[PATCH bpf-next v3 0/7] Enable cpumasks to be used as kptrs

[David Vernet]

This is part 3 of https://lore.kernel.org/all/20230119235833.2948341-1-void@xxxxxxxxxxxxx/

Part 2: https://lore.kernel.org/bpf/20230120192523.3650503-1-void@xxxxxxxxxxxxx/

This series is based off of commit b613d335a743 ("bpf: Allow trusted
args to walk struct when checking BTF IDs").

Changelog:
----------
v2 -> v3:
- Rebase onto master (commit described above). Only conflict that
  required resolution was updating the task_kfunc selftest suite error
  message location.
- Put copyright onto one line in kernel/bpf/cpumask.c.
- Remove now-unneeded pid-checking logic from
  progs/nested_trust_success.c.
- Fix a couple of small grammatical typos in documentation.

v1 -> v2:
- Put back 'static' keyword in bpf_find_btf_id()
  (kernel test robot <lkp@xxxxxxxxx>)
- Surround cpumask kfuncs in __diag() blocks to avoid no-prototype build
  warnings (kernel test robot <lkp@xxxxxxxxx>)
- Enable ___init suffixes to a type definition to signal that a type is
  a nocast alias of another type. That is, that when passed to a kfunc
  that expects one of the two types, the verifier will reject the other
  even if they're equivalent according to the C standard (Kumar and
  Alexei)
- Reject NULL for all trusted args, not just PTR_TO_MEM (Kumar)
- Reject both NULL and PTR_MAYBE_NULL for all trusted args (Kumar and
  Alexei )
- Improve examples given in cpumask documentation (Alexei)
- Use __success macro for nested_trust test (Alexei)
- Fix comment typo in struct bpf_cpumask comment header.
- Fix another example in the bpf_cpumask doc examples.
- Add documentation for ___init suffix change mentioned above.


David Vernet (7):
  bpf: Disallow NULLable pointers for trusted kfuncs
  bpf: Enable cpumasks to be queried and used as kptrs
  selftests/bpf: Add nested trust selftests suite
  selftests/bpf: Add selftest suite for cpumask kfuncs
  bpf/docs: Document cpumask kfuncs in a new file
  bpf/docs: Document how nested trusted fields may be defined
  bpf/docs: Document the nocast aliasing behavior of ___init

 Documentation/bpf/cpumasks.rst                | 393 +++++++++++++++
 Documentation/bpf/index.rst                   |   1 +
 Documentation/bpf/kfuncs.rst                  |  76 ++-
 kernel/bpf/Makefile                           |   1 +
 kernel/bpf/cpumask.c                          | 476 ++++++++++++++++++
 kernel/bpf/verifier.c                         |   6 +
 tools/testing/selftests/bpf/DENYLIST.s390x    |   2 +
 .../selftests/bpf/prog_tests/cgrp_kfunc.c     |   4 +-
 .../selftests/bpf/prog_tests/cpumask.c        |  74 +++
 .../selftests/bpf/prog_tests/nested_trust.c   |  12 +
 .../selftests/bpf/progs/cpumask_common.h      | 114 +++++
 .../selftests/bpf/progs/cpumask_failure.c     | 126 +++++
 .../selftests/bpf/progs/cpumask_success.c     | 426 ++++++++++++++++
 .../selftests/bpf/progs/nested_trust_common.h |  12 +
 .../bpf/progs/nested_trust_failure.c          |  33 ++
 .../bpf/progs/nested_trust_success.c          |  19 +
 .../selftests/bpf/progs/task_kfunc_failure.c  |   4 +-
 17 files changed, 1774 insertions(+), 5 deletions(-)
 create mode 100644 Documentation/bpf/cpumasks.rst
 create mode 100644 kernel/bpf/cpumask.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/cpumask.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/nested_trust.c
 create mode 100644 tools/testing/selftests/bpf/progs/cpumask_common.h
 create mode 100644 tools/testing/selftests/bpf/progs/cpumask_failure.c
 create mode 100644 tools/testing/selftests/bpf/progs/cpumask_success.c
 create mode 100644 tools/testing/selftests/bpf/progs/nested_trust_common.h
 create mode 100644 tools/testing/selftests/bpf/progs/nested_trust_failure.c
 create mode 100644 tools/testing/selftests/bpf/progs/nested_trust_success.c

-- 
2.39.0