From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9B1257A for ; Fri, 13 May 2022 20:22:18 +0000 (UTC) Received: by mail-pj1-f74.google.com with SMTP id i12-20020a17090a64cc00b001dccafbd493so6690880pjm.3 for ; Fri, 13 May 2022 13:22:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=f+v85zCmompJWMzZo0Lo44MXyCG4blaViTEubU7Q5pk=; b=MESMouEFY2G4SFqcafmefQWoFCP7ps3QB1tZ46af/jtYe6cn5zcxOwxTwft4N8E1NQ +UuIHuj5VEcDhbnPdN1c0OsP0m7BBsr8MIip1QKYnYg6zeoMy088Pl9eVtEl5uK0saGo XtR42j6pIymFijnyo6XcDzAed95J3W7UJ8IviGf6zqWy//NvXfkBj+GJVwnuCt9lcOFH Z4nLVMl3mKjxxgvlkFCBZewyyE5+nMu5wsw21EWC3AA96x/4tIfvIZsY75Roh12akrho avQ626Wx3RZtmrx/IEAGQSI1UB2H2FZgt4JgCTLLjEpfu6Qdx7RMgQixkMV7q4jIt2ca yN7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=f+v85zCmompJWMzZo0Lo44MXyCG4blaViTEubU7Q5pk=; b=FAtrFwd1UJ98IDhfBAScjOpjEnod1O2739dSlX/jcC5yliqgYBvbBTMUnzrkqmg86A VvE/8AMAr/EsRGVZ+J4r+SkTSGA1mfng/RIU3xe00GWg8+LARh+j3HuBw4OWTqdyr4QJ c9zuI9G6GUzHrtmWOZjKOVAGLE7WW3RVsvIlNTUc/71NWK7rtuGORA6qk8aARoSJ2RnJ 7GAKLXEbr1/D4K+kUwy2e5CUTpveULbIruLY7vI24D0Bs9AUE8qy3vJjMBTBhweyBD2v 19hDgJm/eGDcHbdGWAkh+bXdpvfUeAega098afa8GDQ1a7swsYLpOIaK7yKjxa5SQ7C/ 6IPQ== X-Gm-Message-State: AOAM532Gx0rltcnhjOctH/0w5LOslXdroQ0oEHxXzJY9NHIigSOrk7wY wjHxgKEZpJVYbyOLTZs9JM73RwHBvpVetthzY1Y= X-Google-Smtp-Source: ABdhPJwfcFjFJSZbXy4dFXWlYx0UTPoVmJGQDFAqlwZxMLFtphKEHH2VS3sWnVMuhcTFKwv+pj6ccI88tY8WuVvcx7E= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:e0:c17e:c2dc:13eb]) (user=samitolvanen job=sendgmr) by 2002:aa7:88d1:0:b0:510:3ee2:3f25 with SMTP id k17-20020aa788d1000000b005103ee23f25mr6048858pff.41.1652473338024; Fri, 13 May 2022 13:22:18 -0700 (PDT) Date: Fri, 13 May 2022 13:21:45 -0700 In-Reply-To: <20220513202159.1550547-1-samitolvanen@google.com> Message-Id: <20220513202159.1550547-8-samitolvanen@google.com> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20220513202159.1550547-1-samitolvanen@google.com> X-Developer-Key: i=samitolvanen@google.com; a=openpgp; fpr=35CCFB63B283D6D3AEB783944CB5F6848BBC56EE X-Developer-Signature: v=1; a=openpgp-sha256; l=2369; h=from:subject; bh=TboG0ryIg4JgbMTsV2OXgx0SX/UFOnu1UldMJxVt8Po=; b=owEB7QES/pANAwAKAUy19oSLvFbuAcsmYgBifr3j4WY4BkbqYI6dC/ZfJbPOV8T4fFdqndEpsBM/ hV5fbI2JAbMEAAEKAB0WIQQ1zPtjsoPW0663g5RMtfaEi7xW7gUCYn694wAKCRBMtfaEi7xW7gMxC/ 4pxFRx4HmL+KUme/ZjGLLUnoT9FbQCcyon3/8qR0GI2jddZNW3zIDnAihW+p9AayVGcFBw/cucqeD6 aXfUmw4i5Efc8tn7VJtIfgwBMJEeT97CO0koKO1cJfqhLgyPXQDEp5x3qbmJIPEvXkFbMwd9T0no37 HPRxilpeC2rxuO4N07WfXvHHMyvz873twQyminhgkImNDn8LWrzNZD2TYLXYTmCSbYCFGu5tXSDEhw ZHK28QweaPZFMYbk0wN8AvV4LKrTN0/LJoOuYP485lixfm/DeCd/25TzV57VDBt4ZfW/VlEHh4RkgX cFHax638u12jlXDQHJK2SS7MLmlojw27IhKgnEszme11T0yFry4yEqhhcfa1m4PMtHA6DBWFAZjYwA CCw/0R+hbTncTA8X3SMH0fWDvX+13ZsaiGA+rH7eLAG+M6F+T6JF6K+96BK3G6xvoablbMV270wlb8 +GZCYAV3P1rotvaWrcFV5saGNcr9RR12T6hfVDEQ+LtAA= X-Mailer: git-send-email 2.36.0.550.gb090851708-goog Subject: [RFC PATCH v2 07/21] cfi: Add type helper macros From: Sami Tolvanen To: linux-kernel@vger.kernel.org Cc: Kees Cook , Josh Poimboeuf , Peter Zijlstra , x86@kernel.org, Catalin Marinas , Will Deacon , Mark Rutland , Nathan Chancellor , Nick Desaulniers , Joao Moreira , Sedat Dilek , Steven Rostedt , linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" With CONFIG_CFI_CLANG, assembly functions called indirectly from C code must be annotated with type identifiers to pass CFI checking. The compiler emits a __kcfi_typeid_ symbol for each address-taken function declaration in C, which contains the expected type identifier. Add typed versions of SYM_FUNC_START and SYM_FUNC_START_ALIAS, which emit the type identifier before the function. Signed-off-by: Sami Tolvanen --- include/linux/cfi_types.h | 57 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 include/linux/cfi_types.h diff --git a/include/linux/cfi_types.h b/include/linux/cfi_types.h new file mode 100644 index 000000000000..dd16e755a197 --- /dev/null +++ b/include/linux/cfi_types.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Clang Control Flow Integrity (CFI) type definitions. + */ +#ifndef _LINUX_CFI_TYPES_H +#define _LINUX_CFI_TYPES_H + +#ifdef CONFIG_CFI_CLANG +#include + +#ifdef __ASSEMBLY__ +/* + * Use the __kcfi_typeid_ type identifier symbol to + * annotate indirectly called assembly functions. The compiler emits + * these symbols for all address-taken function declarations in C + * code. + */ +#ifndef __CFI_TYPE +#define __CFI_TYPE(name) \ + .4byte __kcfi_typeid_##name +#endif + +#define SYM_TYPED_ENTRY(name, fname, linkage, align...) \ + linkage(name) ASM_NL \ + align ASM_NL \ + __CFI_TYPE(fname) ASM_NL \ + name: + +#define __SYM_TYPED_FUNC_START_ALIAS(name, fname) \ + SYM_TYPED_ENTRY(name, fname, SYM_L_GLOBAL, SYM_A_ALIGN) + +#define __SYM_TYPED_FUNC_START(name, fname) \ + SYM_TYPED_ENTRY(name, fname, SYM_L_GLOBAL, SYM_A_ALIGN) + +#endif /* __ASSEMBLY__ */ + +#else /* CONFIG_CFI_CLANG */ + +#ifdef __ASSEMBLY__ +#define __SYM_TYPED_FUNC_START_ALIAS(name, fname) \ + SYM_FUNC_START_ALIAS(name) + +#define __SYM_TYPED_FUNC_START(name, fname) \ + SYM_FUNC_START(name) +#endif /* __ASSEMBLY__ */ + +#endif /* CONFIG_CFI_CLANG */ + +#ifdef __ASSEMBLY__ +#define SYM_TYPED_FUNC_START_ALIAS(name) \ + __SYM_TYPED_FUNC_START_ALIAS(name, name) + +#define SYM_TYPED_FUNC_START(name) \ + __SYM_TYPED_FUNC_START(name, name) +#endif /* __ASSEMBLY__ */ + +#endif /* _LINUX_CFI_TYPES_H */ -- 2.36.0.550.gb090851708-goog