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72739c79f6
The _dl_open_check and _rtld_main_check hooks are not called on the dependencies of a loaded module, so BTI protection was missed on every module other than the main executable and directly dlopened libraries. The fix just iterates over dependencies to enable BTI. Fixes bug 26926.
75 lines
2.0 KiB
C
75 lines
2.0 KiB
C
/* AArch64 BTI functions.
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Copyright (C) 2020 Free Software Foundation, Inc.
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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 <unistd.h>
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#include <errno.h>
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#include <libintl.h>
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#include <ldsodefs.h>
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static int
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enable_bti (struct link_map *map, const char *program)
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{
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const ElfW(Phdr) *phdr;
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unsigned prot;
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for (phdr = map->l_phdr; phdr < &map->l_phdr[map->l_phnum]; ++phdr)
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if (phdr->p_type == PT_LOAD && (phdr->p_flags & PF_X))
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{
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void *start = (void *) (phdr->p_vaddr + map->l_addr);
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size_t len = phdr->p_memsz;
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prot = PROT_EXEC | PROT_BTI;
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if (phdr->p_flags & PF_R)
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prot |= PROT_READ;
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if (phdr->p_flags & PF_W)
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prot |= PROT_WRITE;
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if (__mprotect (start, len, prot) < 0)
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{
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if (program)
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_dl_fatal_printf ("%s: mprotect failed to turn on BTI\n",
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map->l_name);
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else
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_dl_signal_error (errno, map->l_name, "dlopen",
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N_("mprotect failed to turn on BTI"));
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}
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}
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return 0;
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}
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/* Enable BTI for L and its dependencies. */
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void
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_dl_bti_check (struct link_map *l, const char *program)
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{
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if (!GLRO(dl_aarch64_cpu_features).bti)
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return;
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if (l->l_mach.bti)
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enable_bti (l, program);
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unsigned int i = l->l_searchlist.r_nlist;
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while (i-- > 0)
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{
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struct link_map *dep = l->l_initfini[i];
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if (dep->l_init_called)
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continue;
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if (dep->l_mach.bti)
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enable_bti (dep, program);
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}
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}
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