mirror of git://sourceware.org/git/glibc.git
44 lines
1.5 KiB
C
44 lines
1.5 KiB
C
/* PLT rewrite helper function. Linux/x86-64 version.
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Copyright (C) 2024-2025 Free Software Foundation, Inc.
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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 <stdbool.h>
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#include <sys/mman.h>
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static __always_inline bool
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dl_plt_rewrite_supported (void)
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{
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/* PLT rewrite is enabled. Check if mprotect works. */
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void *plt = (void *) INTERNAL_SYSCALL_CALL (mmap, NULL, 4096,
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PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS,
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-1, 0);
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if (__glibc_unlikely (plt == MAP_FAILED))
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return false;
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/* Touch the PROT_READ | PROT_WRITE page. */
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*(int32_t *) plt = 1;
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/* If the updated PROT_READ | PROT_WRITE page can be changed to
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PROT_EXEC | PROT_READ, rewrite PLT. */
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bool status = (INTERNAL_SYSCALL_CALL (mprotect, plt, 4096,
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PROT_EXEC | PROT_READ) == 0);
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INTERNAL_SYSCALL_CALL (munmap, plt, 4096);
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return status;
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}
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