linux-stable/tools/testing/selftests/bpf/progs/test_d_path.c
Jiri Olsa a8a717963f 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: e4d1af4b16 ("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
2020-09-21 16:18:00 -07:00

65 lines
1.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#define MAX_PATH_LEN 128
#define MAX_FILES 7
pid_t my_pid = 0;
__u32 cnt_stat = 0;
__u32 cnt_close = 0;
char paths_stat[MAX_FILES][MAX_PATH_LEN] = {};
char paths_close[MAX_FILES][MAX_PATH_LEN] = {};
int rets_stat[MAX_FILES] = {};
int rets_close[MAX_FILES] = {};
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)
{
pid_t pid = bpf_get_current_pid_tgid() >> 32;
__u32 cnt = cnt_stat;
int ret;
called_stat = 1;
if (pid != my_pid)
return 0;
if (cnt >= MAX_FILES)
return 0;
ret = bpf_d_path(path, paths_stat[cnt], MAX_PATH_LEN);
rets_stat[cnt] = ret;
cnt_stat++;
return 0;
}
SEC("fentry/filp_close")
int BPF_PROG(prog_close, struct file *file, void *id)
{
pid_t pid = bpf_get_current_pid_tgid() >> 32;
__u32 cnt = cnt_close;
int ret;
called_close = 1;
if (pid != my_pid)
return 0;
if (cnt >= MAX_FILES)
return 0;
ret = bpf_d_path(&file->f_path,
paths_close[cnt], MAX_PATH_LEN);
rets_close[cnt] = ret;
cnt_close++;
return 0;
}
char _license[] SEC("license") = "GPL";