Commit 83dff601 authored by Philo Lu's avatar Philo Lu Committed by Martin KaFai Lau
Browse files

selftests/bpf: Expand skb dynptr selftests for tp_btf 



Add 3 test cases for skb dynptr used in tp_btf:
- test_dynptr_skb_tp_btf: use skb dynptr in tp_btf and make sure it is
  read-only.
- skb_invalid_ctx_fentry/skb_invalid_ctx_fexit: bpf_dynptr_from_skb
  should fail in fentry/fexit.

In test_dynptr_skb_tp_btf, to trigger the tracepoint in kfree_skb,
test_pkt_access is used for its test_run, as in kfree_skb.c. Because the
test process is different from others, a new setup type is defined,
i.e., SETUP_SKB_PROG_TP.

The result is like:
$ ./test_progs -t 'dynptr/test_dynptr_skb_tp_btf'
  #84/14   dynptr/test_dynptr_skb_tp_btf:OK
  #84      dynptr:OK
  #127     kfunc_dynptr_param:OK
  Summary: 2/1 PASSED, 0 SKIPPED, 0 FAILED

$ ./test_progs -t 'dynptr/skb_invalid_ctx_f'
  #84/85   dynptr/skb_invalid_ctx_fentry:OK
  #84/86   dynptr/skb_invalid_ctx_fexit:OK
  #84      dynptr:OK
  #127     kfunc_dynptr_param:OK
  Summary: 2/2 PASSED, 0 SKIPPED, 0 FAILED

Also fix two coding style nits (change spaces to tabs).

Signed-off-by: default avatarPhilo Lu <lulie@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240911033719.91468-6-lulie@linux.alibaba.com


Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parent ffc83860

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

+35 −2
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
enum test_setup_type {

	SETUP_SYSCALL_SLEEP,

	SETUP_SKB_PROG,

	SETUP_SKB_PROG_TP,

};



static struct {
@@ -28,6 +29,7 @@ static struct { 
	{"test_dynptr_clone", SETUP_SKB_PROG},

	{"test_dynptr_skb_no_buff", SETUP_SKB_PROG},

	{"test_dynptr_skb_strcmp", SETUP_SKB_PROG},

	{"test_dynptr_skb_tp_btf", SETUP_SKB_PROG_TP},

};



static void verify_success(const char *prog_name, enum test_setup_type setup_type)
@@ -87,6 +89,37 @@ static void verify_success(const char *prog_name, enum test_setup_type setup_typ 


		break;

	}

	case SETUP_SKB_PROG_TP:

	{

		struct __sk_buff skb = {};

		struct bpf_object *obj;

		int aux_prog_fd;



		/* Just use its test_run to trigger kfree_skb tracepoint */

		err = bpf_prog_test_load("./test_pkt_access.bpf.o", BPF_PROG_TYPE_SCHED_CLS,

					 &obj, &aux_prog_fd);

		if (!ASSERT_OK(err, "prog_load sched cls"))

			goto cleanup;



		LIBBPF_OPTS(bpf_test_run_opts, topts,

			    .data_in = &pkt_v4,

			    .data_size_in = sizeof(pkt_v4),

			    .ctx_in = &skb,

			    .ctx_size_in = sizeof(skb),

		);



		link = bpf_program__attach(prog);

		if (!ASSERT_OK_PTR(link, "bpf_program__attach"))

			goto cleanup;



		err = bpf_prog_test_run_opts(aux_prog_fd, &topts);

		bpf_link__destroy(link);



		if (!ASSERT_OK(err, "test_run"))

			goto cleanup;



		break;

	}

	}



	ASSERT_EQ(skel->bss->err, 0, "err");

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

+25 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <stdbool.h>

#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include <linux/if_ether.h>

#include "bpf_misc.h"

#include "bpf_kfuncs.h"
@@ -1254,6 +1255,30 @@ int skb_invalid_ctx(void *ctx) 
	return 0;

}



SEC("fentry/skb_tx_error")

__failure __msg("must be referenced or trusted")

int BPF_PROG(skb_invalid_ctx_fentry, void *skb)

{

	struct bpf_dynptr ptr;



	/* this should fail */

	bpf_dynptr_from_skb(skb, 0, &ptr);



	return 0;

}



SEC("fexit/skb_tx_error")

__failure __msg("must be referenced or trusted")

int BPF_PROG(skb_invalid_ctx_fexit, void *skb)

{

	struct bpf_dynptr ptr;



	/* this should fail */

	bpf_dynptr_from_skb(skb, 0, &ptr);



	return 0;

}



/* Reject writes to dynptr slot for uninit arg */

SEC("?raw_tp")

__failure __msg("potential write to dynptr at off=-16")

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

+23 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include <stdbool.h>

#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include "bpf_misc.h"

#include "bpf_kfuncs.h"

#include "errno.h"
@@ -544,3 +545,25 @@ int test_dynptr_skb_strcmp(struct __sk_buff *skb) 


	return 1;

}



SEC("tp_btf/kfree_skb")

int BPF_PROG(test_dynptr_skb_tp_btf, void *skb, void *location)

{

	__u8 write_data[2] = {1, 2};

	struct bpf_dynptr ptr;

	int ret;



	if (bpf_dynptr_from_skb(skb, 0, &ptr)) {

		err = 1;

		return 1;

	}



	/* since tp_btf skbs are read only, writes should fail */

	ret = bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data), 0);

	if (ret != -EINVAL) {

		err = 2;

		return 1;

	}



	return 1;

}