From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1472218-1518185523-2-9945757670835932076 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 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES roenda, 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=arctest; t=1518185522; b=oHL6zySKOZcl5sYeNBvU5iKVkooJ9f8LNYvDtNFzofn9WxY 3DLSeG5Qie5yP8FUxue7UPA2Xl0zTYUznKZr5cKq0t2noxIjOSrolZ1OrnXgexCk 0eUQGt+ZUWu++pm3dYKLipbcmWj1SbSNxMXwpZ4d+Q7qBFeqMMDoSv90dNbbWI2v p38D7oEdCL9F/LrvN2RWuxdC3vT15ROyseFW50H7yj0feMEXW5NJJg5knrZ85WZU fyUuzNKguMUcV/JaHKp5LiIg0d67NKY4ctXf5yYKAwX+mHmrUi5+vzMPiZWwjVyi l3d7wqj1D5DlItcM0N04An4pPrMIensIbItrW3Q== 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=arctest; t=1518185522; bh=xfSejDediiu2WEb4W5TXzhIQ/3 43HPUxBDvvG+4SSg0=; b=lyuhQEK8ZN+MQIwH7dCPwSllX0VJGQJNUxhbmflYEs IkHp24l7HkaMlvhfy/4LRhl/60AeGwA8OwTyA6ksFsVxZRKSNFMU7GH63eYxHbRn AQqZRfJ0nveAOplxdNDsOUKFLO4jXt+Di5e/G+j+J/ZXJdGk+3o5TkMd88xiMTje cCcxwUDwbyr+LgF1P/ndiP5P+AYWz7b9BvHeWkcnHm7zkNNXTAJN6Wpa8q/SQ42U /fhYzKXPkXaZyIHIhvor4+OdNuJBjt9QpNNqpyhAXWKaO3VQtEUMg1i5hTfveD49 vfz94Yp/jSlBaOrV0LRszLf0wIvjZCPY47YbcSDD3rYQ== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); 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-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 Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); 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-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 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752703AbeBINmB (ORCPT ); Fri, 9 Feb 2018 08:42:01 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:49536 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752781AbeBINl7 (ORCPT ); Fri, 9 Feb 2018 08:41:59 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andi Kleen , Thomas Gleixner , David Woodhouse , torvalds@linux-foundation.org, jeyu@kernel.org, arjan@linux.intel.com, David Woodhouse Subject: [PATCH 4.9 38/92] module/retpoline: Warn about missing retpoline in module Date: Fri, 9 Feb 2018 14:39:07 +0100 Message-Id: <20180209133933.910708237@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180209133931.211869118@linuxfoundation.org> References: <20180209133931.211869118@linuxfoundation.org> User-Agent: quilt/0.65 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: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andi Kleen (cherry picked from commit caf7501a1b4ec964190f31f9c3f163de252273b8) There's a risk that a kernel which has full retpoline mitigations becomes vulnerable when a module gets loaded that hasn't been compiled with the right compiler or the right option. To enable detection of that mismatch at module load time, add a module info string "retpoline" at build time when the module was compiled with retpoline support. This only covers compiled C source, but assembler source or prebuilt object files are not checked. If a retpoline enabled kernel detects a non retpoline protected module at load time, print a warning and report it in the sysfs vulnerability file. [ tglx: Massaged changelog ] Signed-off-by: Andi Kleen Signed-off-by: Thomas Gleixner Cc: David Woodhouse Cc: gregkh@linuxfoundation.org Cc: torvalds@linux-foundation.org Cc: jeyu@kernel.org Cc: arjan@linux.intel.com Link: https://lkml.kernel.org/r/20180125235028.31211-1-andi@firstfloor.org Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/bugs.c | 17 ++++++++++++++++- include/linux/module.h | 9 +++++++++ kernel/module.c | 11 +++++++++++ scripts/mod/modpost.c | 9 +++++++++ 4 files changed, 45 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include @@ -92,6 +93,19 @@ static const char *spectre_v2_strings[] #define pr_fmt(fmt) "Spectre V2 mitigation: " fmt static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE; +static bool spectre_v2_bad_module; + +#ifdef RETPOLINE +bool retpoline_module_ok(bool has_retpoline) +{ + if (spectre_v2_enabled == SPECTRE_V2_NONE || has_retpoline) + return true; + + pr_err("System may be vunerable to spectre v2\n"); + spectre_v2_bad_module = true; + return false; +} +#endif static void __init spec2_print_if_insecure(const char *reason) { @@ -277,6 +291,7 @@ ssize_t cpu_show_spectre_v2(struct devic if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2)) return sprintf(buf, "Not affected\n"); - return sprintf(buf, "%s\n", spectre_v2_strings[spectre_v2_enabled]); + return sprintf(buf, "%s%s\n", spectre_v2_strings[spectre_v2_enabled], + spectre_v2_bad_module ? " - vulnerable module loaded" : ""); } #endif --- a/include/linux/module.h +++ b/include/linux/module.h @@ -791,6 +791,15 @@ static inline void module_bug_finalize(c static inline void module_bug_cleanup(struct module *mod) {} #endif /* CONFIG_GENERIC_BUG */ +#ifdef RETPOLINE +extern bool retpoline_module_ok(bool has_retpoline); +#else +static inline bool retpoline_module_ok(bool has_retpoline) +{ + return true; +} +#endif + #ifdef CONFIG_MODULE_SIG static inline bool module_sig_ok(struct module *module) { --- a/kernel/module.c +++ b/kernel/module.c @@ -2817,6 +2817,15 @@ static int check_modinfo_livepatch(struc } #endif /* CONFIG_LIVEPATCH */ +static void check_modinfo_retpoline(struct module *mod, struct load_info *info) +{ + if (retpoline_module_ok(get_modinfo(info, "retpoline"))) + return; + + pr_warn("%s: loading module not compiled with retpoline compiler.\n", + mod->name); +} + /* Sets info->hdr and info->len. */ static int copy_module_from_user(const void __user *umod, unsigned long len, struct load_info *info) @@ -2969,6 +2978,8 @@ static int check_modinfo(struct module * add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK); } + check_modinfo_retpoline(mod, info); + if (get_modinfo(info, "staging")) { add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK); pr_warn("%s: module is from the staging directory, the quality " --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -2130,6 +2130,14 @@ static void add_intree_flag(struct buffe buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n"); } +/* Cannot check for assembler */ +static void add_retpoline(struct buffer *b) +{ + buf_printf(b, "\n#ifdef RETPOLINE\n"); + buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n"); + buf_printf(b, "#endif\n"); +} + static void add_staging_flag(struct buffer *b, const char *name) { static const char *staging_dir = "drivers/staging"; @@ -2474,6 +2482,7 @@ int main(int argc, char **argv) add_header(&buf, mod); add_intree_flag(&buf, !external_module); + add_retpoline(&buf); add_staging_flag(&buf, mod->name); err |= add_versions(&buf, mod); add_depends(&buf, mod, modules);