tools/testing/selftests/bpf/progs/test_deny_namespace.c

   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
   8 typedef struct { unsigned long long val; } kernel_cap_t;
   9
  10 struct cred {
  11         kernel_cap_t cap_effective;
  12 } __attribute__((preserve_access_index));
  13
  14 char _license[] SEC("license") = "GPL";
  15
  16 SEC("lsm.s/userns_create")
  17 int 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 }