| /* Stack executability handling for GNU dynamic linker. Linux version. |
| Copyright (C) 2003-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <ldsodefs.h> |
| #include <sys/mman.h> |
| #include <errno.h> |
| #include <libintl.h> |
| #include <stdbool.h> |
| #include <stackinfo.h> |
| #include <caller.h> |
| #include <sysdep.h> |
| |
| #include <kernel-features.h> |
| |
| |
| extern int __stack_prot attribute_relro attribute_hidden; |
| |
| |
| int |
| internal_function |
| _dl_make_stack_executable (void **stack_endp) |
| { |
| /* This gives us the highest/lowest page that needs to be changed. */ |
| uintptr_t page = ((uintptr_t) *stack_endp |
| & -(intptr_t) GLRO(dl_pagesize)); |
| int result = 0; |
| |
| /* Challenge the caller. */ |
| if (__builtin_expect (__check_caller (RETURN_ADDRESS (0), |
| allow_ldso|allow_libpthread) != 0, 0) |
| || __builtin_expect (*stack_endp != __libc_stack_end, 0)) |
| return EPERM; |
| |
| if (__builtin_expect (__mprotect ((void *) page, GLRO(dl_pagesize), |
| __stack_prot) == 0, 1)) |
| goto return_success; |
| result = errno; |
| goto out; |
| |
| return_success: |
| /* Clear the address. */ |
| *stack_endp = NULL; |
| |
| /* Remember that we changed the permission. */ |
| GL(dl_stack_flags) |= PF_X; |
| |
| out: |
| #ifdef check_consistency |
| check_consistency (); |
| #endif |
| |
| return result; |
| } |
| rtld_hidden_def (_dl_make_stack_executable) |
