From: Daniel Borkmann <daniel@iogearbox•net>
To: Edward Cree <ecree@solarflare•com>,
davem@davemloft•net,
Alexei Starovoitov <alexei.starovoitov@gmail•com>,
Alexei Starovoitov <ast@fb•com>
Cc: netdev@vger•kernel.org, linux-kernel@vger•kernel.org,
iovisor-dev <iovisor-dev@lists•iovisor.org>
Subject: Re: [PATCH v3 net-next 00/12] bpf: rewrite value tracking in verifier
Date: Wed, 28 Jun 2017 15:50:46 +0200 [thread overview]
Message-ID: <5953B436.6030506@iogearbox.net> (raw)
In-Reply-To: <adc11342-737f-4e06-bce3-f0a92b5594a5@solarflare.com>
Hi Edward,
On 06/27/2017 02:53 PM, Edward Cree wrote:
> This series simplifies alignment tracking, generalises bounds tracking and
> fixes some bounds-tracking bugs in the BPF verifier. Pointer arithmetic on
> packet pointers, stack pointers, map value pointers and context pointers has
> been unified, and bounds on these pointers are only checked when the pointer
> is dereferenced.
> Operations on pointers which destroy all relation to the original pointer
> (such as multiplies and shifts) are disallowed if !env->allow_ptr_leaks,
> otherwise they convert the pointer to an unknown scalar and feed it to the
> normal scalar arithmetic handling.
> Pointer types have been unified with the corresponding adjusted-pointer types
> where those existed (e.g. PTR_TO_MAP_VALUE[_ADJ] or FRAME_PTR vs
> PTR_TO_STACK); similarly, CONST_IMM and UNKNOWN_VALUE have been unified into
> SCALAR_VALUE.
> Pointer types (except CONST_PTR_TO_MAP, PTR_TO_MAP_VALUE_OR_NULL and
> PTR_TO_PACKET_END, which do not allow arithmetic) have a 'fixed offset' and
> a 'variable offset'; the former is used when e.g. adding an immediate or a
> known-constant register, as long as it does not overflow. Otherwise the
> latter is used, and any operation creating a new variable offset creates a
> new 'id' (and, for PTR_TO_PACKET, clears the 'range').
> SCALAR_VALUEs use the 'variable offset' fields to track the range of possible
> values; the 'fixed offset' should never be set on a scalar.
>
> As of patch 12/12, all tests of tools/testing/selftests/bpf/test_verifier
> and tools/testing/selftests/bpf/test_align pass.
>
> v3: added a few more tests; removed RFC tags.
Did you also have a chance in the meantime to look at reducing complexity
along with your unification? I did run the cilium test suite with your
latest set from here and current # worst case processed insns that
verifier has to go through for cilium progs increases from ~53k we have
right now to ~76k. I'm a bit worried that this quickly gets us close to
the upper ~98k max limit starting to reject programs again. Alternative
is to bump the complexity limit again in near future once run into it,
but preferably there's a way to optimize it along with the rewrite? Do
you see any possibilities worth exploring?
> v2: fixed nfp build, made test_align pass again and extended it with a few
> new tests (though still need to add more).
>
> Edward Cree (12):
> selftests/bpf: add test for mixed signed and unsigned bounds checks
> bpf/verifier: rework value tracking
> nfp: change bpf verifier hooks to match new verifier data structures
> bpf/verifier: track signed and unsigned min/max values
> bpf/verifier: more concise register state logs for constant var_off
> selftests/bpf: change test_verifier expectations
> selftests/bpf: rewrite test_align
> selftests/bpf: add a test to test_align
> selftests/bpf: add test for bogus operations on pointers
> selftests/bpf: don't try to access past MAX_PACKET_OFF in
> test_verifier
> selftests/bpf: add tests for subtraction & negative numbers
> selftests/bpf: variable offset negative tests
>
> drivers/net/ethernet/netronome/nfp/bpf/verifier.c | 24 +-
> include/linux/bpf.h | 34 +-
> include/linux/bpf_verifier.h | 56 +-
> include/linux/tnum.h | 81 +
> kernel/bpf/Makefile | 2 +-
> kernel/bpf/tnum.c | 180 ++
> kernel/bpf/verifier.c | 1943 ++++++++++++---------
> tools/testing/selftests/bpf/test_align.c | 462 ++++-
> tools/testing/selftests/bpf/test_verifier.c | 293 ++--
> 9 files changed, 2034 insertions(+), 1041 deletions(-)
> create mode 100644 include/linux/tnum.h
> create mode 100644 kernel/bpf/tnum.c
>
Thanks,
Daniel
next prev parent reply other threads:[~2017-06-28 13:50 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-27 12:53 [PATCH v3 net-next 00/12] bpf: rewrite value tracking in verifier Edward Cree via iovisor-dev
[not found] ` <adc11342-737f-4e06-bce3-f0a92b5594a5-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-06-27 12:56 ` [PATCH v3 net-next 01/12] selftests/bpf: add test for mixed signed and unsigned bounds checks Edward Cree via iovisor-dev
[not found] ` <12c14f90-153c-c2c2-b2e2-834185b7ec3f-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-06-28 13:51 ` Daniel Borkmann via iovisor-dev
2017-06-27 12:56 ` [PATCH v3 net-next 02/12] bpf/verifier: rework value tracking Edward Cree via iovisor-dev
2017-06-28 15:15 ` Daniel Borkmann
[not found] ` <5953C7FE.1050205-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org>
2017-06-28 16:07 ` Edward Cree via iovisor-dev
[not found] ` <71aae126-352d-d916-d64a-9d4045d0abe9-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-06-28 19:44 ` Daniel Borkmann via iovisor-dev
[not found] ` <2244b48b-f415-3239-6912-cb09f0abc546-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-06-28 17:09 ` Daniel Borkmann via iovisor-dev
[not found] ` <5953E2E5.7040106-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org>
2017-06-28 18:28 ` Edward Cree via iovisor-dev
2017-07-06 20:26 ` Nadav Amit via iovisor-dev
2017-07-06 21:21 ` Nadav Amit via iovisor-dev
[not found] ` <E65DE75F-FC5F-41BC-9F7B-C03D324D8C6F-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-07-07 13:48 ` Edward Cree via iovisor-dev
[not found] ` <abd3c014-f33a-6e86-aead-be38697a2cec-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-07-07 17:45 ` Nadav Amit via iovisor-dev
[not found] ` <3A96914E-3009-4E19-B138-7A636A76D9C8-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-07-08 0:54 ` Nadav Amit via iovisor-dev
2017-07-12 19:13 ` Edward Cree via iovisor-dev
[not found] ` <68a2487e-f706-1b61-5c4c-20ffe6d51127-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-07-12 22:07 ` Nadav Amit via iovisor-dev
[not found] ` <12DCE590-7F67-4639-A825-61A24AC44ED3-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-07-17 17:02 ` Edward Cree via iovisor-dev
2017-06-29 7:48 ` kbuild test robot
2017-06-27 12:57 ` [PATCH v3 net-next 03/12] nfp: change bpf verifier hooks to match new verifier data structures Edward Cree via iovisor-dev
[not found] ` <b8418d35-7d3f-1ee3-2bfa-cdf87e5b7c95-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-06-28 20:47 ` Daniel Borkmann via iovisor-dev
2017-06-29 3:47 ` Jakub Kicinski via iovisor-dev
2017-06-27 12:57 ` [PATCH v3 net-next 04/12] bpf/verifier: track signed and unsigned min/max values Edward Cree via iovisor-dev
2017-06-27 12:58 ` [PATCH v3 net-next 05/12] bpf/verifier: more concise register state logs for constant var_off Edward Cree via iovisor-dev
2017-06-27 12:58 ` [PATCH v3 net-next 06/12] selftests/bpf: change test_verifier expectations Edward Cree via iovisor-dev
2017-06-27 12:59 ` [PATCH v3 net-next 07/12] selftests/bpf: rewrite test_align Edward Cree via iovisor-dev
2017-06-27 12:59 ` [PATCH v3 net-next 08/12] selftests/bpf: add a test to test_align Edward Cree via iovisor-dev
2017-06-27 12:59 ` [PATCH v3 net-next 09/12] selftests/bpf: add test for bogus operations on pointers Edward Cree via iovisor-dev
2017-06-27 12:59 ` [PATCH v3 net-next 10/12] selftests/bpf: don't try to access past MAX_PACKET_OFF in test_verifier Edward Cree via iovisor-dev
2017-06-27 13:00 ` [PATCH v3 net-next 11/12] selftests/bpf: add tests for subtraction & negative numbers Edward Cree via iovisor-dev
2017-06-27 13:00 ` [PATCH v3 net-next 12/12] selftests/bpf: variable offset negative tests Edward Cree via iovisor-dev
2017-06-28 13:50 ` Daniel Borkmann [this message]
[not found] ` <5953B436.6030506-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org>
2017-06-28 14:11 ` [PATCH v3 net-next 00/12] bpf: rewrite value tracking in verifier Edward Cree via iovisor-dev
[not found] ` <788035e1-1974-b48e-3008-d294194a8b05-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-06-28 20:38 ` Daniel Borkmann via iovisor-dev
[not found] ` <595413AA.40502-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org>
2017-06-28 21:37 ` Alexei Starovoitov via iovisor-dev
2017-06-30 16:44 ` Edward Cree via iovisor-dev
[not found] ` <91267d15-652a-16d9-4ee9-42958bd842aa-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-06-30 17:34 ` [TEST PATCH] bpf/verifier: roll back ptr&const handling, and fix signed bounds Edward Cree via iovisor-dev
2017-06-30 18:15 ` [PATCH v3 net-next 00/12] bpf: rewrite value tracking in verifier Alexei Starovoitov via iovisor-dev
[not found] ` <ff1ef3ef-71ef-4c23-ede4-b8caeac561ee-b10kYP2dOMg@public.gmane.org>
2017-07-04 19:22 ` Edward Cree via iovisor-dev
[not found] ` <5fa61129-fa82-1607-3363-dfad86aecf1e-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-07-04 22:28 ` Daniel Borkmann via iovisor-dev
2017-07-06 18:27 ` Edward Cree
[not found] ` <54b95191-697d-6b15-ec39-438c85e08adc-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org>
2017-07-07 9:14 ` Daniel Borkmann via iovisor-dev
[not found] ` <595F50F3.2030008-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org>
2017-07-07 12:50 ` Edward Cree via iovisor-dev
2017-07-07 13:05 ` Daniel Borkmann
2017-07-06 14:07 ` Edward Cree via iovisor-dev
2017-07-14 20:03 ` [iovisor-dev] " Y Song
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