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glibc/sysdeps/unix/sysv/linux/dl-execstack.c
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/* Stack executability handling for GNU dynamic linker. Linux version. | |
Copyright (C) 2003-2016 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> | |
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) |