1 /* Copyright (c) 2017 Facebook
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
9 #include <linux/version.h>
10 #include <bpf/bpf_helpers.h>
13 int bpf_prog1(struct bpf_cgroup_dev_ctx *ctx)
15 short type = ctx->access_type & 0xFFFF;
17 short access = ctx->access_type >> 16;
18 char fmt[] = " %d:%d \n";
21 case BPF_DEVCG_DEV_BLOCK:
24 case BPF_DEVCG_DEV_CHAR:
32 if (access & BPF_DEVCG_ACC_READ)
35 if (access & BPF_DEVCG_ACC_WRITE)
38 if (access & BPF_DEVCG_ACC_MKNOD)
41 bpf_trace_printk(fmt, sizeof(fmt), ctx->major, ctx->minor);
44 /* Allow access to /dev/null and /dev/urandom.
45 * Forbid everything else.
47 if (ctx->major != 1 || type != BPF_DEVCG_DEV_CHAR)
51 case 3: /* 1:3 /dev/null */
52 case 9: /* 1:9 /dev/urandom */
59 char _license[] SEC("license") = "GPL";