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From: KP Singh <kpsingh@chromium.org>
To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
	linux-security-module@vger.kernel.org
Cc: "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>,
	"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: [RFC v1 09/14] krsi: Add a helper function for bpf_perf_event_output
Date: Tue, 10 Sep 2019 13:55:22 +0200
Message-ID: <20190910115527.5235-10-kpsingh@chromium.org> (raw)
In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org>

From: KP Singh <kpsingh@google.com>

This helper is mapped to the existing operation
BPF_FUNC_perf_event_output.

An example usage of this function would be:

#define BUF_SIZE 64;

struct bpf_map_def SEC("maps") perf_map = {
        .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
        .key_size = sizeof(int),
        .value_size = sizeof(u32),
        .max_entries = MAX_CPUS,
};

SEC("krsi")
int bpf_prog1(void *ctx)
{
	char buf[BUF_SIZE];
	int len;
	u64 flags = BPF_F_CURRENT_CPU;

	/* some logic that fills up buf with len data*/
	len = fill_up_buf(buf);
	if (len < 0)
		return len;
	if (len > BU)
		return 0;

	bpf_perf_event_output(ctx, &perf_map, flags, buf len);
	return 0;
}

A sample program that showcases the use of bpf_perf_event_output is
added later.

Signed-off-by: KP Singh <kpsingh@google.com>
---
 security/krsi/ops.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/security/krsi/ops.c b/security/krsi/ops.c
index a61508b7018f..57bd304a03f4 100644
--- a/security/krsi/ops.c
+++ b/security/krsi/ops.c
@@ -111,6 +111,26 @@ static bool krsi_prog_is_valid_access(int off, int size,
 	return false;
 }
 
+BPF_CALL_5(krsi_event_output, void *, log,
+	   struct bpf_map *, map, u64, flags, void *, data, u64, size)
+{
+	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
+		return -EINVAL;
+
+	return bpf_event_output(map, flags, data, size, NULL, 0, NULL);
+}
+
+static const struct bpf_func_proto krsi_event_output_proto =  {
+	.func		= krsi_event_output,
+	.gpl_only       = true,
+	.ret_type       = RET_INTEGER,
+	.arg1_type      = ARG_PTR_TO_CTX,
+	.arg2_type      = ARG_CONST_MAP_PTR,
+	.arg3_type      = ARG_ANYTHING,
+	.arg4_type      = ARG_PTR_TO_MEM,
+	.arg5_type      = ARG_CONST_SIZE_OR_ZERO,
+};
+
 static const struct bpf_func_proto *krsi_prog_func_proto(enum bpf_func_id
 							 func_id,
 							 const struct bpf_prog
@@ -121,6 +141,8 @@ static const struct bpf_func_proto *krsi_prog_func_proto(enum bpf_func_id
 		return &bpf_map_lookup_elem_proto;
 	case BPF_FUNC_get_current_pid_tgid:
 		return &bpf_get_current_pid_tgid_proto;
+	case BPF_FUNC_perf_event_output:
+		return &krsi_event_output_proto;
 	default:
 		return NULL;
 	}
-- 
2.20.1


  parent reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-10 11:55 [RFC v1 00/14] Kernel Runtime Security Instrumentation KP Singh
2019-09-10 11:55 ` [RFC v1 01/14] krsi: Add a skeleton and config options for the KRSI LSM KP Singh
2019-09-10 11:55 ` [RFC v1 02/14] krsi: Introduce types for KRSI eBPF KP Singh
2019-09-10 11:55 ` [RFC v1 03/14] bpf: krsi: sync BPF UAPI header with tools KP Singh
2019-09-10 11:55 ` [RFC v1 04/14] krsi: Add support in libbpf for BPF_PROG_TYPE_KRSI KP Singh
2019-09-14 16:09   ` Yonghong Song
2019-09-10 11:55 ` [RFC v1 05/14] krsi: Initialize KRSI hooks and create files in securityfs KP Singh
2019-09-14 16:26   ` Yonghong Song
2019-09-10 11:55 ` [RFC v1 06/14] krsi: Implement eBPF operations, attachment and execution KP Singh
2019-09-14 16:56   ` Yonghong Song
2019-09-15  0:37     ` Yonghong Song
2019-09-10 11:55 ` [RFC v1 07/14] krsi: Check for premissions on eBPF attachment KP Singh
2019-09-10 11:55 ` [RFC v1 08/14] krsi: Show attached program names in hook read handler KP Singh
2019-09-10 11:55 ` KP Singh [this message]
2019-09-14 18:23   ` [RFC v1 09/14] krsi: Add a helper function for bpf_perf_event_output Yonghong Song
2019-09-10 11:55 ` [RFC v1 10/14] krsi: Handle attachment of the same program KP Singh
2019-09-10 11:55 ` [RFC v1 11/14] krsi: Pin argument pages in bprm_check_security hook KP Singh
2019-09-10 11:55 ` [RFC v1 12/14] krsi: Add an eBPF helper function to get the value of an env variable KP Singh
2019-09-15  0:16   ` Yonghong Song
2019-09-10 11:55 ` [RFC v1 13/14] krsi: Provide an example to read and log environment variables KP Singh
2019-09-15  0:24   ` Yonghong Song
2019-09-10 11:55 ` [RFC v1 14/14] krsi: Pin arg pages only when needed KP Singh
2019-09-15  0:33   ` Yonghong Song
2019-09-15  1:40     ` KP Singh

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