Linux kernel mirror (for testing)
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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 */
18struct 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 */
26struct 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#define __ptrauth_key_install_nosync(k, v) \
35do { \
36 struct ptrauth_key __pki_v = (v); \
37 write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \
38 write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \
39} while (0)
40
41#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
42
43struct ptrauth_keys_kernel {
44 struct ptrauth_key apia;
45};
46
47static __always_inline void ptrauth_keys_init_kernel(struct ptrauth_keys_kernel *keys)
48{
49 if (system_supports_address_auth())
50 get_random_bytes(&keys->apia, sizeof(keys->apia));
51}
52
53static __always_inline void ptrauth_keys_switch_kernel(struct ptrauth_keys_kernel *keys)
54{
55 if (!system_supports_address_auth())
56 return;
57
58 __ptrauth_key_install_nosync(APIA, keys->apia);
59 isb();
60}
61
62#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */
63
64static inline void ptrauth_keys_install_user(struct ptrauth_keys_user *keys)
65{
66 if (system_supports_address_auth()) {
67 __ptrauth_key_install_nosync(APIB, keys->apib);
68 __ptrauth_key_install_nosync(APDA, keys->apda);
69 __ptrauth_key_install_nosync(APDB, keys->apdb);
70 }
71
72 if (system_supports_generic_auth())
73 __ptrauth_key_install_nosync(APGA, keys->apga);
74}
75
76static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys)
77{
78 if (system_supports_address_auth()) {
79 get_random_bytes(&keys->apia, sizeof(keys->apia));
80 get_random_bytes(&keys->apib, sizeof(keys->apib));
81 get_random_bytes(&keys->apda, sizeof(keys->apda));
82 get_random_bytes(&keys->apdb, sizeof(keys->apdb));
83 }
84
85 if (system_supports_generic_auth())
86 get_random_bytes(&keys->apga, sizeof(keys->apga));
87
88 ptrauth_keys_install_user(keys);
89}
90
91extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg);
92
93extern int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
94 unsigned long enabled);
95extern int ptrauth_get_enabled_keys(struct task_struct *tsk);
96
97static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
98{
99 return ptrauth_clear_pac(ptr);
100}
101
102static __always_inline void ptrauth_enable(void)
103{
104 if (!system_supports_address_auth())
105 return;
106 sysreg_clear_set(sctlr_el1, 0, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB |
107 SCTLR_ELx_ENDA | SCTLR_ELx_ENDB));
108 isb();
109}
110
111#define ptrauth_suspend_exit() \
112 ptrauth_keys_install_user(¤t->thread.keys_user)
113
114#define ptrauth_thread_init_user() \
115 do { \
116 ptrauth_keys_init_user(¤t->thread.keys_user); \
117 \
118 /* enable all keys */ \
119 if (system_supports_address_auth()) \
120 set_task_sctlr_el1(current->thread.sctlr_user | \
121 SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \
122 SCTLR_ELx_ENDA | SCTLR_ELx_ENDB); \
123 } while (0)
124
125#define ptrauth_thread_switch_user(tsk) \
126 ptrauth_keys_install_user(&(tsk)->thread.keys_user)
127
128#else /* CONFIG_ARM64_PTR_AUTH */
129#define ptrauth_enable()
130#define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL)
131#define ptrauth_set_enabled_keys(tsk, keys, enabled) (-EINVAL)
132#define ptrauth_get_enabled_keys(tsk) (-EINVAL)
133#define ptrauth_strip_insn_pac(lr) (lr)
134#define ptrauth_suspend_exit()
135#define ptrauth_thread_init_user()
136#define ptrauth_thread_switch_user(tsk)
137#endif /* CONFIG_ARM64_PTR_AUTH */
138
139#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
140#define ptrauth_thread_init_kernel(tsk) \
141 ptrauth_keys_init_kernel(&(tsk)->thread.keys_kernel)
142#define ptrauth_thread_switch_kernel(tsk) \
143 ptrauth_keys_switch_kernel(&(tsk)->thread.keys_kernel)
144#else
145#define ptrauth_thread_init_kernel(tsk)
146#define ptrauth_thread_switch_kernel(tsk)
147#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */
148
149#define PR_PAC_ENABLED_KEYS_MASK \
150 (PR_PAC_APIAKEY | PR_PAC_APIBKEY | PR_PAC_APDAKEY | PR_PAC_APDBKEY)
151
152#endif /* __ASM_POINTER_AUTH_H */