From patchwork Thu Oct 14 17:47:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella X-Patchwork-Id: 46228 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 7900A3858427 for ; Thu, 14 Oct 2021 17:52:00 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 7900A3858427 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1634233920; bh=uVFKphTkKIkAD2fumvUOdXlKfOSc7fIonTMEPJvXCh8=; 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=iYncYl4TPMrFUYr+EKoePtqZRo6nyD9+6jje/T6NlOHE3+bKtZAMpaQsy+mZZi0E1 b8EJe1ca1p6v1UufChgcHWOPkVjhSAHmvU11hHIPLb7xihOx42b5eKvo8YY0IT0vAw jXwm5KYi1KiV/xJsoE3JXxpMcbP2ysQtwFidXCmg= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-ua1-x929.google.com (mail-ua1-x929.google.com [IPv6:2607:f8b0:4864:20::929]) by sourceware.org (Postfix) with ESMTPS id C08013857C42 for ; Thu, 14 Oct 2021 17:48:07 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C08013857C42 Received: by mail-ua1-x929.google.com with SMTP id f4so12918353uad.4 for ; Thu, 14 Oct 2021 10:48:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=uVFKphTkKIkAD2fumvUOdXlKfOSc7fIonTMEPJvXCh8=; b=Ym6WxsY2NmwHjb8MnGivDRo5z+HM9JsYpRaroJBvIBvWxuWyLhLqpccEQCYhsa1jai 5OSj+YDf3sq+OS2EPghJmev9uouHea0tG1rYM2bwX4pIhQWgdwuOF0m9hKgzcrCmRS+8 U9K5ioJoJMXu3wwrp6Mj8cpH5XS6DA7OCnG5/raigJwUuNgssxt7AfIyfdEDItI8RT1R feodv9bwWFQT49QByoBX+eP3NNysFSL0FdwRFIYx5lY5dwD8g9uMd0L6x2yNKXnZeDOh 5lRs8sygzE6HtowmoriUo31qIbJftWuUh6PI+yJ0DKQq7HHfRa3qQUcYG7PCvbvQFhFx i1yw== X-Gm-Message-State: AOAM5300/STB7U1pSR1cW6XawTzT//2TkqbAOY5YS5s5ekJ/5kMaQxO2 /zgNbhrY+0c3ZHf1CRTw7FtKtFCcPcTphA== X-Google-Smtp-Source: ABdhPJymCrPKEJrK9bpTTNL+havfHMNL5yrkFkOZaYz3L9Xiqp71uXX0+wWVEIyXNFT8fde4tosoCw== X-Received: by 2002:a67:eb17:: with SMTP id a23mr8651271vso.56.1634233687121; Thu, 14 Oct 2021 10:48:07 -0700 (PDT) Received: from birita.. ([2804:431:c7ca:c6c7:3c65:db0e:6fcc:a8e9]) by smtp.gmail.com with ESMTPSA id q26sm2107237vkn.40.2021.10.14.10.48.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Oct 2021 10:48:06 -0700 (PDT) To: libc-alpha@sourceware.org Subject: [PATCH v4 05/21] elf: Fix initial-exec TLS access on audit modules (BZ #28096) Date: Thu, 14 Oct 2021 14:47:36 -0300 Message-Id: <20211014174752.1651347-6-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211014174752.1651347-1-adhemerval.zanella@linaro.org> References: <20211014174752.1651347-1-adhemerval.zanella@linaro.org> MIME-Version: 1.0 X-Spam-Status: No, score=-12.4 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 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, i686-linux-gnu, and aarch64-linux-gnu. --- elf/Makefile | 5 ++++ 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(+), 4 deletions(-) create mode 100644 elf/tst-audit21.c create mode 100644 elf/tst-auditmod21.c diff --git a/elf/Makefile b/elf/Makefile index 549bd30c7d..4d6075730f 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -224,6 +224,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \ tst-audit18a tst-audit18b \ 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 \ @@ -315,6 +316,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \ tst-auditmod18a tst-auditmod18b tst-audit18bmod \ 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 \ @@ -1541,6 +1543,9 @@ $(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 9260d2d696..512ed9a9dc 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 4bbf71b587..0fe29e49ee 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -1054,6 +1054,8 @@ 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..307cb6fc3b --- /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 *arg) +{ + 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 5b29a4f992..f2cd742e29 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.*/