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 #ifdef CONFIG_ARM64_PTR_AUTH
14 /*
15 * Each key is a 128-bit quantity which is split across a pair of 64-bit
16 * registers (Lo and Hi).
17 */
18 struct ptrauth_key {
19 unsigned long lo, hi;
20 };
21
22 /*
23 * We give each process its own keys, which are shared by all threads. The keys
24 * are inherited upon fork(), and reinitialised upon exec*().
25 */
26 struct ptrauth_keys_user {
27 struct ptrauth_key apia;
28 struct ptrauth_key apib;
29 struct ptrauth_key apda;
30 struct ptrauth_key apdb;
31 struct ptrauth_key apga;
32 };
33
34 struct ptrauth_keys_kernel {
35 struct ptrauth_key apia;
36 };
37
38 #define __ptrauth_key_install_nosync(k, v) \
39 do { \
40 struct ptrauth_key __pki_v = (v); \
41 write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \
42 write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \
43 } while (0)
44
ptrauth_keys_install_user(struct ptrauth_keys_user * keys)45 static inline void ptrauth_keys_install_user(struct ptrauth_keys_user *keys)
46 {
47 if (system_supports_address_auth()) {
48 __ptrauth_key_install_nosync(APIB, keys->apib);
49 __ptrauth_key_install_nosync(APDA, keys->apda);
50 __ptrauth_key_install_nosync(APDB, keys->apdb);
51 }
52
53 if (system_supports_generic_auth())
54 __ptrauth_key_install_nosync(APGA, keys->apga);
55 }
56
ptrauth_keys_init_user(struct ptrauth_keys_user * keys)57 static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys)
58 {
59 if (system_supports_address_auth()) {
60 get_random_bytes(&keys->apia, sizeof(keys->apia));
61 get_random_bytes(&keys->apib, sizeof(keys->apib));
62 get_random_bytes(&keys->apda, sizeof(keys->apda));
63 get_random_bytes(&keys->apdb, sizeof(keys->apdb));
64 }
65
66 if (system_supports_generic_auth())
67 get_random_bytes(&keys->apga, sizeof(keys->apga));
68
69 ptrauth_keys_install_user(keys);
70 }
71
ptrauth_keys_init_kernel(struct ptrauth_keys_kernel * keys)72 static __always_inline void ptrauth_keys_init_kernel(struct ptrauth_keys_kernel *keys)
73 {
74 if (system_supports_address_auth())
75 get_random_bytes(&keys->apia, sizeof(keys->apia));
76 }
77
ptrauth_keys_switch_kernel(struct ptrauth_keys_kernel * keys)78 static __always_inline void ptrauth_keys_switch_kernel(struct ptrauth_keys_kernel *keys)
79 {
80 if (!system_supports_address_auth())
81 return;
82
83 __ptrauth_key_install_nosync(APIA, keys->apia);
84 isb();
85 }
86
87 extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg);
88
89 extern int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
90 unsigned long enabled);
91 extern int ptrauth_get_enabled_keys(struct task_struct *tsk);
92
ptrauth_strip_insn_pac(unsigned long ptr)93 static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
94 {
95 return ptrauth_clear_pac(ptr);
96 }
97
ptrauth_enable(void)98 static __always_inline void ptrauth_enable(void)
99 {
100 if (!system_supports_address_auth())
101 return;
102 sysreg_clear_set(sctlr_el1, 0, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB |
103 SCTLR_ELx_ENDA | SCTLR_ELx_ENDB));
104 isb();
105 }
106
107 #define ptrauth_suspend_exit() \
108 ptrauth_keys_install_user(¤t->thread.keys_user)
109
110 #define ptrauth_thread_init_user() \
111 do { \
112 ptrauth_keys_init_user(¤t->thread.keys_user); \
113 \
114 /* enable all keys */ \
115 if (system_supports_address_auth()) \
116 set_task_sctlr_el1(current->thread.sctlr_user | \
117 SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \
118 SCTLR_ELx_ENDA | SCTLR_ELx_ENDB); \
119 } while (0)
120
121 #define ptrauth_thread_switch_user(tsk) \
122 ptrauth_keys_install_user(&(tsk)->thread.keys_user)
123
124 #define ptrauth_thread_init_kernel(tsk) \
125 ptrauth_keys_init_kernel(&(tsk)->thread.keys_kernel)
126 #define ptrauth_thread_switch_kernel(tsk) \
127 ptrauth_keys_switch_kernel(&(tsk)->thread.keys_kernel)
128
129 #else /* CONFIG_ARM64_PTR_AUTH */
130 #define ptrauth_enable()
131 #define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL)
132 #define ptrauth_set_enabled_keys(tsk, keys, enabled) (-EINVAL)
133 #define ptrauth_get_enabled_keys(tsk) (-EINVAL)
134 #define ptrauth_strip_insn_pac(lr) (lr)
135 #define ptrauth_suspend_exit()
136 #define ptrauth_thread_init_user()
137 #define ptrauth_thread_init_kernel(tsk)
138 #define ptrauth_thread_switch_user(tsk)
139 #define ptrauth_thread_switch_kernel(tsk)
140 #endif /* CONFIG_ARM64_PTR_AUTH */
141
142 #define PR_PAC_ENABLED_KEYS_MASK \
143 (PR_PAC_APIAKEY | PR_PAC_APIBKEY | PR_PAC_APDAKEY | PR_PAC_APDBKEY)
144
145 #endif /* __ASM_POINTER_AUTH_H */
146