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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD309C433EF for ; Wed, 13 Oct 2021 18:17:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9487B61139 for ; Wed, 13 Oct 2021 18:17:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238839AbhJMSTm (ORCPT ); Wed, 13 Oct 2021 14:19:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238629AbhJMSTZ (ORCPT ); Wed, 13 Oct 2021 14:19:25 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E396AC061764 for ; Wed, 13 Oct 2021 11:17:20 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id z130-20020a256588000000b005b6b4594129so4077467ybb.15 for ; Wed, 13 Oct 2021 11:17:20 -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=zmv8JzbzBTLA62LcosQrTnF8inM4/ujL1RSgZDP29E8=; b=jXXnBJxv0b07/cGFqpGevnT1fh+20ZZCm23uU34BS+ygdeR3x+1nkPRE0KVCt2jR68 /sfFg0nXNzG7XAGbrJWaOVvFrygpeVVr0RpLo3kGyx3yNpLk9zTOrzyxhs1F9uC4I9CW 6q3ZZigb34tCL9VSIdGW/lRR/LRAoqEwzNVhPfd78Il8WS6seGvPUse7ePzREuFbMCWx ekEMjQxIoq55uKC1aaCKRhR8H9CY0a5x0Gxb9CVkgqVHzsL7FUAeUULOC1Mwh7gQzfCD /DcgpfktUC7ykZsfB4D62XngGhv6U4CmQ7j2C5rF3EbiQUsib8zrxHGdD/F0SUA/l7l0 LZlg== 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=zmv8JzbzBTLA62LcosQrTnF8inM4/ujL1RSgZDP29E8=; b=PqZY6DWbrM2C7Ux4qp2q1uj04yMwpr/VcpKRR+9v8i52CU7O9499YtHvVDQLV/PtdN hlDD0t2dBOuFCTdEh1BGO0noqbBtPU60/lKoc+NcOBhmM9yRRSuf99PN04zEPfD9ZmD3 x3rrebe7iRwBpDZsLveehfybbXCWTRHipVukDUyDDaCCj8Vg7zmI6eGOgo1t408LsOkg lD4uBIuIzsir8k/ltS3lIU5VD9mVW61j8I4cpGv+Uu0DEu6Wphp0we47g3sPunvDvGRD HlPnadujirYz2DK00jlbJdsAhER3i9ubKAko9/9PlH9T/D1fBOPu4IaHw44zj6GBcQY1 P0rw== X-Gm-Message-State: AOAM5317xiVqlrFSozcIt4YZHOBhn967IQX335sm9j9jLXijNr8lTYrI ukjOCHxse4FsbLQrIiIf9vV85VgXFMDspNKMIMo= X-Google-Smtp-Source: ABdhPJwLTd5lpAUz47nTkqm8bIbmDw/6IEtZGq5BpovbEhi49oVmzIhQGeNKQ41jXqONzZubk/hG/YlyOkmKEICkhYo= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:9ea6:6c27:1876:926c]) (user=samitolvanen job=sendgmr) by 2002:a25:1a07:: with SMTP id a7mr1138062yba.30.1634149040163; Wed, 13 Oct 2021 11:17:20 -0700 (PDT) Date: Wed, 13 Oct 2021 11:16:51 -0700 In-Reply-To: <20211013181658.1020262-1-samitolvanen@google.com> Message-Id: <20211013181658.1020262-9-samitolvanen@google.com> Mime-Version: 1.0 References: <20211013181658.1020262-1-samitolvanen@google.com> X-Developer-Key: i=samitolvanen@google.com; a=openpgp; fpr=35CCFB63B283D6D3AEB783944CB5F6848BBC56EE X-Developer-Signature: v=1; a=openpgp-sha256; l=1880; h=from:subject; bh=aJOu8QEazc9wzBvdGokAB4Q+ctVZ+8OLAvbNqeZO6o0=; b=owEB7QES/pANAwAKAUy19oSLvFbuAcsmYgBhZyKZXRzLEq7R5KD47cFm8izK9OsGJlkTRUagHLJP Bc7BxViJAbMEAAEKAB0WIQQ1zPtjsoPW0663g5RMtfaEi7xW7gUCYWcimQAKCRBMtfaEi7xW7p1JC/ 4m/cUeByxF1jvj7RvWifYnVRReGToai8pyoAp0lJDh9RMTkI/4i7Ngbg+JpNKihPwE0DDQCX0B5m1J kultTTxkwkJD8me5ETr7WDcgA6pZVObTc43irlPQzfWRF1F/K8rjDhOZmDV2EL2lPyE2ha/NCoZJaD 4e6RkyMaHolk3yoKbg0Svz4sjEG5Ps/1uIB2UTOPxOe6BX7G4zZyrf+U+6kWHRIIV6Qm43Oe1R0x4v 3PqgxY+IAF5GJGNMrzQVIQyXkDflEdBnWDKB3olfp6zbboJLvep7CpZQpyCwjWnbFfX8K3jpcUrpwD HZSJqi34gmVWbntJszdl75zGrSchbbe6T+MMb/yconZwPY5QXxE4xbToCoVXFx/7/FU2+DSUz4K7wn 8NZ4eRbNb+jGv1NiL3Ix0iBsdee7Ep62U2B7khisjmNOO537rtsBg9U4wCXauiKYv0ZbkO2leRG6Ma e17h4J4Z868U9gqju5DLF8kMu6/5gSKYYPvX89GRK8VJg= X-Mailer: git-send-email 2.33.0.1079.g6e70778dc9-goog Subject: [PATCH v5 08/15] lkdtm: Use an opaque type for lkdtm_rodata_do_nothing From: Sami Tolvanen To: x86@kernel.org Cc: Kees Cook , Josh Poimboeuf , Peter Zijlstra , Nathan Chancellor , Nick Desaulniers , Sedat Dilek , Steven Rostedt , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use an opaque type for lkdtm_rodata_do_nothing to stop the compiler from generating a CFI jump table entry that jumps to .rodata. Signed-off-by: Sami Tolvanen Acked-by: Kees Cook Tested-by: Nick Desaulniers Tested-by: Sedat Dilek --- drivers/misc/lkdtm/lkdtm.h | 2 +- drivers/misc/lkdtm/perms.c | 2 +- drivers/misc/lkdtm/rodata.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index c212a253edde..35535c422939 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -137,7 +137,7 @@ void lkdtm_REFCOUNT_TIMING(void); void lkdtm_ATOMIC_TIMING(void); /* rodata.c */ -void lkdtm_rodata_do_nothing(void); +DECLARE_NOT_CALLED_FROM_C(lkdtm_rodata_do_nothing); /* usercopy.c */ void __init lkdtm_usercopy_init(void); diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c index 2dede2ef658f..fa2bd90bd8ee 100644 --- a/drivers/misc/lkdtm/perms.c +++ b/drivers/misc/lkdtm/perms.c @@ -151,7 +151,7 @@ void lkdtm_EXEC_VMALLOC(void) void lkdtm_EXEC_RODATA(void) { - execute_location(lkdtm_rodata_do_nothing, CODE_AS_IS); + execute_location((void *)lkdtm_rodata_do_nothing, CODE_AS_IS); } void lkdtm_EXEC_USERSPACE(void) diff --git a/drivers/misc/lkdtm/rodata.c b/drivers/misc/lkdtm/rodata.c index baacb876d1d9..17ed0ad4e6ae 100644 --- a/drivers/misc/lkdtm/rodata.c +++ b/drivers/misc/lkdtm/rodata.c @@ -3,7 +3,7 @@ * This includes functions that are meant to live entirely in .rodata * (via objcopy tricks), to validate the non-executability of .rodata. */ -#include "lkdtm.h" +void lkdtm_rodata_do_nothing(void); void noinstr lkdtm_rodata_do_nothing(void) { -- 2.33.0.1079.g6e70778dc9-goog