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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 C4410C4BA06 for ; Thu, 27 Feb 2020 04:45:18 +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 8F95721D7E for ; Thu, 27 Feb 2020 04:45:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="P7tgEJBx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F95721D7E 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-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=zUnPSXuawSVzj3N0udTR6k1W8mblG8zlBdAE7Xz8T+k=; b=P7tgEJBxdOTEHsul8mzm0d/OC idAZ1E6507NYGVqoZYGnwVe6+doVZySI9AkgMSIAfJQKY0RDXEZpIvGcC6Rjn4UnIHDfE1N/uAwD3 Vik63shRN6/gyh0QKmHonX98CbaRzo5S6c9lzJeeWnWrMEgDz0ktd5IJmTwQnkKgWq+igpspimrOM NgIFW7DEgqhy/NPVzxh0aQK6EGx1DJu+XfQ9OlzxmHsJ6YQH+e/hRe00PCSaR7ZbsikGi3XPVr4jW FseLeq7S2mRlWbw5KItKjCRcgYMf5miYRT8BLyzsqzZ5Au9Xc/nxDquuGLNZ/LY5DYfi06GsofYZ5 XQntMtiDA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j7B30-0007rn-0U; Thu, 27 Feb 2020 04:45:18 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j7B2w-0007ql-Rt for linux-arm-kernel@lists.infradead.org; Thu, 27 Feb 2020 04:45:16 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1595630E; Wed, 26 Feb 2020 20:45:11 -0800 (PST) Received: from [10.162.16.120] (a075563-lin.blr.arm.com [10.162.16.120]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9C5943F73B; Wed, 26 Feb 2020 20:45:04 -0800 (PST) Subject: Re: [PATCH v7 05/11] arm64: elf: Enable BTI at exec based on ELF program properties To: Mark Brown , Catalin Marinas , Will Deacon References: <20200226155714.43937-1-broonie@kernel.org> <20200226155714.43937-6-broonie@kernel.org> From: Amit Kachhap Message-ID: Date: Thu, 27 Feb 2020 10:15:06 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20200226155714.43937-6-broonie@kernel.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200226_204514_991588_CB1C04F8 X-CRM114-Status: GOOD ( 25.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Elliott , Peter Zijlstra , Andrew Jones , Vincenzo Frascino , linux-arch@vger.kernel.org, Marc Zyngier , Eugene Syromiatnikov , Szabolcs Nagy , Dave Martin , "H . J . Lu" , Yu-cheng Yu , Kees Cook , Arnd Bergmann , Jann Horn , Richard Henderson , =?UTF-8?Q?Kristina_Mart=c5=a1enko?= , Alexander Viro , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Florian Weimer , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Sudakshina Das Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Mark, On 2/26/20 9:27 PM, Mark Brown wrote: > From: Dave Martin > > For BTI protection to be as comprehensive as possible, it is > desirable to have BTI enabled from process startup. If this is not > done, the process must use mprotect() to enable BTI for each of its > executable mappings, but this is painful to do in the libc startup > code. It's simpler and more sound to have the kernel do it > instead. > > To this end, detect BTI support in the executable (or ELF > interpreter, as appropriate), via the > NT_GNU_PROGRAM_PROPERTY_TYPE_0 note, and tweak the initial prot > flags for the process' executable pages to include PROT_BTI as > appropriate. > > Signed-off-by: Dave Martin > Signed-off-by: Mark Brown > --- > arch/arm64/Kconfig | 3 +++ > arch/arm64/include/asm/elf.h | 51 ++++++++++++++++++++++++++++++++++++ > arch/arm64/kernel/process.c | 19 ++++++++++++++ > include/uapi/linux/elf.h | 6 +++++ > 4 files changed, 79 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index e37f4f07b990..d65d226a77ec 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -9,6 +9,7 @@ config ARM64 > select ACPI_MCFG if (ACPI && PCI) > select ACPI_SPCR_TABLE if ACPI > select ACPI_PPTT if ACPI > + select ARCH_BINFMT_ELF_STATE > select ARCH_CLOCKSOURCE_DATA > select ARCH_HAS_DEBUG_VIRTUAL > select ARCH_HAS_DEVMEM_IS_ALLOWED > @@ -33,6 +34,7 @@ config ARM64 > select ARCH_HAS_SYSCALL_WRAPPER > select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT > select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST > + select ARCH_HAVE_ELF_PROT > select ARCH_HAVE_NMI_SAFE_CMPXCHG > select ARCH_INLINE_READ_LOCK if !PREEMPTION > select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION > @@ -62,6 +64,7 @@ config ARM64 > select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION > select ARCH_KEEP_MEMBLOCK > select ARCH_USE_CMPXCHG_LOCKREF > + select ARCH_USE_GNU_PROPERTY if BINFMT_ELF > select ARCH_USE_QUEUED_RWLOCKS > select ARCH_USE_QUEUED_SPINLOCKS > select ARCH_SUPPORTS_MEMORY_FAILURE > diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h > index b618017205a3..c72e381fa86d 100644 > --- a/arch/arm64/include/asm/elf.h > +++ b/arch/arm64/include/asm/elf.h > @@ -114,7 +114,11 @@ > > #ifndef __ASSEMBLY__ > > +#include > #include > +#include > +#include > +#include > #include /* for signal_minsigstksz, used by ARCH_DLINFO */ > > typedef unsigned long elf_greg_t; > @@ -224,6 +228,53 @@ extern int aarch32_setup_additional_pages(struct linux_binprm *bprm, > > #endif /* CONFIG_COMPAT */ > > +struct arch_elf_state { > + int flags; > +}; > + > +#define ARM64_ELF_BTI (1 << 0) > + > +#define INIT_ARCH_ELF_STATE { \ > + .flags = 0, \ > +} > + > +static inline int arch_parse_elf_property(u32 type, const void *data, > + size_t datasz, bool compat, > + struct arch_elf_state *arch) > +{ > + /* No known properties for AArch32 yet */ > + if (IS_ENABLED(CONFIG_COMPAT) && compat) > + return 0; > + > + if (type == GNU_PROPERTY_AARCH64_FEATURE_1_AND) { > + const u32 *p = data; > + > + if (datasz != sizeof(*p)) > + return -ENOEXEC; > + > + if (IS_ENABLED(CONFIG_ARM64_BTI) && > + system_supports_bti() && system_supports_bti() has inbuilt CONFIG_ARM64_BTI config check. For all the patch in the series. Reviewed-by: Amit Daniel Kachhap Cheers, Amit > + (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) > + arch->flags |= ARM64_ELF_BTI; > + } > + > + return 0; > +} > + > +static inline int arch_elf_pt_proc(void *ehdr, void *phdr, > + struct file *f, bool is_interp, > + struct arch_elf_state *state) > +{ > + return 0; > +} > + > +static inline int arch_check_elf(void *ehdr, bool has_interp, > + void *interp_ehdr, > + struct arch_elf_state *state) > +{ > + return 0; > +} > + > #endif /* !__ASSEMBLY__ */ > > #endif > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 00626057a384..b8e3faa8d406 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -11,6 +11,7 @@ > > #include > #include > +#include > #include > #include > #include > @@ -18,6 +19,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -654,3 +656,20 @@ asmlinkage void __sched arm64_preempt_schedule_irq(void) > if (system_capabilities_finalized()) > preempt_schedule_irq(); > } > + > +#ifdef CONFIG_BINFMT_ELF > +int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state, > + bool has_interp, bool is_interp) > +{ > + if (is_interp != has_interp) > + return prot; > + > + if (!(state->flags & ARM64_ELF_BTI)) > + return prot; > + > + if (prot & PROT_EXEC) > + prot |= PROT_BTI; > + > + return prot; > +} > +#endif > diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h > index 20900f4496b7..c6dd0215482e 100644 > --- a/include/uapi/linux/elf.h > +++ b/include/uapi/linux/elf.h > @@ -448,4 +448,10 @@ typedef struct elf64_note { > Elf64_Word n_type; /* Content type */ > } Elf64_Nhdr; > > +/* .note.gnu.property types for EM_AARCH64: */ > +#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000 > + > +/* Bits for GNU_PROPERTY_AARCH64_FEATURE_1_BTI */ > +#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0) > + > #endif /* _UAPI_LINUX_ELF_H */ > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel