summaryrefslogtreecommitdiff
path: root/arch/arm64/kernel
diff options
context:
space:
mode:
authorKristina Martsenko <kristina.martsenko@arm.com>2020-03-13 12:04:56 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2020-03-18 12:50:20 +0300
commit33e45234987ea3ed4b05fc512f4441696478f12d (patch)
treee7dbf5120c409f20c20d7b095dca1244ec3f3b85 /arch/arm64/kernel
parent6982934e19f8ebb4152ba77308facdb1a38533f9 (diff)
downloadlinux-33e45234987ea3ed4b05fc512f4441696478f12d.tar.xz
arm64: initialize and switch ptrauth kernel keys
Set up keys to use pointer authentication within the kernel. The kernel will be compiled with APIAKey instructions, the other keys are currently unused. Each task is given its own APIAKey, which is initialized during fork. The key is changed during context switch and on kernel entry from EL0. The keys for idle threads need to be set before calling any C functions, because it is not possible to enter and exit a function with different keys. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> [Amit: Modified secondary cores key structure, comments] Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
-rw-r--r--arch/arm64/kernel/asm-offsets.c5
-rw-r--r--arch/arm64/kernel/entry.S3
-rw-r--r--arch/arm64/kernel/process.c2
-rw-r--r--arch/arm64/kernel/smp.c8
4 files changed, 18 insertions, 0 deletions
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 7b1ea2aece58..9981a0a5a87f 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -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;
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 684e475bfda0..3dad2d000e3c 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -178,6 +178,7 @@ 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
@@ -342,6 +343,7 @@ 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)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 6140e791bf92..7db0302bec00 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -376,6 +376,8 @@ int copy_thread_tls(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;
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index d4ed9a19d8fe..08903413f106 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -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) {