From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C294C43387 for ; Fri, 11 Jan 2019 13:34:41 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CF8DD20874 for ; Fri, 11 Jan 2019 13:34:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="jJZc9m5f" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CF8DD20874 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=w31FEs98qYSLhfEUGXfAU12fCnb8VBnOQUqWtzIK/aU=; b=jJZc9m5fvgf3xn LMnVLRgtRF0fYL987NnAo3lHkvd2t7LX+q2djkXPkijQrX/jmW6tw5afU97rq0BsBhLtPW4nA9nMX Fh22hnOPwnU/UH89O4e0sblIxDl5Diei6S/PTcunUNs1syDdTid6BmhrZykFhSfznSH7VCiQc63b2 dJgh7okNuayKFqKlBTzu1DIIltq8Ws+4ssOqA+fzT766OelzgcKGQqKkQicO25gAXUpFc10Dqft8L Q6Qcp3S4FVCx2VyOXIb8c2W6HuH/qf4BtlF0EvNUBKSlir0EJfO8fy5BcPbRUV6Ewq65qvBF0yW7Z eFyotVIitGT/ySuEWrfw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ghwxL-000074-4h; Fri, 11 Jan 2019 13:34:39 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ghwv6-0006UU-Ql for linux-arm-kernel@lists.infradead.org; Fri, 11 Jan 2019 13:32:59 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1CFB5EBD; Fri, 11 Jan 2019 05:32:20 -0800 (PST) Received: from e103592.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DD4BA3F6CF; Fri, 11 Jan 2019 05:32:18 -0800 (PST) Date: Fri, 11 Jan 2019 13:31:54 +0000 From: Dave Martin To: Kristina Martsenko Subject: Re: [PATCH v2] arm64: add ptrace regsets for ptrauth key management Message-ID: <20190111133146.GA3547@e103592.cambridge.arm.com> References: <20190110193508.31888-1-kristina.martsenko@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190110193508.31888-1-kristina.martsenko@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190111_053222_020404_F229A3A8 X-CRM114-Status: GOOD ( 30.55 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Catalin Marinas , Amit Kachhap , Will Deacon , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jan 10, 2019 at 07:35:08PM +0000, Kristina Martsenko wrote: > Add two new ptrace regsets, which can be used to request and change the > pointer authentication keys of a thread. NT_ARM_PACA_KEYS gives access > to the instruction/data address keys, and NT_ARM_PACG_KEYS to the > generic authentication key. The keys are also part of the core dump file > of the process. > > The regsets are only exposed if the kernel is compiled with > CONFIG_CHECKPOINT_RESTORE=y, as the intended use case is checkpointing > and restoring processes that are using pointer authentication. Normally > applications or debuggers should not need to know the keys (and exposing > the keys is a security risk), so the regsets are not exposed by default. I think the second variant of the patch is the way to go with this, since it seems to result in simpler code. So, I'll comment on the second patch. Cheers ---Dave > > Signed-off-by: Kristina Martsenko > --- > > The previous version of this patch was: > https://lore.kernel.org/lkml/20181207183931.4285-12-kristina.martsenko@arm.com/ > > Changes in v2: > - Convert each field individually between ptrauth_keys and > user_pac_address_keys/user_pac_generic_keys > > Documentation/arm64/pointer-authentication.txt | 5 + > arch/arm64/include/uapi/asm/ptrace.h | 18 ++++ > arch/arm64/kernel/ptrace.c | 144 +++++++++++++++++++++++++ > include/uapi/linux/elf.h | 2 + > 4 files changed, 169 insertions(+) > > diff --git a/Documentation/arm64/pointer-authentication.txt b/Documentation/arm64/pointer-authentication.txt > index a25cd21290e9..5baca42ba146 100644 > --- a/Documentation/arm64/pointer-authentication.txt > +++ b/Documentation/arm64/pointer-authentication.txt > @@ -78,6 +78,11 @@ bits can vary between the two. Note that the masks apply to TTBR0 > addresses, and are not valid to apply to TTBR1 addresses (e.g. kernel > pointers). > > +Additionally, when CONFIG_CHECKPOINT_RESTORE is also set, the kernel > +will expose the NT_ARM_PACA_KEYS and NT_ARM_PACG_KEYS regsets (struct > +user_pac_address_keys and struct user_pac_generic_keys). These can be > +used to get and set the keys for a thread. > + > > Virtualization > -------------- > diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h > index 28d77c9ed531..0affa43602a5 100644 > --- a/arch/arm64/include/uapi/asm/ptrace.h > +++ b/arch/arm64/include/uapi/asm/ptrace.h > @@ -233,6 +233,24 @@ struct user_pac_mask { > __u64 insn_mask; > }; > > +/* pointer authentication keys (NT_ARM_PACA_KEYS, NT_ARM_PACG_KEYS) */ > + > +struct user_pac_address_keys { > + __u64 apiakey_lo; > + __u64 apiakey_hi; > + __u64 apibkey_lo; > + __u64 apibkey_hi; > + __u64 apdakey_lo; > + __u64 apdakey_hi; > + __u64 apdbkey_lo; > + __u64 apdbkey_hi; > +}; > + > +struct user_pac_generic_keys { > + __u64 apgakey_lo; > + __u64 apgakey_hi; > +}; > + > #endif /* __ASSEMBLY__ */ > > #endif /* _UAPI__ASM_PTRACE_H */ > diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c > index 9dce33b0e260..a5f9f07e9eac 100644 > --- a/arch/arm64/kernel/ptrace.c > +++ b/arch/arm64/kernel/ptrace.c > @@ -979,6 +979,128 @@ static int pac_mask_get(struct task_struct *target, > > return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &uregs, 0, -1); > } > + > +#ifdef CONFIG_CHECKPOINT_RESTORE > +static void pac_address_keys_to_user(struct user_pac_address_keys *ukeys, > + struct ptrauth_keys *keys) > +{ > + ukeys->apiakey_lo = keys->apia.lo; > + ukeys->apiakey_hi = keys->apia.hi; > + ukeys->apibkey_lo = keys->apib.lo; > + ukeys->apibkey_hi = keys->apib.hi; > + ukeys->apdakey_lo = keys->apda.lo; > + ukeys->apdakey_hi = keys->apda.hi; > + ukeys->apdbkey_lo = keys->apdb.lo; > + ukeys->apdbkey_hi = keys->apdb.hi; > +} > + > +static void pac_address_keys_from_user(struct user_pac_address_keys *ukeys, > + struct ptrauth_keys *keys) > +{ > + keys->apia.lo = ukeys->apiakey_lo; > + keys->apia.hi = ukeys->apiakey_hi; > + keys->apib.lo = ukeys->apibkey_lo; > + keys->apib.hi = ukeys->apibkey_hi; > + keys->apda.lo = ukeys->apdakey_lo; > + keys->apda.hi = ukeys->apdakey_hi; > + keys->apdb.lo = ukeys->apdbkey_lo; > + keys->apdb.hi = ukeys->apdbkey_hi; > +} > + > +static int pac_address_keys_get(struct task_struct *target, > + const struct user_regset *regset, > + unsigned int pos, unsigned int count, > + void *kbuf, void __user *ubuf) > +{ > + struct ptrauth_keys *keys = &target->thread.keys_user; > + struct user_pac_address_keys user_keys; > + > + if (!system_supports_address_auth()) > + return -EINVAL; > + > + memset(&user_keys, 0, sizeof(user_keys)); > + pac_address_keys_to_user(&user_keys, keys); > + > + return user_regset_copyout(&pos, &count, &kbuf, &ubuf, > + &user_keys, 0, -1); > +} > + > +static int pac_address_keys_set(struct task_struct *target, > + const struct user_regset *regset, > + unsigned int pos, unsigned int count, > + const void *kbuf, const void __user *ubuf) > +{ > + struct ptrauth_keys *keys = &target->thread.keys_user; > + struct user_pac_address_keys user_keys; > + int ret; > + > + if (!system_supports_address_auth()) > + return -EINVAL; > + > + pac_address_keys_to_user(&user_keys, keys); > + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, > + &user_keys, 0, -1); > + if (ret) > + return ret; > + pac_address_keys_from_user(&user_keys, keys); > + > + return 0; > +} > + > +static void pac_generic_keys_to_user(struct user_pac_generic_keys *ukeys, > + struct ptrauth_keys *keys) > +{ > + ukeys->apgakey_lo = keys->apga.lo; > + ukeys->apgakey_hi = keys->apga.hi; > +} > + > +static void pac_generic_keys_from_user(struct user_pac_generic_keys *ukeys, > + struct ptrauth_keys *keys) > +{ > + keys->apga.lo = ukeys->apgakey_lo; > + keys->apga.hi = ukeys->apgakey_hi; > +} > + > +static int pac_generic_keys_get(struct task_struct *target, > + const struct user_regset *regset, > + unsigned int pos, unsigned int count, > + void *kbuf, void __user *ubuf) > +{ > + struct ptrauth_keys *keys = &target->thread.keys_user; > + struct user_pac_generic_keys user_keys; > + > + if (!system_supports_generic_auth()) > + return -EINVAL; > + > + memset(&user_keys, 0, sizeof(user_keys)); > + pac_generic_keys_to_user(&user_keys, keys); > + > + return user_regset_copyout(&pos, &count, &kbuf, &ubuf, > + &user_keys, 0, -1); > +} > + > +static int pac_generic_keys_set(struct task_struct *target, > + const struct user_regset *regset, > + unsigned int pos, unsigned int count, > + const void *kbuf, const void __user *ubuf) > +{ > + struct ptrauth_keys *keys = &target->thread.keys_user; > + struct user_pac_generic_keys user_keys; > + int ret; > + > + if (!system_supports_generic_auth()) > + return -EINVAL; > + > + pac_generic_keys_to_user(&user_keys, keys); > + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, > + &user_keys, 0, -1); > + if (ret) > + return ret; > + pac_generic_keys_from_user(&user_keys, keys); > + > + return 0; > +} > +#endif /* CONFIG_CHECKPOINT_RESTORE */ > #endif /* CONFIG_ARM64_PTR_AUTH */ > > enum aarch64_regset { > @@ -995,6 +1117,10 @@ enum aarch64_regset { > #endif > #ifdef CONFIG_ARM64_PTR_AUTH > REGSET_PAC_MASK, > +#ifdef CONFIG_CHECKPOINT_RESTORE > + REGSET_PACA_KEYS, > + REGSET_PACG_KEYS, > +#endif > #endif > }; > > @@ -1074,6 +1200,24 @@ static const struct user_regset aarch64_regsets[] = { > .get = pac_mask_get, > /* this cannot be set dynamically */ > }, > +#ifdef CONFIG_CHECKPOINT_RESTORE > + [REGSET_PACA_KEYS] = { > + .core_note_type = NT_ARM_PACA_KEYS, > + .n = sizeof(struct user_pac_address_keys) / sizeof(u64), > + .size = sizeof(u64), > + .align = sizeof(u64), > + .get = pac_address_keys_get, > + .set = pac_address_keys_set, > + }, > + [REGSET_PACG_KEYS] = { > + .core_note_type = NT_ARM_PACG_KEYS, > + .n = sizeof(struct user_pac_generic_keys) / sizeof(u64), > + .size = sizeof(u64), > + .align = sizeof(u64), > + .get = pac_generic_keys_get, > + .set = pac_generic_keys_set, > + }, > +#endif > #endif > }; > > diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h > index e4d6ddd93567..34c02e4290fe 100644 > --- a/include/uapi/linux/elf.h > +++ b/include/uapi/linux/elf.h > @@ -421,6 +421,8 @@ typedef struct elf64_shdr { > #define NT_ARM_SYSTEM_CALL 0x404 /* ARM system call number */ > #define NT_ARM_SVE 0x405 /* ARM Scalable Vector Extension registers */ > #define NT_ARM_PAC_MASK 0x406 /* ARM pointer authentication code masks */ > +#define NT_ARM_PACA_KEYS 0x407 /* ARM pointer authentication address keys */ > +#define NT_ARM_PACG_KEYS 0x408 /* ARM pointer authentication generic key */ > #define NT_ARC_V2 0x600 /* ARCv2 accumulator/extra registers */ > #define NT_VMCOREDD 0x700 /* Vmcore Device Dump Note */ > #define NT_MIPS_DSP 0x800 /* MIPS DSP ASE registers */ > -- > 2.11.0 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel