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
ptrauth_keys_init_user(struct ptrauth_keys_user * keys)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_nosync(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
ptrauth_keys_init_kernel(struct ptrauth_keys_kernel * keys)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
ptrauth_keys_switch_kernel(struct ptrauth_keys_kernel * keys)63 static __always_inline void ptrauth_keys_switch_kernel(struct ptrauth_keys_kernel *keys)
64 {
65 if (!system_supports_address_auth())
66 return;
67
68 __ptrauth_key_install_nosync(APIA, keys->apia);
69 isb();
70 }
71
72 extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg);
73
ptrauth_strip_insn_pac(unsigned long ptr)74 static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
75 {
76 return ptrauth_clear_pac(ptr);
77 }
78
79 #define ptrauth_thread_init_user(tsk) \
80 ptrauth_keys_init_user(&(tsk)->thread.keys_user)
81 #define ptrauth_thread_init_kernel(tsk) \
82 ptrauth_keys_init_kernel(&(tsk)->thread.keys_kernel)
83 #define ptrauth_thread_switch_kernel(tsk) \
84 ptrauth_keys_switch_kernel(&(tsk)->thread.keys_kernel)
85
86 #else /* CONFIG_ARM64_PTR_AUTH */
87 #define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL)
88 #define ptrauth_strip_insn_pac(lr) (lr)
89 #define ptrauth_thread_init_user(tsk)
90 #define ptrauth_thread_init_kernel(tsk)
91 #define ptrauth_thread_switch_kernel(tsk)
92 #endif /* CONFIG_ARM64_PTR_AUTH */
93
94 #endif /* __ASM_POINTER_AUTH_H */
95