From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1340521-1526938471-2-7741063341340262467 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.248, MAILING_LIST_MULTI -1, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1526938470; b=LRGbANcthlH2loH0YJqaaw1i25Or1japoEi4NcSxEreI7aexR6 2QXfnVW3a1ItUQ4snnKBn3TTzcpNHKN2E07Khq1vDjFoo1xK6BQjnpvB4xglskCt O+fJG3Ka50FqS91ckEJgAWBxGMSbxFHmGx4/ODPuake0BMEo/xYi1z2BnYQrE1bA 4dpmpmzeCZAU3wNik9w/PWSivOZsuSKX4PUDwkc40k1u/oaAC3E3DQUsm80MiH1v C/ZMNSyFrTij5KSqzr11C6DZHMssPdIB0pvIxHcUOjXfbKJIYocgXRqy+Q3+iJz7 Dj3CPzrrnPtTmjtswHTfn21EA9rgaGrd+DYg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=fm2; t=1526938470; bh=gznkxUDw6eRWRc3wzEpkxO1gNFPP7A VgTZFkZIuYjrU=; b=jfyNbEb5IjEn/J6CvFQgQjTzkjuVgUYifxSgXdwy9bDopX LS2eIe2mCwR9VOPAtQnS+ZFKYHIkc0EXWERtpjs3ZCFcdBjY8AnTLiJr6c62TmQ+ kFaW3nyXvOX0rwPPcwWI6K7/UhUtfmkS5mhTHmN21csiOYNdbcipIjoWVoxovOkd xPKuuVYNwdAlHihp53CoBGoZOlxgz2UNY3iqNPIlzY8OAdOk0IUw4W8GovsGJvXj wLNaMD4cyX6pU8UoSk2u1u0CWUwGFuOrzx2gF0Y7a/SF0oiFf0d6mepr12FunIzs 9l+zZs7+Jxje5hhyRk8fLkwE/7vySFAwpKPQ8DFQ== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=kernel.org header.i=@kernel.org header.b=HWtliuQb x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=kernel.org header.i=@kernel.org header.b=HWtliuQb x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfL9x7sVnW+ot0X4m/9Wv9kUIpuxbO9Ylm22qCdk0SxpUGoUUmh7zB3EcZiDmuO3MY7dc56keF4VMivJg+Frgewtlt3x5fWZ1iqap/mnWszpKdshImB1G OYnSYdpt+g8ZBxuVpOwaBwIlUxUOGhG1lK5fuTVbd2SVypmwBPz/rrWsejBXJsrCkFpss+6T4xtrCiIZa+P+qNCTC/QSLE/mpmVvcuHCKsTjhctumtkdyr8e X-CM-Analysis: v=2.3 cv=E8HjW5Vl c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=VUJBJC2UJ8kA:10 a=cm27Pg_UAAAA:8 a=ag1SF4gXAAAA:8 a=AbmRykLzv6zd4g4xyXcA:9 a=QEXdDO2ut3YA:10 a=xmb-EsYY8bH0VWELuYED:22 a=Yupwre4RP9_Eg_Bd0iYG:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754411AbeEUVZ7 (ORCPT ); Mon, 21 May 2018 17:25:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:40726 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932492AbeEUVZy (ORCPT ); Mon, 21 May 2018 17:25:54 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kees Cook , Thomas Gleixner Subject: [PATCH 4.16 086/110] x86/speculation: Make "seccomp" the default mode for Speculative Store Bypass Date: Mon, 21 May 2018 23:12:23 +0200 Message-Id: <20180521210513.757308335@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180521210503.823249477@linuxfoundation.org> References: <20180521210503.823249477@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit f21b53b20c754021935ea43364dbf53778eeba32 upstream Unless explicitly opted out of, anything running under seccomp will have SSB mitigations enabled. Choosing the "prctl" mode will disable this. [ tglx: Adjusted it to the new arch_seccomp_spec_mitigate() mechanism ] Signed-off-by: Kees Cook Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- Documentation/admin-guide/kernel-parameters.txt | 26 ++++++++++++------- arch/x86/include/asm/nospec-branch.h | 1 arch/x86/kernel/cpu/bugs.c | 32 +++++++++++++++++------- 3 files changed, 41 insertions(+), 18 deletions(-) --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4021,19 +4021,27 @@ This parameter controls whether the Speculative Store Bypass optimization is used. - on - Unconditionally disable Speculative Store Bypass - off - Unconditionally enable Speculative Store Bypass - auto - Kernel detects whether the CPU model contains an - implementation of Speculative Store Bypass and - picks the most appropriate mitigation. - prctl - Control Speculative Store Bypass per thread - via prctl. Speculative Store Bypass is enabled - for a process by default. The state of the control - is inherited on fork. + on - Unconditionally disable Speculative Store Bypass + off - Unconditionally enable Speculative Store Bypass + auto - Kernel detects whether the CPU model contains an + implementation of Speculative Store Bypass and + picks the most appropriate mitigation. If the + CPU is not vulnerable, "off" is selected. If the + CPU is vulnerable the default mitigation is + architecture and Kconfig dependent. See below. + prctl - Control Speculative Store Bypass per thread + via prctl. Speculative Store Bypass is enabled + for a process by default. The state of the control + is inherited on fork. + seccomp - Same as "prctl" above, but all seccomp threads + will disable SSB unless they explicitly opt out. Not specifying this option is equivalent to spec_store_bypass_disable=auto. + Default mitigations: + X86: If CONFIG_SECCOMP=y "seccomp", otherwise "prctl" + spia_io_base= [HW,MTD] spia_fio_base= spia_pedr= --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -233,6 +233,7 @@ enum ssb_mitigation { SPEC_STORE_BYPASS_NONE, SPEC_STORE_BYPASS_DISABLE, SPEC_STORE_BYPASS_PRCTL, + SPEC_STORE_BYPASS_SECCOMP, }; extern char __indirect_thunk_start[]; --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -416,22 +416,25 @@ enum ssb_mitigation_cmd { SPEC_STORE_BYPASS_CMD_AUTO, SPEC_STORE_BYPASS_CMD_ON, SPEC_STORE_BYPASS_CMD_PRCTL, + SPEC_STORE_BYPASS_CMD_SECCOMP, }; static const char *ssb_strings[] = { [SPEC_STORE_BYPASS_NONE] = "Vulnerable", [SPEC_STORE_BYPASS_DISABLE] = "Mitigation: Speculative Store Bypass disabled", - [SPEC_STORE_BYPASS_PRCTL] = "Mitigation: Speculative Store Bypass disabled via prctl" + [SPEC_STORE_BYPASS_PRCTL] = "Mitigation: Speculative Store Bypass disabled via prctl", + [SPEC_STORE_BYPASS_SECCOMP] = "Mitigation: Speculative Store Bypass disabled via prctl and seccomp", }; static const struct { const char *option; enum ssb_mitigation_cmd cmd; } ssb_mitigation_options[] = { - { "auto", SPEC_STORE_BYPASS_CMD_AUTO }, /* Platform decides */ - { "on", SPEC_STORE_BYPASS_CMD_ON }, /* Disable Speculative Store Bypass */ - { "off", SPEC_STORE_BYPASS_CMD_NONE }, /* Don't touch Speculative Store Bypass */ - { "prctl", SPEC_STORE_BYPASS_CMD_PRCTL }, /* Disable Speculative Store Bypass via prctl */ + { "auto", SPEC_STORE_BYPASS_CMD_AUTO }, /* Platform decides */ + { "on", SPEC_STORE_BYPASS_CMD_ON }, /* Disable Speculative Store Bypass */ + { "off", SPEC_STORE_BYPASS_CMD_NONE }, /* Don't touch Speculative Store Bypass */ + { "prctl", SPEC_STORE_BYPASS_CMD_PRCTL }, /* Disable Speculative Store Bypass via prctl */ + { "seccomp", SPEC_STORE_BYPASS_CMD_SECCOMP }, /* Disable Speculative Store Bypass via prctl and seccomp */ }; static enum ssb_mitigation_cmd __init ssb_parse_cmdline(void) @@ -481,8 +484,15 @@ static enum ssb_mitigation_cmd __init __ switch (cmd) { case SPEC_STORE_BYPASS_CMD_AUTO: - /* Choose prctl as the default mode */ - mode = SPEC_STORE_BYPASS_PRCTL; + case SPEC_STORE_BYPASS_CMD_SECCOMP: + /* + * Choose prctl+seccomp as the default mode if seccomp is + * enabled. + */ + if (IS_ENABLED(CONFIG_SECCOMP)) + mode = SPEC_STORE_BYPASS_SECCOMP; + else + mode = SPEC_STORE_BYPASS_PRCTL; break; case SPEC_STORE_BYPASS_CMD_ON: mode = SPEC_STORE_BYPASS_DISABLE; @@ -530,12 +540,14 @@ static void ssb_select_mitigation() } #undef pr_fmt +#define pr_fmt(fmt) "Speculation prctl: " fmt static int ssb_prctl_set(struct task_struct *task, unsigned long ctrl) { bool update; - if (ssb_mode != SPEC_STORE_BYPASS_PRCTL) + if (ssb_mode != SPEC_STORE_BYPASS_PRCTL && + ssb_mode != SPEC_STORE_BYPASS_SECCOMP) return -ENXIO; switch (ctrl) { @@ -583,7 +595,8 @@ int arch_prctl_spec_ctrl_set(struct task #ifdef CONFIG_SECCOMP void arch_seccomp_spec_mitigate(struct task_struct *task) { - ssb_prctl_set(task, PR_SPEC_FORCE_DISABLE); + if (ssb_mode == SPEC_STORE_BYPASS_SECCOMP) + ssb_prctl_set(task, PR_SPEC_FORCE_DISABLE); } #endif @@ -592,6 +605,7 @@ static int ssb_prctl_get(struct task_str switch (ssb_mode) { case SPEC_STORE_BYPASS_DISABLE: return PR_SPEC_DISABLE; + case SPEC_STORE_BYPASS_SECCOMP: case SPEC_STORE_BYPASS_PRCTL: if (task_spec_ssb_force_disable(task)) return PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE;