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authorJiri Olsa <jolsa@kernel.org>2020-09-18 13:23:38 +0200
committerAlexei Starovoitov <ast@kernel.org>2020-09-21 16:18:00 -0700
commita8a717963fe5ecfd274eb93dd1285ee9428ffca7 (patch)
tree62c0f3340551492668d4416a74cd26ba07242258
parentc69d2ddb2072eb7ffca1a31ee5ddc16dcd414ed9 (diff)
downloadbpf-next-a8a717963fe5ecfd274eb93dd1285ee9428ffca7.tar.gz
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. Fixes: e4d1af4b16f8 ("selftests/bpf: Add test for d_path helper") Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200918112338.2618444-1-jolsa@kernel.org
-rw-r--r--kernel/trace/bpf_trace.c8
-rw-r--r--tools/testing/selftests/bpf/prog_tests/d_path.c10
-rw-r--r--tools/testing/selftests/bpf/progs/test_d_path.c9
3 files changed, 26 insertions, 1 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index ebf9be4d0d6a7c..36508f46a8dbf5 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1114,6 +1114,14 @@ BPF_CALL_3(bpf_d_path, struct path *, path, char *, buf, u32, sz)
}
BTF_SET_START(btf_allowlist_d_path)
+#ifdef CONFIG_SECURITY
+BTF_ID(func, security_file_permission)
+BTF_ID(func, security_inode_getattr)
+BTF_ID(func, security_file_open)
+#endif
+#ifdef CONFIG_SECURITY_PATH
+BTF_ID(func, security_path_truncate)
+#endif
BTF_ID(func, vfs_truncate)
BTF_ID(func, vfs_fallocate)
BTF_ID(func, dentry_open)
diff --git a/tools/testing/selftests/bpf/prog_tests/d_path.c b/tools/testing/selftests/bpf/prog_tests/d_path.c
index fc12e0d445ff5e..0a577a248d34a5 100644
--- a/tools/testing/selftests/bpf/prog_tests/d_path.c
+++ b/tools/testing/selftests/bpf/prog_tests/d_path.c
@@ -120,6 +120,16 @@ void test_d_path(void)
if (err < 0)
goto cleanup;
+ if (CHECK(!bss->called_stat,
+ "stat",
+ "trampoline for security_inode_getattr was not called\n"))
+ goto cleanup;
+
+ if (CHECK(!bss->called_close,
+ "close",
+ "trampoline for filp_close was not called\n"))
+ goto cleanup;
+
for (int i = 0; i < MAX_FILES; i++) {
CHECK(strncmp(src.paths[i], bss->paths_stat[i], MAX_PATH_LEN),
"check",
diff --git a/tools/testing/selftests/bpf/progs/test_d_path.c b/tools/testing/selftests/bpf/progs/test_d_path.c
index 61f007855649af..84e1f883f97bc6 100644
--- a/tools/testing/selftests/bpf/progs/test_d_path.c
+++ b/tools/testing/selftests/bpf/progs/test_d_path.c
@@ -15,7 +15,10 @@ char paths_close[MAX_FILES][MAX_PATH_LEN] = {};
int rets_stat[MAX_FILES] = {};
int rets_close[MAX_FILES] = {};
-SEC("fentry/vfs_getattr")
+int called_stat = 0;
+int called_close = 0;
+
+SEC("fentry/security_inode_getattr")
int BPF_PROG(prog_stat, struct path *path, struct kstat *stat,
__u32 request_mask, unsigned int query_flags)
{
@@ -23,6 +26,8 @@ int BPF_PROG(prog_stat, struct path *path, struct kstat *stat,
__u32 cnt = cnt_stat;
int ret;
+ called_stat = 1;
+
if (pid != my_pid)
return 0;
@@ -42,6 +47,8 @@ int BPF_PROG(prog_close, struct file *file, void *id)
__u32 cnt = cnt_close;
int ret;
+ called_close = 1;
+
if (pid != my_pid)
return 0;