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-rw-r--r--arch/arm64/include/asm/pointer_auth.h152
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 000000000..efb098de3
--- /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(&current->thread.keys_user)
+
+#define ptrauth_thread_init_user() \
+ do { \
+ ptrauth_keys_init_user(&current->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 */