diff options
Diffstat (limited to 'arch/arm64/include/asm/pointer_auth.h')
| -rw-r--r-- | arch/arm64/include/asm/pointer_auth.h | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h new file mode 100644 index 000000000000..efb098de3a84 --- /dev/null +++ b/arch/arm64/include/asm/pointer_auth.h @@ -0,0 +1,152 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_POINTER_AUTH_H +#define __ASM_POINTER_AUTH_H + +#include <linux/bitops.h> +#include <linux/prctl.h> +#include <linux/random.h> + +#include <asm/cpufeature.h> +#include <asm/memory.h> +#include <asm/sysreg.h> + +#define PR_PAC_ENABLED_KEYS_MASK \ + (PR_PAC_APIAKEY | PR_PAC_APIBKEY | PR_PAC_APDAKEY | PR_PAC_APDBKEY) + +#ifdef CONFIG_ARM64_PTR_AUTH +/* + * Each key is a 128-bit quantity which is split across a pair of 64-bit + * registers (Lo and Hi). + */ +struct ptrauth_key { + unsigned long lo, hi; +}; + +/* + * We give each process its own keys, which are shared by all threads. The keys + * are inherited upon fork(), and reinitialised upon exec*(). + */ +struct ptrauth_keys_user { + struct ptrauth_key apia; + struct ptrauth_key apib; + struct ptrauth_key apda; + struct ptrauth_key apdb; + struct ptrauth_key apga; +}; + +#define __ptrauth_key_install_nosync(k, v) \ +do { \ + struct ptrauth_key __pki_v = (v); \ + write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \ + write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \ +} while (0) + +#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL + +struct ptrauth_keys_kernel { + struct ptrauth_key apia; +}; + +static __always_inline void ptrauth_keys_init_kernel(struct ptrauth_keys_kernel *keys) +{ + if (system_supports_address_auth()) + get_random_bytes(&keys->apia, sizeof(keys->apia)); +} + +static __always_inline void ptrauth_keys_switch_kernel(struct ptrauth_keys_kernel *keys) +{ + if (!system_supports_address_auth()) + return; + + __ptrauth_key_install_nosync(APIA, keys->apia); + isb(); +} + +#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */ + +static inline void ptrauth_keys_install_user(struct ptrauth_keys_user *keys) +{ + if (system_supports_address_auth()) { + __ptrauth_key_install_nosync(APIB, keys->apib); + __ptrauth_key_install_nosync(APDA, keys->apda); + __ptrauth_key_install_nosync(APDB, keys->apdb); + } + + if (system_supports_generic_auth()) + __ptrauth_key_install_nosync(APGA, keys->apga); +} + +static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys) +{ + if (system_supports_address_auth()) { + get_random_bytes(&keys->apia, sizeof(keys->apia)); + get_random_bytes(&keys->apib, sizeof(keys->apib)); + get_random_bytes(&keys->apda, sizeof(keys->apda)); + get_random_bytes(&keys->apdb, sizeof(keys->apdb)); + } + + if (system_supports_generic_auth()) + get_random_bytes(&keys->apga, sizeof(keys->apga)); + + ptrauth_keys_install_user(keys); +} + +extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg); + +extern int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys, + unsigned long enabled); +extern int ptrauth_get_enabled_keys(struct task_struct *tsk); + +static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr) +{ + return ptrauth_clear_pac(ptr); +} + +static __always_inline void ptrauth_enable(void) +{ + if (!system_supports_address_auth()) + return; + sysreg_clear_set(sctlr_el1, 0, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | + SCTLR_ELx_ENDA | SCTLR_ELx_ENDB)); + isb(); +} + +#define ptrauth_suspend_exit() \ + ptrauth_keys_install_user(¤t->thread.keys_user) + +#define ptrauth_thread_init_user() \ + do { \ + ptrauth_keys_init_user(¤t->thread.keys_user); \ + \ + /* enable all keys */ \ + if (system_supports_address_auth()) \ + ptrauth_set_enabled_keys(current, \ + PR_PAC_ENABLED_KEYS_MASK, \ + PR_PAC_ENABLED_KEYS_MASK); \ + } while (0) + +#define ptrauth_thread_switch_user(tsk) \ + ptrauth_keys_install_user(&(tsk)->thread.keys_user) + +#else /* CONFIG_ARM64_PTR_AUTH */ +#define ptrauth_enable() +#define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL) +#define ptrauth_set_enabled_keys(tsk, keys, enabled) (-EINVAL) +#define ptrauth_get_enabled_keys(tsk) (-EINVAL) +#define ptrauth_strip_insn_pac(lr) (lr) +#define ptrauth_suspend_exit() +#define ptrauth_thread_init_user() +#define ptrauth_thread_switch_user(tsk) +#endif /* CONFIG_ARM64_PTR_AUTH */ + +#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL +#define ptrauth_thread_init_kernel(tsk) \ + ptrauth_keys_init_kernel(&(tsk)->thread.keys_kernel) +#define ptrauth_thread_switch_kernel(tsk) \ + ptrauth_keys_switch_kernel(&(tsk)->thread.keys_kernel) +#else +#define ptrauth_thread_init_kernel(tsk) +#define ptrauth_thread_switch_kernel(tsk) +#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */ + +#endif /* __ASM_POINTER_AUTH_H */ |