From patchwork Mon Jul 30 19:34:28 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "H.J. Lu" X-Patchwork-Id: 28687 Received: (qmail 74474 invoked by alias); 30 Jul 2018 19:34:33 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 74458 invoked by uid 89); 30 Jul 2018 19:34:33 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-25.4 required=5.0 tests=AWL, BAYES_00, FREEMAIL_FROM, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mail-oi0-f68.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=g+WLhJ5+F75dyupJNFxN4XQbDblD+Mh7wBebZ9bcxHg=; b=BB+TRWDQpnkJ8VtQESGVirriubquKOhcwrZqoHzC2o7yZprvQQj45mCp4QHRtPykNl swFLfKfst+HYf5yG6sJzCtO1e+w2O2iBM9+5heIM6qsiXQPGqFQHQVHkyF27eyE9Z8kU kKqxgcmJeCSOuO/K0Wl6V7RtCcN9McYkwOP5+d7wxTh5VrT3oIJeqFE/NP3Y89qWXJmz UyC8kk1Wq4zq+QrHlBUYiFEBwMrKyCuHhCfWZw5TgToBv+0p5YepqOUNdSenI5lCMAyy COJgMVIqQb0b+4SxfGjE9BJFhfeIqmbXUEfXG4kvDPvNW9WnFJm5UtH0CDEZ1JJNCS4r 3PNg== MIME-Version: 1.0 In-Reply-To: <849d6d82-33ec-7604-55ad-852eb319a70c@linaro.org> References: <24b93543-b78b-ba73-764e-389c673c69ad@linaro.org> <849d6d82-33ec-7604-55ad-852eb319a70c@linaro.org> From: "H.J. Lu" Date: Mon, 30 Jul 2018 12:34:28 -0700 Message-ID: Subject: Re: V3 [PATCH] x86/CET: Fix property note parser [BZ #23467] To: Adhemerval Zanella , "Carlos O'Donell" Cc: GNU C Library On Mon, Jul 30, 2018 at 12:09 PM, Adhemerval Zanella wrote: > > > On 30/07/2018 15:56, H.J. Lu wrote: >>>> + >>>> + test (bar); >>>> + >>>> + return EXIT_FAILURE; >>>> +} >>> >>>> diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h >>>> index 35d3f16a23..d9e0770e29 100644 >>>> --- a/sysdeps/x86/dl-prop.h >>>> +++ b/sysdeps/x86/dl-prop.h >>>> @@ -73,7 +73,7 @@ _dl_process_cet_property_note (struct link_map *l, >>>> unsigned char *ptr = (unsigned char *) (note + 1) + 4; >>>> unsigned char *ptr_end = ptr + note->n_descsz; >>>> >>> >>> Should we care for overflow here (I guess not since we don't really >>> protected against ill-formed elf files in general)? >> >> We do protect against ill-formed notes. When we get here, the whole >> note has been loaded into memory. There won't be overflow. > > Indeed, LGTM to me then. This is the updated patch I am going to check in today. Thanks. Reviewed-by: Carlos O'Donell From bed8cb21b6bd67bed148713259779a8a3e3f844d Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Fri, 27 Jul 2018 20:34:55 -0700 Subject: [PATCH] x86/CET: Fix property note parser [BZ #23467] GNU_PROPERTY_X86_FEATURE_1_AND may not be the first property item. We need to check each property item until we reach the end of the property or find GNU_PROPERTY_X86_FEATURE_1_AND. This patch adds 2 tests. The first test checks if IBT is enabled and the second test reads the output from the first test to check if IBT is is enabled. The second second test fails if IBT isn't enabled properly. [BZ #23467] * sysdeps/unix/sysv/linux/x86/Makefile (tests): Add tst-cet-property-1 and tst-cet-property-2 if CET is enabled. (CFLAGS-tst-cet-property-1.o): New. (ASFLAGS-tst-cet-property-dep-2.o): Likewise. ($(objpfx)tst-cet-property-2): Likewise. ($(objpfx)tst-cet-property-2.out): Likewise. * sysdeps/unix/sysv/linux/x86/tst-cet-property-1.c: New file. * sysdeps/unix/sysv/linux/x86/tst-cet-property-2.c: Likewise. * sysdeps/unix/sysv/linux/x86/tst-cet-property-dep-2.S: Likewise. * sysdeps/x86/dl-prop.h (_dl_process_cet_property_note): Parse each property item until GNU_PROPERTY_X86_FEATURE_1_AND is found. --- sysdeps/unix/sysv/linux/x86/Makefile | 15 +++++ .../unix/sysv/linux/x86/tst-cet-property-1.c | 40 +++++++++++++ .../unix/sysv/linux/x86/tst-cet-property-2.c | 58 ++++++++++++++++++ .../sysv/linux/x86/tst-cet-property-dep-2.S | 60 +++++++++++++++++++ sysdeps/x86/dl-prop.h | 24 +++++--- 5 files changed, 188 insertions(+), 9 deletions(-) create mode 100644 sysdeps/unix/sysv/linux/x86/tst-cet-property-1.c create mode 100644 sysdeps/unix/sysv/linux/x86/tst-cet-property-2.c create mode 100644 sysdeps/unix/sysv/linux/x86/tst-cet-property-dep-2.S diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile index a30fdb1dc1..7dc4e61756 100644 --- a/sysdeps/unix/sysv/linux/x86/Makefile +++ b/sysdeps/unix/sysv/linux/x86/Makefile @@ -25,6 +25,21 @@ tests += tst-saved_mask-1 endif ifeq ($(enable-cet),yes) +ifeq ($(subdir),elf) +tests += tst-cet-property-1 tst-cet-property-2 + +CFLAGS-tst-cet-property-1.o += -fcf-protection +ASFLAGS-tst-cet-property-dep-2.o += -fcf-protection + +$(objpfx)tst-cet-property-2: $(objpfx)tst-cet-property-dep-2.o +$(objpfx)tst-cet-property-2.out: $(objpfx)tst-cet-property-2 \ + $(objpfx)tst-cet-property-1.out + env $(run-program-env) $(test-via-rtld-prefix) \ + $(objpfx)tst-cet-property-2 \ + < $(objpfx)tst-cet-property-1.out > $@; \ + $(evaluate-test) +endif + ifeq ($(subdir),stdlib) tests += tst-cet-setcontext-1 CFLAGS-tst-cet-setcontext-1.c += -mshstk diff --git a/sysdeps/unix/sysv/linux/x86/tst-cet-property-1.c b/sysdeps/unix/sysv/linux/x86/tst-cet-property-1.c new file mode 100644 index 0000000000..0a1e155770 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86/tst-cet-property-1.c @@ -0,0 +1,40 @@ +/* Test CET property note parser. + Copyright (C) 2018 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 int +do_test (void) +{ + unsigned int feature_1; +#ifdef __x86_64__ +# define SEG_REG "fs" +#else +# define SEG_REG "gs" +#endif + asm ("movl %%" SEG_REG ":%P1, %0" + : "=r" (feature_1) : "i" (FEATURE_1_OFFSET)); + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0) + printf ("IBT\n"); + + return 0; +} + +#include diff --git a/sysdeps/unix/sysv/linux/x86/tst-cet-property-2.c b/sysdeps/unix/sysv/linux/x86/tst-cet-property-2.c new file mode 100644 index 0000000000..fe793e92b6 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86/tst-cet-property-2.c @@ -0,0 +1,58 @@ +/* Test CET property note parser. + Copyright (C) 2018 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 +#include +#include + +extern void bar (void); + +void +__attribute__ ((noclone, noinline)) +test (void (*func_p) (void)) +{ + func_p (); +} + +static void +sig_handler (int signo) +{ + exit (EXIT_SUCCESS); +} + +static int +do_test (void) +{ + char buf[20]; + + if (scanf ("%20s", buf) != 1) + FAIL_UNSUPPORTED ("IBT not supported"); + + if (strcmp (buf, "IBT") != 0) + FAIL_UNSUPPORTED ("IBT not supported"); + + TEST_VERIFY_EXIT (signal (SIGSEGV, &sig_handler) != SIG_ERR); + + test (bar); + + return EXIT_FAILURE; +} + +#include diff --git a/sysdeps/unix/sysv/linux/x86/tst-cet-property-dep-2.S b/sysdeps/unix/sysv/linux/x86/tst-cet-property-dep-2.S new file mode 100644 index 0000000000..831a8b2e68 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86/tst-cet-property-dep-2.S @@ -0,0 +1,60 @@ +/* Test CET property note parser. + Copyright (C) 2018 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 + + .text + .p2align 4,,15 + .globl bar + .type bar, @function +bar: + .cfi_startproc + ret + .cfi_endproc + .size bar, .-bar + +#if __SIZEOF_PTRDIFF_T__ == 8 +# define ALIGN 3 +#elif __SIZEOF_PTRDIFF_T__ == 4 +# define ALIGN 2 +#endif + + .section ".note.gnu.property", "a" + .p2align ALIGN + + .long 1f - 0f /* name length */ + .long 5f - 2f /* data length */ + .long 5 /* note type */ +0: .asciz "GNU" /* vendor name */ +1: + .p2align ALIGN +2: + .long 1 /* pr_type. */ + .long 4f - 3f /* pr_datasz. */ +3: +#if __SIZEOF_PTRDIFF_T__ == 8 + .long 0x800 + .long 0x800 +#else + .long 0x08000800 +#endif +4: + .p2align ALIGN +5: + + .section .note.GNU-stack,"",@progbits diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h index 35d3f16a23..d9e0770e29 100644 --- a/sysdeps/x86/dl-prop.h +++ b/sysdeps/x86/dl-prop.h @@ -73,7 +73,7 @@ _dl_process_cet_property_note (struct link_map *l, unsigned char *ptr = (unsigned char *) (note + 1) + 4; unsigned char *ptr_end = ptr + note->n_descsz; - while (ptr < ptr_end) + do { unsigned int type = *(unsigned int *) ptr; unsigned int datasz = *(unsigned int *) (ptr + 4); @@ -82,17 +82,23 @@ _dl_process_cet_property_note (struct link_map *l, if ((ptr + datasz) > ptr_end) break; - if (type == GNU_PROPERTY_X86_FEATURE_1_AND - && datasz == 4) + if (type == GNU_PROPERTY_X86_FEATURE_1_AND) { - unsigned int feature_1 = *(unsigned int *) ptr; - if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT)) - l->l_cet |= lc_ibt; - if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK)) - l->l_cet |= lc_shstk; - break; + if (datasz == 4) + { + unsigned int feature_1 = *(unsigned int *) ptr; + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT)) + l->l_cet |= lc_ibt; + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK)) + l->l_cet |= lc_shstk; + } + return; } + + /* Check the next property item. */ + ptr += ALIGN_UP (datasz, sizeof (ElfW(Addr))); } + while ((ptr_end - ptr) >= 8); } /* NB: Note sections like .note.ABI-tag and .note.gnu.build-id are -- 2.17.1