34 lines
763 B
C
34 lines
763 B
C
|
// SPDX-License-Identifier: GPL-2.0
|
||
|
|
#include <linux/bpf.h>
|
||
|
|
#include <bpf/bpf_helpers.h>
|
||
|
|
#include <bpf/bpf_tracing.h>
|
||
|
|
#include <errno.h>
|
||
|
|
#include <linux/capability.h>
|
||
|
|
|
||
|
|
struct kernel_cap_struct {
|
||
|
|
__u32 cap[_LINUX_CAPABILITY_U32S_3];
|
||
|
|
} __attribute__((preserve_access_index));
|
||
|
|
|
||
|
|
struct cred {
|
||
|
|
struct kernel_cap_struct cap_effective;
|
||
|
|
} __attribute__((preserve_access_index));
|
||
|
|
|
||
|
|
char _license[] SEC("license") = "GPL";
|
||
|
|
|
||
|
|
SEC("lsm.s/userns_create")
|
||
|
|
int BPF_PROG(test_userns_create, const struct cred *cred, int ret)
|
||
|
|
{
|
||
|
|
struct kernel_cap_struct caps = cred->cap_effective;
|
||
|
|
int cap_index = CAP_TO_INDEX(CAP_SYS_ADMIN);
|
||
|
|
__u32 cap_mask = CAP_TO_MASK(CAP_SYS_ADMIN);
|
||
|
|
|
||
|
|
if (ret)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
ret = -EPERM;
|
||
|
|
if (caps.cap[cap_index] & cap_mask)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
return -EPERM;
|
||
|
|
}
|