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