From patchwork Tue Aug 22 13:56:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13360848 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 6BDBCEE49AE for ; Tue, 22 Aug 2023 14:07:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236476AbjHVOHG (ORCPT ); Tue, 22 Aug 2023 10:07:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233411AbjHVOHF (ORCPT ); Tue, 22 Aug 2023 10:07:05 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BB20E6F; Tue, 22 Aug 2023 07:06:38 -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 EFFD665433; Tue, 22 Aug 2023 14:05:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85016C433CA; Tue, 22 Aug 2023 14:05:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692713138; bh=DpZhswk3pFnI/AW797F4UsIB+Gb0Tunks8tC2WEtzQY=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=KI9BiFgEPLnl0qQJLEI+qSuGWe/L9LZyjFgjB9jr5fxGDXI9pth2VTDN7uPhQohQr FPROvWnamDdcixi9r9PLXzgy7fBu1IASt0nBftU/a+CrePaR4k+uwV6Qm3QLV3wceE G+xRSjpd3Febv1tw1YY/fPGfGAjXXprlmT+5ZL9QxOqpTNB4/vpKMo8r8N42EhhTdn dcxnC2nJXk0dlJSiE/jbqdwc1gqpHyqUJi3f1xxdvdaYKlle8unIsiODLk1W8yFPNE ty8akJsFZuQUWrp7A/ufu8MjgvLkTqGhrMJnBxxnMmfU043269sIcHsmKZPjBcPDHW riyQrtp6iKh8g== From: Mark Brown Date: Tue, 22 Aug 2023 14:56:58 +0100 Subject: [PATCH v5 25/37] arm64/ptrace: Expose GCS via ptrace and core files MIME-Version: 1.0 Message-Id: <20230822-arm64-gcs-v5-25-9ef181dd6324@kernel.org> References: <20230822-arm64-gcs-v5-0-9ef181dd6324@kernel.org> In-Reply-To: <20230822-arm64-gcs-v5-0-9ef181dd6324@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-034f2 X-Developer-Signature: v=1; a=openpgp-sha256; l=4259; i=broonie@kernel.org; h=from:subject:message-id; bh=DpZhswk3pFnI/AW797F4UsIB+Gb0Tunks8tC2WEtzQY=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBk5MAD4UAuvxPCD+2JS/1OYO1FSVdbr2FHfLZY2xqB xvsTtfOJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZOTAAwAKCRAk1otyXVSH0Lv4B/ 90Fqj+pTPrC/kAVg7I0H0jlhgLYerpXbxl/3W5uR9/E9BxRJzwjqwMKuibxpRI18gc7vazYb560u+o TdllO1UdCgUHyuyYTi+zHu2FRjhPDDJVrp9LnGebV9afCbvZtI3iAqIV30KRZTT9iXWXq5NSxNRCFf sHq9rxGA4snGp0pKG4RnYt4HWH4KHBeTucSGJEGOt1S2LLEsk0AmjNO3BjP4gpY2IccsNGfnp6Zni0 6U8db/6Vp/yjXq4JsER/LNeCm9rUfwKaPFDYoBLgpOFlRFNDYa+Ou7wBmbn/naBnp2Y2+G3sWdCDU8 /PB6fkyY7lP10BIhQnIlA9YhiY9WN3 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 187aa2b175b4..308a8a149717 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include #include @@ -1408,6 +1409,51 @@ 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, @@ -1436,6 +1482,9 @@ 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[] = { @@ -1586,6 +1635,16 @@ 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 */