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 }
31
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