1 /* Stack executability handling for GNU dynamic linker. Linux version.
2 Copyright (C) 2003-2014 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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 <http://www.gnu.org/licenses/>. */
24 #include <stackinfo.h>
29 extern int __stack_prot attribute_relro attribute_hidden
;
34 _dl_make_stack_executable (void **stack_endp
)
36 /* This gives us the highest/lowest page that needs to be changed. */
37 uintptr_t page
= ((uintptr_t) *stack_endp
38 & -(intptr_t) GLRO(dl_pagesize
));
41 /* Challenge the caller. */
42 if (__builtin_expect (__check_caller (RETURN_ADDRESS (0),
43 allow_ldso
|allow_libpthread
) != 0, 0)
44 || __builtin_expect (*stack_endp
!= __libc_stack_end
, 0))
47 if (__builtin_expect (__mprotect ((void *) page
, GLRO(dl_pagesize
),
48 __stack_prot
) == 0, 1))
54 /* Clear the address. */
57 /* Remember that we changed the permission. */
58 GL(dl_stack_flags
) |= PF_X
;
61 #ifdef check_consistency
67 rtld_hidden_def (_dl_make_stack_executable
)