From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by sourceware.org (Postfix) with ESMTPS id 69071385800C for ; Fri, 19 Nov 2021 15:34:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 69071385800C Received: by mail-pj1-x102f.google.com with SMTP id cq22-20020a17090af99600b001a9550a17a5so11285707pjb.2 for ; Fri, 19 Nov 2021 07:34:33 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=1C6x+6a4skpj0uh08vTS/hR239HOYu8ff+pbNZPtOyM=; b=O49M9tH95T7fZLZWat2bqXFHZ9QvoiRk8EgWnprLhlQqZFnRFgSVc7saP8Rd5+ps1q /2Am2b7bafBky9udFmWz/qi6fiaAUHx/A7asY5vKfbWvdzSZT81StoR0T9Uj8rOMkSCt S/GJnRphHMBudMt1LFHXr3VDwfwyN5gAVlPZsVtJ1ARDBowv1jRGU98Mzspmf45JOZEl iBj5uupzhRRR4Baankpcwe78keQ4tnAo78zdWbIgB+pi1K+EHvQO0hUr4ILISqRpa1Yu 2tzWoEHuQcbudjPKxig1WTLWKfTzaUYU+Ohfpih5kG749eXTRo7Q7HXDqpqRSfTfJ9wg Ea4g== X-Gm-Message-State: AOAM530+l3GG4zCLMIkgmVusZCt0yGyDaC0e+lMMUJ5O70SuARxRM5+X 8/r+QZ0Bq7ZAR/gQAwRy6t2pVVpP1a/IrahKSRU= X-Google-Smtp-Source: ABdhPJzTitUdZUXftDRuMK5RshRNqZi2Os9jRxBfw9PPPsULYXmW5CmY8r9QyI6/DBjq/2ttZWDhcxK0ve38xNiu+Yg= X-Received: by 2002:a17:90b:3a85:: with SMTP id om5mr673988pjb.28.1637336072110; Fri, 19 Nov 2021 07:34:32 -0800 (PST) MIME-Version: 1.0 References: <20211119150329.2200675-1-adhemerval.zanella@linaro.org> In-Reply-To: <20211119150329.2200675-1-adhemerval.zanella@linaro.org> From: "H.J. Lu" Date: Fri, 19 Nov 2021 07:33:56 -0800 Message-ID: Subject: Re: [PATCH] elf: Add elf checks for main executable To: Adhemerval Zanella Cc: GNU C Library , Florian Weimer Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3029.0 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=3.4.4 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-List-Received-Date: Fri, 19 Nov 2021 15:34:37 -0000 On Fri, Nov 19, 2021 at 7:03 AM Adhemerval Zanella wrote: > > The ELF header integrity check is only done on open_verify(), i.e, > for objects explicitly loaded. For main executable (issued with > execve() for the binary) only kernel checks are done, which does > not check EI_ABIVERSION. > > To enable it, the loader needs to find where the ELF header is placed > at program start, however Linux auxiliary vectors only provides Is it possible to check __ehdr_start? > the program header table (AT_EHDR). To avoid require upstream > kernel support, the ELF header is implicitly obtained from the PT_LOAD > values by checking for a segment with offset 0 and memory size > different than 0 (For Linux it is start the ELF file issued by > execve()). > > Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. > --- > elf/Makefile | 8 +- > elf/dl-check-err.h | 14 ++ > elf/dl-check.c | 151 ++++++++++++++++++ > elf/dl-check.h | 45 ++++++ > elf/dl-load.c | 114 ++------------ > elf/rtld.c | 8 + > elf/tst-elf-check.c | 209 +++++++++++++++++++++++++ > sysdeps/generic/dl-elf-check.h | 28 ++++ > sysdeps/unix/sysv/linux/dl-elf-check.h | 32 ++++ > 9 files changed, 507 insertions(+), 102 deletions(-) > create mode 100644 elf/dl-check-err.h > create mode 100644 elf/dl-check.c > create mode 100644 elf/dl-check.h > create mode 100644 elf/tst-elf-check.c > create mode 100644 sysdeps/generic/dl-elf-check.h > create mode 100644 sysdeps/unix/sysv/linux/dl-elf-check.h > > diff --git a/elf/Makefile b/elf/Makefile > index 4723c159cb..f09fc5c6ec 100644 > --- a/elf/Makefile > +++ b/elf/Makefile > @@ -36,7 +36,8 @@ dl-routines = $(addprefix dl-,load lookup object reloc deps \ > exception sort-maps lookup-direct \ > call-libc-early-init write \ > thread_gscope_wait tls_init_tp \ > - debug-symbols minimal-malloc) > + debug-symbols minimal-malloc \ > + check) > ifeq (yes,$(use-ldconfig)) > dl-routines += dl-cache > endif > @@ -238,7 +239,8 @@ tests-internal += loadtest unload unload2 circleload1 \ > tst-ptrguard1 tst-stackguard1 \ > tst-create_format1 tst-tls-surplus tst-dl-hwcaps_split > tests-container += tst-pldd tst-dlopen-tlsmodid-container \ > - tst-dlopen-self-container tst-preload-pthread-libc > + tst-dlopen-self-container tst-preload-pthread-libc \ > + tst-elf-check > test-srcs = tst-pathopt > selinux-enabled := $(shell cat /selinux/enforce 2> /dev/null) > ifneq ($(selinux-enabled),1) > @@ -494,6 +496,8 @@ tests-special += $(objpfx)order-cmp.out $(objpfx)tst-array1-cmp.out \ > $(objpfx)tst-unused-dep-cmp.out > endif > > +tst-elf-check-ARGS = -- $(host-test-program-cmd) > + > ifndef avoid-generated > # DSO sorting tests: > # The dso-ordering-test.py script generates testcase source files in $(objpfx), > diff --git a/elf/dl-check-err.h b/elf/dl-check-err.h > new file mode 100644 > index 0000000000..6ca5246eb8 > --- /dev/null > +++ b/elf/dl-check-err.h > @@ -0,0 +1,14 @@ > +_S(DL_ELFHDR_OK, "") > +_S(DL_ELFHDR_ERR_ELFMAG, N_("invalid ELF header")) > +_S(DL_ELFHDR_ERR_CLASS32, N_("wrong ELF class: ELFCLASS32")) > +_S(DL_ELFHDR_ERR_CLASS64, N_("wrong ELF class: ELFCLASS64")) > +_S(DL_ELFHDR_ERR_BENDIAN, N_("ELF file data encoding not big-endian")) > +_S(DL_ELFHDR_ERR_LENDIAN, N_("ELF file data encoding not little-endian")) > +_S(DL_ELFHDR_ERR_EIVERSION, N_("ELF file version ident does not match current one")) > +_S(DL_ELFHDR_ERR_OSABI, N_("ELF file OS ABI invalid")) > +_S(DL_ELFHDR_ERR_ABIVERSION, N_("ELF file ABI version invalid")) > +_S(DL_ELFHDR_ERR_PAD, N_("nonzero padding in e_ident")) > +_S(DL_ELFHDR_ERR_VERSION, N_("ELF file version does not match current one")) > +_S(DL_ELFHDR_ERR_TYPE, N_("only ET_DYN and ET_EXEC can be loaded")) > +_S(DL_ELFHDR_ERR_PHENTSIZE, N_("ELF file's phentsize not the expected size")) > +_S(DL_ELFHDR_ERR_INTERNAL, N_("internal error")) > diff --git a/elf/dl-check.c b/elf/dl-check.c > new file mode 100644 > index 0000000000..ef1720df2a > --- /dev/null > +++ b/elf/dl-check.c > @@ -0,0 +1,151 @@ > +/* ELF header consistency and ABI checks. > + Copyright (C) 1995-2021 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 > +#include > +#include > + > +int > +_dl_elfhdr_check (const ElfW(Ehdr) *ehdr) > +{ > +#define ELF32_CLASS ELFCLASS32 > +#define ELF64_CLASS ELFCLASS64 > +#if BYTE_ORDER == BIG_ENDIAN > +# define byteorder ELFDATA2MSB > +#elif BYTE_ORDER == LITTLE_ENDIAN > +# define byteorder ELFDATA2LSB > +#else > +# error "Unknown BYTE_ORDER " BYTE_ORDER > +# define byteorder ELFDATANONE > +#endif > + MORE_ELF_HEADER_DATA; > + static const unsigned char expected[EI_NIDENT] = > + { > + [EI_MAG0] = ELFMAG0, > + [EI_MAG1] = ELFMAG1, > + [EI_MAG2] = ELFMAG2, > + [EI_MAG3] = ELFMAG3, > + [EI_CLASS] = ELFW(CLASS), > + [EI_DATA] = byteorder, > + [EI_VERSION] = EV_CURRENT, > + [EI_OSABI] = ELFOSABI_SYSV, > + [EI_ABIVERSION] = 0 > + }; > + > + /* See whether the ELF header is what we expect. */ > + if (__glibc_unlikely (! VALID_ELF_HEADER (ehdr->e_ident, expected, > + EI_ABIVERSION) > + || !VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI], > + ehdr->e_ident[EI_ABIVERSION]) > + || memcmp (&ehdr->e_ident[EI_PAD], > + &expected[EI_PAD], > + EI_NIDENT - EI_PAD) != 0)) > + { > + /* Something is wrong. */ > + const Elf32_Word *magp = (const void *) ehdr->e_ident; > + if (*magp != > +#if BYTE_ORDER == LITTLE_ENDIAN > + ((ELFMAG0 << (EI_MAG0 * 8)) > + | (ELFMAG1 << (EI_MAG1 * 8)) > + | (ELFMAG2 << (EI_MAG2 * 8)) > + | (ELFMAG3 << (EI_MAG3 * 8))) > +#else > + ((ELFMAG0 << (EI_MAG3 * 8)) > + | (ELFMAG1 << (EI_MAG2 * 8)) > + | (ELFMAG2 << (EI_MAG1 * 8)) > + | (ELFMAG3 << (EI_MAG0 * 8))) > +#endif > + ) > + return DL_ELFHDR_ERR_ELFMAG; > + else if (ehdr->e_ident[EI_CLASS] != ELFW(CLASS)) > + return ELFW(CLASS) == ELFCLASS32 > + ? DL_ELFHDR_ERR_CLASS64 > + : DL_ELFHDR_ERR_CLASS32; > + else if (ehdr->e_ident[EI_DATA] != byteorder) > + { > + if (BYTE_ORDER == BIG_ENDIAN) > + return DL_ELFHDR_ERR_BENDIAN; > + else > + return DL_ELFHDR_ERR_LENDIAN; > + } > + else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT) > + return DL_ELFHDR_ERR_EIVERSION; > + /* XXX We should be able so set system specific versions which are > + allowed here. */ > + else if (!VALID_ELF_OSABI (ehdr->e_ident[EI_OSABI])) > + return DL_ELFHDR_ERR_OSABI; > + else if (!VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI], > + ehdr->e_ident[EI_ABIVERSION])) > + return DL_ELFHDR_ERR_ABIVERSION; > + else if (memcmp (&ehdr->e_ident[EI_PAD], &expected[EI_PAD], > + EI_NIDENT - EI_PAD) != 0) > + return DL_ELFHDR_ERR_PAD; > + else > + return DL_ELFHDR_ERR_INTERNAL; > + } > + > + if (__glibc_unlikely (ehdr->e_version != EV_CURRENT)) > + return DL_ELFHDR_ERR_VERSION; > + else if (__glibc_unlikely (ehdr->e_type != ET_DYN > + && ehdr->e_type != ET_EXEC)) > + return DL_ELFHDR_ERR_TYPE; > + else if (__glibc_unlikely (ehdr->e_phentsize != sizeof (ElfW(Phdr)))) > + return DL_ELFHDR_ERR_PHENTSIZE; > + > + return DL_ELFHDR_OK; > +} > + > +static const union elfhdr_errstr_t > +{ > + struct > + { > +#define _S(n, s) char str##n[sizeof (s)]; > +#include "dl-check-err.h" > +#undef _S > + }; > + char str[0]; > +} elfhdr_errstr = > +{ > + { > +#define _S(n, s) s, > +#include "dl-check-err.h" > +#undef _S > + } > +}; > + > +static const unsigned short elfhder_erridx[] = > +{ > +#define _S(n, s) [n] = offsetof(union elfhdr_errstr_t, str##n), > +#include "dl-check-err.h" > +#undef _S > +}; > + > +const char * > +_dl_elfhdr_errstr (int err) > +{ > +#if 0 > + if (err >= 0 && err < array_length (elfhdr_errstr)) > + return elfhdr_errstr[err]; > + return NULL; > +#endif > + if (err < 0 || err >= array_length (elfhder_erridx)) > + err = 0; > + return elfhdr_errstr.str + elfhder_erridx[err]; > +} > diff --git a/elf/dl-check.h b/elf/dl-check.h > new file mode 100644 > index 0000000000..5104a353ed > --- /dev/null > +++ b/elf/dl-check.h > @@ -0,0 +1,45 @@ > +/* ELF header consistency and ABI checks. > + Copyright (C) 1995-2021 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 > + . */ > + > +#ifndef _DL_OPENCHECK_H > +#define _DL_OPENCHECK_H > + > +#include > + > +enum > + { > + DL_ELFHDR_OK, > + DL_ELFHDR_ERR_ELFMAG, /* Invalid ELFMAGX value. */ > + DL_ELFHDR_ERR_CLASS32, /* Mismatched EI_CLASS. */ > + DL_ELFHDR_ERR_CLASS64, /* Mismatched EI_CLASS. */ > + DL_ELFHDR_ERR_BENDIAN, /* Mismatched EI_DATA (not big-endian). */ > + DL_ELFHDR_ERR_LENDIAN, /* Mismatched EI_DATA (not little-endian). */ > + DL_ELFHDR_ERR_EIVERSION, /* Invalid EI_VERSION. */ > + DL_ELFHDR_ERR_OSABI, /* Invalid EI_OSABI. */ > + DL_ELFHDR_ERR_ABIVERSION, /* Invalid ABI vrsion. */ > + DL_ELFHDR_ERR_PAD, /* Invalid EI_PAD value. */ > + DL_ELFHDR_ERR_VERSION, /* Invalid e_version. */ > + DL_ELFHDR_ERR_TYPE, /* Invalid e_type. */ > + DL_ELFHDR_ERR_PHENTSIZE, /* Invalid e_phentsize. */ > + DL_ELFHDR_ERR_INTERNAL /* Internal error. */ > + }; > + > +int _dl_elfhdr_check (const ElfW(Ehdr) *ehdr) attribute_hidden; > +const char *_dl_elfhdr_errstr (int err) attribute_hidden; > + > +#endif > diff --git a/elf/dl-load.c b/elf/dl-load.c > index bf8957e73c..45266c3501 100644 > --- a/elf/dl-load.c > +++ b/elf/dl-load.c > @@ -73,19 +73,9 @@ struct filebuf > #include > #include > #include > +#include > #include > > -#include > -#if BYTE_ORDER == BIG_ENDIAN > -# define byteorder ELFDATA2MSB > -#elif BYTE_ORDER == LITTLE_ENDIAN > -# define byteorder ELFDATA2LSB > -#else > -# error "Unknown BYTE_ORDER " BYTE_ORDER > -# define byteorder ELFDATANONE > -#endif > - > -#define STRING(x) __STRING (x) > > > int __stack_prot attribute_hidden attribute_relro > @@ -1598,25 +1588,6 @@ open_verify (const char *name, int fd, > /* This is the expected ELF header. */ > #define ELF32_CLASS ELFCLASS32 > #define ELF64_CLASS ELFCLASS64 > -#ifndef VALID_ELF_HEADER > -# define VALID_ELF_HEADER(hdr,exp,size) (memcmp (hdr, exp, size) == 0) > -# define VALID_ELF_OSABI(osabi) (osabi == ELFOSABI_SYSV) > -# define VALID_ELF_ABIVERSION(osabi,ver) (ver == 0) > -#elif defined MORE_ELF_HEADER_DATA > - MORE_ELF_HEADER_DATA; > -#endif > - static const unsigned char expected[EI_NIDENT] = > - { > - [EI_MAG0] = ELFMAG0, > - [EI_MAG1] = ELFMAG1, > - [EI_MAG2] = ELFMAG2, > - [EI_MAG3] = ELFMAG3, > - [EI_CLASS] = ELFW(CLASS), > - [EI_DATA] = byteorder, > - [EI_VERSION] = EV_CURRENT, > - [EI_OSABI] = ELFOSABI_SYSV, > - [EI_ABIVERSION] = 0 > - }; > static const struct > { > ElfW(Word) vendorlen; > @@ -1709,83 +1680,26 @@ open_verify (const char *name, int fd, > } > > /* See whether the ELF header is what we expect. */ > - if (__glibc_unlikely (! VALID_ELF_HEADER (ehdr->e_ident, expected, > - EI_ABIVERSION) > - || !VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI], > - ehdr->e_ident[EI_ABIVERSION]) > - || memcmp (&ehdr->e_ident[EI_PAD], > - &expected[EI_PAD], > - EI_NIDENT - EI_PAD) != 0)) > + int err = _dl_elfhdr_check (ehdr); > + switch (err) > { > - /* Something is wrong. */ > - const Elf32_Word *magp = (const void *) ehdr->e_ident; > - if (*magp != > -#if BYTE_ORDER == LITTLE_ENDIAN > - ((ELFMAG0 << (EI_MAG0 * 8)) > - | (ELFMAG1 << (EI_MAG1 * 8)) > - | (ELFMAG2 << (EI_MAG2 * 8)) > - | (ELFMAG3 << (EI_MAG3 * 8))) > -#else > - ((ELFMAG0 << (EI_MAG3 * 8)) > - | (ELFMAG1 << (EI_MAG2 * 8)) > - | (ELFMAG2 << (EI_MAG1 * 8)) > - | (ELFMAG3 << (EI_MAG0 * 8))) > -#endif > - ) > - errstring = N_("invalid ELF header"); > - else if (ehdr->e_ident[EI_CLASS] != ELFW(CLASS)) > - { > - /* This is not a fatal error. On architectures where > - 32-bit and 64-bit binaries can be run this might > - happen. */ > - *found_other_class = true; > - goto close_and_out; > - } > - else if (ehdr->e_ident[EI_DATA] != byteorder) > - { > - if (BYTE_ORDER == BIG_ENDIAN) > - errstring = N_("ELF file data encoding not big-endian"); > - else > - errstring = N_("ELF file data encoding not little-endian"); > - } > - else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT) > - errstring > - = N_("ELF file version ident does not match current one"); > - /* XXX We should be able so set system specific versions which are > - allowed here. */ > - else if (!VALID_ELF_OSABI (ehdr->e_ident[EI_OSABI])) > - errstring = N_("ELF file OS ABI invalid"); > - else if (!VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI], > - ehdr->e_ident[EI_ABIVERSION])) > - errstring = N_("ELF file ABI version invalid"); > - else if (memcmp (&ehdr->e_ident[EI_PAD], &expected[EI_PAD], > - EI_NIDENT - EI_PAD) != 0) > - errstring = N_("nonzero padding in e_ident"); > - else > - /* Otherwise we don't know what went wrong. */ > - errstring = N_("internal error"); > + case DL_ELFHDR_OK: > + break; > > - goto lose; > - } > + case DL_ELFHDR_ERR_CLASS32: > + case DL_ELFHDR_ERR_CLASS64: > + /* This is not a fatal error. On architectures where 32-bit and > + 64-bit binaries can be run this might happen. */ > + *found_other_class = true; > + goto close_and_out; > > - if (__glibc_unlikely (ehdr->e_version != EV_CURRENT)) > - { > - errstring = N_("ELF file version does not match current one"); > + default: > + errstring = _dl_elfhdr_errstr (err); > goto lose; > } > + > if (! __glibc_likely (elf_machine_matches_host (ehdr))) > goto close_and_out; > - else if (__glibc_unlikely (ehdr->e_type != ET_DYN > - && ehdr->e_type != ET_EXEC)) > - { > - errstring = N_("only ET_DYN and ET_EXEC can be loaded"); > - goto lose; > - } > - else if (__glibc_unlikely (ehdr->e_phentsize != sizeof (ElfW(Phdr)))) > - { > - errstring = N_("ELF file's phentsize not the expected size"); > - goto lose; > - } > > maplength = ehdr->e_phnum * sizeof (ElfW(Phdr)); > if (ehdr->e_phoff + maplength <= (size_t) fbp->len) > diff --git a/elf/rtld.c b/elf/rtld.c > index 847141e21d..89b3157f31 100644 > --- a/elf/rtld.c > +++ b/elf/rtld.c > @@ -50,6 +50,7 @@ > #include > #include > #include > +#include > > #include > > @@ -1112,6 +1113,7 @@ dl_main (const ElfW(Phdr) *phdr, > ElfW(Addr) *user_entry, > ElfW(auxv_t) *auxv) > { > + const ElfW(Ehdr) *ehdr = NULL; > const ElfW(Phdr) *ph; > struct link_map *main_map; > size_t file_size; > @@ -1518,6 +1520,9 @@ dl_main (const ElfW(Phdr) *phdr, > ElfW(Addr) mapstart; > ElfW(Addr) allocend; > > + if (ph->p_offset == 0 && ph->p_memsz > 0) > + ehdr = (void *) ph->p_vaddr; > + > /* Remember where the main program starts in memory. */ > mapstart = (main_map->l_addr > + (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1))); > @@ -1577,6 +1582,9 @@ dl_main (const ElfW(Phdr) *phdr, > break; > } > > + if (ehdr != NULL) > + _dl_check_ehdr (ehdr); > + > /* Adjust the address of the TLS initialization image in case > the executable is actually an ET_DYN object. */ > if (main_map->l_tls_initimage != NULL) > diff --git a/elf/tst-elf-check.c b/elf/tst-elf-check.c > new file mode 100644 > index 0000000000..175ba6fb5a > --- /dev/null > +++ b/elf/tst-elf-check.c > @@ -0,0 +1,209 @@ > +/* Check ELF header error paths. > + 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 > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +static char *spargv[6]; > +static char *tmpbin; > + > +static void > +do_prepare (int argc, char *argv[]) > +{ > + int fdin = xopen (argv[0], O_RDONLY | O_LARGEFILE, 0); > + struct stat64 st; > + xfstat (fdin, &st); > + int fdout = create_temp_file ("tst-elf-check-", &tmpbin); > + xfchmod (fdout, S_IXUSR | S_IRUSR | S_IWUSR); > + TEST_VERIFY_EXIT (fdout >= 0); > + xcopy_file_range (fdin, NULL, fdout, NULL, st.st_size, 0); > + xclose (fdin); > + xclose (fdout); > +} > + > +static void > +run_test_expect_failure (void (*modify)(ElfW(Ehdr) *), const char *errmsg) > +{ > + int fd = xopen (tmpbin, O_RDWR | O_LARGEFILE, 0); > + ElfW(Ehdr) orig_hdr; > + if (read (fd, &orig_hdr, sizeof (orig_hdr)) != sizeof (orig_hdr)) > + FAIL_EXIT1 ("read (%s): %m\n", tmpbin); > + ElfW(Ehdr) hdr = orig_hdr; > + modify (&hdr); > + if (lseek (fd, 0, SEEK_SET) != 0) > + FAIL_EXIT1 ("lseek: %m"); > + xwrite (fd, &hdr, sizeof (hdr)); > + xclose (fd); > + > + struct support_capture_subprocess proc = > + support_capture_subprogram (spargv[0], spargv); > + support_capture_subprocess_check (&proc, "tst-elf-check", 127, > + sc_allow_stderr); > + TEST_VERIFY (strstr (proc.err.buffer, errmsg) != NULL); > + support_capture_subprocess_free (&proc); > + > + /* Restore previous header. */ > + fd = xopen (tmpbin, O_RDWR | O_LARGEFILE, 0); > + xwrite (fd, &orig_hdr, sizeof (orig_hdr)); > + xclose (fd); > +} > + > +static void > +modify_mag (ElfW(Ehdr) *ehdr) > +{ > + ehdr->e_ident[EI_MAG0] = EI_MAG3; > + ehdr->e_ident[EI_MAG1] = EI_MAG2; > + ehdr->e_ident[EI_MAG2] = EI_MAG1; > + ehdr->e_ident[EI_MAG3] = EI_MAG0; > +} > + > +static void > +modify_class (ElfW(Ehdr) *ehdr) > +{ > + ehdr->e_ident[EI_CLASS] = ELFCLASSNONE; > +} > + > +static void > +modify_endian (ElfW(Ehdr) *ehdr) > +{ > + ehdr->e_ident[EI_DATA] = ELFDATANUM; > +} > + > +static void > +modify_eiversion (ElfW(Ehdr) *ehdr) > +{ > + ehdr->e_ident[EI_VERSION] = EV_CURRENT + 1; > +} > + > +static void > +modify_osabi (ElfW(Ehdr) *ehdr) > +{ > + ehdr->e_ident[EI_OSABI] = ELFOSABI_STANDALONE; > +} > + > +static void > +modify_abiversion (ElfW(Ehdr) *ehdr) > +{ > + ehdr->e_ident[EI_ABIVERSION] = LIBC_ABI_MAX; > +} > + > +static void > +modify_pad (ElfW(Ehdr) *ehdr) > +{ > + memset (&ehdr->e_ident[EI_PAD], 0xff, EI_NIDENT - EI_PAD); > +} > + > +static void > +modify_version (ElfW(Ehdr) *ehdr) > +{ > + ehdr->e_version = EV_NONE; > +} > + > +static void > +modify_type (ElfW(Ehdr) *ehdr) > +{ > + ehdr->e_type = ET_NONE; > +} > + > +static void > +modify_phentsize (ElfW(Ehdr) *ehdr) > +{ > + ehdr->e_phentsize = sizeof (ElfW(Phdr)) + 1; > +} > + > +static void > +do_test_kernel (void) > +{ > + run_test_expect_failure (modify_mag, > + "invalid ELF header"); > + run_test_expect_failure (modify_type, > + "only ET_DYN and ET_EXEC can be loaded"); > + run_test_expect_failure (modify_phentsize, > + "ELF file's phentsize not the expected size"); > + run_test_expect_failure (modify_class, > + "wrong ELF class"); > +} > + > +static void > +do_test_common (void) > +{ > + run_test_expect_failure (modify_endian, > + "ELF file data encoding not"); > + run_test_expect_failure (modify_eiversion, > + "ELF file version ident does not match current one"); > + run_test_expect_failure (modify_pad, > + "nonzero padding in e_ident"); > + run_test_expect_failure (modify_osabi, > + "ELF file OS ABI invalid"); > + run_test_expect_failure (modify_abiversion, > + "ELF file ABI version invalid"); > + run_test_expect_failure (modify_version, > + "ELF file version does not match current one"); > +} > + > +static int > +do_test (int argc, char *argv[]) > +{ > + /* We must have one or four parameters: > + + argv[0]: the application name > + + argv[1]: path for ld.so optional > + + argv[2]: "--library-path" optional > + + argv[3]: the library path optional > + + argv[4/1]: the application name */ > + > + bool hardpath = argc == 2; > + > + int i; > + for (i = 0; i < argc - 2; i++) > + spargv[i] = argv[i+1]; > + spargv[i++] = tmpbin; > + spargv[i++] = (char *) "--direct"; > + spargv[i] = NULL; > + > + /* Some fields are checked by the kernel results in a execve failure, so skip > + them for --enable-hardcoded-path-in-tests. */ > + if (!hardpath) > + do_test_kernel (); > + do_test_common (); > + > + /* Also run the tests without issuing the loader. */ > + if (hardpath) > + return 0; > + > + spargv[0] = tmpbin; > + spargv[1] = (char *) "--direct"; > + spargv[2] = NULL; > + > + do_test_common (); > + > + return 0; > +} > + > +#define PREPARE do_prepare > +#define TEST_FUNCTION_ARGV do_test > +#include > diff --git a/sysdeps/generic/dl-elf-check.h b/sysdeps/generic/dl-elf-check.h > new file mode 100644 > index 0000000000..48eb82e9e7 > --- /dev/null > +++ b/sysdeps/generic/dl-elf-check.h > @@ -0,0 +1,28 @@ > +/* ELF header consistency and ABI checks. > + 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 > + . */ > + > +#ifndef _DL_ELF_CHECK_H > +#define _DL_ELF_CHECK_H > + > +/* Called from the loader just after the program headers are processed. */ > +static inline void > +_dl_check_ehdr (const ElfW(Ehdr) *ehdr) > +{ > +} > + > +#endif > diff --git a/sysdeps/unix/sysv/linux/dl-elf-check.h b/sysdeps/unix/sysv/linux/dl-elf-check.h > new file mode 100644 > index 0000000000..9e4925c090 > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/dl-elf-check.h > @@ -0,0 +1,32 @@ > +/* ELF header consistency and ABI checks. > + 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 > + . */ > + > +#ifndef _DL_ELF_CHECK_H > +#define _DL_ELF_CHECK_H > + > +#include > + > +static inline void > +_dl_check_ehdr (const ElfW(Ehdr) *ehdr) > +{ > + int err = _dl_elfhdr_check (ehdr); > + if (err != DL_ELFHDR_OK) > + _dl_fatal_printf ("program loading error: %s\n", _dl_elfhdr_errstr (err)); > +} > + > +#endif > -- > 2.32.0 > -- H.J.