cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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pointer_auth.c (2860B)

      1// SPDX-License-Identifier: GPL-2.0
      2
      3#include <linux/compat.h>
      4#include <linux/errno.h>
      5#include <linux/prctl.h>
      6#include <linux/random.h>
      7#include <linux/sched.h>
      8#include <asm/cpufeature.h>
      9#include <asm/pointer_auth.h>
     10
     11int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
     12{
     13	struct ptrauth_keys_user *keys = &tsk->thread.keys_user;
     14	unsigned long addr_key_mask = PR_PAC_APIAKEY | PR_PAC_APIBKEY |
     15				      PR_PAC_APDAKEY | PR_PAC_APDBKEY;
     16	unsigned long key_mask = addr_key_mask | PR_PAC_APGAKEY;
     17
     18	if (!system_supports_address_auth() && !system_supports_generic_auth())
     19		return -EINVAL;
     20
     21	if (is_compat_thread(task_thread_info(tsk)))
     22		return -EINVAL;
     23
     24	if (!arg) {
     25		ptrauth_keys_init_user(keys);
     26		return 0;
     27	}
     28
     29	if (arg & ~key_mask)
     30		return -EINVAL;
     31
     32	if (((arg & addr_key_mask) && !system_supports_address_auth()) ||
     33	    ((arg & PR_PAC_APGAKEY) && !system_supports_generic_auth()))
     34		return -EINVAL;
     35
     36	if (arg & PR_PAC_APIAKEY)
     37		get_random_bytes(&keys->apia, sizeof(keys->apia));
     38	if (arg & PR_PAC_APIBKEY)
     39		get_random_bytes(&keys->apib, sizeof(keys->apib));
     40	if (arg & PR_PAC_APDAKEY)
     41		get_random_bytes(&keys->apda, sizeof(keys->apda));
     42	if (arg & PR_PAC_APDBKEY)
     43		get_random_bytes(&keys->apdb, sizeof(keys->apdb));
     44	if (arg & PR_PAC_APGAKEY)
     45		get_random_bytes(&keys->apga, sizeof(keys->apga));
     46	ptrauth_keys_install_user(keys);
     47
     48	return 0;
     49}
     50
     51static u64 arg_to_enxx_mask(unsigned long arg)
     52{
     53	u64 sctlr_enxx_mask = 0;
     54
     55	WARN_ON(arg & ~PR_PAC_ENABLED_KEYS_MASK);
     56	if (arg & PR_PAC_APIAKEY)
     57		sctlr_enxx_mask |= SCTLR_ELx_ENIA;
     58	if (arg & PR_PAC_APIBKEY)
     59		sctlr_enxx_mask |= SCTLR_ELx_ENIB;
     60	if (arg & PR_PAC_APDAKEY)
     61		sctlr_enxx_mask |= SCTLR_ELx_ENDA;
     62	if (arg & PR_PAC_APDBKEY)
     63		sctlr_enxx_mask |= SCTLR_ELx_ENDB;
     64	return sctlr_enxx_mask;
     65}
     66
     67int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
     68			     unsigned long enabled)
     69{
     70	u64 sctlr;
     71
     72	if (!system_supports_address_auth())
     73		return -EINVAL;
     74
     75	if (is_compat_thread(task_thread_info(tsk)))
     76		return -EINVAL;
     77
     78	if ((keys & ~PR_PAC_ENABLED_KEYS_MASK) || (enabled & ~keys))
     79		return -EINVAL;
     80
     81	preempt_disable();
     82	sctlr = tsk->thread.sctlr_user;
     83	sctlr &= ~arg_to_enxx_mask(keys);
     84	sctlr |= arg_to_enxx_mask(enabled);
     85	tsk->thread.sctlr_user = sctlr;
     86	if (tsk == current)
     87		update_sctlr_el1(sctlr);
     88	preempt_enable();
     89
     90	return 0;
     91}
     92
     93int ptrauth_get_enabled_keys(struct task_struct *tsk)
     94{
     95	int retval = 0;
     96
     97	if (!system_supports_address_auth())
     98		return -EINVAL;
     99
    100	if (is_compat_thread(task_thread_info(tsk)))
    101		return -EINVAL;
    102
    103	if (tsk->thread.sctlr_user & SCTLR_ELx_ENIA)
    104		retval |= PR_PAC_APIAKEY;
    105	if (tsk->thread.sctlr_user & SCTLR_ELx_ENIB)
    106		retval |= PR_PAC_APIBKEY;
    107	if (tsk->thread.sctlr_user & SCTLR_ELx_ENDA)
    108		retval |= PR_PAC_APDAKEY;
    109	if (tsk->thread.sctlr_user & SCTLR_ELx_ENDB)
    110		retval |= PR_PAC_APDBKEY;
    111
    112	return retval;
    113}