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selftests/bpf: Add BPF_CORE_READ and BPF_CORE_READ_STR_INTO macro tests

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Validate BPF_CORE_READ correctness and handling of up to 9 levels of
nestedness using cyclic task->(group_leader->)*->tgid chains.

Also add a test of maximum-dpeth BPF_CORE_READ_STR_INTO() macro.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20191008175942.1769476-8-andriin@fb.com
This commit is contained in:
Andrii Nakryiko 2019-10-08 10:59:42 -07:00 committed by Daniel Borkmann
parent 7db3822ab9
commit ee2eb063d3
3 changed files with 68 additions and 3 deletions
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8
tools/testing/selftests/bpf/prog_tests/core_reloc.c
View File

@ -193,8 +193,12 @@ static struct core_reloc_test_case test_cases[] = {
.btf_src_file = NULL, /* load from /lib/modules/$(uname -r) */
.input = "",
.input_len = 0,
.output = "\1", /* true */
.output_len = 1,
.output = STRUCT_TO_CHAR_PTR(core_reloc_kernel_output) {
.valid = { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, },
.comm = "test_progs\0\0\0\0\0",
.comm_len = 11,
},
.output_len = sizeof(struct core_reloc_kernel_output),
},
/* validate BPF program can use multiple flavors to match against

9
tools/testing/selftests/bpf/progs/core_reloc_types.h
View File

@ -1,5 +1,14 @@
#include <stdint.h>
#include <stdbool.h>
/*
* KERNEL
*/
struct core_reloc_kernel_output {
int valid[10];
char comm[16];
int comm_len;
};
/*
* FLAVORS

54
tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
View File

@ -13,9 +13,17 @@ static volatile struct data {
char out[256];
} data;
struct core_reloc_kernel_output {
int valid[10];
char comm[16];
int comm_len;
};
struct task_struct {
int pid;
int tgid;
char comm[16];
struct task_struct *group_leader;
};
#define CORE_READ(dst, src) bpf_core_read(dst, sizeof(*(dst)), src)
@ -24,7 +32,9 @@ SEC("raw_tracepoint/sys_enter")
int test_core_kernel(void *ctx)
{
struct task_struct *task = (void *)bpf_get_current_task();
struct core_reloc_kernel_output *out = (void *)&data.out;
uint64_t pid_tgid = bpf_get_current_pid_tgid();
uint32_t real_tgid = (uint32_t)pid_tgid;
int pid, tgid;
if (CORE_READ(&pid, &task->pid) ||
@ -32,7 +42,49 @@ int test_core_kernel(void *ctx)
return 1;
/* validate pid + tgid matches */
data.out[0] = (((uint64_t)pid << 32) | tgid) == pid_tgid;
out->valid[0] = (((uint64_t)pid << 32) | tgid) == pid_tgid;
/* test variadic BPF_CORE_READ macros */
out->valid[1] = BPF_CORE_READ(task,
tgid) == real_tgid;
out->valid[2] = BPF_CORE_READ(task,
group_leader,
tgid) == real_tgid;
out->valid[3] = BPF_CORE_READ(task,
group_leader, group_leader,
tgid) == real_tgid;
out->valid[4] = BPF_CORE_READ(task,
group_leader, group_leader, group_leader,
tgid) == real_tgid;
out->valid[5] = BPF_CORE_READ(task,
group_leader, group_leader, group_leader,
group_leader,
tgid) == real_tgid;
out->valid[6] = BPF_CORE_READ(task,
group_leader, group_leader, group_leader,
group_leader, group_leader,
tgid) == real_tgid;
out->valid[7] = BPF_CORE_READ(task,
group_leader, group_leader, group_leader,
group_leader, group_leader, group_leader,
tgid) == real_tgid;
out->valid[8] = BPF_CORE_READ(task,
group_leader, group_leader, group_leader,
group_leader, group_leader, group_leader,
group_leader,
tgid) == real_tgid;
out->valid[9] = BPF_CORE_READ(task,
group_leader, group_leader, group_leader,
group_leader, group_leader, group_leader,
group_leader, group_leader,
tgid) == real_tgid;
/* test BPF_CORE_READ_STR_INTO() returns correct code and contents */
out->comm_len = BPF_CORE_READ_STR_INTO(
&out->comm, task,
group_leader, group_leader, group_leader, group_leader,
group_leader, group_leader, group_leader, group_leader,
comm);
return 0;
}