From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: davem@davemloft.net
Cc: daniel@iogearbox.net, netdev@vger.kernel.org,
bpf@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH v2 bpf-next 0/3] bpf: Pointers beyond packet end.
Date: Tue, 10 Nov 2020 19:12:10 -0800 [thread overview]
Message-ID: <20201111031213.25109-1-alexei.starovoitov@gmail.com> (raw)
From: Alexei Starovoitov <ast@kernel.org>
v1->v2:
- removed set-but-unused variable.
- added Jiri's Tested-by.
In some cases LLVM uses the knowledge that branch is taken to optimze the code
which causes the verifier to reject valid programs.
Teach the verifier to recognize that
r1 = skb->data;
r1 += 10;
r2 = skb->data_end;
if (r1 > r2) {
here r1 points beyond packet_end and subsequent
if (r1 > r2) // always evaluates to "true".
}
Alexei Starovoitov (3):
bpf: Support for pointers beyond pkt_end.
selftests/bpf: Add skb_pkt_end test
selftests/bpf: Add asm tests for pkt vs pkt_end comparison.
include/linux/bpf_verifier.h | 2 +-
kernel/bpf/verifier.c | 129 +++++++++++++++---
.../bpf/prog_tests/test_skb_pkt_end.c | 41 ++++++
.../testing/selftests/bpf/progs/skb_pkt_end.c | 54 ++++++++
.../testing/selftests/bpf/verifier/ctx_skb.c | 42 ++++++
5 files changed, 245 insertions(+), 23 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/test_skb_pkt_end.c
create mode 100644 tools/testing/selftests/bpf/progs/skb_pkt_end.c
--
2.24.1
next reply other threads:[~2020-11-11 3:12 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-11 3:12 Alexei Starovoitov [this message]
2020-11-11 3:12 ` [PATCH v2 bpf-next 1/3] bpf: Support for pointers beyond pkt_end Alexei Starovoitov
2020-11-12 19:16 ` John Fastabend
2020-11-12 23:56 ` Daniel Borkmann
2020-11-13 0:09 ` Alexei Starovoitov
2020-11-13 0:50 ` Daniel Borkmann
2020-11-12 23:59 ` Alexei Starovoitov
2020-11-13 0:35 ` John Fastabend
2020-11-11 3:12 ` [PATCH v2 bpf-next 2/3] selftests/bpf: Add skb_pkt_end test Alexei Starovoitov
2020-11-12 19:19 ` John Fastabend
2020-11-11 3:12 ` [PATCH v2 bpf-next 3/3] selftests/bpf: Add asm tests for pkt vs pkt_end comparison Alexei Starovoitov
2020-11-12 19:24 ` John Fastabend
2021-01-20 20:51 ` Jiri Olsa
2020-11-13 0:50 ` [PATCH v2 bpf-next 0/3] bpf: Pointers beyond packet end patchwork-bot+netdevbpf
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