mirror of
https://sourceware.org/git/glibc.git
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251 lines
6.8 KiB
C
251 lines
6.8 KiB
C
/* Copyright (C) 1999-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <elf-read-prop.h>
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/* This code is a heavily simplified version of the readelf program
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that's part of the current binutils development version. For architectures
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which need to handle both 32bit and 64bit ELF libraries, this file is
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included twice for each arch size. */
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/* check_ptr checks that a pointer is in the mmaped file and doesn't
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point outside it. */
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#undef check_ptr
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#define check_ptr(ptr) \
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do \
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{ \
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if ((void *)(ptr) < file_contents \
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|| (void *)(ptr) > (file_contents+file_length)) \
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{ \
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error (0, 0, _("file %s is truncated\n"), file_name); \
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return 1; \
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} \
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} \
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while (0);
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/* Returns 0 if everything is ok, != 0 in case of error. */
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int
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process_elf_file (const char *file_name, const char *lib, int *flag,
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unsigned int *isa_level, char **soname, void *file_contents,
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size_t file_length)
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{
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int i;
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unsigned int dynamic_addr;
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size_t dynamic_size;
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char *program_interpreter;
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ElfW(Ehdr) *elf_header;
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ElfW(Phdr) *elf_pheader, *segment;
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ElfW(Dyn) *dynamic_segment, *dyn_entry;
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char *dynamic_strings;
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elf_header = (ElfW(Ehdr) *) file_contents;
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if (elf_header->e_ident [EI_CLASS] != ElfW (CLASS))
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{
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if (opt_verbose)
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{
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if (elf_header->e_ident [EI_CLASS] == ELFCLASS32)
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error (0, 0, _("%s is a 32 bit ELF file.\n"), file_name);
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else if (elf_header->e_ident [EI_CLASS] == ELFCLASS64)
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error (0, 0, _("%s is a 64 bit ELF file.\n"), file_name);
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else
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error (0, 0, _("Unknown ELFCLASS in file %s.\n"), file_name);
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}
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return 1;
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}
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if (elf_header->e_type != ET_DYN)
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{
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error (0, 0, _("%s is not a shared object file (Type: %d).\n"), file_name,
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elf_header->e_type);
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return 1;
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}
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/* Get information from elf program header. */
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elf_pheader = (ElfW(Phdr) *) (elf_header->e_phoff + file_contents);
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check_ptr (elf_pheader);
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/* The library is an elf library. */
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*flag = FLAG_ELF_LIBC6;
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/* The default ISA level is 0. */
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*isa_level = 0;
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dynamic_addr = 0;
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dynamic_size = 0;
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program_interpreter = NULL;
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for (i = 0, segment = elf_pheader;
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i < elf_header->e_phnum; i++, segment++)
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{
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check_ptr (segment);
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switch (segment->p_type)
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{
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case PT_DYNAMIC:
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if (dynamic_addr)
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error (0, 0, _("more than one dynamic segment\n"));
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dynamic_addr = segment->p_offset;
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dynamic_size = segment->p_filesz;
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break;
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case PT_INTERP:
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program_interpreter = (char *) (file_contents + segment->p_offset);
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check_ptr (program_interpreter);
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break;
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case PT_GNU_PROPERTY:
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/* The NT_GNU_PROPERTY_TYPE_0 note must be aligned to 4 bytes
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in 32-bit objects and to 8 bytes in 64-bit objects. Skip
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notes with incorrect alignment. */
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if (segment->p_align == (__ELF_NATIVE_CLASS / 8))
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{
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const ElfW(Nhdr) *note = (const void *) (file_contents
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+ segment->p_offset);
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const ElfW(Addr) size = segment->p_filesz;
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const ElfW(Addr) align = segment->p_align;
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const ElfW(Addr) start = (ElfW(Addr)) (uintptr_t) note;
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unsigned int last_type = 0;
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while ((ElfW(Addr)) (uintptr_t) (note + 1) - start < size)
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{
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/* Find the NT_GNU_PROPERTY_TYPE_0 note. */
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if (note->n_namesz == 4
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&& note->n_type == NT_GNU_PROPERTY_TYPE_0
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&& memcmp (note + 1, "GNU", 4) == 0)
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{
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/* Check for invalid property. */
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if (note->n_descsz < 8
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|| (note->n_descsz % sizeof (ElfW(Addr))) != 0)
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goto done;
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/* Start and end of property array. */
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unsigned char *ptr = (unsigned char *) (note + 1) + 4;
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unsigned char *ptr_end = ptr + note->n_descsz;
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do
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{
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unsigned int type = *(unsigned int *) ptr;
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unsigned int datasz = *(unsigned int *) (ptr + 4);
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/* Property type must be in ascending order. */
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if (type < last_type)
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goto done;
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ptr += 8;
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if ((ptr + datasz) > ptr_end)
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goto done;
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last_type = type;
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/* Target specific property processing.
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Return value:
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false: Continue processing the properties.
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true : Stop processing the properties.
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*/
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if (read_gnu_property (isa_level, type,
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datasz, ptr))
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goto done;
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/* Check the next property item. */
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ptr += ALIGN_UP (datasz, sizeof (ElfW(Addr)));
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}
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while ((ptr_end - ptr) >= 8);
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/* Only handle one NT_GNU_PROPERTY_TYPE_0. */
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goto done;
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}
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note = ((const void *) note
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+ ELF_NOTE_NEXT_OFFSET (note->n_namesz,
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note->n_descsz,
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align));
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}
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}
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done:
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break;
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default:
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break;
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}
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}
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/* Now we can read the dynamic sections. */
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if (dynamic_size == 0)
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return 1;
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dynamic_segment = (ElfW(Dyn) *) (file_contents + dynamic_addr);
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check_ptr (dynamic_segment);
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/* Find the string table. */
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dynamic_strings = NULL;
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for (dyn_entry = dynamic_segment; dyn_entry->d_tag != DT_NULL;
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++dyn_entry)
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{
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check_ptr (dyn_entry);
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if (dyn_entry->d_tag == DT_STRTAB)
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{
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/* Find the file offset of the segment containing the dynamic
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string table. */
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ElfW(Off) loadoff = -1;
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for (i = 0, segment = elf_pheader;
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i < elf_header->e_phnum; i++, segment++)
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{
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if (segment->p_type == PT_LOAD
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&& dyn_entry->d_un.d_val >= segment->p_vaddr
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&& (dyn_entry->d_un.d_val - segment->p_vaddr
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< segment->p_filesz))
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{
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loadoff = segment->p_vaddr - segment->p_offset;
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break;
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}
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}
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if (loadoff == (ElfW(Off)) -1)
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{
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/* Very strange. */
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loadoff = 0;
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}
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dynamic_strings = (char *) (file_contents + dyn_entry->d_un.d_val
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- loadoff);
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check_ptr (dynamic_strings);
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break;
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}
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}
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if (dynamic_strings == NULL)
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return 1;
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/* Now read the DT_SONAME entries. */
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for (dyn_entry = dynamic_segment; dyn_entry->d_tag != DT_NULL;
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++dyn_entry)
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{
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if (dyn_entry->d_tag == DT_SONAME)
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{
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char *name = dynamic_strings + dyn_entry->d_un.d_val;
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check_ptr (name);
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*soname = xstrdup (name);
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return 0;
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}
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}
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return 0;
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}
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