From patchwork Mon May 18 12:26:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "H.J. Lu" X-Patchwork-Id: 39291 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 254953870888; Mon, 18 May 2020 12:27:17 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 254953870888 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1589804837; bh=rp1ZDtLICJs1EsWuGdZ/uPkF70a3YywGdJdSdlb6pMg=; h=References:In-Reply-To:Date:Subject:To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=caec9fWNwV9sTXQWE6GmR4EV04oIEMqKd6k3ll32MPCLaWSl9/W3uivBEXOJ8Inbi +EIlmKfq/o4b3WI+xKXoXSgGGXc+jHcL9dByxfCivWe1qhGX9zW6dtdJNRn0Fz9afC h4jMyMO6jVVNaFa6GozlJria9WHOdhLJg/mRRnjY= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-il1-x141.google.com (mail-il1-x141.google.com [IPv6:2607:f8b0:4864:20::141]) by sourceware.org (Postfix) with ESMTPS id 1BD8F3851C21 for ; Mon, 18 May 2020 12:27:13 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 1BD8F3851C21 Received: by mail-il1-x141.google.com with SMTP id o67so4964375ila.0 for ; Mon, 18 May 2020 05:27:13 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=rp1ZDtLICJs1EsWuGdZ/uPkF70a3YywGdJdSdlb6pMg=; b=EW+OBjjECobim7Fu6KNdtVRXutkgzv9EtKfH/f4TTQg4RaybAEbsktKEDvhZNPijDb cCmqMPZT8WDcRO1opV6dZk34RsLvo7fLps6tW8fTVKbSFpXxfd6uNxS5gbq6rxqwr87O N5oQRTDxP/KF9hLg2HxlxHJPIfiZ3GfCMx5zUnvGvdD74P/IGQYhckRrYyx7ZxJfYR8h cKX+1k6NwL1FgTZXDWgtwQKdrFIjh2C56m7z4xE6vEXm4ESZX3dN5482Xn4j3nLJV2Qt qQFbXbYNPaD/dcOtC1vHF246lPoDpsH8FshDxEkLutbVJj0vhTw8ORIwTDU6EL6VFpeU e0VQ== X-Gm-Message-State: AOAM531A5hBow+y6WC6QIdhUzFmsxDJ2kBdTX99BSGXrrCFda3UlvFrW pVIuayIrHGuInZzYxhdNFYdD1n+5nN0Kj4PxjHo= X-Google-Smtp-Source: ABdhPJyXfDEXx8xW07pnheWDpSp8DfylfN8fcochn6MvxQVTgWJS+UqTHA8Q408D53OLtJT5DD8IrzEtXshUWWiuelo= X-Received: by 2002:a92:9f4b:: with SMTP id u72mr14664839ili.273.1589804832506; Mon, 18 May 2020 05:27:12 -0700 (PDT) MIME-Version: 1.0 References: <20200428215243.236312-1-hjl.tools@gmail.com> <20200428215243.236312-2-hjl.tools@gmail.com> <871rnjoknd.fsf@mid.deneb.enyo.de> <87mu65g16k.fsf@oldenburg2.str.redhat.com> In-Reply-To: <87mu65g16k.fsf@oldenburg2.str.redhat.com> Date: Mon, 18 May 2020 05:26:36 -0700 Message-ID: Subject: V2 [PATCH] x86: Move CET control to _dl_x86_feature_control [BZ #25887] To: Florian Weimer X-Spam-Status: No, score=-9.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) 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: "H.J. Lu via Libc-alpha" From: "H.J. Lu" Reply-To: "H.J. Lu" Cc: "H.J. Lu via Libc-alpha" Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" On Mon, May 18, 2020 at 12:19 AM Florian Weimer wrote: > > * H. J. Lu via Libc-alpha: > > > Here is the updated patch to use bitfields. > > Thanks, I like this better. > > > diff --git a/sysdeps/x86/cet-tunables.h b/sysdeps/x86/cet-control.h > > similarity index 61% > > rename from sysdeps/x86/cet-tunables.h > > rename to sysdeps/x86/cet-control.h > > index 5e1e42df10..3a314f9609 100644 > > --- a/sysdeps/x86/cet-tunables.h > > +++ b/sysdeps/x86/cet-control.h > > @@ -16,14 +16,26 @@ > > License along with the GNU C Library; if not, see > > . */ > > > > -/* Valid control values: > > - 0: Enable CET features based on ELF property note. > > - 1: Always disable CET features. > > - 2: Always enable CET features. > > - 3: Enable CET features permissively. > > - */ > > -#define CET_ELF_PROPERTY 0 > > -#define CET_ALWAYS_OFF 1 > > -#define CET_ALWAYS_ON 2 > > -#define CET_PERMISSIVE 3 > > -#define CET_MAX CET_PERMISSIVE > > +#ifndef _CET_CONTROL_H > > +#define _CET_CONTROL_H > > + > > +/* For each CET feature, IBT and SHSTK, valid control values */ > > Missing ”.” at end of comment. Fixed. > > +enum dl_x86_cet_control > > +{ > > + /* Enable CET features based on ELF property note. */ > > + elf_property = 0, > > + /* Always enable CET features. */ > > + always_on, > > + /* Always disable CET features. */ > > + always_off, > > + /* Enable CET features permissively. */ > > Missing double space after “.”. Fixed. > > + permissive > > +}; > > Given enum constantse are not not scoped and this is a widely-included > header, I think you should include at least a “cet_” prefix in these > enum constants. Fixed. > It's still not clear to me why CET control variables have to be in > _rtld_global. Regular global variables would likely lead to clearer > code, I think. _rtld_global is needed for read-write data that is > shared with libc/libdl, and this does not seem to apply to CET control > settings. We don't have a pure local struct for rtld. _rtld_local is a hidden alias of _rtld_global: extern struct rtld_global _rtld_local __attribute__ ((alias ("_rtld_global"), visibility ("hidden"))); struct rtld_global is used to improve IP-relative access. It may not be important for x86-64. But it is still useful for i386 which doesn't have IP-relative addressing. Here is the updated patch. I combined Include to get architecture specific initializer in rtld_global. OK for master? Thanks. From cf798745862c0461194f9676a2d1a5ce70dbc7a3 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 28 Apr 2020 10:05:25 -0700 Subject: [PATCH] x86: Move CET control to _dl_x86_feature_control [BZ #25887] 1. Include to get architecture specific initializer in rtld_global. 2. Change _dl_x86_feature_1[2] to _dl_x86_feature_1. 3. Add _dl_x86_feature_control after _dl_x86_feature_1, which is a struct of 2 bitfields for IBT and SHSTK control This fixes [BZ #25887]. --- elf/rtld.c | 2 + sysdeps/i386/dl-machine.h | 2 +- sysdeps/unix/sysv/linux/x86/cpu-features.c | 2 +- sysdeps/x86/{cet-tunables.h => cet-control.h} | 34 ++++++++++----- sysdeps/x86/cpu-features.c | 12 +++--- sysdeps/x86/cpu-tunables.c | 31 +++---------- sysdeps/x86/dl-cet.c | 43 +++++++++---------- sysdeps/x86/dl-procruntime.c | 22 +++++++++- sysdeps/x86/ldsodefs.h | 1 + 9 files changed, 81 insertions(+), 68 deletions(-) rename sysdeps/x86/{cet-tunables.h => cet-control.h} (60%) diff --git a/elf/rtld.c b/elf/rtld.c index 5ccc3c2dbb..882b070cc0 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -315,6 +315,8 @@ rtld_hidden_def (_dl_starting_up) (except those which cannot be added for some reason). */ struct rtld_global _rtld_global = { + /* Get architecture specific initializer. */ +#include /* Generally the default presumption without further information is an * executable stack but this is not true for all platforms. */ ._dl_stack_flags = DEFAULT_STACK_PERMS, diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h index 8af0789a9c..0f08079e48 100644 --- a/sysdeps/i386/dl-machine.h +++ b/sysdeps/i386/dl-machine.h @@ -71,7 +71,7 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile) extern void _dl_runtime_profile_shstk (Elf32_Word) attribute_hidden; /* Check if SHSTK is enabled by kernel. */ bool shstk_enabled - = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0; + = (GL(dl_x86_feature_1) & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0; if (l->l_info[DT_JMPREL] && lazy) { diff --git a/sysdeps/unix/sysv/linux/x86/cpu-features.c b/sysdeps/unix/sysv/linux/x86/cpu-features.c index d67b300595..fc0e32827d 100644 --- a/sysdeps/unix/sysv/linux/x86/cpu-features.c +++ b/sysdeps/unix/sysv/linux/x86/cpu-features.c @@ -34,7 +34,7 @@ static inline void x86_setup_tls (void) { __libc_setup_tls (); - THREAD_SETMEM (THREAD_SELF, header.feature_1, GL(dl_x86_feature_1)[0]); + THREAD_SETMEM (THREAD_SELF, header.feature_1, GL(dl_x86_feature_1)); } # define ARCH_SETUP_TLS() x86_setup_tls () diff --git a/sysdeps/x86/cet-tunables.h b/sysdeps/x86/cet-control.h similarity index 60% rename from sysdeps/x86/cet-tunables.h rename to sysdeps/x86/cet-control.h index 5e1e42df10..e163a7f55b 100644 --- a/sysdeps/x86/cet-tunables.h +++ b/sysdeps/x86/cet-control.h @@ -16,14 +16,26 @@ License along with the GNU C Library; if not, see . */ -/* Valid control values: - 0: Enable CET features based on ELF property note. - 1: Always disable CET features. - 2: Always enable CET features. - 3: Enable CET features permissively. - */ -#define CET_ELF_PROPERTY 0 -#define CET_ALWAYS_OFF 1 -#define CET_ALWAYS_ON 2 -#define CET_PERMISSIVE 3 -#define CET_MAX CET_PERMISSIVE +#ifndef _CET_CONTROL_H +#define _CET_CONTROL_H + +/* For each CET feature, IBT and SHSTK, valid control values. */ +enum dl_x86_cet_control +{ + /* Enable CET features based on ELF property note. */ + cet_elf_property = 0, + /* Always enable CET features. */ + cet_always_on, + /* Always disable CET features. */ + cet_always_off, + /* Enable CET features permissively. */ + cet_permissive +}; + +struct dl_x86_feature_control +{ + enum dl_x86_cet_control ibt : 2; + enum dl_x86_cet_control shstk : 2; +}; + +#endif /* cet-control.h */ diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index bfb415f05a..b6d5d9d4b1 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -39,7 +39,6 @@ extern void TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *) #if CET_ENABLED # include -# include #endif static void @@ -620,7 +619,7 @@ no_cpuid: if (cet_status) { - GL(dl_x86_feature_1)[0] = cet_status; + GL(dl_x86_feature_1) = cet_status; # ifndef SHARED /* Check if IBT and SHSTK are enabled by kernel. */ @@ -644,14 +643,13 @@ no_cpuid: /* Clear the disabled bits in dl_x86_feature_1. */ if (res == 0) - GL(dl_x86_feature_1)[0] &= ~cet_feature; + GL(dl_x86_feature_1) &= ~cet_feature; } /* Lock CET if IBT or SHSTK is enabled in executable. Don't - lock CET if SHSTK is enabled permissively. */ - if (((GL(dl_x86_feature_1)[1] >> CET_MAX) - & ((1 << CET_MAX) - 1)) - != CET_PERMISSIVE) + lock CET if IBT or SHSTK is enabled permissively. */ + if (GL(dl_x86_feature_control).ibt != cet_permissive + && GL(dl_x86_feature_control).shstk != cet_permissive) dl_cet_lock_cet (); } # endif diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c index 861bd7bcaa..38ad2c2e84 100644 --- a/sysdeps/x86/cpu-tunables.c +++ b/sysdeps/x86/cpu-tunables.c @@ -336,28 +336,18 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp) } # if CET_ENABLED -# include attribute_hidden void TUNABLE_CALLBACK (set_x86_ibt) (tunable_val_t *valp) { if (DEFAULT_MEMCMP (valp->strval, "on", sizeof ("on")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1); - GL(dl_x86_feature_1)[1] |= CET_ALWAYS_ON; - } + GL(dl_x86_feature_control).ibt = cet_always_on; else if (DEFAULT_MEMCMP (valp->strval, "off", sizeof ("off")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1); - GL(dl_x86_feature_1)[1] |= CET_ALWAYS_OFF; - } + GL(dl_x86_feature_control).ibt = cet_always_off; else if (DEFAULT_MEMCMP (valp->strval, "permissive", sizeof ("permissive")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1); - GL(dl_x86_feature_1)[1] |= CET_PERMISSIVE; - } + GL(dl_x86_feature_control).ibt = cet_permissive; } attribute_hidden @@ -365,21 +355,12 @@ void TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *valp) { if (DEFAULT_MEMCMP (valp->strval, "on", sizeof ("on")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX); - GL(dl_x86_feature_1)[1] |= (CET_ALWAYS_ON << CET_MAX); - } + GL(dl_x86_feature_control).shstk = cet_always_on; else if (DEFAULT_MEMCMP (valp->strval, "off", sizeof ("off")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX); - GL(dl_x86_feature_1)[1] |= (CET_ALWAYS_OFF << CET_MAX); - } + GL(dl_x86_feature_control).shstk = cet_always_off; else if (DEFAULT_MEMCMP (valp->strval, "permissive", sizeof ("permissive")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX); - GL(dl_x86_feature_1)[1] |= (CET_PERMISSIVE << CET_MAX); - } + GL(dl_x86_feature_control).shstk = cet_permissive; } # endif #endif diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c index c7029f1b51..5524b66038 100644 --- a/sysdeps/x86/dl-cet.c +++ b/sysdeps/x86/dl-cet.c @@ -20,7 +20,6 @@ #include #include #include -#include /* GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK are defined in , which are only available for C sources. @@ -39,23 +38,23 @@ static void dl_cet_check (struct link_map *m, const char *program) { /* Check how IBT should be enabled. */ - unsigned int enable_ibt_type - = GL(dl_x86_feature_1)[1] & ((1 << CET_MAX) - 1); + enum dl_x86_cet_control enable_ibt_type + = GL(dl_x86_feature_control).ibt; /* Check how SHSTK should be enabled. */ - unsigned int enable_shstk_type - = ((GL(dl_x86_feature_1)[1] >> CET_MAX) & ((1 << CET_MAX) - 1)); + enum dl_x86_cet_control enable_shstk_type + = GL(dl_x86_feature_control).shstk; /* No legacy object check if both IBT and SHSTK are always on. */ - if (enable_ibt_type == CET_ALWAYS_ON - && enable_shstk_type == CET_ALWAYS_ON) + if (enable_ibt_type == cet_always_on + && enable_shstk_type == cet_always_on) return; /* Check if IBT is enabled by kernel. */ bool ibt_enabled - = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0; + = (GL(dl_x86_feature_1) & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0; /* Check if SHSTK is enabled by kernel. */ bool shstk_enabled - = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0; + = (GL(dl_x86_feature_1) & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0; if (ibt_enabled || shstk_enabled) { @@ -65,9 +64,9 @@ dl_cet_check (struct link_map *m, const char *program) /* Check if IBT and SHSTK are enabled in object. */ bool enable_ibt = (ibt_enabled - && enable_ibt_type != CET_ALWAYS_OFF); + && enable_ibt_type != cet_always_off); bool enable_shstk = (shstk_enabled - && enable_shstk_type != CET_ALWAYS_OFF); + && enable_shstk_type != cet_always_off); if (program) { /* Enable IBT and SHSTK only if they are enabled in executable. @@ -76,10 +75,10 @@ dl_cet_check (struct link_map *m, const char *program) GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK */ enable_ibt &= (HAS_CPU_FEATURE (IBT) - && (enable_ibt_type == CET_ALWAYS_ON + && (enable_ibt_type == cet_always_on || (m->l_cet & lc_ibt) != 0)); enable_shstk &= (HAS_CPU_FEATURE (SHSTK) - && (enable_shstk_type == CET_ALWAYS_ON + && (enable_shstk_type == cet_always_on || (m->l_cet & lc_shstk) != 0)); } @@ -111,7 +110,7 @@ dl_cet_check (struct link_map *m, const char *program) /* IBT is enabled only if it is enabled in executable as well as all shared objects. */ - enable_ibt &= (enable_ibt_type == CET_ALWAYS_ON + enable_ibt &= (enable_ibt_type == cet_always_on || (l->l_cet & lc_ibt) != 0); if (!found_ibt_legacy && enable_ibt != ibt_enabled) { @@ -121,7 +120,7 @@ dl_cet_check (struct link_map *m, const char *program) /* SHSTK is enabled only if it is enabled in executable as well as all shared objects. */ - enable_shstk &= (enable_shstk_type == CET_ALWAYS_ON + enable_shstk &= (enable_shstk_type == cet_always_on || (l->l_cet & lc_shstk) != 0); if (enable_shstk != shstk_enabled) { @@ -137,7 +136,7 @@ dl_cet_check (struct link_map *m, const char *program) { if (!program) { - if (enable_ibt_type != CET_PERMISSIVE) + if (enable_ibt_type != cet_permissive) { /* When IBT is enabled, we cannot dlopen a shared object without IBT. */ @@ -148,7 +147,7 @@ dl_cet_check (struct link_map *m, const char *program) N_("rebuild shared object with IBT support enabled")); } - if (enable_shstk_type != CET_PERMISSIVE) + if (enable_shstk_type != cet_permissive) { /* When SHSTK is enabled, we cannot dlopen a shared object without SHSTK. */ @@ -159,8 +158,8 @@ dl_cet_check (struct link_map *m, const char *program) N_("rebuild shared object with SHSTK support enabled")); } - if (enable_ibt_type != CET_PERMISSIVE - && enable_shstk_type != CET_PERMISSIVE) + if (enable_ibt_type != cet_permissive + && enable_shstk_type != cet_permissive) return; } @@ -190,7 +189,7 @@ dl_cet_check (struct link_map *m, const char *program) } /* Clear the disabled bits in dl_x86_feature_1. */ - GL(dl_x86_feature_1)[0] &= ~cet_feature; + GL(dl_x86_feature_1) &= ~cet_feature; cet_feature_changed = true; } @@ -199,9 +198,9 @@ dl_cet_check (struct link_map *m, const char *program) if (program && (ibt_enabled || shstk_enabled)) { if ((!ibt_enabled - || enable_ibt_type != CET_PERMISSIVE) + || enable_ibt_type != cet_permissive) && (!shstk_enabled - || enable_shstk_type != CET_PERMISSIVE)) + || enable_shstk_type != cet_permissive)) { /* Lock CET if IBT or SHSTK is enabled in executable unless IBT or SHSTK is enabled permissively. */ diff --git a/sysdeps/x86/dl-procruntime.c b/sysdeps/x86/dl-procruntime.c index 5e39a38133..2c3e97952b 100644 --- a/sysdeps/x86/dl-procruntime.c +++ b/sysdeps/x86/dl-procruntime.c @@ -47,7 +47,27 @@ # if !defined PROCINFO_DECL && defined SHARED ._dl_x86_feature_1 # else -PROCINFO_CLASS unsigned int _dl_x86_feature_1[2] +PROCINFO_CLASS unsigned int _dl_x86_feature_1 +# endif +# ifndef PROCINFO_DECL += 0 +# endif +# if !defined SHARED || defined PROCINFO_DECL +; +# else +, +# endif + +# if !defined PROCINFO_DECL && defined SHARED + ._dl_x86_feature_control +# else +PROCINFO_CLASS struct dl_x86_feature_control _dl_x86_feature_control +# endif +# ifndef PROCINFO_DECL += { + .ibt = cet_elf_property, + .shstk = cet_elf_property + } # endif # if !defined SHARED || defined PROCINFO_DECL ; diff --git a/sysdeps/x86/ldsodefs.h b/sysdeps/x86/ldsodefs.h index 072f826666..5b1b09dbf8 100644 --- a/sysdeps/x86/ldsodefs.h +++ b/sysdeps/x86/ldsodefs.h @@ -61,6 +61,7 @@ struct La_x32_retval; struct La_x86_64_retval *, \ const char *) +#include #include_next #endif -- 2.26.2