netdev - [PATCH bpf-next v3 0/4] bpf: verifier: use target program's type for access verifications

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Message-ID: <20200825232003.2877030-1-udippant@fb.com>
Date:   Tue, 25 Aug 2020 16:19:59 -0700
From:   Udip Pant <udippant@...com>
To:     Udip Pant <udippant@...com>, Alexei Starovoitov <ast@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        Andrii Nakryiko <andriin@...com>,
        "David S . Miller" <davem@...emloft.net>
CC:     <netdev@...r.kernel.org>, <bpf@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH bpf-next v3 0/4] bpf: verifier: use target program's type for access verifications

This patch series adds changes in verifier to make decisions such as granting
of read / write access or enforcement of return code status based on
the program type of the target program while using dynamic program
extension (of type BPF_PROG_TYPE_EXT).

The BPF_PROG_TYPE_EXT type can be used to extend types such as XDP, SKB
and others. Since the BPF_PROG_TYPE_EXT program type on itself is just a
placeholder for those, we need this extended check for those extended
programs to actually work with proper access, while using this option.

Patch #1 includes changes in the verifier.
Patch #2 adds selftests to verify write access on a packet for a valid 
extension program type
Patch #3 adds selftests to verify proper check for the return code
Patch #4 adds selftests to ensure access permissions and restrictions 
for some map types such sockmap.

Changelogs:
  v2 -> v3:
    * more comprehensive resolution of the program type in the verifier
      based on the target program (and not just for the packet access)
    * selftests for checking return code and map access
    * Also moved this patch to 'bpf-next' from 'bpf' tree
  v1 -> v2:
    * extraction of the logic to resolve prog type into a separate method
    * selftests to check for packet access for a valid freplace prog

Udip Pant (4):
  bpf: verifier: use target program's type for access verifications
  selftests/bpf: add test for freplace program with write access
  selftests/bpf: test for checking return code for the extended prog
  selftests/bpf: test for map update access from within EXT programs

 kernel/bpf/verifier.c                         | 32 ++++++---
 .../selftests/bpf/prog_tests/fexit_bpf2bpf.c  | 68 +++++++++++++++++++
 .../selftests/bpf/progs/fexit_bpf2bpf.c       | 27 ++++++++
 .../bpf/progs/freplace_attach_probe.c         | 40 +++++++++++
 .../bpf/progs/freplace_cls_redirect.c         | 34 ++++++++++
 .../bpf/progs/freplace_connect_v4_prog.c      | 19 ++++++
 .../selftests/bpf/progs/test_pkt_access.c     | 20 ++++++
 7 files changed, 229 insertions(+), 11 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/freplace_attach_probe.c
 create mode 100644 tools/testing/selftests/bpf/progs/freplace_cls_redirect.c
 create mode 100644 tools/testing/selftests/bpf/progs/freplace_connect_v4_prog.c

-- 
2.24.1