154 lines
4.7 KiB
C
154 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_POINTER_AUTH_H
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#define __ASM_POINTER_AUTH_H
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#include <linux/bitops.h>
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#include <linux/prctl.h>
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#include <linux/random.h>
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#include <asm/cpufeature.h>
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#include <asm/memory.h>
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#include <asm/sysreg.h>
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/*
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* The EL0/EL1 pointer bits used by a pointer authentication code.
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* This is dependent on TBI0/TBI1 being enabled, or bits 63:56 would also apply.
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*/
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#define ptrauth_user_pac_mask() GENMASK_ULL(54, vabits_actual)
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#define ptrauth_kernel_pac_mask() GENMASK_ULL(63, vabits_actual)
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#define PR_PAC_ENABLED_KEYS_MASK \
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(PR_PAC_APIAKEY | PR_PAC_APIBKEY | PR_PAC_APDAKEY | PR_PAC_APDBKEY)
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#ifdef CONFIG_ARM64_PTR_AUTH
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/*
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* Each key is a 128-bit quantity which is split across a pair of 64-bit
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* registers (Lo and Hi).
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*/
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struct ptrauth_key {
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unsigned long lo, hi;
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};
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/*
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* We give each process its own keys, which are shared by all threads. The keys
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* are inherited upon fork(), and reinitialised upon exec*().
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*/
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struct ptrauth_keys_user {
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struct ptrauth_key apia;
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struct ptrauth_key apib;
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struct ptrauth_key apda;
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struct ptrauth_key apdb;
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struct ptrauth_key apga;
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};
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#define __ptrauth_key_install_nosync(k, v) \
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do { \
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struct ptrauth_key __pki_v = (v); \
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write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \
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write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \
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} while (0)
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#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
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struct ptrauth_keys_kernel {
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struct ptrauth_key apia;
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};
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static __always_inline void ptrauth_keys_init_kernel(struct ptrauth_keys_kernel *keys)
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{
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if (system_supports_address_auth())
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get_random_bytes(&keys->apia, sizeof(keys->apia));
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}
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static __always_inline void ptrauth_keys_switch_kernel(struct ptrauth_keys_kernel *keys)
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{
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if (!system_supports_address_auth())
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return;
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__ptrauth_key_install_nosync(APIA, keys->apia);
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isb();
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}
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#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */
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static inline void ptrauth_keys_install_user(struct ptrauth_keys_user *keys)
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{
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if (system_supports_address_auth()) {
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__ptrauth_key_install_nosync(APIB, keys->apib);
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__ptrauth_key_install_nosync(APDA, keys->apda);
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__ptrauth_key_install_nosync(APDB, keys->apdb);
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}
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if (system_supports_generic_auth())
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__ptrauth_key_install_nosync(APGA, keys->apga);
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}
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static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys)
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{
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if (system_supports_address_auth()) {
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get_random_bytes(&keys->apia, sizeof(keys->apia));
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get_random_bytes(&keys->apib, sizeof(keys->apib));
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get_random_bytes(&keys->apda, sizeof(keys->apda));
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get_random_bytes(&keys->apdb, sizeof(keys->apdb));
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}
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if (system_supports_generic_auth())
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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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}
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extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg);
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extern int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
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unsigned long enabled);
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extern int ptrauth_get_enabled_keys(struct task_struct *tsk);
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static __always_inline void ptrauth_enable(void)
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{
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if (!system_supports_address_auth())
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return;
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sysreg_clear_set(sctlr_el1, 0, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB |
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SCTLR_ELx_ENDA | SCTLR_ELx_ENDB));
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isb();
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}
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#define ptrauth_suspend_exit() \
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ptrauth_keys_install_user(¤t->thread.keys_user)
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#define ptrauth_thread_init_user() \
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do { \
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ptrauth_keys_init_user(¤t->thread.keys_user); \
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\
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/* enable all keys */ \
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if (system_supports_address_auth()) \
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ptrauth_set_enabled_keys(current, \
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PR_PAC_ENABLED_KEYS_MASK, \
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PR_PAC_ENABLED_KEYS_MASK); \
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} while (0)
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#define ptrauth_thread_switch_user(tsk) \
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ptrauth_keys_install_user(&(tsk)->thread.keys_user)
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#else /* CONFIG_ARM64_PTR_AUTH */
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#define ptrauth_enable()
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#define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL)
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#define ptrauth_set_enabled_keys(tsk, keys, enabled) (-EINVAL)
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#define ptrauth_get_enabled_keys(tsk) (-EINVAL)
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#define ptrauth_suspend_exit()
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#define ptrauth_thread_init_user()
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#define ptrauth_thread_switch_user(tsk)
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#endif /* CONFIG_ARM64_PTR_AUTH */
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#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
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#define ptrauth_thread_init_kernel(tsk) \
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ptrauth_keys_init_kernel(&(tsk)->thread.keys_kernel)
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#define ptrauth_thread_switch_kernel(tsk) \
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ptrauth_keys_switch_kernel(&(tsk)->thread.keys_kernel)
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#else
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#define ptrauth_thread_init_kernel(tsk)
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#define ptrauth_thread_switch_kernel(tsk)
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#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */
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#endif /* __ASM_POINTER_AUTH_H */
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