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0c34259423
The BZ 32653 fix (12a497c716) kept the stack pointer zeroing from make_main_stack_executable on _dl_make_stack_executable. However, previously the 'stack_endp' pointed to temporary variable created before the call of _dl_map_object_from_fd; while now we use the __libc_stack_end directly. Since pthread_getattr_np relies on correct __libc_stack_end, if _dl_make_stack_executable is called (for instance, when glibc.rtld.execstack=2 is set) __libc_stack_end will be set to zero, and the call will always fail. The __libc_stack_end zero was used a mitigation hardening, but since52a01100adit is used solely on pthread_getattr_np code. So there is no point in zeroing anymore. Checked on x86_64-linux-gnu and i686-linux-gnu. Reviewed-by: Sam James <sam@gentoo.org>
49 lines
1.6 KiB
C
49 lines
1.6 KiB
C
/* Stack executability handling for GNU dynamic linker. Hurd version.
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Copyright (C) 2004-2025 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 <hurdstartup.h>
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#include <errno.h>
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extern struct hurd_startup_data *_dl_hurd_data attribute_hidden;
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/* There is no portable way to know the bounds of the initial thread's stack
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so as to mprotect it. */
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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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/* Challenge the caller. */
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if (__glibc_unlikely (stack_endp != __libc_stack_end))
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return EPERM;
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#if IS_IN (rtld)
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if (__mprotect ((void *)_dl_hurd_data->stack_base, _dl_hurd_data->stack_size,
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PROT_READ|PROT_WRITE|PROT_EXEC) != 0)
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return errno;
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/* Remember that we changed the permission. */
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GL(dl_stack_flags) |= PF_X;
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return 0;
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#else
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/* We don't bother to implement this for static linking. */
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return ENOSYS;
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#endif
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}
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