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  1. 22 Apr, 2024 2 commits
  3. 21 Apr, 2024 2 commits
  5. 20 Apr, 2024 7 commits
  7. 18 Apr, 2024 1 commit
  9. 17 Apr, 2024 2 commits
    • Quentin Deslandes's avatar
      libbpf: Fix dump of subsequent char arrays · e739e01d
      Quentin Deslandes authored 
      When dumping a character array, libbpf will watch for a '\0' and set
is_array_terminated=true if found. This prevents libbpf from printing
the remaining characters of the array, treating it as a nul-terminated
string.

However, once this flag is set, it's never reset, leading to subsequent
characters array not being printed properly:

.str_multi = (__u8[2][16])[
    [
        'H',
        'e',
        'l',
    ],
],

This patch saves the is_array_terminated flag and restores its
default (false) value before looping over the elements of an array,
then restores it afterward. This way, libbpf's behavior is unchanged
when dumping the characters of an array, but subsequent arrays are
printed properly:

.str_multi = (__u8[2][16])[
    [
        'H',
        'e',
        'l',
    ],
    [
        'l',
        'o',
    ],
],
Signed-off-by: default avatarQuentin Deslandes <qde@naccy.de>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240413211258.134421-3-qde@naccy.de
      e739e01d
    • Quentin Deslandes's avatar
      libbpf: Fix misaligned array closing bracket · 9213e529
      Quentin Deslandes authored 
      In btf_dump_array_data(), libbpf will call btf_dump_dump_type_data() for
each element. For an array of characters, each element will be
processed the following way:

- btf_dump_dump_type_data() is called to print the character
- btf_dump_data_pfx() prefixes the current line with the proper number
  of indentations
- btf_dump_int_data() is called to print the character
- After the last character is printed, btf_dump_dump_type_data() calls
  btf_dump_data_pfx() before writing the closing bracket

However, for an array containing characters, btf_dump_int_data() won't
print any '\0' and subsequent characters. This leads to situations where
the line prefix is written, no character is added, then the prefix is
written again before adding the closing bracket:

(struct sk_metadata){
    .str_array = (__u8[14])[
        'H',
        'e',
        'l',
        'l',
        'o',
                ],

This change solves this issue by printing the '\0' character, which
has two benefits:

- The bracket closing the array is properly aligned
- It's clear from a user point of view that libbpf uses '\0' as a
  terminator for arrays of characters.
Signed-off-by: default avatarQuentin Deslandes <qde@naccy.de>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240413211258.134421-2-qde@naccy.de
      9213e529
  11. 16 Apr, 2024 5 commits
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  21. 06 Apr, 2024 4 commits
  23. 05 Apr, 2024 1 commit
    • Andrii Nakryiko's avatar
      Merge branch 'bpf-allow-invoking-kfuncs-from-bpf_prog_type_syscall-progs' · d564ffde
      Andrii Nakryiko authored 
      David Vernet says:

====================
bpf: Allow invoking kfuncs from BPF_PROG_TYPE_SYSCALL progs

Currently, a set of core BPF kfuncs (e.g. bpf_task_*, bpf_cgroup_*,
bpf_cpumask_*, etc) cannot be invoked from BPF_PROG_TYPE_SYSCALL
programs. The whitelist approach taken for enabling kfuncs makes sense:
it not safe to call these kfuncs from every program type. For example,
it may not be safe to call bpf_task_acquire() in an fentry to
free_task().

BPF_PROG_TYPE_SYSCALL, on the other hand, is a perfectly safe program
type from which to invoke these kfuncs, as it's a very controlled
environment, and we should never be able to run into any of the typical
problems such as recursive invoations, acquiring references on freeing
kptrs, etc. Being able to invoke these kfuncs would be useful, as
BPF_PROG_TYPE_SYSCALL can be invoked with BPF_PROG_RUN, and would
therefore enable user space programs to synchronously call into BPF to
manipulate these kptrs.
---

v1: https://lore.kernel.org/all/20240404010308.334604-1-void@manifault.com/
v1 -> v2:

- Create new verifier_kfunc_prog_types testcase meant to specifically
  validate calling core kfuncs from various program types. Remove the
  macros and testcases that had been added to the task, cgrp, and
  cpumask kfunc testcases (Andrii and Yonghong)
====================

Link: https://lore.kernel.org/r/20240405143041.632519-1-void@manifault.comSigned-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      d564ffde
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