From b5237c0746fcf5252fc88291a63782c59167fcb5 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 20 Dec 2021 18:33:55 -0800 Subject: [PATCH] elf: Add a test for PT_LOAD segments with mixed p_align [BZ #28676] Add tst-p_alignmod1-edit to edit the copy of tst-p_alignmod-base.so to reduce p_align of the first PT_LOAD segment by half and verify that the shared library is mapped with the maximum p_align of all PT_LOAD segments. Reviewed-by: Adhemerval Zanella --- elf/Makefile | 17 ++++++ elf/tst-elf-edit.h | 126 +++++++++++++++++++++++++++++++++++++++++++++ elf/tst-p_align.h | 20 +++++++ elf/tst-p_align1.c | 27 ++++++++++ elf/tst-p_alignmod-base.c | 41 +++++++++++++++ elf/tst-p_alignmod1-edit.c | 27 ++++++++++ 6 files changed, 258 insertions(+) create mode 100644 elf/tst-elf-edit.h create mode 100644 elf/tst-p_align.h create mode 100644 elf/tst-p_align1.c create mode 100644 elf/tst-p_alignmod-base.c create mode 100644 elf/tst-p_alignmod1-edit.c diff --git a/elf/Makefile b/elf/Makefile index a749ef6..1758259 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -413,6 +413,8 @@ tests += \ tst-nodelete-opened \ tst-noload \ tst-null-argv \ + tst-p_alignmod1-edit \ + tst-p_align1 \ tst-relsort1 \ tst-ro-dynamic \ tst-rtld-run-static \ @@ -737,6 +739,7 @@ modules-names = \ tst-nodelete-dlclose-plugin \ tst-nodelete-opened-lib \ tst-null-argv-lib \ + tst-p_alignmod-base \ tst-relsort1mod1 \ tst-relsort1mod2 \ tst-ro-dynamic-mod \ @@ -2592,3 +2595,17 @@ CFLAGS-tst-dl_find_object-mod6.c += -funwind-tables CFLAGS-tst-dl_find_object-mod7.c += -funwind-tables CFLAGS-tst-dl_find_object-mod8.c += -funwind-tables CFLAGS-tst-dl_find_object-mod9.c += -funwind-tables + +$(objpfx)tst-p_alignmod-base.so: $(libsupport) +LDFLAGS-tst-p_alignmod-base.so += -Wl,-z,max-page-size=0x200000 + +$(objpfx)tst-p_align1: $(objpfx)tst-p_alignmod1.so + +# Make a copy of tst-p_alignmod-base.so and lower p_align of the first +# PT_LOAD segment. +$(objpfx)tst-p_alignmod1.so: $(objpfx)tst-p_alignmod1-edit \ + $(objpfx)tst-p_alignmod-base.so + rm -f $@ + cp $(objpfx)tst-p_alignmod-base.so $@ + $(test-wrapper-env) $(run-program-env) $(rtld-prefix) \ + $(objpfx)tst-p_alignmod1-edit $@ diff --git a/elf/tst-elf-edit.h b/elf/tst-elf-edit.h new file mode 100644 index 0000000..b764e78 --- /dev/null +++ b/elf/tst-elf-edit.h @@ -0,0 +1,126 @@ +/* Update p_align of the first PT_LOAD segment. + Copyright (C) 2022 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 + +const char *file_name; + +static size_t update_p_align (size_t); + +int +main (int argc, char ** argv) +{ + if (argc != 2) + { + printf ("Usage: %s: file\n", argv[0]); + return 0; + } + + file_name = argv[1]; + struct stat statbuf; + int errno_saved; + + if (stat (file_name, &statbuf) < 0) + error (1, errno, "%s: not exist", file_name); + + ElfW(Ehdr) *ehdr; + + if (statbuf.st_size < sizeof (*ehdr)) + error (1, 0, "%s: too small", file_name); + + int fd = open (file_name, O_RDWR); + if (fd < 0) + error (1, errno, "%s: can't open", file_name); + + /* Map in the whole file. */ + void *base = mmap (NULL, statbuf.st_size, PROT_READ | PROT_WRITE, + MAP_SHARED, fd, 0); + if (base == MAP_FAILED) + { + errno_saved = errno; + close (fd); + error (1, errno_saved, "%s: failed to map", file_name); + } + + ehdr = (ElfW(Ehdr) *) base; + if (ehdr->e_ident[EI_MAG0] != ELFMAG0 + || ehdr->e_ident[EI_MAG1] != ELFMAG1 + || ehdr->e_ident[EI_MAG2] != ELFMAG2 + || ehdr->e_ident[EI_MAG3] != ELFMAG3) + { + close (fd); + error (1, 0, "%s: bad ELF header", file_name); + } + + if (ehdr->e_type != ET_DYN) + { + close (fd); + error (1, 0, "%s: not shared library", file_name); + } + + bool unsupported_class = true; + switch (ehdr->e_ident[EI_CLASS]) + { + default: + break; + + case ELFCLASS32: + unsupported_class = __ELF_NATIVE_CLASS != 32; + break; + + case ELFCLASS64: + unsupported_class = __ELF_NATIVE_CLASS != 64; + break; + } + + if (unsupported_class) + { + close (fd); + error (1, 0, "%s: unsupported ELF class: %d", + file_name, ehdr->e_ident[EI_CLASS]); + } + + size_t phdr_size = sizeof (ElfW(Phdr)) * ehdr->e_phentsize; + if (statbuf.st_size < (ehdr->e_phoff + phdr_size)) + { + close (fd); + error (1, 0, "%s: too small", file_name); + } + + ElfW(Phdr) *phdr = (ElfW(Phdr) *) (base + ehdr->e_phoff); + for (int i = 0; i < ehdr->e_phnum; i++, phdr++) + if (phdr->p_type == PT_LOAD) + { + /* Update p_align of the first PT_LOAD segment. */ + phdr->p_align = update_p_align (phdr->p_align); + break; + } + + munmap (base, statbuf.st_size); + close (fd); + + return 0; +} diff --git a/elf/tst-p_align.h b/elf/tst-p_align.h new file mode 100644 index 0000000..cef9233 --- /dev/null +++ b/elf/tst-p_align.h @@ -0,0 +1,20 @@ +/* Prototypes to check different alignments of PT_LOAD segments in + a shared library. + Copyright (C) 2022 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 + . */ + +extern int do_load_test (void); diff --git a/elf/tst-p_align1.c b/elf/tst-p_align1.c new file mode 100644 index 0000000..961c7fb --- /dev/null +++ b/elf/tst-p_align1.c @@ -0,0 +1,27 @@ +/* Check different alignments of PT_LOAD segments in a shared library. + Copyright (C) 2022 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 "tst-p_align.h" + +static int +do_test (void) +{ + return do_load_test (); +} + +#include diff --git a/elf/tst-p_alignmod-base.c b/elf/tst-p_alignmod-base.c new file mode 100644 index 0000000..0fc1b75 --- /dev/null +++ b/elf/tst-p_alignmod-base.c @@ -0,0 +1,41 @@ +/* Check alignment of PT_LOAD segment in a shared library. + Copyright (C) 2022 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 "tst-p_align.h" + +int foo __attribute__ ((aligned (ALIGN))) = 1; + +bool +__attribute__ ((weak, noclone, noinline)) +is_aligned_p (void *p, int align) +{ + return (((uintptr_t) p) & (align - 1)) == 0; +} + +int +do_load_test (void) +{ + printf ("foo: %p\n", &foo); + TEST_VERIFY (is_aligned_p (&foo, ALIGN)); + return 0; +} diff --git a/elf/tst-p_alignmod1-edit.c b/elf/tst-p_alignmod1-edit.c new file mode 100644 index 0000000..06d9c63 --- /dev/null +++ b/elf/tst-p_alignmod1-edit.c @@ -0,0 +1,27 @@ +/* Reduce p_align of the first PT_LOAD segment by half. + Copyright (C) 2022 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 "tst-elf-edit.h" + +/* Reduce p_align by half. */ + +static size_t +update_p_align (size_t p_align) +{ + return p_align >> 1; +} -- 2.7.4