1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
3 
4 #include "vmlinux.h"
5 #include <bpf/bpf_helpers.h>
6 
7 char _license[] SEC("license") = "GPL";
8 
9 /* rodata section */
10 const volatile pid_t pid;
11 const volatile size_t bss_array_len;
12 const volatile size_t data_array_len;
13 
14 /* bss section */
15 int sum = 0;
16 int array[1];
17 
18 /* custom data secton */
19 int my_array[1] SEC(".data.custom");
20 
21 /* custom data section which should NOT be resizable,
22  * since it contains a single var which is not an array
23  */
24 int my_int SEC(".data.non_array");
25 
26 /* custom data section which should NOT be resizable,
27  * since its last var is not an array
28  */
29 int my_array_first[1] SEC(".data.array_not_last");
30 int my_int_last SEC(".data.array_not_last");
31 
32 int percpu_arr[1] SEC(".data.percpu_arr");
33 
34 SEC("tp/syscalls/sys_enter_getpid")
bss_array_sum(void * ctx)35 int bss_array_sum(void *ctx)
36 {
37 	if (pid != (bpf_get_current_pid_tgid() >> 32))
38 		return 0;
39 
40 	/* this will be zero, we just rely on verifier not rejecting this */
41 	sum = percpu_arr[bpf_get_smp_processor_id()];
42 
43 	for (size_t i = 0; i < bss_array_len; ++i)
44 		sum += array[i];
45 
46 	return 0;
47 }
48 
49 SEC("tp/syscalls/sys_enter_getuid")
data_array_sum(void * ctx)50 int data_array_sum(void *ctx)
51 {
52 	if (pid != (bpf_get_current_pid_tgid() >> 32))
53 		return 0;
54 
55 	/* this will be zero, we just rely on verifier not rejecting this */
56 	sum = percpu_arr[bpf_get_smp_processor_id()];
57 
58 	for (size_t i = 0; i < data_array_len; ++i)
59 		sum += my_array[i];
60 
61 	return 0;
62 }
63