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-rw-r--r--arch/arm64/kernel/pointer_auth.c113
1 files changed, 113 insertions, 0 deletions
diff --git a/arch/arm64/kernel/pointer_auth.c b/arch/arm64/kernel/pointer_auth.c
new file mode 100644
index 000000000..2708b620b
--- /dev/null
+++ b/arch/arm64/kernel/pointer_auth.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/compat.h>
+#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_user *keys = &tsk->thread.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 (is_compat_thread(task_thread_info(tsk)))
+ return -EINVAL;
+
+ if (!arg) {
+ ptrauth_keys_init_user(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_install_user(keys);
+
+ return 0;
+}
+
+static u64 arg_to_enxx_mask(unsigned long arg)
+{
+ u64 sctlr_enxx_mask = 0;
+
+ WARN_ON(arg & ~PR_PAC_ENABLED_KEYS_MASK);
+ if (arg & PR_PAC_APIAKEY)
+ sctlr_enxx_mask |= SCTLR_ELx_ENIA;
+ if (arg & PR_PAC_APIBKEY)
+ sctlr_enxx_mask |= SCTLR_ELx_ENIB;
+ if (arg & PR_PAC_APDAKEY)
+ sctlr_enxx_mask |= SCTLR_ELx_ENDA;
+ if (arg & PR_PAC_APDBKEY)
+ sctlr_enxx_mask |= SCTLR_ELx_ENDB;
+ return sctlr_enxx_mask;
+}
+
+int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
+ unsigned long enabled)
+{
+ u64 sctlr;
+
+ if (!system_supports_address_auth())
+ return -EINVAL;
+
+ if (is_compat_thread(task_thread_info(tsk)))
+ return -EINVAL;
+
+ if ((keys & ~PR_PAC_ENABLED_KEYS_MASK) || (enabled & ~keys))
+ return -EINVAL;
+
+ preempt_disable();
+ sctlr = tsk->thread.sctlr_user;
+ sctlr &= ~arg_to_enxx_mask(keys);
+ sctlr |= arg_to_enxx_mask(enabled);
+ tsk->thread.sctlr_user = sctlr;
+ if (tsk == current)
+ update_sctlr_el1(sctlr);
+ preempt_enable();
+
+ return 0;
+}
+
+int ptrauth_get_enabled_keys(struct task_struct *tsk)
+{
+ int retval = 0;
+
+ if (!system_supports_address_auth())
+ return -EINVAL;
+
+ if (is_compat_thread(task_thread_info(tsk)))
+ return -EINVAL;
+
+ if (tsk->thread.sctlr_user & SCTLR_ELx_ENIA)
+ retval |= PR_PAC_APIAKEY;
+ if (tsk->thread.sctlr_user & SCTLR_ELx_ENIB)
+ retval |= PR_PAC_APIBKEY;
+ if (tsk->thread.sctlr_user & SCTLR_ELx_ENDA)
+ retval |= PR_PAC_APDAKEY;
+ if (tsk->thread.sctlr_user & SCTLR_ELx_ENDB)
+ retval |= PR_PAC_APDBKEY;
+
+ return retval;
+}