diff options
Diffstat (limited to 'lib/explicit_bzero.c')
| -rw-r--r-- | lib/explicit_bzero.c | 69 |
1 files changed, 11 insertions, 58 deletions
diff --git a/lib/explicit_bzero.c b/lib/explicit_bzero.c index ad0bfd170ca..fc309f81d61 100644 --- a/lib/explicit_bzero.c +++ b/lib/explicit_bzero.c | |||
| @@ -1,74 +1,27 @@ | |||
| 1 | /* Erasure of sensitive data, generic implementation. | 1 | /* Erasure of sensitive data, generic implementation. |
| 2 | Copyright (C) 2016-2022 Free Software Foundation, Inc. | 2 | Copyright (C) 2016-2022 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. | ||
| 4 | 3 | ||
| 5 | The GNU C Library is free software; you can redistribute it and/or | 4 | This file is free software: you can redistribute it and/or modify |
| 6 | modify it under the terms of the GNU Lesser General Public | 5 | it under the terms of the GNU Lesser General Public License as |
| 7 | License as published by the Free Software Foundation; either | 6 | published by the Free Software Foundation; either version 2.1 of the |
| 8 | version 2.1 of the License, or (at your option) any later version. | 7 | License, or (at your option) any later version. |
| 9 | 8 | ||
| 10 | The GNU C Library is distributed in the hope that it will be useful, | 9 | This file is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | Lesser General Public License for more details. | 12 | GNU Lesser General Public License for more details. |
| 14 | 13 | ||
| 15 | You should have received a copy of the GNU Lesser General Public | 14 | You should have received a copy of the GNU Lesser General Public License |
| 16 | License along with the GNU C Library; if not, see | 15 | along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| 17 | <https://www.gnu.org/licenses/>. */ | ||
| 18 | 16 | ||
| 19 | /* An assembler implementation of explicit_bzero can be created as an | 17 | #include <config.h> |
| 20 | assembler alias of an optimized bzero implementation. | ||
| 21 | Architecture-specific implementations also need to define | ||
| 22 | __explicit_bzero_chk. */ | ||
| 23 | |||
| 24 | #if !_LIBC | ||
| 25 | # include <config.h> | ||
| 26 | #endif | ||
| 27 | |||
| 28 | /* memset_s need this define */ | ||
| 29 | #if HAVE_MEMSET_S | ||
| 30 | # define __STDC_WANT_LIB_EXT1__ 1 | ||
| 31 | #endif | ||
| 32 | 18 | ||
| 33 | #include <string.h> | 19 | #include <string.h> |
| 34 | 20 | ||
| 35 | #if defined _WIN32 && !defined __CYGWIN__ | ||
| 36 | # define WIN32_LEAN_AND_MEAN | ||
| 37 | # include <windows.h> | ||
| 38 | #endif | ||
| 39 | |||
| 40 | #if _LIBC | ||
| 41 | /* glibc-internal users use __explicit_bzero_chk, and explicit_bzero | ||
| 42 | redirects to that. */ | ||
| 43 | # undef explicit_bzero | ||
| 44 | #endif | ||
| 45 | |||
| 46 | /* Set LEN bytes of S to 0. The compiler will not delete a call to | 21 | /* Set LEN bytes of S to 0. The compiler will not delete a call to |
| 47 | this function, even if S is dead after the call. */ | 22 | this function, even if S is dead after the call. */ |
| 48 | void | 23 | void |
| 49 | explicit_bzero (void *s, size_t len) | 24 | explicit_bzero (void *s, size_t len) |
| 50 | { | 25 | { |
| 51 | #if defined _WIN32 && !defined __CYGWIN__ | 26 | memset_explicit (s, 0, len); |
| 52 | (void) SecureZeroMemory (s, len); | ||
| 53 | #elif HAVE_EXPLICIT_MEMSET | ||
| 54 | explicit_memset (s, '\0', len); | ||
| 55 | #elif HAVE_MEMSET_S | ||
| 56 | (void) memset_s (s, len, '\0', len); | ||
| 57 | #elif defined __GNUC__ && !defined __clang__ | ||
| 58 | memset (s, '\0', len); | ||
| 59 | /* Compiler barrier. */ | ||
| 60 | asm volatile ("" ::: "memory"); | ||
| 61 | #elif defined __clang__ | ||
| 62 | memset (s, '\0', len); | ||
| 63 | /* Compiler barrier. */ | ||
| 64 | /* With asm ("" ::: "memory") LLVM analyzes uses of 's' and finds that the | ||
| 65 | whole thing is dead and eliminates it. Use 'g' to work around this | ||
| 66 | problem. See <https://bugs.llvm.org/show_bug.cgi?id=15495#c11>. */ | ||
| 67 | __asm__ volatile ("" : : "g"(s) : "memory"); | ||
| 68 | #else | ||
| 69 | /* Invoke memset through a volatile function pointer. This defeats compiler | ||
| 70 | optimizations. */ | ||
| 71 | void * (* const volatile volatile_memset) (void *, int, size_t) = memset; | ||
| 72 | (void) volatile_memset (s, '\0', len); | ||
| 73 | #endif | ||
| 74 | } | 27 | } |