From patchwork Mon Jul 24 12:46:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13324711 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 88D74C001B0 for ; Mon, 24 Jul 2023 12:52:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231454AbjGXMw1 (ORCPT ); Mon, 24 Jul 2023 08:52:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230447AbjGXMvc (ORCPT ); Mon, 24 Jul 2023 08:51:32 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8365A2695; Mon, 24 Jul 2023 05:49:33 -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 5881861159; Mon, 24 Jul 2023 12:49:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8FE5C43395; Mon, 24 Jul 2023 12:49:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690202972; bh=0QIP38ZumyMQzrMYtc7Z/0L/bXiC+1OudC2zVRODlMU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=S2by7fTwtza1j7xK4vbG8/TPOT2ELIzrq6FBkXgnpc6RctcJGbowE2cdinUL4ulWk 7kgfWBLa3QPeh67Bq/HwoBGJPM3YKT3ieNSZa3vjgLZvwW6V298RjM3nH+udx3CZ7C BalpvWV9J6jGIyyXUu5c/FlFhlhXbavjPDUawnWhwgNT/Wf2N/860D5yMszrT+6AnJ u25J44GdZV9Dr/bbXzh20oPEcGz+lcIPgUy2JEBop64BJ1G/yRUV/1MQNCVuhE2pbT JmF6sNtU8bcS1oP52Rijepzl0lILyOL3xAYAStMey/6YrpMjkwefKWab1SHoNzf58u lAzw2ITdTjNfA== From: Mark Brown Date: Mon, 24 Jul 2023 13:46:11 +0100 Subject: [PATCH v2 24/35] arm64/ptrace: Expose GCS via ptrace and core files MIME-Version: 1.0 Message-Id: <20230724-arm64-gcs-v2-24-dc2c1d44c2eb@kernel.org> References: <20230724-arm64-gcs-v2-0-dc2c1d44c2eb@kernel.org> In-Reply-To: <20230724-arm64-gcs-v2-0-dc2c1d44c2eb@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/pANAwAKASTWi3JdVIfQAcsmYgBkvnKnsKf0W3lFoB635rzoGTaz2yndy/CskcQVKCzm 47uSwjaJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZL5ypwAKCRAk1otyXVSH0AebB/ 9puHQ2nwuUf5/vMSPRgsFleh5e8Wzb39H2Z5TEz9UwGoC/oIWJUEWVBE4rq/Rh28vaZI7jO8ZJyAta 21BWYzIEGw6stgm713SrMoFk2ZjG7RqY0nnGCWqcnSEb0pNnKbzaXp0reUarS0StFUw6hli3dYbmBN QtVbuiA+19RLe6CiXaEG8sQecaHQquhFMUjYf2OOpLdfB8IzlPHpE93YRBqRK8t1AcKPzkGab0+uN4 FjBtounVbAZNw2iobITFysaexYdZPhDsMqBbufwQGQhzhsXveM2YJWEjo3+yvHwtajHgHDwAjJpdvo 1whVPHF41mLonD9s5b5HGyBbHehGOz 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 */