From: "H.J. Lu" <hjl.tools@gmail.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: GNU C Library <libc-alpha@sourceware.org>,
Florian Weimer <fweimer@redhat.com>
Subject: Re: [PATCH] elf: Add elf checks for main executable
Date: Fri, 19 Nov 2021 07:33:56 -0800 [thread overview]
Message-ID: <CAMe9rOqbHH4n3WecaCVsBTkEpW6anQ53mnpA3yfV3byJQx1DGQ@mail.gmail.com> (raw)
In-Reply-To: <20211119150329.2200675-1-adhemerval.zanella@linaro.org>
On Fri, Nov 19, 2021 at 7:03 AM Adhemerval Zanella
<adhemerval.zanella@linaro.org> 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
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <array_length.h>
> +#include <dl-check.h>
> +#include <endian.h>
> +#include <ldsodefs.h>
> +#include <libintl.h>
> +
> +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
> + <https://www.gnu.org/licenses/>. */
> +
> +#ifndef _DL_OPENCHECK_H
> +#define _DL_OPENCHECK_H
> +
> +#include <link.h>
> +
> +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 <dl-machine-reject-phdr.h>
> #include <dl-sysdep-open.h>
> #include <dl-prop.h>
> +#include <dl-check.h>
> #include <not-cancel.h>
>
> -#include <endian.h>
> -#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 <gnu/lib-names.h>
> #include <dl-tunables.h>
> #include <get-dynamic-info.h>
> +#include <dl-elf-check.h>
>
> #include <assert.h>
>
> @@ -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
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <elf.h>
> +#include <link.h>
> +#include <libc-abis.h>
> +#include <fcntl.h>
> +#include <string.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <support/capture_subprocess.h>
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <support/xunistd.h>
> +#include <support/temp_file.h>
> +
> +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 <support/test-driver.c>
> 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
> + <https://www.gnu.org/licenses/>. */
> +
> +#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
> + <https://www.gnu.org/licenses/>. */
> +
> +#ifndef _DL_ELF_CHECK_H
> +#define _DL_ELF_CHECK_H
> +
> +#include <dl-check.h>
> +
> +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.
next prev parent reply other threads:[~2021-11-19 15:34 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-19 15:03 Adhemerval Zanella
2021-11-19 15:33 ` H.J. Lu [this message]
2021-11-19 16:05 ` H.J. Lu
2021-11-19 17:06 ` Adhemerval Zanella
2021-12-06 19:03 ` H.J. Lu
2021-12-06 19:09 ` Florian Weimer
2021-12-06 19:22 ` H.J. Lu
2021-12-06 20:31 ` Adhemerval Zanella
2021-12-06 20:37 ` Florian Weimer
2021-12-06 21:07 ` Adhemerval Zanella
2021-12-07 15:45 ` Florian Weimer
2021-12-07 17:35 ` Adhemerval Zanella
2021-12-08 0:01 ` Fāng-ruì Sòng
2021-12-08 10:19 ` Florian Weimer
2021-12-14 0:17 ` Fāng-ruì Sòng
2021-12-14 9:03 ` Florian Weimer
2021-12-14 9:09 ` Fāng-ruì Sòng
2021-12-14 9:18 ` Florian Weimer
2021-12-14 19:03 ` Fangrui Song
2021-12-14 12:28 ` Adhemerval Zanella
2021-12-14 12:23 ` Adhemerval Zanella
2021-12-14 19:24 ` Fangrui Song
2021-12-14 21:07 ` Adhemerval Zanella
2021-12-14 21:30 ` Fangrui Song
2021-12-14 21:53 ` Florian Weimer
2021-12-14 23:08 ` Fangrui Song
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