1// SPDX-License-Identifier: GPL-2.0
 2
 3#include <linux/errno.h>
 4#include <linux/prctl.h>
 5#include <linux/random.h>
 6#include <linux/sched.h>
 7#include <asm/cpufeature.h>
 8#include <asm/pointer_auth.h>
 9
10int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
11{
12	struct ptrauth_keys_user *keys = &tsk->thread.keys_user;
13	unsigned long addr_key_mask = PR_PAC_APIAKEY | PR_PAC_APIBKEY |
14				      PR_PAC_APDAKEY | PR_PAC_APDBKEY;
15	unsigned long key_mask = addr_key_mask | PR_PAC_APGAKEY;
16
17	if (!system_supports_address_auth() && !system_supports_generic_auth())
18		return -EINVAL;
19
20	if (!arg) {
21		ptrauth_keys_init_user(keys);
22		return 0;
23	}
24
25	if (arg & ~key_mask)
26		return -EINVAL;
27
28	if (((arg & addr_key_mask) && !system_supports_address_auth()) ||
29	    ((arg & PR_PAC_APGAKEY) && !system_supports_generic_auth()))
30		return -EINVAL;
31
32	if (arg & PR_PAC_APIAKEY)
33		get_random_bytes(&keys->apia, sizeof(keys->apia));
34	if (arg & PR_PAC_APIBKEY)
35		get_random_bytes(&keys->apib, sizeof(keys->apib));
36	if (arg & PR_PAC_APDAKEY)
37		get_random_bytes(&keys->apda, sizeof(keys->apda));
38	if (arg & PR_PAC_APDBKEY)
39		get_random_bytes(&keys->apdb, sizeof(keys->apdb));
40	if (arg & PR_PAC_APGAKEY)
41		get_random_bytes(&keys->apga, sizeof(keys->apga));
42
43	return 0;
44}