1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __ASM_POINTER_AUTH_H 3 #define __ASM_POINTER_AUTH_H 4 5 #include <linux/bitops.h> 6 #include <linux/prctl.h> 7 #include <linux/random.h> 8 9 #include <asm/cpufeature.h> 10 #include <asm/memory.h> 11 #include <asm/sysreg.h> 12 13 /* 14 * The EL0/EL1 pointer bits used by a pointer authentication code. 15 * This is dependent on TBI0/TBI1 being enabled, or bits 63:56 would also apply. 16 */ 17 #define ptrauth_user_pac_mask() GENMASK_ULL(54, vabits_actual) 18 #define ptrauth_kernel_pac_mask() GENMASK_ULL(63, vabits_actual) 19 20 #define PR_PAC_ENABLED_KEYS_MASK \ 21 (PR_PAC_APIAKEY | PR_PAC_APIBKEY | PR_PAC_APDAKEY | PR_PAC_APDBKEY) 22 23 #ifdef CONFIG_ARM64_PTR_AUTH 24 /* 25 * Each key is a 128-bit quantity which is split across a pair of 64-bit 26 * registers (Lo and Hi). 27 */ 28 struct ptrauth_key { 29 unsigned long lo, hi; 30 }; 31 32 /* 33 * We give each process its own keys, which are shared by all threads. The keys 34 * are inherited upon fork(), and reinitialised upon exec*(). 35 */ 36 struct ptrauth_keys_user { 37 struct ptrauth_key apia; 38 struct ptrauth_key apib; 39 struct ptrauth_key apda; 40 struct ptrauth_key apdb; 41 struct ptrauth_key apga; 42 }; 43 44 #define __ptrauth_key_install_nosync(k, v) \ 45 do { \ 46 struct ptrauth_key __pki_v = (v); \ 47 write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \ 48 write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \ 49 } while (0) 50 51 #ifdef CONFIG_ARM64_PTR_AUTH_KERNEL 52 53 struct ptrauth_keys_kernel { 54 struct ptrauth_key apia; 55 }; 56 57 static __always_inline void ptrauth_keys_init_kernel(struct ptrauth_keys_kernel *keys) 58 { 59 if (system_supports_address_auth()) 60 get_random_bytes(&keys->apia, sizeof(keys->apia)); 61 } 62 63 static __always_inline void ptrauth_keys_switch_kernel(struct ptrauth_keys_kernel *keys) 64 { 65 if (!system_supports_address_auth()) 66 return; 67 68 __ptrauth_key_install_nosync(APIA, keys->apia); 69 isb(); 70 } 71 72 #endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */ 73 74 static inline void ptrauth_keys_install_user(struct ptrauth_keys_user *keys) 75 { 76 if (system_supports_address_auth()) { 77 __ptrauth_key_install_nosync(APIB, keys->apib); 78 __ptrauth_key_install_nosync(APDA, keys->apda); 79 __ptrauth_key_install_nosync(APDB, keys->apdb); 80 } 81 82 if (system_supports_generic_auth()) 83 __ptrauth_key_install_nosync(APGA, keys->apga); 84 } 85 86 static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys) 87 { 88 if (system_supports_address_auth()) { 89 get_random_bytes(&keys->apia, sizeof(keys->apia)); 90 get_random_bytes(&keys->apib, sizeof(keys->apib)); 91 get_random_bytes(&keys->apda, sizeof(keys->apda)); 92 get_random_bytes(&keys->apdb, sizeof(keys->apdb)); 93 } 94 95 if (system_supports_generic_auth()) 96 get_random_bytes(&keys->apga, sizeof(keys->apga)); 97 98 ptrauth_keys_install_user(keys); 99 } 100 101 extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg); 102 103 extern int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys, 104 unsigned long enabled); 105 extern int ptrauth_get_enabled_keys(struct task_struct *tsk); 106 107 static __always_inline void ptrauth_enable(void) 108 { 109 if (!system_supports_address_auth()) 110 return; 111 sysreg_clear_set(sctlr_el1, 0, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | 112 SCTLR_ELx_ENDA | SCTLR_ELx_ENDB)); 113 isb(); 114 } 115 116 #define ptrauth_suspend_exit() \ 117 ptrauth_keys_install_user(¤t->thread.keys_user) 118 119 #define ptrauth_thread_init_user() \ 120 do { \ 121 ptrauth_keys_init_user(¤t->thread.keys_user); \ 122 \ 123 /* enable all keys */ \ 124 if (system_supports_address_auth()) \ 125 ptrauth_set_enabled_keys(current, \ 126 PR_PAC_ENABLED_KEYS_MASK, \ 127 PR_PAC_ENABLED_KEYS_MASK); \ 128 } while (0) 129 130 #define ptrauth_thread_switch_user(tsk) \ 131 ptrauth_keys_install_user(&(tsk)->thread.keys_user) 132 133 #else /* CONFIG_ARM64_PTR_AUTH */ 134 #define ptrauth_enable() 135 #define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL) 136 #define ptrauth_set_enabled_keys(tsk, keys, enabled) (-EINVAL) 137 #define ptrauth_get_enabled_keys(tsk) (-EINVAL) 138 #define ptrauth_suspend_exit() 139 #define ptrauth_thread_init_user() 140 #define ptrauth_thread_switch_user(tsk) 141 #endif /* CONFIG_ARM64_PTR_AUTH */ 142 143 #ifdef CONFIG_ARM64_PTR_AUTH_KERNEL 144 #define ptrauth_thread_init_kernel(tsk) \ 145 ptrauth_keys_init_kernel(&(tsk)->thread.keys_kernel) 146 #define ptrauth_thread_switch_kernel(tsk) \ 147 ptrauth_keys_switch_kernel(&(tsk)->thread.keys_kernel) 148 #else 149 #define ptrauth_thread_init_kernel(tsk) 150 #define ptrauth_thread_switch_kernel(tsk) 151 #endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */ 152 153 #endif /* __ASM_POINTER_AUTH_H */ 154