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
34struct ptrauth_keys_kernel {
35 struct ptrauth_key apia;
36};
37
38#define __ptrauth_key_install_nosync(k, v) \
39do { \
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
45static 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
57static 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
72static __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
78static __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
87extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg);
88
89extern int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
90 unsigned long enabled);
91extern int ptrauth_get_enabled_keys(struct task_struct *tsk);
92
93static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
94{
95 return ptrauth_clear_pac(ptr);
96}
97
98static __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 */