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e7b5532721
For a static PIE with non-zero load address, its PT_DYNAMIC segment entries contain the relocated values for the load address in static PIE. Since static PIE usually doesn't have PT_PHDR segment, use p_vaddr of the PT_LOAD segment with offset == 0 as the load address in static PIE and adjust the entries of PT_DYNAMIC segment in static PIE by properly setting the l_addr field for static PIE. This fixes BZ #31799. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
91 lines
3.0 KiB
C
91 lines
3.0 KiB
C
/* Support for relocating static PIE.
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Copyright (C) 2017-2024 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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#if ENABLE_STATIC_PIE
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/* Mark symbols hidden in static PIE for early self relocation to work. */
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# pragma GCC visibility push(hidden)
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#include <assert.h>
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#include <unistd.h>
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#include <ldsodefs.h>
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#include <dl-machine.h>
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#include <dl-debug.h>
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#define RESOLVE_MAP(map, scope, sym, version, flags) map
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#include "dynamic-link.h"
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#include "get-dynamic-info.h"
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/* Relocate static executable with PIE. */
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void
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_dl_relocate_static_pie (void)
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{
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struct link_map *main_map = _dl_get_dl_main_map ();
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/* NB: elf_machine_load_address () returns the run-time load address
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of static PIE. The l_addr field contains the difference between the
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link-time load address in the ELF file and the run-time load address
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in memory. We must subtract the link-time load address of static PIE,
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which can be non-zero, when computing the l_addr field. Since static
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PIE usually doesn't have PT_PHDR segment, use p_vaddr of the PT_LOAD
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segment with offset == 0 as the load address of static PIE. */
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ElfW(Addr) file_p_vaddr = 0;
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const ElfW(Phdr) *ph, *phdr = GL(dl_phdr);
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size_t phnum = GL(dl_phnum);
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for (ph = phdr; ph < &phdr[phnum]; ++ph)
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switch (ph->p_type)
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{
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case PT_LOAD:
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if (ph->p_offset == 0)
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file_p_vaddr = ph->p_vaddr;
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break;
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case PT_DYNAMIC:
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main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
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break;
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default:
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break;
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}
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/* Figure out the run-time load address of static PIE. */
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ElfW(Addr) l_addr = elf_machine_load_address ();
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main_map->l_addr = l_addr - file_p_vaddr;
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/* Read our own dynamic section and fill in the info array. */
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main_map->l_ld = ((void *) l_addr + elf_machine_dynamic ());
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elf_get_dynamic_info (main_map, false, true);
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# ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
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ELF_MACHINE_BEFORE_RTLD_RELOC (main_map, main_map->l_info);
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# endif
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/* Relocate ourselves so we can do normal function calls and
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data access using the global offset table. */
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ELF_DYNAMIC_RELOCATE (main_map, NULL, 0, 0, 0);
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main_map->l_relocated = 1;
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/* Initialize _r_debug_extended. */
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struct r_debug *r = _dl_debug_initialize (0, LM_ID_BASE);
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r->r_state = RT_CONSISTENT;
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/* Set up debugging before the debugger is notified for the first
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time. */
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elf_setup_debug_entry (main_map, r);
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}
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#endif
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