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3b2b88ccee
This patch replaces _dl_stack_flags global variable by _dl_stack_prot_flags. The advantage is that any convertion from p_flags to final used mprotect flags occurs at loading of p_flags. It avoids repeated spurious convertions of _dl_stack_flags, for example in allocate_thread_stack. This modification was suggested in: https://sourceware.org/pipermail/libc-alpha/2025-March/165537.html Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
44 lines
1.4 KiB
C
44 lines
1.4 KiB
C
/* Stack executability handling for GNU dynamic linker. Linux version.
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Copyright (C) 2003-2025 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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<https://www.gnu.org/licenses/>. */
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#include <ldsodefs.h>
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#include <stackinfo.h>
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int
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_dl_make_stack_executable (const 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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if (__mprotect ((void *) page, GLRO(dl_pagesize),
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PROT_READ | PROT_WRITE | PROT_EXEC
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#if _STACK_GROWS_DOWN
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| PROT_GROWSDOWN
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#elif _STACK_GROWS_UP
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| PROT_GROWSUP
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#endif
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) != 0)
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return errno;
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/* Remember that we changed the permission. */
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GL(dl_stack_prot_flags) |= PROT_EXEC;
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return 0;
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}
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