From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (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 0A48572 for ; Wed, 13 Oct 2021 18:17:21 +0000 (UTC) Received: by mail-yb1-f202.google.com with SMTP id p8-20020a056902114800b005bad2571fbeso3991293ybu.23 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=sU7MHAh3e48nStQP45cwkD29oyST5Bq6VlGWemlH8DKjiB74/goyv+BGLpqu6qBUUg 2KcKvMAEDNP/VaQ7N2GfJsxluyEjTM9Ge6WSgaYARJX1Jy/a+jxmT2/cB0tmlUYgz8iK dhUZ1D5BddSZuniIwIfxZdwfXiHVZ7XjEs5Ftse5OvgERpk9aijt3irvuqGjEvqPc/f+ gZA1WI2guiXCLUeW40O8ySMmCf2WNO2y4qrU21FBMqxRnnGbcFxfJCyHOY3dtmZZNmpZ 4JfNC5ZystvlamW0VDzlyAia+oIG/34OxcsGi+BL50UYDeW4/PzPqyz7AiIdL6TePB1P vm+Q== X-Gm-Message-State: AOAM533tjyojpmvYDpVMmPNXCl4YCbto2ALMKG7Z1YFElQ8qcQRa5Uii MZK/HTR5muUlvgVtmX2HXS8b/y2PcOXsuhQYGio= 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> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: 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" 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