[PATCH bpf-next v4 0/4] bpf: Don't EFAULT for {g,s}setsockopt with wrong optlen

[Stanislav Fomichev <sdf@google.com>]

optval larger than PAGE_SIZE leads to EFAULT if the BPF program
isn't careful enough. This is often overlooked and might break
completely unrelated socket options. Instead of EFAULT,
let's ignore BPF program buffer changes. See the first patch for
more info.

In addition, clearly document this corner case and reset optlen
in our selftests (in case somebody copy-pastes from them).

v4:
- ignore retval as well when optlen > PAGE_SIZE (Martin)

v3:
- don't hard-code PAGE_SIZE (Martin)
- reset orig_optlen in getsockopt when kernel part succeeds (Martin)

Stanislav Fomichev (4):
  bpf: Don't EFAULT for {g,s}setsockopt with wrong optlen
  selftests/bpf: Update EFAULT {g,s}etsockopt selftests
  selftests/bpf: Correctly handle optlen > 4096
  bpf: Document EFAULT changes for sockopt

 Documentation/bpf/prog_cgroup_sockopt.rst     |  57 ++++++++-
 kernel/bpf/cgroup.c                           |  15 +++
 .../bpf/prog_tests/cgroup_getset_retval.c     |  20 ++++
 .../selftests/bpf/prog_tests/sockopt.c        | 103 +++++++++++++++-
 .../bpf/prog_tests/sockopt_inherit.c          |  59 +++-------
 .../selftests/bpf/prog_tests/sockopt_multi.c  | 110 +++++-------------
 .../bpf/prog_tests/sockopt_qos_to_cc.c        |   2 +
 .../progs/cgroup_getset_retval_getsockopt.c   |  13 +++
 .../progs/cgroup_getset_retval_setsockopt.c   |  17 +++
 .../selftests/bpf/progs/sockopt_inherit.c     |  18 ++-
 .../selftests/bpf/progs/sockopt_multi.c       |  26 ++++-
 .../selftests/bpf/progs/sockopt_qos_to_cc.c   |  10 +-
 .../testing/selftests/bpf/progs/sockopt_sk.c  |  25 ++--
 13 files changed, 335 insertions(+), 140 deletions(-)

-- 
2.40.1.521.gf1e218fcd8-goog