From patchwork Mon Apr 17 21:54:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 84484 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp2426739vqo; Mon, 17 Apr 2023 15:01:47 -0700 (PDT) X-Google-Smtp-Source: AKy350al0CMGEZJQb71dK+wsvmzgBgrI67DsBI2tNQCq1Oj8ECDnV0oykyRVuj3wNm0NbVvqXPDU X-Received: by 2002:a05:6a20:2795:b0:c7:5cb6:2ff7 with SMTP id s21-20020a056a20279500b000c75cb62ff7mr13904003pzf.22.1681768907089; Mon, 17 Apr 2023 15:01:47 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1681768907; cv=none; d=google.com; s=arc-20160816; b=PBrQ9Bqu9ceRHehfrUrMHSkdu7bQCMM70c345LH1NmPBlIANwZsOJZn/Ke1T0UpqMr dFYtNMKlY4Ng0AxyqQZQG8KjFxABy0mYCj8TmJU44HtyTQ6GOhEdjzHOmzgjpS4t6b9n YBSUbV91psGAnqd6rR3d9AgRj/T7U8mbsIS6rA1NqcqCPzNojkkZOMJaJXvBc1u/3L/c 847bX+kVlJifNo3r1zm0bIQIQ5bKJ6dBSJ7KshSxyQIz4c8v7R1HVZLhnIhh59m5hafH 8ktip5MOw4CAmW8+SI9lJM0cot3/qmpbgXQkK65Qtdgcc2HX0cc9eoaQ7ZPZkXETaESe GQKw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=1ROFbMOV6yOo0pF0esK8s0D/4X+P3zglkAv5TCX1cqs=; b=G3Zy9T6yebL4LwEPqOP425Xf2cUj06gBd5t7MN0IVFQ3hw090Gg927i99s/pwv6maU oWx8rEmuEpC0V4p7I+iyFA4XbTR7zn0sa4VVqKiFVfddzotwC4mccdqfuYVNA8h7/5tm 4HviTsrqNoJGOjtwEMXT9EjcHwuGt3nJCMfw3ySZF+4udz7q5aCJG7YCNmboi+r1zw/g FNtEB3gLlk6wILG9gzlwFJElyx/zYP/M29vv6eXYuMJ5VBdRPfYUqZQLrMnAJfnqTL/9 mz4Ig9BMfYAcxaVmQ/EeZVyvf5VjXZIQUH+0EXJfVhhpFKuuGhx4GRPQiJy5e++lcUY1 AdEg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=Pz9Wmj1C; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id b189-20020a6367c6000000b0051f179c48e9si264412pgc.684.2023.04.17.15.01.32; Mon, 17 Apr 2023 15:01:47 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=Pz9Wmj1C; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230434AbjDQVyS (ORCPT + 99 others); Mon, 17 Apr 2023 17:54:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230242AbjDQVyP (ORCPT ); Mon, 17 Apr 2023 17:54:15 -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 CE361213D for ; Mon, 17 Apr 2023 14:54:14 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id v200-20020a252fd1000000b00b8f548a72bbso12042959ybv.9 for ; Mon, 17 Apr 2023 14:54:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1681768454; x=1684360454; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=1ROFbMOV6yOo0pF0esK8s0D/4X+P3zglkAv5TCX1cqs=; b=Pz9Wmj1CrPl1IL4L95VxcDW5MmG+o1YPeNyX6BDBGEP92+EkCITMnKQ7UvdtMPMQrW 5bYV8UujE5AJG6UrgZbcInh+uPT0vISasCoVTa9GdHTMvh7SiOQT0tBNXckQ7dxh9qL6 MDsM1qiT6eXbhT/g07gKJB/FHU4Z2NOE55ctur65xeJEowmDoi4VUxVBK8MeN9wKgmlQ +QtduWbRt7SYN5f4lKm6WYiBh7HlmwIs5OOF8pSxz6DzkhLpLFxOCeKx8e03x9wv8S4K /q0vzu5/DOn9g1FiqjN0UvWzgQZgBvjCwjFiN/YUGv30+JQXuxzHBbyEmpQY4Z9u+myL 5Rvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681768454; x=1684360454; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=1ROFbMOV6yOo0pF0esK8s0D/4X+P3zglkAv5TCX1cqs=; b=Amf+0L1vyLZieU1SJv/J/odorXeGVA7lXV7NMithOOj6z41ILZUhY14TxJTMk3IG3A mK0rx2cZD3auIfXiMOHr7++Y3BbrYd0O3/wA60b4M+dT0q1amsmjc4kcl/A/73joPA3X R93+G4ovF9pfLPB6owUFjU1i9jnadwQ0nVNwgAi605biIyo3JzElqLNOpgbHFrrJxOhG GTdMySoO6VvSd2rm8G80TidOIy6f1XZ/1yPiXZo850KFSshRTxMFoB3H04MHCCep3qVO DlcLEE+JgU2YIR5R+YufIW5iaXPId+BfqkYG+eFlJ4x4utw6RsOGOSCxMwmgRlIyUUjZ eCGA== X-Gm-Message-State: AAQBX9fqYqT5WvY0+nQOd174l1rveNl/qGrZLDoD+XxhFuec5Svam2EU 2skWHhSB1rTBO3n0qagBzjFFCAVl99I6k50sjzA= X-Received: from ndesaulniers-desktop.svl.corp.google.com ([2620:15c:2d1:203:e8f1:df30:2fb2:cf8a]) (user=ndesaulniers job=sendgmr) by 2002:a25:cc05:0:b0:b8b:eea7:525a with SMTP id l5-20020a25cc05000000b00b8beea7525amr8187707ybf.7.1681768454118; Mon, 17 Apr 2023 14:54:14 -0700 (PDT) Date: Mon, 17 Apr 2023 14:54:07 -0700 In-Reply-To: <20230412-no_stackp-v1-0-86d2034a4d06@google.com> Mime-Version: 1.0 References: <20230412-no_stackp-v1-0-86d2034a4d06@google.com> X-Developer-Key: i=ndesaulniers@google.com; a=ed25519; pk=UIrHvErwpgNbhCkRZAYSX0CFd/XFEwqX3D0xqtqjNug= X-Developer-Signature: v=1; a=ed25519-sha256; t=1681768450; l=3068; i=ndesaulniers@google.com; s=20220923; h=from:subject:message-id; bh=Y+mVeYQgxmjVxZ8TAgHiUAti6DIYAGqhexs7SrW7nh8=; b=Xv2k6tZ4Tz1DoWi+BSx+JfcGKmmndDJLVOOT4V3InkpHqs2Txr0BldqG6172TGpaJXU4waGOC7cP UJyi1aBABQQ+iDuRy15lwJ7Wtd0/eqT1u+ZHYnEmGlM+mVeB9tBI X-Mailer: b4 0.12.2 Message-ID: <20230412-no_stackp-v1-1-86d2034a4d06@google.com> Subject: [PATCH 1/2] start_kernel: add no_stack_protector fn attr From: ndesaulniers@google.com To: "Borislav Petkov (AMD)" Cc: Peter Zijlstra , Josh Poimboeuf , x86@kernel.org, Michael Ellerman , Nicholas Piggin , Christophe Leroy , Miguel Ojeda , Nathan Chancellor , Tom Rix , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Nick Desaulniers X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1763462513604760208?= X-GMAIL-MSGID: =?utf-8?q?1763462513604760208?= Back during the discussion of commit a9a3ed1eff36 ("x86: Fix early boot crash on gcc-10, third try") we discussed the need for a function attribute to control the omission of stack protectors on a per-function basis; at the time Clang had support for no_stack_protector but GCC did not. This was fixed in gcc-11. Now that the function attribute is available, let's start using it. Callers of boot_init_stack_canary need to use this function attribute unless they're compiled with -fno-stack-protector, otherwise the canary stored in the stack slot of the caller will differ upon the call to boot_init_stack_canary. This will lead to a call to __stack_chk_fail then panic. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94722 Link: https://lore.kernel.org/all/20200316130414.GC12561@hirez.programming.kicks-ass.net/ Tested-by: Nathan Chancellor Acked-by: Michael Ellerman (powerpc) Acked-by: Miguel Ojeda Acked-by: Peter Zijlstra (Intel) Signed-off-by: Nick Desaulniers --- arch/powerpc/kernel/smp.c | 1 + include/linux/compiler_attributes.h | 12 ++++++++++++ init/main.c | 3 ++- 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index f62e5e651bcd..48acae0da034 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -1603,6 +1603,7 @@ static void add_cpu_to_masks(int cpu) } /* Activate a secondary processor. */ +__no_stack_protector void start_secondary(void *unused) { unsigned int cpu = raw_smp_processor_id(); diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h index e659cb6fded3..84864767a56a 100644 --- a/include/linux/compiler_attributes.h +++ b/include/linux/compiler_attributes.h @@ -255,6 +255,18 @@ */ #define __noreturn __attribute__((__noreturn__)) +/* + * Optional: only supported since GCC >= 11.1, clang >= 7.0. + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-no_005fstack_005fprotector-function-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#no-stack-protector-safebuffers + */ +#if __has_attribute(__no_stack_protector__) +# define __no_stack_protector __attribute__((__no_stack_protector__)) +#else +# define __no_stack_protector +#endif + /* * Optional: not supported by gcc. * diff --git a/init/main.c b/init/main.c index 5d6365510173..1265c8d11052 100644 --- a/init/main.c +++ b/init/main.c @@ -941,7 +941,8 @@ static void __init print_unknown_bootoptions(void) memblock_free(unknown_options, len); } -asmlinkage __visible void __init __no_sanitize_address __noreturn start_kernel(void) +asmlinkage __visible __init __no_sanitize_address __noreturn __no_stack_protector +void start_kernel(void) { char *command_line; char *after_dashes; From patchwork Mon Apr 17 21:54:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 84486 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp2430975vqo; Mon, 17 Apr 2023 15:09:10 -0700 (PDT) X-Google-Smtp-Source: AKy350YVaYtr3d2Yx49rpv76TOxfa2hzOEjBom85BNcQ2wl5sfBorQrvhVr25CTm0ziTLHDYQa9a X-Received: by 2002:a05:6a00:1785:b0:63c:6485:d5e5 with SMTP id s5-20020a056a00178500b0063c6485d5e5mr7008970pfg.22.1681769350096; Mon, 17 Apr 2023 15:09:10 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1681769350; cv=none; d=google.com; s=arc-20160816; b=kuok9hWiGCCM6y2qj3fEOxJ7/HNt2hBk+DjSfX46J8tNJMGNK2Amduykcb/K5RrayL 2Pvn5cFLwBvPIBUHttgajiNQJ1W2dYCxJBS1NdYgYKOFdCGUW+k0795bvWgx2FUcUvF9 WxzaMzJ+WEojHSWvhZf2TaGBmEObKblKtKrlh4A7C8tcV71zt2HvrU9kyeUaqMma2Ky7 bnVwUMbZqBzpL8sY1SlvTDoO8avvaHzw9zywbgv6qgqnkCLhrlNMxTOaTF1j1SaoVlC4 mT90dTjesYzdzn5AIPsadMdWj6hfT2D22OQwOC7c3WYfN2wMzDrjmUbdjB/Q/QFcg6ni T0xg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=TqlZpSOgvA1JLW3vzN7VqdCnxfAnggXybW0yzcDiFj0=; b=LBEmJuEwdBJgwCOhv1TamZPosuH3Hrp1orOHS5XVeBKXaa4IsZFCLElDBLE9CYMGDI qkZUY7vgZzYHbiaVfKHxx2yaiwPXZB3+f8Y1q80dlNl5IQXF8Xq2S2UeXxgSO2GVgNPR s9n71hhchH0EaaWhcfix7hKoLSFpaJPBIPEGoLACQazFBJl3hb5qzQ0tfCJPdEIfku9v P5kDlKFBc+xwEVXhGULsC0nKd5K9xWtb5XZVJ2Wq3AXQByCraLxVVCdGiLcQ1kdR74Tn ZjgTwfKj+Ox0DXdw3FUqF9YaYZtNuTVdz4yYRMwkd3l9yqdlk5y5kc20q3XqNHBeOiXW 5WJg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=6Ok0UESU; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. 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Now that we have no_stack_protector function attribute (gcc-11+, clang-7+) and use it on start_kernel, remove the call to prevent_tail_call_optimization such that we may one day remove it outright. Reviewed-by: Nathan Chancellor Acked-by: Peter Zijlstra (Intel) Signed-off-by: Nick Desaulniers --- init/main.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/init/main.c b/init/main.c index 1265c8d11052..c6eef497c8c9 100644 --- a/init/main.c +++ b/init/main.c @@ -1152,7 +1152,13 @@ void start_kernel(void) /* Do the rest non-__init'ed, we're now alive */ arch_call_rest_init(); + /* + * Avoid stack canaries in callers of boot_init_stack_canary for gcc-10 + * and older. + */ +#if !__has_attribute(__no_stack_protector__) prevent_tail_call_optimization(); +#endif } /* Call all constructor functions linked into the kernel. */