linux-kernel - [PATCH v5 bpf-next 0/5] bpf: fix stackmap on perf

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 23 Jul 2020 11:06:43 -0700
From:   Song Liu <songliubraving@...com>
To:     <linux-kernel@...r.kernel.org>, <bpf@...r.kernel.org>,
        <netdev@...r.kernel.org>
CC:     <ast@...nel.org>, <daniel@...earbox.net>, <kernel-team@...com>,
        <john.fastabend@...il.com>, <kpsingh@...omium.org>,
        <brouer@...hat.com>, <peterz@...radead.org>,
        Song Liu <songliubraving@...com>
Subject: [PATCH v5 bpf-next 0/5] bpf: fix stackmap on perf_events with PEBS

Calling get_perf_callchain() on perf_events from PEBS entries may cause
unwinder errors. To fix this issue, perf subsystem fetches callchain early,
and marks perf_events are marked with __PERF_SAMPLE_CALLCHAIN_EARLY.
Similar issue exists when BPF program calls get_perf_callchain() via
helper functions. For more information about this issue, please refer to
discussions in [1].

This set fixes this issue with helper proto bpf_get_stackid_pe and
bpf_get_stack_pe.

[1] https://lore.kernel.org/lkml/ED7B9430-6489-4260-B3C5-9CFA2E3AA87A@fb.com/

Changes v4 => v5:
1. Return -EPROTO instead of -EINVAL on PERF_EVENT_IOC_SET_BPF errors.
   (Alexei)
2. Let libbpf print a hint message when PERF_EVENT_IOC_SET_BPF returns
   -EPROTO. (Alexei)

Changes v3 => v4:
1. Fix error check logic in bpf_get_stackid_pe and bpf_get_stack_pe.
   (Alexei)
2. Do not allow attaching BPF programs with bpf_get_stack|stackid to
   perf_event with precise_ip > 0, but not proper callchain. (Alexei)
3. Add selftest get_stackid_cannot_attach.

Changes v2 => v3:
1. Fix handling of stackmap skip field. (Andrii)
2. Simplify the code in a few places. (Andrii)

Changes v1 => v2:
1. Simplify the design and avoid introducing new helper function. (Andrii)

Song Liu (5):
  bpf: separate bpf_get_[stack|stackid] for perf events BPF
  bpf: fail PERF_EVENT_IOC_SET_BPF when bpf_get_[stack|stackid] cannot
    work
  libbpf: print hint when PERF_EVENT_IOC_SET_BPF returns -EPROTO
  selftests/bpf: add callchain_stackid
  selftests/bpf: add get_stackid_cannot_attach

 include/linux/bpf.h                           |   2 +
 include/linux/filter.h                        |   3 +-
 kernel/bpf/stackmap.c                         | 184 ++++++++++++++++--
 kernel/bpf/verifier.c                         |   3 +
 kernel/events/core.c                          |  18 ++
 kernel/trace/bpf_trace.c                      |   4 +-
 tools/lib/bpf/libbpf.c                        |   3 +
 .../prog_tests/get_stackid_cannot_attach.c    |  91 +++++++++
 .../bpf/prog_tests/perf_event_stackmap.c      | 116 +++++++++++
 .../selftests/bpf/progs/perf_event_stackmap.c |  59 ++++++
 10 files changed, 462 insertions(+), 21 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/get_stackid_cannot_attach.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_event_stackmap.c
 create mode 100644 tools/testing/selftests/bpf/progs/perf_event_stackmap.c

--
2.24.1