From patchwork Thu Mar 10 12:44:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 1603865 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=pass (1024-bit key; secure) header.d=sourceware.org header.i=@sourceware.org header.a=rsa-sha256 header.s=default header.b=iVcv8umv; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=8.43.85.97; helo=sourceware.org; envelope-from=libc-alpha-bounces+incoming=patchwork.ozlabs.org@sourceware.org; receiver=) Received: from sourceware.org (ip-8-43-85-97.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4KDpgR5lnTz9sFs for ; Thu, 10 Mar 2022 23:45:07 +1100 (AEDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id A9B613857C59 for ; Thu, 10 Mar 2022 12:45:05 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A9B613857C59 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1646916305; bh=GPw4y5zj0Ksd2jabWAWz5TVL8eT5Gn6qQmDCkV+iBBo=; h=To:Subject:In-Reply-To:References:Date:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=iVcv8umveZ6tV2McWmj2mIHXbi8GDXl3Yfxh1YtJKmUdvC1nrnHdGW1vfY7ZIkEVd J1LRG+ebRjYwEEZeBR1vqw5kkng0XyuJzR1k1U9BcwArw427D5kyyUn6AmdLw+yb/s qWj6JogZT6C9PM2PUi5ETOMsRZ8+H9lbCu8JJZBk= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 5BA203858425 for ; Thu, 10 Mar 2022 12:44:30 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 5BA203858425 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-499-n5c5OG9GNDuZoSQLYxWm-g-1; Thu, 10 Mar 2022 07:44:27 -0500 X-MC-Unique: n5c5OG9GNDuZoSQLYxWm-g-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9AA7C1854E21 for ; Thu, 10 Mar 2022 12:44:26 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.88]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B2F137B5F0 for ; Thu, 10 Mar 2022 12:44:25 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [PATCH 2/2] nss: Protect against errno changes in function lookup (bug 28953) In-Reply-To: <308dcd6582b5aad4446e70db9de9bf675b870471.1646916217.git.fweimer@redhat.com> References: <308dcd6582b5aad4446e70db9de9bf675b870471.1646916217.git.fweimer@redhat.com> X-From-Line: cd03ff6ef7f7aece02cbe5e2ee50991fae53ad19 Mon Sep 17 00:00:00 2001 Message-Id: Date: Thu, 10 Mar 2022 13:44:23 +0100 User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-11.9 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H5, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Florian Weimer via Libc-alpha From: Florian Weimer Reply-To: Florian Weimer Errors-To: libc-alpha-bounces+incoming=patchwork.ozlabs.org@sourceware.org Sender: "Libc-alpha" dlopen may clobber errno. The nss_test_errno module uses an ELF constructor to achieve that, but there could be internal errors during dlopen that cause this, too. Therefore, the NSS framework has to guard against such errno clobbers. __nss_module_get_function is currently the only function that calls __nss_module_load, so it is sufficient to save and restore errno around this call. Tested on i386-linux-gnu and x86_64-linux-gnu. --- nss/Makefile | 13 +++++++-- nss/nss_module.c | 5 ++++ nss/nss_test_errno.c | 58 ++++++++++++++++++++++++++++++++++++++++ nss/tst-nss-test_errno.c | 43 +++++++++++++++++++++++++++++ 4 files changed, 117 insertions(+), 2 deletions(-) create mode 100644 nss/nss_test_errno.c create mode 100644 nss/tst-nss-test_errno.c diff --git a/nss/Makefile b/nss/Makefile index 4125d13f87..1d166cd39e 100644 --- a/nss/Makefile +++ b/nss/Makefile @@ -60,7 +60,8 @@ tests = test-netdb test-digits-dots tst-nss-getpwent bug17079 \ tst-nss-test1 \ tst-nss-test2 \ tst-nss-test4 \ - tst-nss-test5 + tst-nss-test5 \ + tst-nss-test_errno xtests = bug-erange tests-container = \ @@ -132,7 +133,7 @@ libnss_compat-inhibit-o = $(filter-out .os,$(object-suffixes)) ifeq ($(build-static-nss),yes) tests-static += tst-nss-static endif -extra-test-objs += nss_test1.os nss_test2.os +extra-test-objs += nss_test1.os nss_test2.os nss_test_errno.os include ../Rules @@ -166,16 +167,21 @@ rtld-tests-LDFLAGS += -Wl,--dynamic-list=nss_test.ver libof-nss_test1 = extramodules libof-nss_test2 = extramodules +libof-nss_test_errno = extramodules $(objpfx)/libnss_test1.so: $(objpfx)nss_test1.os $(link-libc-deps) $(build-module) $(objpfx)/libnss_test2.so: $(objpfx)nss_test2.os $(link-libc-deps) $(build-module) +$(objpfx)/libnss_test_errno.so: $(objpfx)nss_test_errno.os $(link-libc-deps) + $(build-module) $(objpfx)nss_test2.os : nss_test1.c # The .2 suffix comes from the nss_files version in shlib-versions. $(objpfx)/libnss_test1.so.2: $(objpfx)/libnss_test1.so $(make-link) $(objpfx)/libnss_test2.so.2: $(objpfx)/libnss_test2.so $(make-link) +$(objpfx)/libnss_test_errno.so.2: $(objpfx)/libnss_test_errno.so + $(make-link) $(patsubst %,$(objpfx)%.out,$(tests) $(tests-container)) : \ $(objpfx)/libnss_test1.so.2 \ $(objpfx)/libnss_test2.so.2 @@ -194,3 +200,6 @@ LDFLAGS-tst-nss-test2 = -Wl,--disable-new-dtags LDFLAGS-tst-nss-test3 = -Wl,--disable-new-dtags LDFLAGS-tst-nss-test4 = -Wl,--disable-new-dtags LDFLAGS-tst-nss-test5 = -Wl,--disable-new-dtags +LDFLAGS-tst-nss-test_errno = -Wl,--disable-new-dtags + +$(objpfx)tst-nss-test_errno.out: $(objpfx)/libnss_test_errno.so.2 diff --git a/nss/nss_module.c b/nss/nss_module.c index f9a1263e5a..4839448e35 100644 --- a/nss/nss_module.c +++ b/nss/nss_module.c @@ -330,9 +330,14 @@ name_search (const void *left, const void *right) void * __nss_module_get_function (struct nss_module *module, const char *name) { + /* A successful dlopen might clobber errno. */ + int saved_errno = errno; + if (!__nss_module_load (module)) return NULL; + __set_errno (saved_errno); + function_name *name_entry = bsearch (name, nss_function_name_array, array_length (nss_function_name_array), sizeof (function_name), name_search); diff --git a/nss/nss_test_errno.c b/nss/nss_test_errno.c new file mode 100644 index 0000000000..3a3c4e53a5 --- /dev/null +++ b/nss/nss_test_errno.c @@ -0,0 +1,58 @@ +/* NSS service provider with errno clobber. + Copyright (C) 2017-2022 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include + +/* Catch misnamed and functions. */ +#pragma GCC diagnostic error "-Wmissing-prototypes" +NSS_DECLARE_MODULE_FUNCTIONS (test_errno) + +static void __attribute__ ((constructor)) +init (void) +{ + /* An arbitrary error code which is otherwise not used. */ + errno = ELIBBAD; +} + +/* Lookup functions for pwd follow that do not return any data. */ + +/* Catch misnamed function definitions. */ + +enum nss_status +_nss_test_errno_setpwent (int stayopen) +{ + setenv ("_nss_test_errno_setpwent", "yes", 1); + return NSS_STATUS_SUCCESS; +} + +enum nss_status +_nss_test_errno_getpwent_r (struct passwd *result, + char *buffer, size_t size, int *errnop) +{ + setenv ("_nss_test_errno_getpwent_r", "yes", 1); + return NSS_STATUS_NOTFOUND; +} + +enum nss_status +_nss_test_errno_endpwent (void) +{ + setenv ("_nss_test_errno_endpwent", "yes", 1); + return NSS_STATUS_SUCCESS; +} diff --git a/nss/tst-nss-test_errno.c b/nss/tst-nss-test_errno.c new file mode 100644 index 0000000000..fae447b76f --- /dev/null +++ b/nss/tst-nss-test_errno.c @@ -0,0 +1,43 @@ +#include +#include +#include +#include +#include +#include +#include + +static int +do_test (void) +{ + __nss_configure_lookup ("passwd", "files test_errno"); + + errno = 0; + setpwent (); + TEST_COMPARE (errno, 0); + + bool root_seen = false; + while (true) + { + errno = 0; + struct passwd *e = getpwent (); + if (e == NULL) + break; + if (strcmp (e->pw_name, "root")) + root_seen = true; + } + + TEST_COMPARE (errno, 0); + TEST_VERIFY (root_seen); + + errno = 0; + endpwent (); + TEST_COMPARE (errno, 0); + + TEST_COMPARE_STRING (getenv ("_nss_test_errno_setpwent"), "yes"); + TEST_COMPARE_STRING (getenv ("_nss_test_errno_getpwent_r"), "yes"); + TEST_COMPARE_STRING (getenv ("_nss_test_errno_endpwent"), "yes"); + + return 0; +} + +#include