From patchwork Mon Jul 31 13:43:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13334732 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF08EC41513 for ; Mon, 31 Jul 2023 13:56:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233105AbjGaN4d (ORCPT ); Mon, 31 Jul 2023 09:56:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230508AbjGaNz3 (ORCPT ); Mon, 31 Jul 2023 09:55:29 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B726171A; Mon, 31 Jul 2023 06:53:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id AE86D61164; Mon, 31 Jul 2023 13:53:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 69939C433CA; Mon, 31 Jul 2023 13:53:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690811598; bh=0QIP38ZumyMQzrMYtc7Z/0L/bXiC+1OudC2zVRODlMU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=kf/VAjRupL/UYNVna66864hPZC0Z4Zps8RjmLNer+U1PJK6oGmFsQaOtCK02JyGdv TAYEmlR7L4KET3/ZQYs1qY1v5dW7eWU4d3khsopy26E8vurcebl3y081rG3fZvixEX gBDynhbsdDsNL6AzP4eM31RJ58adC0bBqtc1kauXH+qXvLajnttVgRqAujjmFg/7pP NnC+CstD86v4WdmpKd6+J5NgufRREJZhVdwDx1i2BPnJJo+uNLRDauvvIrMx70/kPE OiuQR6474eL6tfiJG9/g706rDV1LW6oa9HDhu00Zo/DwwsgenArvnDOCXoxUpPfTIb 4EAFzhJ9yvvLw== From: Mark Brown Date: Mon, 31 Jul 2023 14:43:33 +0100 Subject: [PATCH v3 24/36] arm64/ptrace: Expose GCS via ptrace and core files MIME-Version: 1.0 Message-Id: <20230731-arm64-gcs-v3-24-cddf9f980d98@kernel.org> References: <20230731-arm64-gcs-v3-0-cddf9f980d98@kernel.org> In-Reply-To: <20230731-arm64-gcs-v3-0-cddf9f980d98@kernel.org> To: Catalin Marinas , Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Kees Cook , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy Cc: "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Mark Brown X-Mailer: b4 0.13-dev-099c9 X-Developer-Signature: v=1; a=openpgp-sha256; l=4259; i=broonie@kernel.org; h=from:subject:message-id; bh=0QIP38ZumyMQzrMYtc7Z/0L/bXiC+1OudC2zVRODlMU=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBkx7wnGgzojpN5zdFSj8GBe/e35MxJdmr5azLrGhuQ zAaJd5iJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZMe8JwAKCRAk1otyXVSH0MoOB/ 9aNcLSaGjWPcqT/oKLsWBclSvFItKKdzMbWIkF4AgS56t258sb8yBM6z+7Dvip+AsyM0oW5wlzEYqk LS3Hdcp1Cs2/4MEIYoaXRRpmE77HgEeb74JaodRxOak//j0CoirqfszxxUy60R/6VTlp96Ssoau1S4 Mjt8YYQjztaXCE2Yx9rgh6zOudXzm7AQxScLFwfJXfx4YXd53Mv3xaIE8U68zwRJhguXpC7DAOBVSe wGzAwWZ+8Kuwb/3HdQ4iT+qqK1s4ZVBelTlHSqHJOLItbVB62fBEwJNxhIGYPoOCrsUWs/V+xjoYMP mi3MqsudHaYzSgIlovD2GVKCeh0a5V X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Provide a new register type NT_ARM_GCS reporting the current GCS mode and pointer for EL0. Due to the interactions with allocation and deallocation of Guarded Control Stacks we do not permit any changes to the GCS mode via ptrace, only GCSPR_EL0 may be changed. Signed-off-by: Mark Brown --- arch/arm64/include/uapi/asm/ptrace.h | 8 +++++ arch/arm64/kernel/ptrace.c | 59 ++++++++++++++++++++++++++++++++++++ include/uapi/linux/elf.h | 1 + 3 files changed, 68 insertions(+) diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h index 7fa2f7036aa7..0f39ba4f3efd 100644 --- a/arch/arm64/include/uapi/asm/ptrace.h +++ b/arch/arm64/include/uapi/asm/ptrace.h @@ -324,6 +324,14 @@ struct user_za_header { #define ZA_PT_SIZE(vq) \ (ZA_PT_ZA_OFFSET + ZA_PT_ZA_SIZE(vq)) +/* GCS state (NT_ARM_GCS) */ + +struct user_gcs { + __u64 features_enabled; + __u64 features_locked; + __u64 gcspr_el0; +}; + #endif /* __ASSEMBLY__ */ #endif /* _UAPI__ASM_PTRACE_H */ diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index d7f4f0d1ae12..c159090bc731 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include #include @@ -1390,6 +1391,51 @@ static int tagged_addr_ctrl_set(struct task_struct *target, const struct } #endif +#ifdef CONFIG_ARM64_GCS +static int gcs_get(struct task_struct *target, + const struct user_regset *regset, + struct membuf to) +{ + struct user_gcs user_gcs; + + if (target == current) + gcs_preserve_current_state(); + + user_gcs.features_enabled = target->thread.gcs_el0_mode; + user_gcs.features_locked = target->thread.gcs_el0_locked; + user_gcs.gcspr_el0 = target->thread.gcspr_el0; + + return membuf_write(&to, &user_gcs, sizeof(user_gcs)); +} + +static int gcs_set(struct task_struct *target, const struct + user_regset *regset, unsigned int pos, + unsigned int count, const void *kbuf, const + void __user *ubuf) +{ + int ret; + struct user_gcs user_gcs; + + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &user_gcs, 0, -1); + if (ret) + return ret; + + if (user_gcs.features_enabled & ~PR_SHADOW_STACK_SUPPORTED_STATUS_MASK) + return -EINVAL; + + /* Do not allow enable via ptrace */ + if ((user_gcs.features_enabled & PR_SHADOW_STACK_ENABLE) && + !!(target->thread.gcs_el0_mode & PR_SHADOW_STACK_ENABLE)) + return -EBUSY; + + target->thread.gcs_el0_mode = user_gcs.features_enabled; + target->thread.gcs_el0_locked = user_gcs.features_locked; + target->thread.gcspr_el0 = user_gcs.gcspr_el0; + + return 0; +} +#endif + enum aarch64_regset { REGSET_GPR, REGSET_FPR, @@ -1418,6 +1464,9 @@ enum aarch64_regset { #ifdef CONFIG_ARM64_TAGGED_ADDR_ABI REGSET_TAGGED_ADDR_CTRL, #endif +#ifdef CONFIG_ARM64_GCS + REGSET_GCS, +#endif }; static const struct user_regset aarch64_regsets[] = { @@ -1568,6 +1617,16 @@ static const struct user_regset aarch64_regsets[] = { .set = tagged_addr_ctrl_set, }, #endif +#ifdef CONFIG_ARM64_GCS + [REGSET_GCS] = { + .core_note_type = NT_ARM_GCS, + .n = sizeof(struct user_gcs) / sizeof(u64), + .size = sizeof(u64), + .align = sizeof(u64), + .regset_get = gcs_get, + .set = gcs_set, + }, +#endif }; static const struct user_regset_view user_aarch64_view = { diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index 0c8cf359ea5b..00f698a2ab17 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -438,6 +438,7 @@ typedef struct elf64_shdr { #define NT_ARM_SSVE 0x40b /* ARM Streaming SVE registers */ #define NT_ARM_ZA 0x40c /* ARM SME ZA registers */ #define NT_ARM_ZT 0x40d /* ARM SME ZT registers */ +#define NT_ARM_GCS 0x40e /* ARM GCS state */ #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 */