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f42373f911
We can't relocate entries in dynamic section if it is readonly:
1. Add a l_ld_readonly field to struct link_map to indicate if dynamic
section is readonly and set it based on p_flags of PT_DYNAMIC segment.
2. Replace DL_RO_DYN_SECTION with dl_relocate_ld to decide if dynamic
section should be relocated.
3. Remove DL_RO_DYN_TEMP_CNT.
4. Don't use a static dynamic section to make readonly dynamic section
in vDSO writable.
5. Remove the temp argument from elf_get_dynamic_info.
This fixes BZ #28340.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
(cherry picked from commit b413280cfb)
81 lines
2.7 KiB
C
81 lines
2.7 KiB
C
/* Support for relocating static PIE.
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Copyright (C) 2017-2021 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 <unistd.h>
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#include <ldsodefs.h>
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#include "dynamic-link.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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# define STATIC_PIE_BOOTSTRAP
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# define BOOTSTRAP_MAP (main_map)
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# define RESOLVE_MAP(sym, version, flags) BOOTSTRAP_MAP
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# include "dynamic-link.h"
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/* Figure out the run-time load address of static PIE. */
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main_map->l_addr = elf_machine_load_address ();
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/* Read our own dynamic section and fill in the info array. */
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main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ());
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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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if (ph->p_type == PT_DYNAMIC)
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{
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main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
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break;
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}
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elf_get_dynamic_info (main_map);
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# ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
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ELF_MACHINE_BEFORE_RTLD_RELOC (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, 0, 0, 0);
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main_map->l_relocated = 1;
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/* Initialize _r_debug. */
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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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# ifdef ELF_MACHINE_DEBUG_SETUP
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/* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
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ELF_MACHINE_DEBUG_SETUP (main_map, r);
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# else
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if (main_map->l_info[DT_DEBUG] != NULL)
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/* There is a DT_DEBUG entry in the dynamic section. Fill it in
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with the run-time address of the r_debug structure */
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main_map->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
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# endif
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}
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#endif
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