@@ -35,11 +35,25 @@ alternative_if ARM64_HAS_GENERIC_AUTH
alternative_else_nop_endif
.endm
+ .macro ptrauth_keys_install_kernel tsk, tmp1, tmp2, tmp3
+alternative_if ARM64_HAS_ADDRESS_AUTH
+ mov \tmp1, #THREAD_KEYS_KERNEL
+ add \tmp1, \tsk, \tmp1
+ ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_KERNEL_KEY_APIA]
+ msr_s SYS_APIAKEYLO_EL1, \tmp2
+ msr_s SYS_APIAKEYHI_EL1, \tmp3
+ isb
+alternative_else_nop_endif
+ .endm
+
#else /* CONFIG_ARM64_PTR_AUTH */
.macro ptrauth_keys_install_user tsk, tmp1, tmp2, tmp3
.endm
+ .macro ptrauth_keys_install_kernel tsk, tmp1, tmp2, tmp3
+ .endm
+
#endif /* CONFIG_ARM64_PTR_AUTH */
#endif /* __ASM_ASM_POINTER_AUTH_H */
@@ -30,6 +30,10 @@ struct ptrauth_keys_user {
struct ptrauth_key apga;
};
+struct ptrauth_keys_kernel {
+ struct ptrauth_key apia;
+};
+
static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys)
{
if (system_supports_address_auth()) {
@@ -50,6 +54,12 @@ do { \
write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \
} while (0)
+static inline void ptrauth_keys_init_kernel(struct ptrauth_keys_kernel *keys)
+{
+ if (system_supports_address_auth())
+ get_random_bytes(&keys->apia, sizeof(keys->apia));
+}
+
extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg);
/*
@@ -66,11 +76,14 @@ static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
#define ptrauth_thread_init_user(tsk) \
ptrauth_keys_init_user(&(tsk)->thread.keys_user)
+#define ptrauth_thread_init_kernel(tsk) \
+ ptrauth_keys_init_kernel(&(tsk)->thread.keys_kernel)
#else /* CONFIG_ARM64_PTR_AUTH */
#define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL)
#define ptrauth_strip_insn_pac(lr) (lr)
#define ptrauth_thread_init_user(tsk)
+#define ptrauth_thread_init_kernel(tsk)
#endif /* CONFIG_ARM64_PTR_AUTH */
#endif /* __ASM_POINTER_AUTH_H */
@@ -147,6 +147,7 @@ struct thread_struct {
struct debug_info debug; /* debugging */
#ifdef CONFIG_ARM64_PTR_AUTH
struct ptrauth_keys_user keys_user;
+ struct ptrauth_keys_kernel keys_kernel;
#endif
};
@@ -36,6 +36,7 @@
#include <linux/threads.h>
#include <linux/cpumask.h>
#include <linux/thread_info.h>
+#include <asm/pointer_auth.h>
DECLARE_PER_CPU_READ_MOSTLY(int, cpu_number);
@@ -93,6 +94,9 @@ asmlinkage void secondary_start_kernel(void);
struct secondary_data {
void *stack;
struct task_struct *task;
+#ifdef CONFIG_ARM64_PTR_AUTH
+ struct ptrauth_keys_kernel ptrauth_key;
+#endif
long status;
};
@@ -42,6 +42,7 @@ int main(void)
DEFINE(THREAD_CPU_CONTEXT, offsetof(struct task_struct, thread.cpu_context));
#ifdef CONFIG_ARM64_PTR_AUTH
DEFINE(THREAD_KEYS_USER, offsetof(struct task_struct, thread.keys_user));
+ DEFINE(THREAD_KEYS_KERNEL, offsetof(struct task_struct, thread.keys_kernel));
#endif
BLANK();
DEFINE(S_X0, offsetof(struct pt_regs, regs[0]));
@@ -91,6 +92,9 @@ int main(void)
BLANK();
DEFINE(CPU_BOOT_STACK, offsetof(struct secondary_data, stack));
DEFINE(CPU_BOOT_TASK, offsetof(struct secondary_data, task));
+#ifdef CONFIG_ARM64_PTR_AUTH
+ DEFINE(CPU_BOOT_PTRAUTH_KEY, offsetof(struct secondary_data, ptrauth_key));
+#endif
BLANK();
#ifdef CONFIG_KVM_ARM_HOST
DEFINE(VCPU_CONTEXT, offsetof(struct kvm_vcpu, arch.ctxt));
@@ -137,6 +141,7 @@ int main(void)
DEFINE(PTRAUTH_USER_KEY_APDA, offsetof(struct ptrauth_keys_user, apda));
DEFINE(PTRAUTH_USER_KEY_APDB, offsetof(struct ptrauth_keys_user, apdb));
DEFINE(PTRAUTH_USER_KEY_APGA, offsetof(struct ptrauth_keys_user, apga));
+ DEFINE(PTRAUTH_KERNEL_KEY_APIA, offsetof(struct ptrauth_keys_kernel, apia));
BLANK();
#endif
return 0;
@@ -174,6 +174,7 @@ alternative_cb_end
apply_ssbd 1, x22, x23
+ ptrauth_keys_install_kernel tsk, x20, x22, x23
.else
add x21, sp, #S_FRAME_SIZE
get_current_task tsk
@@ -345,6 +346,7 @@ alternative_else_nop_endif
msr cntkctl_el1, x1
4:
#endif
+ /* No kernel C function calls after this as user keys are set. */
ptrauth_keys_install_user tsk, x0, x1, x2
apply_ssbd 0, x0, x1
@@ -898,6 +900,7 @@ ENTRY(cpu_switch_to)
ldr lr, [x8]
mov sp, x9
msr sp_el0, x1
+ ptrauth_keys_install_kernel x1, x8, x9, x10
ret
ENDPROC(cpu_switch_to)
NOKPROBE(cpu_switch_to)
@@ -376,6 +376,8 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
*/
fpsimd_flush_task_state(p);
+ ptrauth_thread_init_kernel(p);
+
if (likely(!(p->flags & PF_KTHREAD))) {
*childregs = *current_pt_regs();
childregs->regs[0] = 0;
@@ -112,6 +112,10 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
*/
secondary_data.task = idle;
secondary_data.stack = task_stack_page(idle) + THREAD_SIZE;
+#if defined(CONFIG_ARM64_PTR_AUTH)
+ secondary_data.ptrauth_key.apia.lo = idle->thread.keys_kernel.apia.lo;
+ secondary_data.ptrauth_key.apia.hi = idle->thread.keys_kernel.apia.hi;
+#endif
update_cpu_boot_status(CPU_MMU_OFF);
__flush_dcache_area(&secondary_data, sizeof(secondary_data));
@@ -138,6 +142,10 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
secondary_data.task = NULL;
secondary_data.stack = NULL;
+#if defined(CONFIG_ARM64_PTR_AUTH)
+ secondary_data.ptrauth_key.apia.lo = 0;
+ secondary_data.ptrauth_key.apia.hi = 0;
+#endif
__flush_dcache_area(&secondary_data, sizeof(secondary_data));
status = READ_ONCE(secondary_data.status);
if (ret && status) {
@@ -491,6 +491,10 @@ ENTRY(__cpu_setup)
ubfx x2, x2, #ID_AA64ISAR1_APA_SHIFT, #8
cbz x2, 3f
+ /*
+ * The primary cpu keys are reset here and can be
+ * re-initialised with some proper values later.
+ */
msr_s SYS_APIAKEYLO_EL1, xzr
msr_s SYS_APIAKEYHI_EL1, xzr
@@ -503,6 +507,14 @@ alternative_if_not ARM64_HAS_ADDRESS_AUTH
b 3f
alternative_else_nop_endif
+ /* Install ptrauth key for secondary cpus */
+ adr_l x2, secondary_data
+ ldr x3, [x2, #CPU_BOOT_TASK] // get secondary_data.task
+ cbz x3, 2f // check for slow booting cpus
+ ldp x3, x4, [x2, #CPU_BOOT_PTRAUTH_KEY]
+ msr_s SYS_APIAKEYLO_EL1, x3
+ msr_s SYS_APIAKEYHI_EL1, x4
+
2: /* Enable ptrauth instructions */
ldr x2, =SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \
SCTLR_ELx_ENDA | SCTLR_ELx_ENDB