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 X-Spam-Level: X-Spam-Status: No, score=-6.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43EE3C677D4 for ; Mon, 8 Oct 2018 18:34:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0961D214C2 for ; Mon, 8 Oct 2018 18:34:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ChAOnM3N" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0961D214C2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727745AbeJIBrW (ORCPT ); Mon, 8 Oct 2018 21:47:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:58434 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726568AbeJIBrV (ORCPT ); Mon, 8 Oct 2018 21:47:21 -0400 Received: from localhost (ip-213-127-77-176.ip.prioritytelecom.net [213.127.77.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9D50D214C3; Mon, 8 Oct 2018 18:34:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1539023659; bh=9ie+ra4UaHkzlO3F4aiv3XB83aqXeBRTUNsc2EH55TM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ChAOnM3Nf64IuI99W8hpMyu4XKn83OZIfG0mpGHmpBd/PyCgPBmXGsNut0UxUe/8a oiqYaZTbPRHEJAk8C72zXEqNw8z5OAISwZTcE54je5SXjugRIBo+Z34n9XO7V9HEiu /AjFXgpqNTmzA4qm+gOBuA3loET5k1258bu0/XAE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josh Poimboeuf , Jessica Yu , Sasha Levin Subject: [PATCH 4.4 040/113] module: exclude SHN_UNDEF symbols from kallsyms api Date: Mon, 8 Oct 2018 20:30:41 +0200 Message-Id: <20181008175532.788656523@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20181008175530.864641368@linuxfoundation.org> References: <20181008175530.864641368@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jessica Yu [ Upstream commit 9f2d1e68cf4d641def734adaccfc3823d3575e6c ] Livepatch modules are special in that we preserve their entire symbol tables in order to be able to apply relocations after module load. The unwanted side effect of this is that undefined (SHN_UNDEF) symbols of livepatch modules are accessible via the kallsyms api and this can confuse symbol resolution in livepatch (klp_find_object_symbol()) and cause subtle bugs in livepatch. Have the module kallsyms api skip over SHN_UNDEF symbols. These symbols are usually not available for normal modules anyway as we cut down their symbol tables to just the core (non-undefined) symbols, so this should really just affect livepatch modules. Note that this patch doesn't affect the display of undefined symbols in /proc/kallsyms. Reported-by: Josh Poimboeuf Tested-by: Josh Poimboeuf Reviewed-by: Josh Poimboeuf Signed-off-by: Jessica Yu Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/module.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/kernel/module.c +++ b/kernel/module.c @@ -3860,7 +3860,7 @@ static unsigned long mod_find_symname(st for (i = 0; i < kallsyms->num_symtab; i++) if (strcmp(name, symname(kallsyms, i)) == 0 && - kallsyms->symtab[i].st_info != 'U') + kallsyms->symtab[i].st_shndx != SHN_UNDEF) return kallsyms->symtab[i].st_value; return 0; } @@ -3906,6 +3906,10 @@ int module_kallsyms_on_each_symbol(int ( if (mod->state == MODULE_STATE_UNFORMED) continue; for (i = 0; i < kallsyms->num_symtab; i++) { + + if (kallsyms->symtab[i].st_shndx == SHN_UNDEF) + continue; + ret = fn(data, symname(kallsyms, i), mod, kallsyms->symtab[i].st_value); if (ret != 0)