From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Amit Daniel Kachhap <amit.kachhap@arm.com>,
linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Kees Cook <keescook@chromium.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Kristina Martsenko <kristina.martsenko@arm.com>,
Dave Martin <Dave.Martin@arm.com>,
Mark Brown <broonie@kernel.org>,
James Morse <james.morse@arm.com>,
Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>,
Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>
Subject: Re: [PATCH v6 10/18] arm64: initialize and switch ptrauth kernel keys
Date: Tue, 10 Mar 2020 15:07:12 +0000 [thread overview]
Message-ID: <d5d7a6ce-5fa8-210b-e778-b94fbf8d4229@arm.com> (raw)
In-Reply-To: <1583476525-13505-11-git-send-email-amit.kachhap@arm.com>
On 3/6/20 6:35 AM, Amit Daniel Kachhap wrote:
> From: Kristina Martsenko <kristina.martsenko@arm.com>
>
> 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: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Catalin Marinas <catalin.marinas@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>
> ---
> arch/arm64/include/asm/asm_pointer_auth.h | 14 ++++++++++++++
> arch/arm64/include/asm/pointer_auth.h | 13 +++++++++++++
> arch/arm64/include/asm/processor.h | 1 +
> arch/arm64/include/asm/smp.h | 4 ++++
> arch/arm64/kernel/asm-offsets.c | 5 +++++
> arch/arm64/kernel/entry.S | 3 +++
> arch/arm64/kernel/process.c | 2 ++
> arch/arm64/kernel/smp.c | 8 ++++++++
> arch/arm64/mm/proc.S | 12 ++++++++++++
> 9 files changed, 62 insertions(+)
>
> diff --git a/arch/arm64/include/asm/asm_pointer_auth.h b/arch/arm64/include/asm/asm_pointer_auth.h
> index f820a13..4152afe 100644
> --- a/arch/arm64/include/asm/asm_pointer_auth.h
> +++ b/arch/arm64/include/asm/asm_pointer_auth.h
> @@ -39,11 +39,25 @@ 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 */
> diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h
> index dabe026..aa956ca 100644
> --- a/arch/arm64/include/asm/pointer_auth.h
> +++ b/arch/arm64/include/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 */
> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> index 496a928..4c77da5 100644
> --- a/arch/arm64/include/asm/processor.h
> +++ b/arch/arm64/include/asm/processor.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
> };
>
> diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h
> index 5334d69..4e92150 100644
> --- a/arch/arm64/include/asm/smp.h
> +++ b/arch/arm64/include/asm/smp.h
> @@ -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;
> };
>
> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
> index 7b1ea2a..9981a0a 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 684e475..3dad2d0 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 6140e79..7db0302 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 f2761a9..3fa0fbf 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) {
> diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
> index 4cf19a2..5a11a89 100644
> --- a/arch/arm64/mm/proc.S
> +++ b/arch/arm64/mm/proc.S
> @@ -485,6 +485,10 @@ SYM_FUNC_START(__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
>
> @@ -497,6 +501,14 @@ 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
>
--
Regards,
Vincenzo
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-03-10 15:06 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-06 6:35 [PATCH v6 00/18] arm64: return address signing Amit Daniel Kachhap
2020-03-06 6:35 ` [PATCH v6 01/18] arm64: cpufeature: Fix meta-capability cpufeature check Amit Daniel Kachhap
2020-03-10 10:59 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 02/18] arm64: cpufeature: add pointer auth meta-capabilities Amit Daniel Kachhap
2020-03-10 11:18 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 03/18] arm64: rename ptrauth key structures to be user-specific Amit Daniel Kachhap
2020-03-10 11:35 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 04/18] arm64: install user ptrauth keys at kernel exit time Amit Daniel Kachhap
2020-03-06 19:07 ` James Morse
2020-03-10 11:48 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 05/18] arm64: create macro to park cpu in an infinite loop Amit Daniel Kachhap
2020-03-10 12:02 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 06/18] arm64: ptrauth: Add bootup/runtime flags for __cpu_setup Amit Daniel Kachhap
2020-03-06 19:07 ` James Morse
2020-03-09 17:04 ` Catalin Marinas
2020-03-10 12:14 ` Vincenzo Frascino
2020-03-11 9:28 ` Amit Kachhap
2020-03-06 6:35 ` [PATCH v6 07/18] arm64: cpufeature: Move cpu capability helpers inside C file Amit Daniel Kachhap
2020-03-10 12:20 ` Vincenzo Frascino
2020-03-10 12:53 ` Amit Kachhap
2020-03-11 10:50 ` Catalin Marinas
2020-03-11 11:44 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 08/18] arm64: cpufeature: handle conflicts based on capability Amit Daniel Kachhap
2020-03-10 12:31 ` Vincenzo Frascino
2020-03-11 11:03 ` Catalin Marinas
2020-03-11 11:46 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 09/18] arm64: enable ptrauth earlier Amit Daniel Kachhap
2020-03-10 15:45 ` Vincenzo Frascino
2020-03-11 6:26 ` Amit Kachhap
2020-03-11 10:26 ` Vincenzo Frascino
2020-03-11 10:46 ` Amit Kachhap
2020-03-11 10:49 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 10/18] arm64: initialize and switch ptrauth kernel keys Amit Daniel Kachhap
2020-03-10 15:07 ` Vincenzo Frascino [this message]
2020-03-06 6:35 ` [PATCH v6 11/18] arm64: initialize ptrauth keys for kernel booting task Amit Daniel Kachhap
2020-03-10 15:09 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 12/18] arm64: mask PAC bits of __builtin_return_address Amit Daniel Kachhap
2020-03-06 19:07 ` James Morse
2020-03-09 12:27 ` Amit Kachhap
2020-03-06 6:35 ` [PATCH v6 13/18] arm64: unwind: strip PAC from kernel addresses Amit Daniel Kachhap
2020-03-09 19:03 ` James Morse
2020-03-10 12:28 ` Amit Kachhap
2020-03-10 17:37 ` James Morse
2020-03-11 6:07 ` Amit Kachhap
2020-03-11 9:09 ` James Morse
2020-03-06 6:35 ` [PATCH v6 14/18] arm64: __show_regs: strip PAC from lr in printk Amit Daniel Kachhap
2020-03-10 15:11 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 15/18] arm64: suspend: restore the kernel ptrauth keys Amit Daniel Kachhap
2020-03-10 15:18 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 16/18] kconfig: Add support for 'as-option' Amit Daniel Kachhap
2020-03-06 11:37 ` Masahiro Yamada
2020-03-06 11:49 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 17/18] arm64: compile the kernel with ptrauth return address signing Amit Daniel Kachhap
2020-03-10 15:20 ` Vincenzo Frascino
2020-03-06 6:35 ` [PATCH v6 18/18] lkdtm: arm64: test kernel pointer authentication Amit Daniel Kachhap
2020-03-10 15:59 ` [PATCH v6 00/18] arm64: return address signing Rémi Denis-Courmont
2020-03-11 9:28 ` James Morse
2020-03-12 6:53 ` Amit Kachhap
2020-03-12 8:06 ` Amit Kachhap
2020-03-12 12:47 ` [PATCH v6 00/18] (as long a Marc Zyngier
2020-03-12 13:21 ` Amit Kachhap
2020-03-12 15:05 ` [PATCH v6 00/18] arm64: return address signing Marc Zyngier
2020-03-12 17:26 ` James Morse
2020-03-12 17:31 ` Marc Zyngier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=d5d7a6ce-5fa8-210b-e778-b94fbf8d4229@arm.com \
--to=vincenzo.frascino@arm.com \
--cc=Dave.Martin@arm.com \
--cc=amit.kachhap@arm.com \
--cc=ardb@kernel.org \
--cc=broonie@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=james.morse@arm.com \
--cc=keescook@chromium.org \
--cc=kristina.martsenko@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=mark.rutland@arm.com \
--cc=ramana.radhakrishnan@arm.com \
--cc=suzuki.poulose@arm.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).