2020-06-22 17:57:20 +08:00
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/* 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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2020-07-13 18:28:18 +08:00
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unsigned prot;
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2020-06-22 17:57:20 +08:00
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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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2020-07-13 18:28:18 +08:00
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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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2020-06-22 17:57:20 +08:00
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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 if required. */
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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 && l->l_mach.bti)
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enable_bti (l, program);
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}
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