selftests/bpf: Fix stat probe in d_path test

Some kernels builds might inline vfs_getattr call within fstat syscall code path, so fentry/vfs_getattr trampoline is not called. Add security_inode_getattr to allowlist and switch the d_path test stat trampoline to security_inode_getattr. Keeping dentry_open and filp_close, because they are in their own files, so unlikely to be inlined, but in case they are, adding security_file_open. Adding flags that indicate trampolines were called and failing the test if any of them got missed, so it's easier to identify the issue next time.

Jiri Olsa committed 6 years ago

Commit a8a71791 parent c69d2dd3 files · +26 −1Browse files

Unified · Split

3 files

kernel/trace/bpf_trace.c +8 −0
tools/testing/selftests/bpf/prog_tests/d_path.c +10 −0
tools/testing/selftests/bpf/progs/test_d_path.c +8 −1

kernel/trace/bpf_trace.c+8−0

@@ -1114,6 +1114,14 @@ BPF_CALL_3(bpf_d_path, struct path , path, char , buf, u32, sz) · 1113 unmodified lines
1114	1114	}
1115	1115
1116	1116	BTF_SET_START(btf_allowlist_d_path)
	1117	+#ifdef CONFIG_SECURITY
	1118	+BTF_ID(func, security_file_permission)
	1119	+BTF_ID(func, security_inode_getattr)
	1120	+BTF_ID(func, security_file_open)
	1121	+#endif
	1122	+#ifdef CONFIG_SECURITY_PATH
	1123	+BTF_ID(func, security_path_truncate)
	1124	+#endif
1117	1125	BTF_ID(func, vfs_truncate)
1118	1126	BTF_ID(func, vfs_fallocate)
1119	1127	BTF_ID(func, dentry_open)

tools/testing/selftests/bpf/prog_tests/d_path.c+10−0

@@ -120,6 +120,16 @@ void test_d_path(void) · 119 unmodified lines
120	120	if (err < 0)
121	121	goto cleanup;
122	122
	123	+ if (CHECK(!bss->called_stat,
	124	+ "stat",
	125	+ "trampoline for security_inode_getattr was not called\n"))
	126	+ goto cleanup;
	127	+
	128	+ if (CHECK(!bss->called_close,
	129	+ "close",
	130	+ "trampoline for filp_close was not called\n"))
	131	+ goto cleanup;
	132	+
123	133	for (int i = 0; i < MAX_FILES; i++) {
124	134	CHECK(strncmp(src.paths[i], bss->paths_stat[i], MAX_PATH_LEN),
125	135	"check",

tools/testing/selftests/bpf/progs/test_d_path.c+8−1

@@ -15,7 +15,10 @@ char paths_close[MAX_FILES][MAX_PATH_LEN] = {}; · 14 unmodified lines
15	15	int rets_stat[MAX_FILES] = {};
16	16	int rets_close[MAX_FILES] = {};
17	17
18		−SEC("fentry/vfs_getattr")
	18	+int called_stat = 0;
	19	+int called_close = 0;
	20	+
	21	+SEC("fentry/security_inode_getattr")
19	22	int BPF_PROG(prog_stat, struct path path, struct kstat stat,
20	23	__u32 request_mask, unsigned int query_flags)
21	24	{
@@ -23,6 +26,8 @@ int BPF_PROG(prog_stat, struct path path, struct kstat stat, · 1 unmodified line
23	26	__u32 cnt = cnt_stat;
24	27	int ret;
25	28
	29	+ called_stat = 1;
	30	+
26	31	if (pid != my_pid)
27	32	return 0;
28	33
@@ -42,6 +47,8 @@ int BPF_PROG(prog_close, struct file file, void id) · 13 unmodified lines
42	47	__u32 cnt = cnt_close;
43	48	int ret;
44	49
	50	+ called_close = 1;
	51	+
45	52	if (pid != my_pid)
46	53	return 0;
47	54

selftests/bpf: Fix stat probe in d_path test

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