Commit 17d3f386 authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
Browse files

selftests/bpf: Adding test for arg dereference in extension trace 



Adding test that setup following program:

  SEC("classifier/test_pkt_md_access")
  int test_pkt_md_access(struct __sk_buff *skb)

with its extension:

  SEC("freplace/test_pkt_md_access")
  int test_pkt_md_access_new(struct __sk_buff *skb)

and tracing that extension with:

  SEC("fentry/test_pkt_md_access_new")
  int BPF_PROG(fentry, struct sk_buff *skb)

The test verifies that the tracing program can
dereference skb argument properly.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/160138355603.48470.9072073357530773228.stgit@toke.dk
parent f6429476

tools/testing/selftests/bpf/prog_tests/trace_ext.c

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// SPDX-License-Identifier: GPL-2.0



#define _GNU_SOURCE

#include <test_progs.h>

#include <network_helpers.h>

#include <sys/stat.h>

#include <linux/sched.h>

#include <sys/syscall.h>



#include "test_pkt_md_access.skel.h"

#include "test_trace_ext.skel.h"

#include "test_trace_ext_tracing.skel.h"



static __u32 duration;



void test_trace_ext(void)

{

	struct test_pkt_md_access *skel_pkt = NULL;

	struct test_trace_ext_tracing *skel_trace = NULL;

	struct test_trace_ext_tracing__bss *bss_trace;

	struct test_trace_ext *skel_ext = NULL;

	struct test_trace_ext__bss *bss_ext;

	int err, pkt_fd, ext_fd;

	struct bpf_program *prog;

	char buf[100];

	__u32 retval;

	__u64 len;



	/* open/load/attach test_pkt_md_access */

	skel_pkt = test_pkt_md_access__open_and_load();

	if (CHECK(!skel_pkt, "setup", "classifier/test_pkt_md_access open failed\n"))

		goto cleanup;



	err = test_pkt_md_access__attach(skel_pkt);

	if (CHECK(err, "setup", "classifier/test_pkt_md_access attach failed: %d\n", err))

		goto cleanup;



	prog = skel_pkt->progs.test_pkt_md_access;

	pkt_fd = bpf_program__fd(prog);



	/* open extension */

	skel_ext = test_trace_ext__open();

	if (CHECK(!skel_ext, "setup", "freplace/test_pkt_md_access open failed\n"))

		goto cleanup;



	/* set extension's attach target - test_pkt_md_access  */

	prog = skel_ext->progs.test_pkt_md_access_new;

	bpf_program__set_attach_target(prog, pkt_fd, "test_pkt_md_access");



	/* load/attach extension */

	err = test_trace_ext__load(skel_ext);

	if (CHECK(err, "setup", "freplace/test_pkt_md_access load failed\n")) {

		libbpf_strerror(err, buf, sizeof(buf));

		fprintf(stderr, "%s\n", buf);

		goto cleanup;

	}



	err = test_trace_ext__attach(skel_ext);

	if (CHECK(err, "setup", "freplace/test_pkt_md_access attach failed: %d\n", err))

		goto cleanup;



	prog = skel_ext->progs.test_pkt_md_access_new;

	ext_fd = bpf_program__fd(prog);



	/* open tracing  */

	skel_trace = test_trace_ext_tracing__open();

	if (CHECK(!skel_trace, "setup", "tracing/test_pkt_md_access_new open failed\n"))

		goto cleanup;



	/* set tracing's attach target - fentry */

	prog = skel_trace->progs.fentry;

	bpf_program__set_attach_target(prog, ext_fd, "test_pkt_md_access_new");



	/* set tracing's attach target - fexit */

	prog = skel_trace->progs.fexit;

	bpf_program__set_attach_target(prog, ext_fd, "test_pkt_md_access_new");



	/* load/attach tracing */

	err = test_trace_ext_tracing__load(skel_trace);

	if (CHECK(err, "setup", "tracing/test_pkt_md_access_new load failed\n")) {

		libbpf_strerror(err, buf, sizeof(buf));

		fprintf(stderr, "%s\n", buf);

		goto cleanup;

	}



	err = test_trace_ext_tracing__attach(skel_trace);

	if (CHECK(err, "setup", "tracing/test_pkt_md_access_new attach failed: %d\n", err))

		goto cleanup;



	/* trigger the test */

	err = bpf_prog_test_run(pkt_fd, 1, &pkt_v4, sizeof(pkt_v4),

				NULL, NULL, &retval, &duration);

	CHECK(err || retval, "run", "err %d errno %d retval %d\n", err, errno, retval);



	bss_ext = skel_ext->bss;

	bss_trace = skel_trace->bss;



	len = bss_ext->ext_called;



	CHECK(bss_ext->ext_called == 0,

		"check", "failed to trigger freplace/test_pkt_md_access\n");

	CHECK(bss_trace->fentry_called != len,

		"check", "failed to trigger fentry/test_pkt_md_access_new\n");

	CHECK(bss_trace->fexit_called != len,

		"check", "failed to trigger fexit/test_pkt_md_access_new\n");



cleanup:

	test_trace_ext_tracing__destroy(skel_trace);

	test_trace_ext__destroy(skel_ext);

	test_pkt_md_access__destroy(skel_pkt);

}

tools/testing/selftests/bpf/progs/test_trace_ext.c

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// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2019 Facebook

#include <linux/bpf.h>

#include <stdbool.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_endian.h>

#include <bpf/bpf_tracing.h>



__u64 ext_called = 0;



SEC("freplace/test_pkt_md_access")

int test_pkt_md_access_new(struct __sk_buff *skb)

{

	ext_called = skb->len;

	return 0;

}



char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/progs/test_trace_ext_tracing.c

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// SPDX-License-Identifier: GPL-2.0



#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>



__u64 fentry_called = 0;



SEC("fentry/test_pkt_md_access_new")

int BPF_PROG(fentry, struct sk_buff *skb)

{

	fentry_called = skb->len;

	return 0;

}



__u64 fexit_called = 0;



SEC("fexit/test_pkt_md_access_new")

int BPF_PROG(fexit, struct sk_buff *skb)

{

	fexit_called = skb->len;

	return 0;

}



char _license[] SEC("license") = "GPL";