUSTED_ARGS which require
_either_ an argument with ref_obj_id > 0, _or_ (ref->type &
BPF_REG_TRUSTED_MODIFIERS) (and no unsafe modifiers allowed), KF_RELEASE
only allows for ref_obj_id > 0.  Because KF_RELEASE today doesn't
automatically imply KF_TRUSTED_ARGS, some of these requirements are
enforced in different ways that can make the behavior of the verifier
feel unpredictable. For example, a KF_RELEASE kfunc with a NULL-able
argument will currently fail in the verifier with a message like, "arg#0
is ptr_or_null_ expected ptr_ or socket" rather than "Possibly NULL
pointer passed to trusted arg0". Our intention is the same, but the
semantics are different due to implemenetation details that kfunc authors
and BPF program writers should not need to care about.

Let's make the behavior of the verifier more consistent and intuitive by
having KF_RELEASE kfuncs imply the presence of KF_TRUSTED_ARGS. Our
eventual goal is to have all kfuncs assume KF_TRUSTED_ARGS by default
anyways, so this takes us a step in that direction.

Note that it does not make sense to assume KF_TRUSTED_ARGS for all
KF_ACQUIRE kfuncs. KF_ACQUIRE kfuncs can have looser semantics than
KF_RELEASE, with e.g. KF_RCU | KF_RET_NULL. We may want to have
KF_ACQUIRE imply KF_TRUSTED_ARGS _unless_ KF_RCU is specified, but that
can be left to another patch set, and there are no such subtleties to
address for KF_RELEASE.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230325213144.486885-4-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 16:56:22 -07:00
David Vernet
fb2211a57c bpf: Remove now-unnecessary NULL checks for KF_RELEASE kfuncs
Now that we're not invoking kfunc destructors when the kptr in a map was
NULL, we no longer require NULL checks in many of our KF_RELEASE kfuncs.
This patch removes those NULL checks.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230325213144.486885-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 16:56:22 -07:00
Alexander Lobakin
e5995bc7e2 bpf, test_run: fix crashes due to XDP frame overwriting/corruption
syzbot and Ilya faced the splats when %XDP_PASS happens for bpf_test_run
after skb PP recycling was enabled for {__,}xdp_build_skb_from_frame():

BUG: kernel NULL pointer dereference, address: 0000000000000d28
RIP: 0010:memset_erms+0xd/0x20 arch/x86/lib/memset_64.S:66
[...]
Call Trace:
 <TASK>
 __finalize_skb_around net/core/skbuff.c:321 [inline]
 __build_skb_around+0x232/0x3a0 net/core/skbuff.c:379
 build_skb_around+0x32/0x290 net/core/skbuff.c:444
 __xdp_build_skb_from_frame+0x121/0x760 net/core/xdp.c:622
 xdp_recv_frames net/bpf/test_run.c:248 [inline]
 xdp_test_run_batch net/bpf/test_run.c:334 [inline]
 bpf_test_run_xdp_live+0x1289/0x1930 net/bpf/test_run.c:362
 bpf_prog_test_run_xdp+0xa05/0x14e0 net/bpf/test_run.c:1418
[...]

This happens due to that it calls xdp_scrub_frame(), which nullifies
xdpf->data. bpf_test_run code doesn't reinit the frame when the XDP
program doesn't adjust head or tail. Previously, %XDP_PASS meant the
page will be released from the pool and returned to the MM layer, but
now it does return to the Pool with the nullified xdpf->data, which
doesn't get reinitialized then.
So, in addition to checking whether the head and/or tail have been
adjusted, check also for a potential XDP frame corruption. xdpf->data
is 100% affected and also xdpf->flags is the field closest to the
metadata / frame start. Checking for these two should be enough for
non-extreme cases.

Fixes: 9c94bbf9a8 ("xdp: recycle Page Pool backed skbs built from XDP frames")
Reported-by: syzbot+e1d1b65f7c32f2a86a9f@syzkaller.appspotmail.com
Link: https://lore.kernel.org/bpf/000000000000f1985705f6ef2243@google.com
Reported-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/bpf/e07dd94022ad5731705891b9487cc9ed66328b94.camel@linux.ibm.com
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230316175051.922550-2-aleksander.lobakin@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-16 22:20:09 -07:00
Viktor Malik
aa3d65de4b bpf/selftests: Test fentry attachment to shadowed functions
Adds a new test that tries to attach a program to fentry of two
functions of the same name, one located in vmlinux and the other in
bpf_testmod.

To avoid conflicts with existing tests, a new function
"bpf_fentry_shadow_test" was created both in vmlinux and in bpf_testmod.

The previous commit fixed a bug which caused this test to fail. The
verifier would always use the vmlinux function's address as the target
trampoline address, hence trying to create two trampolines for a single
address, which is forbidden.

The test (similarly to other fentry/fexit tests) is not working on arm64
at the moment.

Signed-off-by: Viktor Malik <vmalik@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/5fe2f364190b6f79b085066ed7c5989c5bc475fa.1678432753.git.vmalik@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-15 18:38:30 -07:00
Jakub Kicinski
d0ddf5065f Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Documentation/bpf/bpf_devel_QA.rst
  b7abcd9c65 ("bpf, doc: Link to submitting-patches.rst for general patch submission info")
  d56b0c461d ("bpf, docs: Fix link to netdev-FAQ target")
https://lore.kernel.org/all/20230307095812.236eb1be@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-03-09 22:22:11 -08:00
Alexander Lobakin
294635a816 bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES
&xdp_buff and &xdp_frame are bound in a way that

xdp_buff->data_hard_start == xdp_frame

It's always the case and e.g. xdp_convert_buff_to_frame() relies on
this.
IOW, the following:

	for (u32 i = 0; i < 0xdead; i++) {
		xdpf = xdp_convert_buff_to_frame(&xdp);
		xdp_convert_frame_to_buff(xdpf, &xdp);
	}

shouldn't ever modify @xdpf's contents or the pointer itself.
However, "live packet" code wrongly treats &xdp_frame as part of its
context placed *before* the data_hard_start. With such flow,
data_hard_start is sizeof(*xdpf) off to the right and no longer points
to the XDP frame.

Instead of replacing `sizeof(ctx)` with `offsetof(ctx, xdpf)` in several
places and praying that there are no more miscalcs left somewhere in the
code, unionize ::frm with ::data in a flex array, so that both starts
pointing to the actual data_hard_start and the XDP frame actually starts
being a part of it, i.e. a part of the headroom, not the context.
A nice side effect is that the maximum frame size for this mode gets
increased by 40 bytes, as xdp_buff::frame_sz includes everything from
data_hard_start (-> includes xdpf already) to the end of XDP/skb shared
info.
Also update %MAX_PKT_SIZE accordingly in the selftests code. Leave it
hardcoded for 64 bit && 4k pages, it can be made more flexible later on.

Minor: align `&head->data` with how `head->frm` is assigned for
consistency.
Minor #2: rename 'frm' to 'frame' in &xdp_page_head while at it for
clarity.

(was found while testing XDP traffic generator on ice, which calls
 xdp_convert_frame_to_buff() for each XDP frame)

Fixes: b530e9e106 ("bpf: Add "live packet" mode for XDP in BPF_PROG_RUN")
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://lore.kernel.org/r/20230224163607.2994755-1-aleksander.lobakin@intel.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-03-06 11:15:54 -08:00
Alexei Starovoitov
20c09d92fa bpf: Introduce kptr_rcu.
The life time of certain kernel structures like 'struct cgroup' is protected by RCU.
Hence it's safe to dereference them directly from __kptr tagged pointers in bpf maps.
The resulting pointer is MEM_RCU and can be passed to kfuncs that expect KF_RCU.
Derefrence of other kptr-s returns PTR_UNTRUSTED.

For example:
struct map_value {
   struct cgroup __kptr *cgrp;
};

SEC("tp_btf/cgroup_mkdir")
int BPF_PROG(test_cgrp_get_ancestors, struct cgroup *cgrp_arg, const char *path)
{
  struct cgroup *cg, *cg2;

  cg = bpf_cgroup_acquire(cgrp_arg); // cg is PTR_TRUSTED and ref_obj_id > 0
  bpf_kptr_xchg(&v->cgrp, cg);

  cg2 = v->cgrp; // This is new feature introduced by this patch.
  // cg2 is PTR_MAYBE_NULL | MEM_RCU.
  // When cg2 != NULL, it's a valid cgroup, but its percpu_ref could be zero

  if (cg2)
    bpf_cgroup_ancestor(cg2, level); // safe to do.
}

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230303041446.3630-4-alexei.starovoitov@gmail.com
2023-03-03 17:42:20 +01:00
Martin KaFai Lau
181127fb76 Revert "bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES"
This reverts commit 6c20822fad.

build bot failed on arch with different cache line size:
https://lore.kernel.org/bpf/50c35055-afa9-d01e-9a05-ea5351280e4f@intel.com/

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-02-17 12:24:33 -08:00
Martin KaFai Lau
af2d0d09ea bpf: Disable bh in bpf_test_run for xdp and tc prog
Some of the bpf helpers require bh disabled. eg. The bpf_fib_lookup
helper that will be used in a latter selftest. In particular, it
calls ___neigh_lookup_noref that expects the bh disabled.

This patch disables bh before calling bpf_prog_run[_xdp], so
the testing prog can also use those helpers.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230217004150.2980689-2-martin.lau@linux.dev
2023-02-17 16:19:23 +01:00
Alexander Lobakin
6c20822fad bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES
&xdp_buff and &xdp_frame are bound in a way that

xdp_buff->data_hard_start == xdp_frame

It's always the case and e.g. xdp_convert_buff_to_frame() relies on
this.
IOW, the following:

	for (u32 i = 0; i < 0xdead; i++) {
		xdpf = xdp_convert_buff_to_frame(&xdp);
		xdp_convert_frame_to_buff(xdpf, &xdp);
	}

shouldn't ever modify @xdpf's contents or the pointer itself.
However, "live packet" code wrongly treats &xdp_frame as part of its
context placed *before* the data_hard_start. With such flow,
data_hard_start is sizeof(*xdpf) off to the right and no longer points
to the XDP frame.

Instead of replacing `sizeof(ctx)` with `offsetof(ctx, xdpf)` in several
places and praying that there are no more miscalcs left somewhere in the
code, unionize ::frm with ::data in a flex array, so that both starts
pointing to the actual data_hard_start and the XDP frame actually starts
being a part of it, i.e. a part of the headroom, not the context.
A nice side effect is that the maximum frame size for this mode gets
increased by 40 bytes, as xdp_buff::frame_sz includes everything from
data_hard_start (-> includes xdpf already) to the end of XDP/skb shared
info.
Also update %MAX_PKT_SIZE accordingly in the selftests code. Leave it
hardcoded for 64 bit && 4k pages, it can be made more flexible later on.

Minor: align `&head->data` with how `head->frm` is assigned for
consistency.
Minor #2: rename 'frm' to 'frame' in &xdp_page_head while at it for
clarity.

(was found while testing XDP traffic generator on ice, which calls
 xdp_convert_frame_to_buff() for each XDP frame)

Fixes: b530e9e106 ("bpf: Add "live packet" mode for XDP in BPF_PROG_RUN")
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://lore.kernel.org/r/20230215185440.4126672-1-aleksander.lobakin@intel.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-02-15 17:39:36 -08:00
Jakub Kicinski
de42873367 bpf-next-for-netdev
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Daniel Borkmann says:

====================
pull-request: bpf-next 2023-02-11

We've added 96 non-merge commits during the last 14 day(s) which contain
a total of 152 files changed, 4884 insertions(+), 962 deletions(-).

There is a minor conflict in drivers/net/ethernet/intel/ice/ice_main.c
between commit 5b246e533d ("ice: split probe into smaller functions")
from the net-next tree and commit 66c0e13ad2 ("drivers: net: turn on
XDP features") from the bpf-next tree. Remove the hunk given ice_cfg_netdev()
is otherwise there a 2nd time, and add XDP features to the existing
ice_cfg_netdev() one:

        [...]
        ice_set_netdev_features(netdev);
        netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
                               NETDEV_XDP_ACT_XSK_ZEROCOPY;
        ice_set_ops(netdev);
        [...]

Stephen's merge conflict mail:
https://lore.kernel.org/bpf/20230207101951.21a114fa@canb.auug.org.au/

The main changes are:

1) Add support for BPF trampoline on s390x which finally allows to remove many
   test cases from the BPF CI's DENYLIST.s390x, from Ilya Leoshkevich.

2) Add multi-buffer XDP support to ice driver, from Maciej Fijalkowski.

3) Add capability to export the XDP features supported by the NIC.
   Along with that, add a XDP compliance test tool,
   from Lorenzo Bianconi & Marek Majtyka.

4) Add __bpf_kfunc tag for marking kernel functions as kfuncs,
   from David Vernet.

5) Add a deep dive documentation about the verifier's register
   liveness tracking algorithm, from Eduard Zingerman.

6) Fix and follow-up cleanups for resolve_btfids to be compiled
   as a host program to avoid cross compile issues,
   from Jiri Olsa & Ian Rogers.

7) Batch of fixes to the BPF selftest for xdp_hw_metadata which resulted
   when testing on different NICs, from Jesper Dangaard Brouer.

8) Fix libbpf to better detect kernel version code on Debian, from Hao Xiang.

9) Extend libbpf to add an option for when the perf buffer should
   wake up, from Jon Doron.

10) Follow-up fix on xdp_metadata selftest to just consume on TX
    completion, from Stanislav Fomichev.

11) Extend the kfuncs.rst document with description on kfunc
    lifecycle & stability expectations, from David Vernet.

12) Fix bpftool prog profile to skip attaching to offline CPUs,
    from Tonghao Zhang.

====================

Link: https://lore.kernel.org/r/20230211002037.8489-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-02-10 17:51:27 -08:00
Jakub Kicinski
025a785ff0 net: skbuff: drop the word head from skb cache
skbuff_head_cache is misnamed (perhaps for historical reasons?)
because it does not hold heads. Head is the buffer which skb->data
points to, and also where shinfo lives. struct sk_buff is a metadata
structure, not the head.

Eric recently added skb_small_head_cache (which allocates actual
head buffers), let that serve as an excuse to finally clean this up :)

Leave the user-space visible name intact, it could possibly be uAPI.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-02-10 09:10:28 +00:00
David Vernet
6aed15e330 selftests/bpf: Add testcase for static kfunc with unused arg
kfuncs are allowed to be static, or not use one or more of their
arguments. For example, bpf_xdp_metadata_rx_hash() in net/core/xdp.c is
meant to be implemented by drivers, with the default implementation just
returning -EOPNOTSUPP. As described in [0], such kfuncs can have their
arguments elided, which can cause BTF encoding to be skipped. The new
__bpf_kfunc macro should address this, and this patch adds a selftest
which verifies that a static kfunc with at least one unused argument can
still be encoded and invoked by a BPF program.

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230201173016.342758-5-void@manifault.com
2023-02-02 00:25:14 +01:00
David Vernet
400031e05a bpf: Add __bpf_kfunc tag to all kfuncs
Now that we have the __bpf_kfunc tag, we should use add it to all
existing kfuncs to ensure that they'll never be elided in LTO builds.

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230201173016.342758-4-void@manifault.com
2023-02-02 00:25:14 +01:00
Ilya Leoshkevich
be6b5c10ec selftests/bpf: Add a sign-extension test for kfuncs
s390x ABI requires the caller to zero- or sign-extend the arguments.
eBPF already deals with zero-extension (by definition of its ABI), but
not with sign-extension.

Add a test to cover that potentially problematic area.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-15-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-28 12:30:09 -08:00
David Vernet
7dd880592a bpf/selftests: Verify struct_ops prog sleepable behavior
In a set of prior changes, we added the ability for struct_ops programs
to be sleepable. This patch enhances the dummy_st_ops selftest suite to
validate this behavior by adding a new sleepable struct_ops entry to
dummy_st_ops.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125164735.785732-5-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-25 10:25:57 -08:00
Stanislav Fomichev
3d76a4d3d4 bpf: XDP metadata RX kfuncs
Define a new kfunc set (xdp_metadata_kfunc_ids) which implements all possible
XDP metatada kfuncs. Not all devices have to implement them. If kfunc is not
supported by the target device, the default implementation is called instead.
The verifier, at load time, replaces a call to the generic kfunc with a call
to the per-device one. Per-device kfunc pointers are stored in separate
struct xdp_metadata_ops.

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-8-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-01-23 09:38:11 -08:00
Linus Torvalds
4f292c4de4 New Feature:
* Randomize the per-cpu entry areas
 Cleanups:
 * Have CR3_ADDR_MASK use PHYSICAL_PAGE_MASK instead of open
   coding it
 * Move to "native" set_memory_rox() helper
 * Clean up pmd_get_atomic() and i386-PAE
 * Remove some unused page table size macros
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Merge tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 mm updates from Dave Hansen:
 "New Feature:

   - Randomize the per-cpu entry areas

  Cleanups:

   - Have CR3_ADDR_MASK use PHYSICAL_PAGE_MASK instead of open coding it

   - Move to "native" set_memory_rox() helper

   - Clean up pmd_get_atomic() and i386-PAE

   - Remove some unused page table size macros"

* tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
  x86/mm: Ensure forced page table splitting
  x86/kasan: Populate shadow for shared chunk of the CPU entry area
  x86/kasan: Add helpers to align shadow addresses up and down
  x86/kasan: Rename local CPU_ENTRY_AREA variables to shorten names
  x86/mm: Populate KASAN shadow for entire per-CPU range of CPU entry area
  x86/mm: Recompute physical address for every page of per-CPU CEA mapping
  x86/mm: Rename __change_page_attr_set_clr(.checkalias)
  x86/mm: Inhibit _PAGE_NX changes from cpa_process_alias()
  x86/mm: Untangle __change_page_attr_set_clr(.checkalias)
  x86/mm: Add a few comments
  x86/mm: Fix CR3_ADDR_MASK
  x86/mm: Remove P*D_PAGE_MASK and P*D_PAGE_SIZE macros
  mm: Convert __HAVE_ARCH_P..P_GET to the new style
  mm: Remove pointless barrier() after pmdp_get_lockless()
  x86/mm/pae: Get rid of set_64bit()
  x86_64: Remove pointless set_64bit() usage
  x86/mm/pae: Be consistent with pXXp_get_and_clear()
  x86/mm/pae: Use WRITE_ONCE()
  x86/mm/pae: Don't (ab)use atomic64
  mm/gup: Fix the lockless PMD access
  ...
2022-12-17 14:06:53 -06:00
Peter Zijlstra
d48567c9a0 mm: Introduce set_memory_rox()
Because endlessly repeating:

	set_memory_ro()
	set_memory_x()

is getting tedious.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/Y1jek64pXOsougmz@hirez.programming.kicks-ass.net
2022-12-15 10:37:26 -08:00
Jakub Kicinski
26f708a284 bpf-next-for-netdev
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2022-12-11

We've added 74 non-merge commits during the last 11 day(s) which contain
a total of 88 files changed, 3362 insertions(+), 789 deletions(-).

The main changes are:

1) Decouple prune and jump points handling in the verifier, from Andrii.

2) Do not rely on ALLOW_ERROR_INJECTION for fmod_ret, from Benjamin.
   Merged from hid tree.

3) Do not zero-extend kfunc return values. Necessary fix for 32-bit archs,
   from Björn.

4) Don't use rcu_users to refcount in task kfuncs, from David.

5) Three reg_state->id fixes in the verifier, from Eduard.

6) Optimize bpf_mem_alloc by reusing elements from free_by_rcu, from Hou.

7) Refactor dynptr handling in the verifier, from Kumar.

8) Remove the "/sys" mount and umount dance in {open,close}_netns
  in bpf selftests, from Martin.

9) Enable sleepable support for cgrp local storage, from Yonghong.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (74 commits)
  selftests/bpf: test case for relaxed prunning of active_lock.id
  selftests/bpf: Add pruning test case for bpf_spin_lock
  bpf: use check_ids() for active_lock comparison
  selftests/bpf: verify states_equal() maintains idmap across all frames
  bpf: states_equal() must build idmap for all function frames
  selftests/bpf: test cases for regsafe() bug skipping check_id()
  bpf: regsafe() must not skip check_ids()
  docs/bpf: Add documentation for BPF_MAP_TYPE_SK_STORAGE
  selftests/bpf: Add test for dynptr reinit in user_ringbuf callback
  bpf: Use memmove for bpf_dynptr_{read,write}
  bpf: Move PTR_TO_STACK alignment check to process_dynptr_func
  bpf: Rework check_func_arg_reg_off
  bpf: Rework process_dynptr_func
  bpf: Propagate errors from process_* checks in check_func_arg
  bpf: Refactor ARG_PTR_TO_DYNPTR checks into process_dynptr_func
  bpf: Skip rcu_barrier() if rcu_trace_implies_rcu_gp() is true
  bpf: Reuse freed element in free_by_rcu during allocation
  selftests/bpf: Bring test_offload.py back to life
  bpf: Fix comment error in fixup_kfunc_call function
  bpf: Do not zero-extend kfunc return values
  ...
====================

Link: https://lore.kernel.org/r/20221212024701.73809-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-12-12 11:27:42 -08:00
Kees Cook
ce098da149 skbuff: Introduce slab_build_skb()
syzkaller reported:

  BUG: KASAN: slab-out-of-bounds in __build_skb_around+0x235/0x340 net/core/skbuff.c:294
  Write of size 32 at addr ffff88802aa172c0 by task syz-executor413/5295

For bpf_prog_test_run_skb(), which uses a kmalloc()ed buffer passed to
build_skb().

When build_skb() is passed a frag_size of 0, it means the buffer came
from kmalloc. In these cases, ksize() is used to find its actual size,
but since the allocation may not have been made to that size, actually
perform the krealloc() call so that all the associated buffer size
checking will be correctly notified (and use the "new" pointer so that
compiler hinting works correctly). Split this logic out into a new
interface, slab_build_skb(), but leave the original 0 checking for now
to catch any stragglers.

Reported-by: syzbot+fda18eaa8c12534ccb3b@syzkaller.appspotmail.com
Link: https://groups.google.com/g/syzkaller-bugs/c/UnIKxTtU5-0/m/-wbXinkgAQAJ
Fixes: 38931d8989 ("mm: Make ksize() a reporting-only function")
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: pepsipu <soopthegoop@gmail.com>
Cc: syzbot+fda18eaa8c12534ccb3b@syzkaller.appspotmail.com
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: kasan-dev <kasan-dev@googlegroups.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: ast@kernel.org
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Hao Luo <haoluo@google.com>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: jolsa@kernel.org
Cc: KP Singh <kpsingh@kernel.org>
Cc: martin.lau@linux.dev
Cc: Stanislav Fomichev <sdf@google.com>
Cc: song@kernel.org
Cc: Yonghong Song <yhs@fb.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221208060256.give.994-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-12-09 19:47:41 -08:00
Alexei Starovoitov
0a6ea1ce82 for-alexei-2022120701
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Merge "do not rely on ALLOW_ERROR_INJECTION for fmod_ret" into bpf-next

Merge commit 5b481acab4 ("bpf: do not rely on ALLOW_ERROR_INJECTION for fmod_ret")
from hid tree into bpf-next.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-12-07 13:49:21 -08:00
Benjamin Tissoires
5b481acab4 bpf: do not rely on ALLOW_ERROR_INJECTION for fmod_ret
The current way of expressing that a non-bpf kernel component is willing
to accept that bpf programs can be attached to it and that they can change
the return value is to abuse ALLOW_ERROR_INJECTION.
This is debated in the link below, and the result is that it is not a
reasonable thing to do.

Reuse the kfunc declaration structure to also tag the kernel functions
we want to be fmodret. This way we can control from any subsystem which
functions are being modified by bpf without touching the verifier.

Link: https://lore.kernel.org/all/20221121104403.1545f9b5@gandalf.local.home/
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20221206145936.922196-2-benjamin.tissoires@redhat.com
2022-12-07 15:31:08 +01:00
Jakub Kicinski
d6dc62fca6 bpf-next-for-netdev
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Daniel Borkmann says:

====================
bpf-next 2022-11-25

We've added 101 non-merge commits during the last 11 day(s) which contain
a total of 109 files changed, 8827 insertions(+), 1129 deletions(-).

The main changes are:

1) Support for user defined BPF objects: the use case is to allocate own
   objects, build own object hierarchies and use the building blocks to
   build own data structures flexibly, for example, linked lists in BPF,
   from Kumar Kartikeya Dwivedi.

2) Add bpf_rcu_read_{,un}lock() support for sleepable programs,
   from Yonghong Song.

3) Add support storing struct task_struct objects as kptrs in maps,
   from David Vernet.

4) Batch of BPF map documentation improvements, from Maryam Tahhan
   and Donald Hunter.

5) Improve BPF verifier to propagate nullness information for branches
   of register to register comparisons, from Eduard Zingerman.

6) Fix cgroup BPF iter infra to hold reference on the start cgroup,
   from Hou Tao.

7) Fix BPF verifier to not mark fentry/fexit program arguments as trusted
   given it is not the case for them, from Alexei Starovoitov.

8) Improve BPF verifier's realloc handling to better play along with dynamic
   runtime analysis tools like KASAN and friends, from Kees Cook.

9) Remove legacy libbpf mode support from bpftool,
   from Sahid Orentino Ferdjaoui.

10) Rework zero-len skb redirection checks to avoid potentially breaking
    existing BPF test infra users, from Stanislav Fomichev.

11) Two small refactorings which are independent and have been split out
    of the XDP queueing RFC series, from Toke Høiland-Jørgensen.

12) Fix a memory leak in LSM cgroup BPF selftest, from Wang Yufen.

13) Documentation on how to run BPF CI without patch submission,
    from Daniel Müller.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
====================

Link: https://lore.kernel.org/r/20221125012450.441-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-28 19:42:17 -08:00
Stanislav Fomichev
114039b342 bpf: Move skb->len == 0 checks into __bpf_redirect
To avoid potentially breaking existing users.

Both mac/no-mac cases have to be amended; mac_header >= network_header
is not enough (verified with a new test, see next patch).

Fixes: fd18942244 ("bpf: Don't redirect packets with invalid pkt_len")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20221121180340.1983627-1-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2022-11-21 12:47:04 -08:00
Kumar Kartikeya Dwivedi
6728aea721 bpf: Refactor btf_struct_access
Instead of having to pass multiple arguments that describe the register,
pass the bpf_reg_state into the btf_struct_access callback. Currently,
all call sites simply reuse the btf and btf_id of the reg they want to
check the access of. The only exception to this pattern is the callsite
in check_ptr_to_map_access, hence for that case create a dummy reg to
simulate PTR_TO_BTF_ID access.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221114191547.1694267-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-14 21:52:45 -08:00
Baisong Zhong
d3fd203f36 bpf, test_run: Fix alignment problem in bpf_prog_test_run_skb()
We got a syzkaller problem because of aarch64 alignment fault
if KFENCE enabled. When the size from user bpf program is an odd
number, like 399, 407, etc, it will cause the struct skb_shared_info's
unaligned access. As seen below:

  BUG: KFENCE: use-after-free read in __skb_clone+0x23c/0x2a0 net/core/skbuff.c:1032

  Use-after-free read at 0xffff6254fffac077 (in kfence-#213):
   __lse_atomic_add arch/arm64/include/asm/atomic_lse.h:26 [inline]
   arch_atomic_add arch/arm64/include/asm/atomic.h:28 [inline]
   arch_atomic_inc include/linux/atomic-arch-fallback.h:270 [inline]
   atomic_inc include/asm-generic/atomic-instrumented.h:241 [inline]
   __skb_clone+0x23c/0x2a0 net/core/skbuff.c:1032
   skb_clone+0xf4/0x214 net/core/skbuff.c:1481
   ____bpf_clone_redirect net/core/filter.c:2433 [inline]
   bpf_clone_redirect+0x78/0x1c0 net/core/filter.c:2420
   bpf_prog_d3839dd9068ceb51+0x80/0x330
   bpf_dispatcher_nop_func include/linux/bpf.h:728 [inline]
   bpf_test_run+0x3c0/0x6c0 net/bpf/test_run.c:53
   bpf_prog_test_run_skb+0x638/0xa7c net/bpf/test_run.c:594
   bpf_prog_test_run kernel/bpf/syscall.c:3148 [inline]
   __do_sys_bpf kernel/bpf/syscall.c:4441 [inline]
   __se_sys_bpf+0xad0/0x1634 kernel/bpf/syscall.c:4381

  kfence-#213: 0xffff6254fffac000-0xffff6254fffac196, size=407, cache=kmalloc-512

  allocated by task 15074 on cpu 0 at 1342.585390s:
   kmalloc include/linux/slab.h:568 [inline]
   kzalloc include/linux/slab.h:675 [inline]
   bpf_test_init.isra.0+0xac/0x290 net/bpf/test_run.c:191
   bpf_prog_test_run_skb+0x11c/0xa7c net/bpf/test_run.c:512
   bpf_prog_test_run kernel/bpf/syscall.c:3148 [inline]
   __do_sys_bpf kernel/bpf/syscall.c:4441 [inline]
   __se_sys_bpf+0xad0/0x1634 kernel/bpf/syscall.c:4381
   __arm64_sys_bpf+0x50/0x60 kernel/bpf/syscall.c:4381

To fix the problem, we adjust @size so that (@size + @hearoom) is a
multiple of SMP_CACHE_BYTES. So we make sure the struct skb_shared_info
is aligned to a cache line.

Fixes: 1cf1cae963 ("bpf: introduce BPF_PROG_TEST_RUN command")
Signed-off-by: Baisong Zhong <zhongbaisong@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20221102081620.1465154-1-zhongbaisong@huawei.com
2022-11-04 16:22:34 +01:00
Benjamin Tissoires
22ed8d5a46 selftests/bpf: Add tests for kfunc returning a memory pointer
We add 2 new kfuncs that are following the RET_PTR_TO_MEM
capability from the previous commit.
Then we test them in selftests:
the first tests are testing valid case, and are not failing,
and the later ones are actually preventing the program to be loaded
because they are wrong.

To work around that, we mark the failing ones as not autoloaded
(with SEC("?tc")), and we manually enable them one by one, ensuring
the verifier rejects them.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220906151303.2780789-8-benjamin.tissoires@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-09-07 11:05:17 -07:00
Benjamin Tissoires
fb66223a24 selftests/bpf: add test for accessing ctx from syscall program type
We need to also export the kfunc set to the syscall program type,
and then add a couple of eBPF programs that are testing those calls.

The first one checks for valid access, and the second one is OK
from a static analysis point of view but fails at run time because
we are trying to access outside of the allocated memory.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220906151303.2780789-5-benjamin.tissoires@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-09-07 11:04:27 -07:00
Jakub Kicinski
3f5f728a72 Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Andrii Nakryiko says:

====================
bpf-next 2022-08-17

We've added 45 non-merge commits during the last 14 day(s) which contain
a total of 61 files changed, 986 insertions(+), 372 deletions(-).

The main changes are:

1) New bpf_ktime_get_tai_ns() BPF helper to access CLOCK_TAI, from Kurt
   Kanzenbach and Jesper Dangaard Brouer.

2) Few clean ups and improvements for libbpf 1.0, from Andrii Nakryiko.

3) Expose crash_kexec() as kfunc for BPF programs, from Artem Savkov.

4) Add ability to define sleepable-only kfuncs, from Benjamin Tissoires.

5) Teach libbpf's bpf_prog_load() and bpf_map_create() to gracefully handle
   unsupported names on old kernels, from Hangbin Liu.

6) Allow opting out from auto-attaching BPF programs by libbpf's BPF skeleton,
   from Hao Luo.

7) Relax libbpf's requirement for shared libs to be marked executable, from
   Henqgi Chen.

8) Improve bpf_iter internals handling of error returns, from Hao Luo.

9) Few accommodations in libbpf to support GCC-BPF quirks, from James Hilliard.

10) Fix BPF verifier logic around tracking dynptr ref_obj_id, from Joanne Koong.

11) bpftool improvements to handle full BPF program names better, from Manu
    Bretelle.

12) bpftool fixes around libcap use, from Quentin Monnet.

13) BPF map internals clean ups and improvements around memory allocations,
    from Yafang Shao.

14) Allow to use cgroup_get_from_file() on cgroupv1, allowing BPF cgroup
    iterator to work on cgroupv1, from Yosry Ahmed.

15) BPF verifier internal clean ups, from Dave Marchevsky and Joanne Koong.

16) Various fixes and clean ups for selftests/bpf and vmtest.sh, from Daniel
    Xu, Artem Savkov, Joanne Koong, Andrii Nakryiko, Shibin Koikkara Reeny.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (45 commits)
  selftests/bpf: Few fixes for selftests/bpf built in release mode
  libbpf: Clean up deprecated and legacy aliases
  libbpf: Streamline bpf_attr and perf_event_attr initialization
  libbpf: Fix potential NULL dereference when parsing ELF
  selftests/bpf: Tests libbpf autoattach APIs
  libbpf: Allows disabling auto attach
  selftests/bpf: Fix attach point for non-x86 arches in test_progs/lsm
  libbpf: Making bpf_prog_load() ignore name if kernel doesn't support
  selftests/bpf: Update CI kconfig
  selftests/bpf: Add connmark read test
  selftests/bpf: Add existing connection bpf_*_ct_lookup() test
  bpftool: Clear errno after libcap's checks
  bpf: Clear up confusion in bpf_skb_adjust_room()'s documentation
  bpftool: Fix a typo in a comment
  libbpf: Add names for auxiliary maps
  bpf: Use bpf_map_area_alloc consistently on bpf map creation
  bpf: Make __GFP_NOWARN consistent in bpf map creation
  bpf: Use bpf_map_area_free instread of kvfree
  bpf: Remove unneeded memset in queue_stack_map creation
  libbpf: preserve errno across pr_warn/pr_info/pr_debug
  ...
====================

Link: https://lore.kernel.org/r/20220817215656.1180215-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-17 20:29:36 -07:00
Artem Savkov
e338945816 selftests/bpf: add destructive kfunc test
Add a test checking that programs calling destructive kfuncs can only do
so if they have CAP_SYS_BOOT capabilities.

Signed-off-by: Artem Savkov <asavkov@redhat.com>
Link: https://lore.kernel.org/r/20220810065905.475418-4-asavkov@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-10 09:22:18 -07:00
Kumar Kartikeya Dwivedi
1f0752628e bpf: Allow calling bpf_prog_test kfuncs in tracing programs
In addition to TC hook, enable these in tracing programs so that they
can be used in selftests.

Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220809213033.24147-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-09 18:46:11 -07:00
Kumar Kartikeya Dwivedi
56e948ffc0 bpf: Add support for forcing kfunc args to be trusted
Teach the verifier to detect a new KF_TRUSTED_ARGS kfunc flag, which
means each pointer argument must be trusted, which we define as a
pointer that is referenced (has non-zero ref_obj_id) and also needs to
have its offset unchanged, similar to how release functions expect their
argument. This allows a kfunc to receive pointer arguments unchanged
from the result of the acquire kfunc.

This is required to ensure that kfunc that operate on some object only
work on acquired pointers and not normal PTR_TO_BTF_ID with same type
which can be obtained by pointer walking. The restrictions applied to
release arguments also apply to trusted arguments. This implies that
strict type matching (not deducing type by recursively following members
at offset) and OBJ_RELEASE offset checks (ensuring they are zero) are
used for trusted pointer arguments.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-21 21:03:09 -07:00
Kumar Kartikeya Dwivedi
a4703e3184 bpf: Switch to new kfunc flags infrastructure
Instead of populating multiple sets to indicate some attribute and then
researching the same BTF ID in them, prepare a single unified BTF set
which indicates whether a kfunc is allowed to be called, and also its
attributes if any at the same time. Now, only one call is needed to
perform the lookup for both kfunc availability and its attributes.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-21 20:59:42 -07:00
Zhengchao Shao
fd18942244 bpf: Don't redirect packets with invalid pkt_len
Syzbot found an issue [1]: fq_codel_drop() try to drop a flow whitout any
skbs, that is, the flow->head is null.
The root cause, as the [2] says, is because that bpf_prog_test_run_skb()
run a bpf prog which redirects empty skbs.
So we should determine whether the length of the packet modified by bpf
prog or others like bpf_prog_test is valid before forwarding it directly.

LINK: [1] https://syzkaller.appspot.com/bug?id=0b84da80c2917757915afa89f7738a9d16ec96c5
LINK: [2] https://www.spinics.net/lists/netdev/msg777503.html

Reported-by: syzbot+7a12909485b94426aceb@syzkaller.appspotmail.com
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220715115559.139691-1-shaozhengchao@huawei.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-19 09:50:54 -07:00
Daniel Xu
988d0d5899 bpf, test_run: Remove unnecessary prog type checks
These checks were effectively noops b/c there's only one way these
functions get called: through prog_ops dispatching. And since there's no
other callers, we can be sure that `prog` is always the correct type.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/0a9aaac329f76ddb17df1786b001117823ffefa5.1653855302.git.dxu@dxuuu.xyz
2022-06-03 14:53:33 -07:00