1 /* Stack executability handling for GNU dynamic linker. Hurd version. 2 Copyright (C) 2004-2021 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library; if not, see 17 <https://www.gnu.org/licenses/>. */ 18 19 #include <ldsodefs.h> 20 #include <hurdstartup.h> 21 #include <errno.h> 22 23 extern struct hurd_startup_data *_dl_hurd_data attribute_hidden; 24 25 /* There is no portable way to know the bounds of the initial thread's stack 26 so as to mprotect it. */ 27 28 int _dl_make_stack_executable(void ** stack_endp)29_dl_make_stack_executable (void **stack_endp) 30 { 31 /* Challenge the caller. */ 32 if (__builtin_expect (*stack_endp != __libc_stack_end, 0)) 33 return EPERM; 34 *stack_endp = NULL; 35 36 #if IS_IN (rtld) 37 if (__mprotect ((void *)_dl_hurd_data->stack_base, _dl_hurd_data->stack_size, 38 PROT_READ|PROT_WRITE|PROT_EXEC) != 0) 39 return errno; 40 41 /* Remember that we changed the permission. */ 42 GL(dl_stack_flags) |= PF_X; 43 44 return 0; 45 #else 46 /* We don't bother to implement this for static linking. */ 47 return ENOSYS; 48 #endif 49 } 50 rtld_hidden_def (_dl_make_stack_executable) 51