selftests/bpf: Add BPF_CORE_READ and BPF_CORE_READ_STR_INTO macro tests

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

diff --git a/tools/testing/selftests/bpf/prog_tests/core_reloc.c b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
index f3863f976a48e337032c0a522be0ad7eb80cd54e..21a0dff662412fbdf8bc6b3e31a8b8b7bd72e497 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/core_reloc.c
+++ b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
@@ -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

diff --git a/tools/testing/selftests/bpf/progs/core_reloc_types.h b/tools/testing/selftests/bpf/progs/core_reloc_types.h
index f686a8138d90a26d630afa4a61d44dce457ae24a..9a6bdeb4894c4201ee91862504a04df0af375cac 100644 (file)
--- a/tools/testing/selftests/bpf/progs/core_reloc_types.h
+++ b/tools/testing/selftests/bpf/progs/core_reloc_types.h
@@ -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

diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c b/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
index 14ce688463de2d737cc7a0696c8026df52c18a4b..50f609618b65f443e52ea2fec71f3d88062acaf7 100644 (file)
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
@@ -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;
 }