explicit_bzero.c 1.4 KB

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  1. /* Erasure of sensitive data, generic implementation.
  2. Copyright (C) 2016-2026 Free Software Foundation, Inc.
  3. This file is part of the GNU C Library.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, see
  14. <https://www.gnu.org/licenses/>. */
  15. /* An assembler implementation of explicit_bzero can be created as an
  16. assembler alias of an optimized bzero implementation.
  17. Architecture-specific implementations also need to define
  18. __explicit_bzero_chk. */
  19. #include <string.h>
  20. /* glibc-internal users use __explicit_bzero_chk, and explicit_bzero
  21. redirects to that. */
  22. #undef explicit_bzero
  23. /* Set LEN bytes of S to 0. The compiler will not delete a call to
  24. this function, even if S is dead after the call. */
  25. void
  26. explicit_bzero (void *s, size_t len)
  27. {
  28. memset (s, '\0', len);
  29. /* Compiler barrier. */
  30. asm volatile ("" ::: "memory");
  31. }