// SPDX-License-Identifier: GPL-2.0
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#include <linux/compat.h>
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#include <linux/errno.h>
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#include <linux/prctl.h>
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#include <linux/random.h>
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#include <linux/sched.h>
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#include <asm/cpufeature.h>
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#include <asm/pointer_auth.h>
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int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
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{
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struct ptrauth_keys_user *keys = &tsk->thread.keys_user;
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unsigned long addr_key_mask = PR_PAC_APIAKEY | PR_PAC_APIBKEY |
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PR_PAC_APDAKEY | PR_PAC_APDBKEY;
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unsigned long key_mask = addr_key_mask | PR_PAC_APGAKEY;
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if (!system_supports_address_auth() && !system_supports_generic_auth())
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return -EINVAL;
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if (is_compat_thread(task_thread_info(tsk)))
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return -EINVAL;
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if (!arg) {
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ptrauth_keys_init_user(keys);
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return 0;
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}
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if (arg & ~key_mask)
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return -EINVAL;
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if (((arg & addr_key_mask) && !system_supports_address_auth()) ||
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((arg & PR_PAC_APGAKEY) && !system_supports_generic_auth()))
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return -EINVAL;
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if (arg & PR_PAC_APIAKEY)
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get_random_bytes(&keys->apia, sizeof(keys->apia));
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if (arg & PR_PAC_APIBKEY)
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get_random_bytes(&keys->apib, sizeof(keys->apib));
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if (arg & PR_PAC_APDAKEY)
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get_random_bytes(&keys->apda, sizeof(keys->apda));
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if (arg & PR_PAC_APDBKEY)
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get_random_bytes(&keys->apdb, sizeof(keys->apdb));
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if (arg & PR_PAC_APGAKEY)
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get_random_bytes(&keys->apga, sizeof(keys->apga));
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ptrauth_keys_install_user(keys);
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return 0;
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}
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static u64 arg_to_enxx_mask(unsigned long arg)
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{
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u64 sctlr_enxx_mask = 0;
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WARN_ON(arg & ~PR_PAC_ENABLED_KEYS_MASK);
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if (arg & PR_PAC_APIAKEY)
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sctlr_enxx_mask |= SCTLR_ELx_ENIA;
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if (arg & PR_PAC_APIBKEY)
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sctlr_enxx_mask |= SCTLR_ELx_ENIB;
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if (arg & PR_PAC_APDAKEY)
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sctlr_enxx_mask |= SCTLR_ELx_ENDA;
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if (arg & PR_PAC_APDBKEY)
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sctlr_enxx_mask |= SCTLR_ELx_ENDB;
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return sctlr_enxx_mask;
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}
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int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
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unsigned long enabled)
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{
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u64 sctlr;
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if (!system_supports_address_auth())
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return -EINVAL;
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if (is_compat_thread(task_thread_info(tsk)))
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return -EINVAL;
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if ((keys & ~PR_PAC_ENABLED_KEYS_MASK) || (enabled & ~keys))
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return -EINVAL;
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preempt_disable();
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sctlr = tsk->thread.sctlr_user;
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sctlr &= ~arg_to_enxx_mask(keys);
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sctlr |= arg_to_enxx_mask(enabled);
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tsk->thread.sctlr_user = sctlr;
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if (tsk == current)
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update_sctlr_el1(sctlr);
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preempt_enable();
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return 0;
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}
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int ptrauth_get_enabled_keys(struct task_struct *tsk)
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{
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int retval = 0;
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if (!system_supports_address_auth())
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return -EINVAL;
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if (is_compat_thread(task_thread_info(tsk)))
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return -EINVAL;
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if (tsk->thread.sctlr_user & SCTLR_ELx_ENIA)
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retval |= PR_PAC_APIAKEY;
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if (tsk->thread.sctlr_user & SCTLR_ELx_ENIB)
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retval |= PR_PAC_APIBKEY;
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if (tsk->thread.sctlr_user & SCTLR_ELx_ENDA)
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retval |= PR_PAC_APDAKEY;
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if (tsk->thread.sctlr_user & SCTLR_ELx_ENDB)
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retval |= PR_PAC_APDBKEY;
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return retval;
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}
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