bpf: Move BPF sysctls from kernel/sysctl.c to BPF core
We're moving sysctls out of kernel/sysctl.c as it is a mess. We
already moved all filesystem sysctls out. And with time the goal
is to move all sysctls out to their own subsystem/actual user.
kernel/sysctl.c has grown to an insane mess and its easy to run
into conflicts with it. The effort to move them out into various
subsystems is part of this.
Signed-off-by: Yan Zhu <zhuyan34@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/bpf/20220407070759.29506-1-zhuyan34@huawei.com
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index cdaa115..e9621cf 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4908,3 +4908,90 @@ const struct bpf_verifier_ops bpf_syscall_verifier_ops = {
const struct bpf_prog_ops bpf_syscall_prog_ops = {
.test_run = bpf_prog_test_run_syscall,
};
+
+#ifdef CONFIG_SYSCTL
+static int bpf_stats_handler(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ struct static_key *key = (struct static_key *)table->data;
+ static int saved_val;
+ int val, ret;
+ struct ctl_table tmp = {
+ .data = &val,
+ .maxlen = sizeof(val),
+ .mode = table->mode,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ };
+
+ if (write && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ mutex_lock(&bpf_stats_enabled_mutex);
+ val = saved_val;
+ ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+ if (write && !ret && val != saved_val) {
+ if (val)
+ static_key_slow_inc(key);
+ else
+ static_key_slow_dec(key);
+ saved_val = val;
+ }
+ mutex_unlock(&bpf_stats_enabled_mutex);
+ return ret;
+}
+
+void __weak unpriv_ebpf_notify(int new_state)
+{
+}
+
+static int bpf_unpriv_handler(struct ctl_table *table, int write,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ int ret, unpriv_enable = *(int *)table->data;
+ bool locked_state = unpriv_enable == 1;
+ struct ctl_table tmp = *table;
+
+ if (write && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ tmp.data = &unpriv_enable;
+ ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+ if (write && !ret) {
+ if (locked_state && unpriv_enable != 1)
+ return -EPERM;
+ *(int *)table->data = unpriv_enable;
+ }
+
+ unpriv_ebpf_notify(unpriv_enable);
+
+ return ret;
+}
+
+static struct ctl_table bpf_syscall_table[] = {
+ {
+ .procname = "unprivileged_bpf_disabled",
+ .data = &sysctl_unprivileged_bpf_disabled,
+ .maxlen = sizeof(sysctl_unprivileged_bpf_disabled),
+ .mode = 0644,
+ .proc_handler = bpf_unpriv_handler,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_TWO,
+ },
+ {
+ .procname = "bpf_stats_enabled",
+ .data = &bpf_stats_enabled_key.key,
+ .maxlen = sizeof(bpf_stats_enabled_key),
+ .mode = 0644,
+ .proc_handler = bpf_stats_handler,
+ },
+ { }
+};
+
+static int __init bpf_syscall_sysctl_init(void)
+{
+ register_sysctl_init("kernel", bpf_syscall_table);
+ return 0;
+}
+late_initcall(bpf_syscall_sysctl_init);
+#endif /* CONFIG_SYSCTL */
