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=-24.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 B84F9C433DB for ; Wed, 27 Jan 2021 23:00:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9037064DE6 for ; Wed, 27 Jan 2021 23:00:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233434AbhA0W7u (ORCPT ); Wed, 27 Jan 2021 17:59:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:39082 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232220AbhA0W4T (ORCPT ); Wed, 27 Jan 2021 17:56:19 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id CE60B64DD7; Wed, 27 Jan 2021 22:46:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611787564; bh=uROissysf+CU6pZjzSRwu08EBosF7bzlGdIMuNFG3zI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JOQIW5BS1ZFMSzOuJ9u+9XhodGwsSr5aV8xy1886Ou4+dKQzm5cisXenswjogpF30 jJUQM1o28F4IPO9y8MMxxovXTcOmucI4uoxm1XOvWYtaf+2NSupdtKT9llqm9Mtlnt cXrtGy2xjs5dc8dqWgNBzSu+xfOKiwXuZvkaKpckUb6FFLOHPBAa1ZSfYWzSFc+c/r lstY66RnwNggohTgRyG4bFGr18473Zt+KSA1AeREgb2+v2QT3YqVMOK3BvsCtm2/ZU tpLMfXgksSIAP+M5tx3UAUOZANRqUPSZaiAbf2Y5oFa2WkeL0GHocTIcksUq6VCxio lz8Synao9jD7w== From: Nathan Chancellor To: Andrew Morton Cc: Kees Cook , Nick Desaulniers , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Nathan Chancellor Subject: [PATCH v3] ubsan: Implement __ubsan_handle_alignment_assumption Date: Wed, 27 Jan 2021 15:44:52 -0700 Message-Id: <20210127224451.2587372-1-nathan@kernel.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210113001242.1662786-1-natechancellor@gmail.com> References: <20210113001242.1662786-1-natechancellor@gmail.com> MIME-Version: 1.0 X-Patchwork-Bot: notify Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Archived-At: List-Archive: List-Post: When building ARCH=mips 32r2el_defconfig with CONFIG_UBSAN_ALIGNMENT: ld.lld: error: undefined symbol: __ubsan_handle_alignment_assumption >>> referenced by slab.h:557 (include/linux/slab.h:557) >>> main.o:(do_initcalls) in archive init/built-in.a >>> referenced by slab.h:448 (include/linux/slab.h:448) >>> do_mounts_rd.o:(rd_load_image) in archive init/built-in.a >>> referenced by slab.h:448 (include/linux/slab.h:448) >>> do_mounts_rd.o:(identify_ramdisk_image) in archive init/built-in.a >>> referenced 1579 more times Implement this for the kernel based on LLVM's handleAlignmentAssumptionImpl because the kernel is not linked against the compiler runtime. Link: https://github.com/ClangBuiltLinux/linux/issues/1245 Link: https://github.com/llvm/llvm-project/blob/llvmorg-11.0.1/compiler-rt/lib/ubsan/ubsan_handlers.cpp#L151-L190 Acked-by: Kees Cook Signed-off-by: Nathan Chancellor --- v2 -> v3: * Add prototype right above definition to avoid introducing a warning with W=1. v1 -> v2: * Use __ffs instead of ffs because due to size of input (unsigned long vs int) and we want a zero based index (Nick Desaulniers). * Pick up Kees's ack. lib/ubsan.c | 31 +++++++++++++++++++++++++++++++ lib/ubsan.h | 6 ++++++ 2 files changed, 37 insertions(+) diff --git a/lib/ubsan.c b/lib/ubsan.c index 3e3352f3d0da..bec38c64d6a6 100644 --- a/lib/ubsan.c +++ b/lib/ubsan.c @@ -427,3 +427,34 @@ void __ubsan_handle_load_invalid_value(void *_data, void *val) ubsan_epilogue(); } EXPORT_SYMBOL(__ubsan_handle_load_invalid_value); + +void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, + unsigned long align, + unsigned long offset); +void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, + unsigned long align, + unsigned long offset) +{ + struct alignment_assumption_data *data = _data; + unsigned long real_ptr; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, "alignment-assumption"); + + if (offset) + pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed", + align, offset, data->type->type_name); + else + pr_err("assumption of %lu byte alignment for pointer of type %s failed", + align, data->type->type_name); + + real_ptr = ptr - offset; + pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes", + offset ? "offset " : "", BIT(real_ptr ? __ffs(real_ptr) : 0), + real_ptr & (align - 1)); + + ubsan_epilogue(); +} +EXPORT_SYMBOL(__ubsan_handle_alignment_assumption); diff --git a/lib/ubsan.h b/lib/ubsan.h index 7b56c09473a9..9a0b71c5ff9f 100644 --- a/lib/ubsan.h +++ b/lib/ubsan.h @@ -78,6 +78,12 @@ struct invalid_value_data { struct type_descriptor *type; }; +struct alignment_assumption_data { + struct source_location location; + struct source_location assumption_location; + struct type_descriptor *type; +}; + #if defined(CONFIG_ARCH_SUPPORTS_INT128) typedef __int128 s_max; typedef unsigned __int128 u_max; base-commit: 6ee1d745b7c9fd573fba142a2efdad76a9f1cb04 -- 2.30.0