Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
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>,
        =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= <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>
In-Reply-To: <20190910115527.5235-1-kpsingh@chromium.org>
References: <20190910115527.5235-1-kpsingh@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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