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/random.h> 7 8 #include <asm/cpufeature.h> 9 #include <asm/memory.h> 10 #include <asm/sysreg.h> 11 12 #ifdef CONFIG_ARM64_PTR_AUTH 13 /* 14 * Each key is a 128-bit quantity which is split across a pair of 64-bit 15 * registers (Lo and Hi). 16 */ 17 struct ptrauth_key { 18 unsigned long lo, hi; 19 }; 20 21 /* 22 * We give each process its own keys, which are shared by all threads. The keys 23 * are inherited upon fork(), and reinitialised upon exec*(). 24 */ 25 struct ptrauth_keys_user { 26 struct ptrauth_key apia; 27 struct ptrauth_key apib; 28 struct ptrauth_key apda; 29 struct ptrauth_key apdb; 30 struct ptrauth_key apga; 31 }; 32 33 struct ptrauth_keys_kernel { 34 struct ptrauth_key apia; 35 }; 36 37 static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys) 38 { 39 if (system_supports_address_auth()) { 40 get_random_bytes(&keys->apia, sizeof(keys->apia)); 41 get_random_bytes(&keys->apib, sizeof(keys->apib)); 42 get_random_bytes(&keys->apda, sizeof(keys->apda)); 43 get_random_bytes(&keys->apdb, sizeof(keys->apdb)); 44 } 45 46 if (system_supports_generic_auth()) 47 get_random_bytes(&keys->apga, sizeof(keys->apga)); 48 } 49 50 #define __ptrauth_key_install(k, v) \ 51 do { \ 52 struct ptrauth_key __pki_v = (v); \ 53 write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \ 54 write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \ 55 } while (0) 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 __ptrauth_key_install(APIA, keys->apia); 67 } 68 69 extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg); 70 71 static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr) 72 { 73 return ptrauth_clear_pac(ptr); 74 } 75 76 #define ptrauth_thread_init_user(tsk) \ 77 ptrauth_keys_init_user(&(tsk)->thread.keys_user) 78 #define ptrauth_thread_init_kernel(tsk) \ 79 ptrauth_keys_init_kernel(&(tsk)->thread.keys_kernel) 80 #define ptrauth_thread_switch_kernel(tsk) \ 81 ptrauth_keys_switch_kernel(&(tsk)->thread.keys_kernel) 82 83 #else /* CONFIG_ARM64_PTR_AUTH */ 84 #define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL) 85 #define ptrauth_strip_insn_pac(lr) (lr) 86 #define ptrauth_thread_init_user(tsk) 87 #define ptrauth_thread_init_kernel(tsk) 88 #define ptrauth_thread_switch_kernel(tsk) 89 #endif /* CONFIG_ARM64_PTR_AUTH */ 90 91 #endif /* __ASM_POINTER_AUTH_H */ 92