2020-08-25 23:23:40

by Udip Pant

[permalink] [raw]
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


2020-08-26 00:11:34

by Yonghong Song

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



On 8/25/20 4:19 PM, Udip Pant wrote:
> 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

Thanks. LGTM. Ack for the whole series.
Acked-by: Yonghong Song <[email protected]>

2020-08-26 09:27:41

by Toke Høiland-Jørgensen

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

Udip Pant <[email protected]> writes:

> 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.

Thanks for fixing this!

For the series:
Acked-by: Toke Høiland-Jørgensen <[email protected]>

2020-08-26 19:56:29

by Alexei Starovoitov

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

On Tue, Aug 25, 2020 at 04:19:59PM -0700, Udip Pant wrote:
> 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

Applied. Thanks