netdev - [PATCH bpf v2 0/2] Fix narrow loads from an offset outside of target field

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Date:   Thu, 23 Jul 2020 11:59:51 +0200
From:   Jakub Sitnicki <jakub@...udflare.com>
To:     bpf@...r.kernel.org
Cc:     netdev@...r.kernel.org, kernel-team@...udflare.com,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Yonghong Song <yhs@...com>
Subject: [PATCH bpf v2 0/2] Fix narrow loads from an offset outside of target field

This is a second attempt at fixing narrow loads from context fields backed
by smaller-in-size target fields, when load offset is beyond the target
field.

Following Yonghong suggestion, verifier now emits an 'wX = 0' or 'rX = 0'
instruction for loads from offsets outside of target field.

Cc: Yonghong Song <yhs@...com>

[v1] https://lore.kernel.org/bpf/20200710173123.427983-1-jakub@cloudflare.com/

Jakub Sitnicki (2):
  bpf: Load zeros for narrow loads beyond target field
  selftests/bpf: Add test for narrow loads from context at an offset

 kernel/bpf/verifier.c                         | 23 ++++-
 .../selftests/bpf/prog_tests/narrow_load.c    | 84 +++++++++++++++++++
 .../selftests/bpf/progs/test_narrow_load.c    | 43 ++++++++++
 3 files changed, 148 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/narrow_load.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_narrow_load.c

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2.25.4