From patchwork Thu Apr 8 18:28:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 12192245 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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 0A249C433B4 for ; Thu, 8 Apr 2021 18:32:48 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 6B72A610A8 for ; Thu, 8 Apr 2021 18:32:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B72A610A8 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Cc:To:From:Subject:References:Mime-Version: Message-Id:In-Reply-To:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=BBudzDP3uTEClE7KNurJtWEds30LA2AflUTlT9CO1KU=; b=ai2XOIwloxrfb/ KruBFowtIA+uVjGOGsyqIHEDoTV/0rf3rDCDRuYZVjwGKbfWoBXAO48BHRDRb6yqn9diRU9qaZE66 X1Yhlneppju7/1WoG2ybzl5gmeBx/bBT4sBHs9S/N8OMFBSi2SjDXpKTWdHI9jkzWflqOkSTScw2q tDY2SQhpAJ/eVHkrIwk3Kvj0l3Ug4573beTi4BMEVeBEl9nAcFUXNKgUYclyhWz0l9iSJ/DRWcXxl VlAl6cCX+Ydks1lguxmwuVk69pCLJlpJbt+hlvkqNVdB/g48HYwmbFy0sFvo4Dw6i10Dr32gWXMja 5kQrP7bH1xSO4sL1x9/A==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lUZQL-008vHP-NJ; Thu, 08 Apr 2021 18:30:38 +0000 Received: from mail-yb1-xb4a.google.com ([2607:f8b0:4864:20::b4a]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lUZOt-008uh6-Ed for linux-arm-kernel@lists.infradead.org; Thu, 08 Apr 2021 18:29:10 +0000 Received: by mail-yb1-xb4a.google.com with SMTP id n13so2841852ybp.14 for ; Thu, 08 Apr 2021 11:28:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=eRIdrbJ2jhHVLL9Tut/j9YYL8eIOqR89a+xPlg5BO0U=; b=nmyke+h8npDMiaqZwmNe2cMGG5hnU/u86z+9PT3d46wvKA7EcCFmI0rQdqzR05Y94d x+FoWT2ztku/VLu13xl6nOzxWcgAQBZNzaVQoRT/BZKY/QCn5viNJODflkqOHL2h8bIc aXPxyU21LsZKarOM3mV+jnfOkvN12Im/BNNAstmefU7NUVKXda8sDV56EdzQGZkRH6HI Ge28ESdL5igzDlIGSLdtjCKbzqfFWKAA99mnu1WYMj3ofZprEP9yhJ6F5n03KpOYXGRd 9RB68j79aY/kCAHYgMOUSzHniKYM03/nbKN1xwcZ+T/TTnJ7hc/Hh/o5UhWr0z4dfbls JpkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=eRIdrbJ2jhHVLL9Tut/j9YYL8eIOqR89a+xPlg5BO0U=; b=R/5xQ3NQOvhFC+jMrx7uo9DPu9vLR67ctvxoeCiPzO710NJekNxTRrvPb4NoEpI1kK RF/2S+Mx2qseviU4lHFDciPpF9Q6kZx1KXEAZFQlYgHzmQcPr4bImPjqwElNr/NYP8C4 GwyZ/nPo2rIZ16rfs2D28lu0kue7IgFHxrUSKkNsQXSVfHAmqZa2sXpoFWLKnva+kAaf HmQSJMCuMGiumDL8whpZ4FovZ8F35iL4azxGkuaw0sEiTYR7lRpQUER+hOv8ugqgHIIo k8IN6ZItnCAcrCjAlcBQtnRuYQzT3nfBuJX52gLkmIiAi0Sd7r+KfiGzjFuakHSO/Qv5 ELyw== X-Gm-Message-State: AOAM532p/N/c24bfd566q8HOLpHPQFx+nH/75d5sl3OeP1H+UUnFUugU +wRwSrqFNntEdjHYlH+eRiPyk0Tbo1Juvplpa0g= X-Google-Smtp-Source: ABdhPJyMT0E4fOxaTOJdEe713UBqERQEDC7/usw7J6XiontVMo/EZlk1EZRRx22SXnar09N3hws8MrTfLQISf5YJ/HU= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:3560:8505:40a2:e021]) (user=samitolvanen job=sendgmr) by 2002:a25:3c9:: with SMTP id 192mr14007073ybd.319.1617906533406; Thu, 08 Apr 2021 11:28:53 -0700 (PDT) Date: Thu, 8 Apr 2021 11:28:29 -0700 In-Reply-To: <20210408182843.1754385-1-samitolvanen@google.com> Message-Id: <20210408182843.1754385-5-samitolvanen@google.com> Mime-Version: 1.0 References: <20210408182843.1754385-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog Subject: [PATCH v6 04/18] module: ensure __cfi_check alignment From: Sami Tolvanen To: Kees Cook Cc: Nathan Chancellor , Nick Desaulniers , Masahiro Yamada , Will Deacon , Jessica Yu , Arnd Bergmann , Tejun Heo , "Paul E. McKenney" , Christoph Hellwig , Peter Zijlstra , Sedat Dilek , Mark Rutland , Catalin Marinas , bpf@vger.kernel.org, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Sami Tolvanen X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210408_192907_531527_D3418541 X-CRM114-Status: GOOD ( 13.63 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org CONFIG_CFI_CLANG_SHADOW assumes the __cfi_check() function is page aligned and at the beginning of the .text section. While Clang would normally align the function correctly, it fails to do so for modules with no executable code. This change ensures the correct __cfi_check() location and alignment. It also discards the .eh_frame section, which Clang can generate with certain sanitizers, such as CFI. Link: https://bugs.llvm.org/show_bug.cgi?id=46293 Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Acked-by: Jessica Yu Tested-by: Nathan Chancellor --- scripts/module.lds.S | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 2c52535f9b56..04c5685c25cf 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -3,10 +3,20 @@ * Archs are free to supply their own linker scripts. ld will * combine them automatically. */ +#ifdef CONFIG_CFI_CLANG +# include +# define ALIGN_CFI ALIGN(PAGE_SIZE) +# define SANITIZER_DISCARDS *(.eh_frame) +#else +# define ALIGN_CFI +# define SANITIZER_DISCARDS +#endif + SECTIONS { /DISCARD/ : { *(.discard) *(.discard.*) + SANITIZER_DISCARDS } __ksymtab 0 : { *(SORT(___ksymtab+*)) } @@ -41,7 +51,14 @@ SECTIONS { *(.rodata..L*) } - .text : { *(.text .text.[0-9a-zA-Z_]*) } + /* + * With CONFIG_CFI_CLANG, we assume __cfi_check is at the beginning + * of the .text section, and is aligned to PAGE_SIZE. + */ + .text : ALIGN_CFI { + *(.text.__cfi_check) + *(.text .text.[0-9a-zA-Z_]* .text..L.cfi*) + } #endif }