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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;
- 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;
- preempt_disable();
- sctlr = tsk->thread.sctlr_user;
- sctlr &= ~arg_to_enxx_mask(keys);
- sctlr |= arg_to_enxx_mask(enabled);
- tsk->thread.sctlr_user = sctlr;
- if (tsk == current)
- update_sctlr_el1(sctlr);
- preempt_enable();
- 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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