[PATCH v4 bpf-next 0/2] bpf: add cg_skb_is_valid_access

[Song Liu <songliubraving@fb.com>]

Changes v3 -> v4:
1. Fixed crash issue reported by Alexei.

Changes v2 -> v3:
1. Added helper function bpf_compute_and_save_data_pointers() and
   bpf_restore_data_pointers().

Changes v1 -> v2:
1. Updated the list of read-only fields, and read-write fields.
2. Added dummy sk to bpf_prog_test_run_skb().

This set enables BPF program of type BPF_PROG_TYPE_CGROUP_SKB to access
some __skb_buff data directly.

Song Liu (2):
  bpf: add cg_skb_is_valid_access for BPF_PROG_TYPE_CGROUP_SKB
  bpf: add tests for direct packet access from CGROUP_SKB

 include/linux/filter.h                      |  24 +++
 kernel/bpf/cgroup.c                         |   6 +
 net/bpf/test_run.c                          |   7 +
 net/core/filter.c                           |  36 ++++-
 tools/testing/selftests/bpf/test_verifier.c | 170 ++++++++++++++++++++
 5 files changed, 242 insertions(+), 1 deletion(-)