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70 lines
2.0 KiB
C
70 lines
2.0 KiB
C
/* Stack executability handling for GNU dynamic linker. Linux version.
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Copyright (C) 2003-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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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<http://www.gnu.org/licenses/>. */
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#include <ldsodefs.h>
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#include <sys/mman.h>
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#include <errno.h>
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#include <libintl.h>
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#include <stdbool.h>
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#include <stackinfo.h>
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#include <caller.h>
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#include <sysdep.h>
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#include <kernel-features.h>
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extern int __stack_prot attribute_relro attribute_hidden;
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int
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internal_function
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_dl_make_stack_executable (void **stack_endp)
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{
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/* This gives us the highest/lowest page that needs to be changed. */
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uintptr_t page = ((uintptr_t) *stack_endp
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& -(intptr_t) GLRO(dl_pagesize));
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int result = 0;
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/* Challenge the caller. */
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if (__builtin_expect (__check_caller (RETURN_ADDRESS (0),
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allow_ldso|allow_libpthread) != 0, 0)
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|| __builtin_expect (*stack_endp != __libc_stack_end, 0))
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return EPERM;
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if (__builtin_expect (__mprotect ((void *) page, GLRO(dl_pagesize),
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__stack_prot) == 0, 1))
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goto return_success;
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result = errno;
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goto out;
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return_success:
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/* Clear the address. */
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*stack_endp = NULL;
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/* Remember that we changed the permission. */
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GL(dl_stack_flags) |= PF_X;
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out:
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#ifdef check_consistency
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check_consistency ();
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#endif
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return result;
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}
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rtld_hidden_def (_dl_make_stack_executable)
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