| // SPDX-License-Identifier: GPL-2.0 |
| /* Copyright (c) 2022 Google */ |
| |
| #include "vmlinux.h" |
| #include <bpf/bpf_helpers.h> |
| #include <bpf/bpf_tracing.h> |
| |
| extern const int bpf_prog_active __ksym; |
| |
| SEC("fentry/security_inode_getattr") |
| int BPF_PROG(d_path_check_rdonly_mem, struct path *path, struct kstat *stat, |
| __u32 request_mask, unsigned int query_flags) |
| { |
| void *active; |
| __u32 cpu; |
| |
| cpu = bpf_get_smp_processor_id(); |
| active = (void *)bpf_per_cpu_ptr(&bpf_prog_active, cpu); |
| if (active) { |
| /* FAIL here! 'active' points to readonly memory. bpf helpers |
| * that update its arguments can not write into it. |
| */ |
| bpf_d_path(path, active, sizeof(int)); |
| } |
| return 0; |
| } |
| |
| char _license[] SEC("license") = "GPL"; |