2 files changed, 48 insertions, 0 deletions
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 583334ce1c2c..df08d735b21d 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -58,6 +58,7 @@ arm64-obj-$(CONFIG_CRASH_DUMP)		+= crash_dump.o
 arm64-obj-$(CONFIG_CRASH_CORE)		+= crash_core.o
 arm64-obj-$(CONFIG_ARM_SDE_INTERFACE)	+= sdei.o
 arm64-obj-$(CONFIG_ARM64_SSBD)		+= ssbd.o
+arm64-obj-$(CONFIG_ARM64_PTR_AUTH)	+= pointer_auth.o
 
 obj-y					+= $(arm64-obj-y) vdso/ probes/
 obj-m					+= $(arm64-obj-m)
diff --git a/arch/arm64/kernel/pointer_auth.c b/arch/arm64/kernel/pointer_auth.c
new file mode 100644
index 000000000000..b9f6f5f3409a
--- /dev/null
+++ b/arch/arm64/kernel/pointer_auth.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/errno.h>
+#include <linux/prctl.h>
+#include <linux/random.h>
+#include <linux/sched.h>
+#include <asm/cpufeature.h>
+#include <asm/pointer_auth.h>
+
+int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
+{
+	struct ptrauth_keys *keys = &tsk->thread_info.keys_user;
+	unsigned long addr_key_mask = PR_PAC_APIAKEY | PR_PAC_APIBKEY |
+				      PR_PAC_APDAKEY | PR_PAC_APDBKEY;
+	unsigned long key_mask = addr_key_mask | PR_PAC_APGAKEY;
+
+	if (!system_supports_address_auth() && !system_supports_generic_auth())
+		return -EINVAL;
+
+	if (!arg) {
+		ptrauth_keys_init(keys);
+		ptrauth_keys_switch(keys);
+		return 0;
+	}
+
+	if (arg & ~key_mask)
+		return -EINVAL;
+
+	if (((arg & addr_key_mask) && !system_supports_address_auth()) ||
+	    ((arg & PR_PAC_APGAKEY) && !system_supports_generic_auth()))
+		return -EINVAL;
+
+	if (arg & PR_PAC_APIAKEY)
+		get_random_bytes(&keys->apia, sizeof(keys->apia));
+	if (arg & PR_PAC_APIBKEY)
+		get_random_bytes(&keys->apib, sizeof(keys->apib));
+	if (arg & PR_PAC_APDAKEY)
+		get_random_bytes(&keys->apda, sizeof(keys->apda));
+	if (arg & PR_PAC_APDBKEY)
+		get_random_bytes(&keys->apdb, sizeof(keys->apdb));
+	if (arg & PR_PAC_APGAKEY)
+		get_random_bytes(&keys->apga, sizeof(keys->apga));
+
+	ptrauth_keys_switch(keys);
+
+	return 0;
+}