Skip to content

Commit

Permalink
selftests/bpf: Expand skb dynptr selftests for tp_btf
Browse files Browse the repository at this point in the history
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'
  torvalds#84/14   dynptr/test_dynptr_skb_tp_btf:OK
  torvalds#84      dynptr:OK
  torvalds#127     kfunc_dynptr_param:OK
  Summary: 2/1 PASSED, 0 SKIPPED, 0 FAILED

$ ./test_progs -t 'dynptr/skb_invalid_ctx_f'
  torvalds#84/85   dynptr/skb_invalid_ctx_fentry:OK
  torvalds#84/86   dynptr/skb_invalid_ctx_fexit:OK
  torvalds#84      dynptr:OK
  torvalds#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: Philo Lu <[email protected]>
  • Loading branch information
Philo Lu authored and intel-lab-lkp committed Sep 5, 2024
1 parent cca5c67 commit b6a5168
Show file tree
Hide file tree
Showing 3 changed files with 82 additions and 2 deletions.
36 changes: 34 additions & 2 deletions tools/testing/selftests/bpf/prog_tests/dynptr.c
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
enum test_setup_type {
SETUP_SYSCALL_SLEEP,
SETUP_SKB_PROG,
SETUP_SKB_PROG_TP,
};

static struct {
Expand All @@ -28,14 +29,15 @@ 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)
{
struct dynptr_success *skel;
struct bpf_program *prog;
struct bpf_link *link;
int err;
int err;

skel = dynptr_success__open();
if (!ASSERT_OK_PTR(skel, "dynptr_success__open"))
Expand All @@ -47,7 +49,7 @@ static void verify_success(const char *prog_name, enum test_setup_type setup_typ
if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
goto cleanup;

bpf_program__set_autoload(prog, true);
bpf_program__set_autoload(prog, true);

err = dynptr_success__load(skel);
if (!ASSERT_OK(err, "dynptr_success__load"))
Expand Down Expand Up @@ -87,6 +89,36 @@ 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);

if (!ASSERT_OK(err, "test_run"))
goto cleanup;

break;
}
}

ASSERT_EQ(skel->bss->err, 0, "err");
Expand Down
25 changes: 25 additions & 0 deletions tools/testing/selftests/bpf/progs/dynptr_fail.c
Original file line number Diff line number Diff line change
Expand Up @@ -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"
Expand Down Expand Up @@ -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")
Expand Down
23 changes: 23 additions & 0 deletions tools/testing/selftests/bpf/progs/dynptr_success.c
Original file line number Diff line number Diff line change
Expand Up @@ -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"
Expand Down Expand Up @@ -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;
}

0 comments on commit b6a5168

Please sign in to comment.