1// SPDX-License-Identifier: GPL-2.0 2#include <linux/bpf.h> 3#include <bpf/bpf_helpers.h> 4#include <bpf/bpf_tracing.h> 5#include <errno.h> 6#include <linux/capability.h> 7 8typedef struct { unsigned long long val; } kernel_cap_t; 9 10struct cred { 11 kernel_cap_t cap_effective; 12} __attribute__((preserve_access_index)); 13 14char _license[] SEC("license") = "GPL"; 15 16SEC("lsm.s/userns_create") 17int BPF_PROG(test_userns_create, const struct cred *cred, int ret) 18{ 19 kernel_cap_t caps = cred->cap_effective; 20 __u64 cap_mask = 1ULL << CAP_SYS_ADMIN; 21 22 if (ret) 23 return 0; 24 25 ret = -EPERM; 26 if (caps.val & cap_mask) 27 return 0; 28 29 return -EPERM; 30} 31