From patchwork Tue Jun 25 14:57:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13711421 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3E6C3178385; Tue, 25 Jun 2024 15:03:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719327820; cv=none; b=ufCie8YNzIY1qLtm4LZ1PpXK6aGDZ4eUdv4/5Fscyrujon2afaIRlaEERubGC1JOfPopJbCeP96/FmfF2+24KOpSvSnIDIsEHe9N7lzmY8IAQxwZR8CFKd3azzRFQtmjSTH+ahqMIAcIz9fwOclAkA8/7waIVQO+1KCxLAtflxo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719327820; c=relaxed/simple; bh=qLuXO3WTZsbuYPpzI7zPKGWHTzDvnQwqGL+bk49RD84=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=AGTeMcbVOXr0OpEnusSUpWpZFs9ybc4WmK/e7W1i3Z9MvVA1hnH+6Tk6IuOJfdqBa0bEYKbNxCgKar7rhbX/gq5ot6DUxCuqRJvg7hBkP2Q66GldSgB/cIAT5EUifxCnAm2xEAN5m3MndNNW9XcIDkPApMcAhLLOgkQTFkdi3ac= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hkDTstIo; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hkDTstIo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29B1CC4AF0E; Tue, 25 Jun 2024 15:03:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719327819; bh=qLuXO3WTZsbuYPpzI7zPKGWHTzDvnQwqGL+bk49RD84=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=hkDTstIokDbII+NgDXV9ygGKcAbZfi8xcMVYYBinLFGzUbWA3/1aC/jkLX9TnILxY CEketVMlSoxdyZPQm6qRfTzTiYkPed/+304fFSUpPpj1120NlP7ix/o2Z/nkWcoRfu gJmZwP/Kc885SgOeQkoIhj+q8he90o8ZC8GY6VtWUJgCdsfuk6WoiTiSgs01UoVtu5 W6X+h6T77fpf98Hd+jPAuXX4SS2uNEXCOOkhhYZgfeqW7dKQTy7zQAa8kI5Ehz1OE/ t/WFvdAS6r389/Xi4ws2uXHHfq0b+wuu58cA7xdK0rm+qyV2+vu4ltK5osvm0by8SB cHhG49/bgy6Sw== From: Mark Brown Date: Tue, 25 Jun 2024 15:57:53 +0100 Subject: [PATCH v9 25/39] arm64/ptrace: Expose GCS via ptrace and core files Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240625-arm64-gcs-v9-25-0f634469b8f0@kernel.org> References: <20240625-arm64-gcs-v9-0-0f634469b8f0@kernel.org> In-Reply-To: <20240625-arm64-gcs-v9-0-0f634469b8f0@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 , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , Kees Cook Cc: "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , Thiago Jung Bauermann , Ross Burton , 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 0.14-dev-d4707 X-Developer-Signature: v=1; a=openpgp-sha256; l=4329; i=broonie@kernel.org; h=from:subject:message-id; bh=qLuXO3WTZsbuYPpzI7zPKGWHTzDvnQwqGL+bk49RD84=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBmetuGTfR0xNzu1+84q9CMfy/yxjpeiuKLfYT2znrk GoY1/N+JATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZnrbhgAKCRAk1otyXVSH0G+jB/ sG6g96RCMiqgpbeydGZ6sxqiXuFMRbeInyskwKusJZFWMvPLBsIZX8FlYwjIxI2gTyJlNcNnGQmE5R NY2i8h4sxZMNgre4QDrQ6wdkv2cwZ9bO0hWIFqTFjNqSN9iUX6ZIKMwgvbZsHGR4zvGmhMqMY9i1ck HKr4syx2DDMAIUdAZlQkdkekG8w/X5QwNY9ueCZdNRgywiImEMQSOKZPA4QU7fu2W+SHjDD/0V5DF3 54Z7V9ECYDcOIrBX/dnHAADN3GLG3H8zwa8K0RfcXl1SBbW9voHlHgTqubiMscyG6ZDHLdrktic433 MSUgxVm08hXgJhgbB89Ac4XSk5AZQr X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB 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. Reviewed-by: Thiago Jung Bauermann 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 0d022599eb61..9db0b669fee3 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include #include @@ -1440,6 +1441,51 @@ 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, @@ -1469,6 +1515,9 @@ 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[] = { @@ -1628,6 +1677,16 @@ 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 b54b313bcf07..77d4910bbb9d 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -441,6 +441,7 @@ typedef struct elf64_shdr { #define NT_ARM_ZA 0x40c /* ARM SME ZA registers */ #define NT_ARM_ZT 0x40d /* ARM SME ZT registers */ #define NT_ARM_FPMR 0x40e /* ARM floating point mode register */ +#define NT_ARM_GCS 0x40f /* 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 */