From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: KP Singh <kpsingh@chromium.org>
Cc: "open list" <linux-kernel@vger.kernel.org>,
bpf <bpf@vger.kernel.org>,
linux-security-module@vger.kernel.org,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"James Morris" <jmorris@namei.org>,
"Kees Cook" <keescook@chromium.org>,
"Thomas Garnier" <thgarnie@chromium.org>,
"Michael Halcrow" <mhalcrow@google.com>,
"Paul Turner" <pjt@google.com>,
"Brendan Gregg" <brendan.d.gregg@gmail.com>,
"Jann Horn" <jannh@google.com>,
"Matthew Garrett" <mjg59@google.com>,
"Christian Brauner" <christian@brauner.io>,
"Mickaël Salaün" <mic@digikod.net>,
"Florent Revest" <revest@chromium.org>,
"Brendan Jackman" <jackmanb@chromium.org>,
"Martin KaFai Lau" <kafai@fb.com>,
"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
"Serge E. Hallyn" <serge@hallyn.com>,
"Mauro Carvalho Chehab" <mchehab+samsung@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Nicolas Ferre" <nicolas.ferre@microchip.com>,
"Stanislav Fomichev" <sdf@google.com>,
"Quentin Monnet" <quentin.monnet@netronome.com>,
"Andrey Ignatov" <rdna@fb.com>, "Joe Stringer" <joe@wand.net.nz>
Subject: Re: [PATCH bpf-next v1 12/13] bpf: lsm: Add selftests for BPF_PROG_TYPE_LSM
Date: Thu, 9 Jan 2020 09:59:35 -0800 [thread overview]
Message-ID: <CAEf4Bzam_k99z-bh_kH=M9HUS3+nh_eSGJLffPO4y=_9psH9GA@mail.gmail.com> (raw)
In-Reply-To: <20200104000955.GB23487@chromium.org>
On Fri, Jan 3, 2020 at 4:09 PM KP Singh <kpsingh@chromium.org> wrote:
>
> On 23-Dez 22:49, Andrii Nakryiko wrote:
> > On Fri, Dec 20, 2019 at 7:42 AM KP Singh <kpsingh@chromium.org> wrote:
> > >
> > > From: KP Singh <kpsingh@google.com>
> > >
> > > * Load a BPF program that audits mprotect calls
> > > * Attach the program to the "file_mprotect" LSM hook
> > > * Verify if the program is actually loading by reading
> > > securityfs
> > > * Initialize the perf events buffer and poll for audit events
> > > * Do an mprotect on some memory allocated on the heap
> > > * Verify if the audit event was received
> > >
> > > Signed-off-by: KP Singh <kpsingh@google.com>
> > > ---
> > > MAINTAINERS | 2 +
> > > .../bpf/prog_tests/lsm_mprotect_audit.c | 129 ++++++++++++++++++
> > > .../selftests/bpf/progs/lsm_mprotect_audit.c | 58 ++++++++
> > > 3 files changed, 189 insertions(+)
> > > create mode 100644 tools/testing/selftests/bpf/prog_tests/lsm_mprotect_audit.c
> > > create mode 100644 tools/testing/selftests/bpf/progs/lsm_mprotect_audit.c
> > >
> >
> > [...]
> >
> > > +/*
> > > + * Define some of the structs used in the BPF program.
> > > + * Only the field names and their sizes need to be the
> > > + * same as the kernel type, the order is irrelevant.
> > > + */
> > > +struct mm_struct {
> > > + unsigned long start_brk, brk, start_stack;
> > > +};
> > > +
> > > +struct vm_area_struct {
> > > + unsigned long start_brk, brk, start_stack;
> > > + unsigned long vm_start, vm_end;
> > > + struct mm_struct *vm_mm;
> > > + unsigned long vm_flags;
> > > +};
> > > +
> > > +BPF_TRACE_3("lsm/file_mprotect", mprotect_audit,
> > > + struct vm_area_struct *, vma,
> > > + unsigned long, reqprot, unsigned long, prot)
> > > +{
> > > + struct mprotect_audit_log audit_log = {};
> > > + int is_heap = 0;
> > > +
> > > + __builtin_preserve_access_index(({
> >
> > you don't need __builtin_preserve_access_index, if you mark
> > vm_area_struct and mm_struct with
> > __attribute__((preserve_access_index)
>
> Cool, updated!
>
> >
> > > + is_heap = (vma->vm_start >= vma->vm_mm->start_brk &&
> > > + vma->vm_end <= vma->vm_mm->brk);
> > > + }));
> > > +
> > > + audit_log.magic = MPROTECT_AUDIT_MAGIC;
> > > + audit_log.is_heap = is_heap;
> > > + bpf_lsm_event_output(&perf_buf_map, BPF_F_CURRENT_CPU, &audit_log,
> > > + sizeof(audit_log));
> >
> > You test would be much simpler if you use global variables to pass
> > data back to userspace, instead of using perf buffer.
> >
> > Also please see fentry_fexit.c test for example of using BPF skeleton
> > to shorten and simpify userspace part of test.
>
> Thanks for the skeleton work!
>
> This makes using global variables easier and the tests are indeed much
> simpler, I have updated it for the next revision.
>
> One follow up question regarding global variables, let's say I have
> the following global variable defined in the BPF program:
>
> struct result_info {
> __u32 count;
> };
>
> struct result_info result = {
> .count = 0,
> };
>
> The defintion of result_info needs to be included before the .skel.h
> as it's not automatically generated or maybe I am missing a
> trick here?
>
> For now, I have defined this in a header which gets included both in
> the program and the test.
Yes, ideally all common types should be shared in a common header. My
initial implementation actually supported dumping out all the types in
a generated skeleton, but that was inconvenient in a lot of cases, so
I dropped that.
>
> - KP
>
> >
> > > + return 0;
> > > +}
> > > --
> > > 2.20.1
> > >
next prev parent reply other threads:[~2020-01-09 17:59 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-20 15:41 [PATCH bpf-next v1 00/13] MAC and Audit policy using eBPF (KRSI) KP Singh
2019-12-20 15:41 ` [PATCH bpf-next v1 01/13] bpf: Refactor BPF_EVENT context macros to its own header KP Singh
2019-12-20 20:10 ` Andrii Nakryiko
2019-12-20 20:26 ` KP Singh
2019-12-20 15:41 ` [PATCH bpf-next v1 02/13] bpf: lsm: Add a skeleton and config options KP Singh
2020-01-07 21:13 ` James Morris
2019-12-20 15:41 ` [PATCH bpf-next v1 03/13] bpf: lsm: Introduce types for eBPF based LSM KP Singh
2019-12-20 15:41 ` [PATCH bpf-next v1 04/13] bpf: lsm: Allow btf_id based attachment for LSM hooks KP Singh
2019-12-23 23:54 ` Andrii Nakryiko
2019-12-30 19:22 ` KP Singh
2019-12-20 15:42 ` [PATCH bpf-next v1 05/13] tools/libbpf: Add support in libbpf for BPF_PROG_TYPE_LSM KP Singh
2019-12-24 0:07 ` Andrii Nakryiko
2019-12-24 0:09 ` Andrii Nakryiko
2020-01-03 23:59 ` KP Singh
2019-12-20 15:42 ` [PATCH bpf-next v1 06/13] bpf: lsm: Init Hooks and create files in securityfs KP Singh
2019-12-24 6:28 ` Andrii Nakryiko
2019-12-30 15:37 ` KP Singh
2019-12-30 18:52 ` Andrii Nakryiko
2019-12-30 19:20 ` Kees Cook
2020-01-03 23:53 ` KP Singh
2020-01-07 21:22 ` James Morris
2019-12-20 15:42 ` [PATCH bpf-next v1 07/13] bpf: lsm: Implement attach, detach and execution KP Singh
2019-12-24 5:48 ` Andrii Nakryiko
2020-01-07 21:27 ` James Morris
2019-12-20 15:42 ` [PATCH bpf-next v1 08/13] bpf: lsm: Show attached program names in hook read handler KP Singh
2020-01-07 21:28 ` James Morris
2019-12-20 15:42 ` [PATCH bpf-next v1 09/13] bpf: lsm: Add a helper function bpf_lsm_event_output KP Singh
2019-12-24 6:36 ` Andrii Nakryiko
2019-12-30 15:11 ` KP Singh
2019-12-30 18:56 ` Andrii Nakryiko
2019-12-20 15:42 ` [PATCH bpf-next v1 10/13] bpf: lsm: Handle attachment of the same program KP Singh
2019-12-24 6:38 ` Andrii Nakryiko
2020-01-08 18:21 ` James Morris
2019-12-20 15:42 ` [PATCH bpf-next v1 11/13] tools/libbpf: Add bpf_program__attach_lsm KP Singh
2019-12-24 6:44 ` Andrii Nakryiko
2020-01-08 18:24 ` James Morris
2019-12-20 15:42 ` [PATCH bpf-next v1 12/13] bpf: lsm: Add selftests for BPF_PROG_TYPE_LSM KP Singh
2019-12-24 6:49 ` Andrii Nakryiko
2020-01-04 0:09 ` KP Singh
2020-01-09 17:59 ` Andrii Nakryiko [this message]
2020-01-08 18:25 ` James Morris
2019-12-20 15:42 ` [PATCH bpf-next v1 13/13] bpf: lsm: Add Documentation KP Singh
2019-12-20 17:17 ` [PATCH bpf-next v1 00/13] MAC and Audit policy using eBPF (KRSI) Casey Schaufler
2019-12-20 17:38 ` KP Singh
2019-12-30 19:15 ` Kees Cook
2020-01-08 15:25 ` Stephen Smalley
2020-01-08 18:58 ` James Morris
2020-01-08 19:33 ` Stephen Smalley
2020-01-09 18:11 ` James Morris
2020-01-09 18:23 ` Greg Kroah-Hartman
2020-01-09 18:58 ` Stephen Smalley
2020-01-09 19:07 ` James Morris
2020-01-09 19:43 ` KP Singh
2020-01-09 19:47 ` Stephen Smalley
2020-01-10 15:27 ` KP Singh
2020-01-10 17:48 ` James Morris
2020-01-10 17:53 ` Alexei Starovoitov
2020-01-14 16:54 ` Stephen Smalley
2020-01-14 17:42 ` Stephen Smalley
2020-01-15 2:48 ` Alexei Starovoitov
2020-01-15 13:59 ` Stephen Smalley
2020-01-15 14:09 ` Greg Kroah-Hartman
2020-01-15 22:23 ` Alexei Starovoitov
2020-01-09 19:11 ` KP Singh
2020-01-08 18:27 ` James Morris
2019-12-20 22:46 ` Mickaël Salaün
2019-12-30 19:30 ` Kees Cook
2019-12-31 12:11 ` Mickaël Salaün
2019-12-22 1:27 ` Alexei Starovoitov
2019-12-30 14:58 ` KP Singh
2019-12-30 19:14 ` Andrii Nakryiko
2019-12-24 6:51 ` Andrii Nakryiko
2019-12-30 15:04 ` KP Singh
2019-12-30 18:58 ` Andrii Nakryiko
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