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// SPDX-License-Identifier: GPL-2.0
#include <linux/compat.h>
#include <linux/errno.h>
#include <linux/prctl.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <asm/cpufeature.h>
#include <asm/pointer_auth.h>
int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
{
struct ptrauth_keys_user *keys = &tsk->thread.keys_user;
unsigned long addr_key_mask = PR_PAC_APIAKEY | PR_PAC_APIBKEY |
PR_PAC_APDAKEY | PR_PAC_APDBKEY;
unsigned long key_mask = addr_key_mask | PR_PAC_APGAKEY;
if (!system_supports_address_auth() && !system_supports_generic_auth())
return -EINVAL;
if (is_compat_thread(task_thread_info(tsk)))
return -EINVAL;
if (!arg) {
ptrauth_keys_init_user(keys);
return 0;
}
if (arg & ~key_mask)
return -EINVAL;
if (((arg & addr_key_mask) && !system_supports_address_auth()) ||
((arg & PR_PAC_APGAKEY) && !system_supports_generic_auth()))
return -EINVAL;
if (arg & PR_PAC_APIAKEY)
get_random_bytes(&keys->apia, sizeof(keys->apia));
if (arg & PR_PAC_APIBKEY)
get_random_bytes(&keys->apib, sizeof(keys->apib));
if (arg & PR_PAC_APDAKEY)
get_random_bytes(&keys->apda, sizeof(keys->apda));
if (arg & PR_PAC_APDBKEY)
get_random_bytes(&keys->apdb, sizeof(keys->apdb));
if (arg & PR_PAC_APGAKEY)
get_random_bytes(&keys->apga, sizeof(keys->apga));
ptrauth_keys_install_user(keys);
return 0;
}
static u64 arg_to_enxx_mask(unsigned long arg)
{
u64 sctlr_enxx_mask = 0;
WARN_ON(arg & ~PR_PAC_ENABLED_KEYS_MASK);
if (arg & PR_PAC_APIAKEY)
sctlr_enxx_mask |= SCTLR_ELx_ENIA;
if (arg & PR_PAC_APIBKEY)
sctlr_enxx_mask |= SCTLR_ELx_ENIB;
if (arg & PR_PAC_APDAKEY)
sctlr_enxx_mask |= SCTLR_ELx_ENDA;
if (arg & PR_PAC_APDBKEY)
sctlr_enxx_mask |= SCTLR_ELx_ENDB;
return sctlr_enxx_mask;
}
int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
unsigned long enabled)
{
u64 sctlr = tsk->thread.sctlr_user;
if (!system_supports_address_auth())
return -EINVAL;
if (is_compat_thread(task_thread_info(tsk)))
return -EINVAL;
if ((keys & ~PR_PAC_ENABLED_KEYS_MASK) || (enabled & ~keys))
return -EINVAL;
sctlr &= ~arg_to_enxx_mask(keys);
sctlr |= arg_to_enxx_mask(enabled);
if (tsk == current)
set_task_sctlr_el1(sctlr);
else
tsk->thread.sctlr_user = sctlr;
return 0;
}
int ptrauth_get_enabled_keys(struct task_struct *tsk)
{
int retval = 0;
if (!system_supports_address_auth())
return -EINVAL;
if (is_compat_thread(task_thread_info(tsk)))
return -EINVAL;
if (tsk->thread.sctlr_user & SCTLR_ELx_ENIA)
retval |= PR_PAC_APIAKEY;
if (tsk->thread.sctlr_user & SCTLR_ELx_ENIB)
retval |= PR_PAC_APIBKEY;
if (tsk->thread.sctlr_user & SCTLR_ELx_ENDA)
retval |= PR_PAC_APDAKEY;
if (tsk->thread.sctlr_user & SCTLR_ELx_ENDB)
retval |= PR_PAC_APDBKEY;
return retval;
}
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