From patchwork Mon Jul 19 14:33:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella Netto X-Patchwork-Id: 44392 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id F2C40395205C for ; Mon, 19 Jul 2021 14:38:39 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org F2C40395205C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1626705520; bh=8S9FYl6dYg45u6z+ckdHxGSaII7YFk3aCqLabBVYZSU=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=rGnHzgUH6God1HKglPOZWTHH+uGBr5KGn50gyeaLHvlHxMv3wNt/A7pIStutMuORT 6dlaXTHTzArdH4Vi95qj/8ALdZsFWCpTb+migMaYLoadUTgQTZ9YarZbZQ0z9UMe3b VVFMznWl59yMStkhukRjATQJWA7x6OTQ/ktSEpNM= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by sourceware.org (Postfix) with ESMTPS id 11AAF3951883 for ; Mon, 19 Jul 2021 14:33:41 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 11AAF3951883 Received: by mail-pj1-x1030.google.com with SMTP id g24so11558734pji.4 for ; Mon, 19 Jul 2021 07:33:41 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=8S9FYl6dYg45u6z+ckdHxGSaII7YFk3aCqLabBVYZSU=; b=hpJtj72S33OK2FsqzrqlGWzcJsKzwF89V6Sm5q07bKrBdttp3fJuzZwTK2oVBJfpLL K/KAdvgyCAkBtjHlx+b+gP23g0Qe5lj//kCa9uAJlL4inrbaeohe9p/FWaG6nQ1CVL/+ PLkbeKXOHyqLcyKPrwHTHX7qgydR1sB2FoieiHGSZWY1RqRIPMKmn8IhwFfxu9wpOXNg sYepaIY4kbJlORBG+QSzKWhZ9Do2yzATG/12ic80D1zdDHIM5roC38y6ILdXPCQBlAR1 9NWYrh24K74BQVXfcOTP+kSdeexCM/s39usexMOzIQnV9rlR+8HimU9JJofXj8H9P4no 1prw== X-Gm-Message-State: AOAM532oRUjKxwyk0QW7P5ZHH7hjJPgbUuyhxRbFlF6NQNn5sQE87v74 ljYFHSNHPteCvfICGHtwSvYxF4I3b3O6Sg== X-Google-Smtp-Source: ABdhPJzZpbz/DvbCH9HI+b9Hrxsb3USLGuwJ5gAOJXMn5x+zz5FvSlPgrJJomCscf4ZVHHyYHJX/wQ== X-Received: by 2002:a17:90a:6c61:: with SMTP id x88mr31400639pjj.122.1626705220006; Mon, 19 Jul 2021 07:33:40 -0700 (PDT) Received: from birita.. ([2804:431:c7ca:1133:c8a4:b05d:5ba9:3665]) by smtp.gmail.com with ESMTPSA id y13sm21461214pgp.16.2021.07.19.07.33.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Jul 2021 07:33:39 -0700 (PDT) To: libc-alpha@sourceware.org Subject: [PATCH v2 6/6] elf: Fix initial-exec TLS access on audit modules (BZ #28096) Date: Mon, 19 Jul 2021 11:33:09 -0300 Message-Id: <20210719143309.2848878-7-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210719143309.2848878-1-adhemerval.zanella@linaro.org> References: <20210719143309.2848878-1-adhemerval.zanella@linaro.org> MIME-Version: 1.0 X-Spam-Status: No, score=-12.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP 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: Adhemerval Zanella via Libc-alpha From: Adhemerval Zanella Netto Reply-To: Adhemerval Zanella Cc: John Mellor-Crummey Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" For ldaudit modules or dependencies with initial-exec TLS, we can not set the initial TLS image on default loader initialization because it would already be set by the ldaudit setup. However, subsequent thread creation would need to follow the default behaviour. This patch fixes by making_dl_new_object() sets a new link_map flag 'l_dont_set_tls_static' only for __RTLD_AUDIT modules. The flag is later reset on _dl_allocate_tls_init(). Checked on x86_64-linux-gnu. --- elf/Makefile | 6 +++- elf/dl-object.c | 3 ++ elf/dl-tls.c | 16 +++++++--- elf/rtld.c | 2 ++ elf/tst-audit21.c | 42 +++++++++++++++++++++++++++ elf/tst-auditmod21.c | 69 ++++++++++++++++++++++++++++++++++++++++++++ include/link.h | 2 ++ 7 files changed, 135 insertions(+), 5 deletions(-) create mode 100644 elf/tst-audit21.c create mode 100644 elf/tst-auditmod21.c diff --git a/elf/Makefile b/elf/Makefile index c429023b66..498c4dc3b9 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -220,7 +220,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \ tst-dlopenfail-2 \ tst-filterobj tst-filterobj-dlopen tst-auxobj tst-auxobj-dlopen \ tst-audit14 tst-audit15 tst-audit16 tst-audit17 tst-audit18 \ - tst-audit19 tst-audit20 \ + tst-audit19 tst-audit20 tst-audit21 \ tst-single_threaded tst-single_threaded-pthread \ tst-tls-ie tst-tls-ie-dlmopen argv0test \ tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \ @@ -304,6 +304,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \ tst-auditmod9a tst-auditmod9b \ tst-auditmod18 tst-auditmod19 \ tst-auditmod20 tst-audit20mod \ + tst-auditmod21 \ $(if $(CXX),tst-unique3lib tst-unique3lib2 tst-unique4lib \ tst-nodelete-uniquemod tst-nodelete-rtldmod \ tst-nodelete-zmod \ @@ -1516,6 +1517,9 @@ $(objpfx)tst-audit20.out: $(objpfx)tst-auditmod20.so \ $(objpfx)tst-audit20mod.so tst-audit20-ARGS = -- $(host-test-program-cmd) +$(objpfx)tst-audit21.out: $(objpfx)tst-auditmod21.so +tst-audit21-ENV = LD_AUDIT=$(objpfx)tst-auditmod21.so + # tst-sonamemove links against an older implementation of the library. LDFLAGS-tst-sonamemove-linkmod1.so = \ -Wl,--version-script=tst-sonamemove-linkmod1.map \ diff --git a/elf/dl-object.c b/elf/dl-object.c index 1875599eb2..eb2158a84b 100644 --- a/elf/dl-object.c +++ b/elf/dl-object.c @@ -175,6 +175,9 @@ _dl_new_object (char *realname, const char *libname, int type, new->l_local_scope[0] = &new->l_searchlist; + if (mode & __RTLD_AUDIT) + new->l_dont_set_tls_static = 1; + /* Determine the origin. If allocating the link map for the main executable, the realname is not known and "". In this case, the origin needs to be determined by other means. However, in case diff --git a/elf/dl-tls.c b/elf/dl-tls.c index 423e380f7c..4763fdb856 100644 --- a/elf/dl-tls.c +++ b/elf/dl-tls.c @@ -593,10 +593,18 @@ _dl_allocate_tls_init (void *result) some platforms use in static programs requires it. */ dtv[map->l_tls_modid].pointer.val = dest; - /* Copy the initialization image and clear the BSS part. */ - memset (__mempcpy (dest, map->l_tls_initimage, - map->l_tls_initimage_size), '\0', - map->l_tls_blocksize - map->l_tls_initimage_size); + /* Copy the initialization image and clear the BSS part. For + ldaudit modules or depedencies with initial-exec TLS, we can not + set the initial TLS image on default loader initialization + because it would already be set by the ldaudit setup. However, + subsequent thread creation would need to follow the default + behaviour. */ + if (__glibc_unlikely (!map->l_dont_set_tls_static)) + memset (__mempcpy (dest, map->l_tls_initimage, + map->l_tls_initimage_size), '\0', + map->l_tls_blocksize - map->l_tls_initimage_size); + else + map->l_dont_set_tls_static = 0; } total += cnt; diff --git a/elf/rtld.c b/elf/rtld.c index 374bf86a69..1312378b5f 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -1053,6 +1053,8 @@ ERROR: audit interface '%s' requires version %d (maximum supported version %d); /* Mark the DSO as being used for auditing. */ dlmargs.map->l_auditing = 1; + /* Mark the DSO to not clear the TLS bss in tls initialization. */ + dlmargs.map->l_dont_set_tls_static = 1; } /* Notify the the audit modules that the object MAP has already been diff --git a/elf/tst-audit21.c b/elf/tst-audit21.c new file mode 100644 index 0000000000..7f4996d66f --- /dev/null +++ b/elf/tst-audit21.c @@ -0,0 +1,42 @@ +/* Check DT_AUDIT with static TLS. + Copyright (C) 2021 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 + +static volatile __thread int out __attribute__ ((tls_model ("initial-exec"))); + +static void * +tf (void *) +{ + TEST_COMPARE (out, 0); + out = isspace (' '); + return NULL; +} + +int main (int argc, char *argv[]) +{ + TEST_COMPARE (out, 0); + out = isspace (' '); + + pthread_t t = xpthread_create (NULL, tf, NULL); + xpthread_join (t); + + return 0; +} diff --git a/elf/tst-auditmod21.c b/elf/tst-auditmod21.c new file mode 100644 index 0000000000..e6248622f4 --- /dev/null +++ b/elf/tst-auditmod21.c @@ -0,0 +1,69 @@ +/* Check DT_AUDIT with static TLS. + Copyright (C) 2021 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 + +#define tls_ie __attribute__ ((tls_model ("initial-exec"))) + +__thread int tls_var0 tls_ie; +__thread int tls_var1 tls_ie = 0x10; + +static volatile int out; + +static void +call_libc (void) +{ + /* isspace() access the initial-exec glibc TLS variables, which are + setup in glibc initialization. */ + out = isspace (' '); +} + +unsigned int +la_version (unsigned int v) +{ + tls_var0 = 0x1; + if (tls_var1 != 0x10) + abort (); + tls_var1 = 0x20; + call_libc (); + return LAV_CURRENT; +} + +unsigned int +la_objopen (struct link_map* map, Lmid_t lmid, uintptr_t* cookie) +{ + call_libc (); + *cookie = (uintptr_t) map; + return 0; +} + +void +la_activity (uintptr_t* cookie, unsigned int flag) +{ + if (tls_var0 != 0x1 || tls_var1 != 0x20) + abort (); + call_libc (); +} + +void +la_preinit (uintptr_t* cookie) +{ + call_libc (); +} diff --git a/include/link.h b/include/link.h index ebd0f511e2..aca6fa58dc 100644 --- a/include/link.h +++ b/include/link.h @@ -190,6 +190,8 @@ struct link_map unsigned int l_need_tls_init:1; /* Nonzero if GL(dl_init_static_tls) should be called on this link map when relocation finishes. */ + unsigned int l_dont_set_tls_static:1; /* Non zero if static TLS setup should + not be initialized. */ unsigned int l_auditing:1; /* Nonzero if the DSO is used in auditing. */ unsigned int l_audit_any_plt:1; /* Nonzero if at least one audit module is interested in the PLT interception.*/