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Diffstat (limited to 'lib/random_rand_s.c')
| -rw-r--r-- | lib/random_rand_s.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/lib/random_rand_s.c b/lib/random_rand_s.c new file mode 100644 index 000000000000..46156563c91c --- /dev/null +++ b/lib/random_rand_s.c @@ -0,0 +1,88 @@ +/* + __ __ _ + ___\ \/ /_ __ __ _| |_ + / _ \\ /| '_ \ / _` | __| + | __// \| |_) | (_| | |_ + \___/_/\_\ .__/ \__,_|\__| + |_| XML parser + + Copyright (c) 2019 David Loffredo <loffredo@steptools.com> + Copyright (c) 2019-2026 Sebastian Pipping <sebastian@pipping.org> + Copyright (c) 2019 Ben Wagner <bungeman@chromium.org> + Copyright (c) 2019 Vadim Zeitlin <vadim@zeitlins.org> + Copyright (c) 2026 Matthew Fernandez <matthew.fernandez@gmail.com> + Licensed under the MIT license: + + Permission is hereby granted, free of charge, to any person obtaining + a copy of this software and associated documentation files (the + "Software"), to deal in the Software without restriction, including + without limitation the rights to use, copy, modify, merge, publish, + distribute, sublicense, and/or sell copies of the Software, and to permit + persons to whom the Software is furnished to do so, subject to the + following conditions: + + The above copyright notice and this permission notice shall be included + in all copies or substantial portions of the Software. + + THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN + NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, + DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR + OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE + USE OR OTHER DEALINGS IN THE SOFTWARE. +*/ + +#include "random_rand_s.h" + +/* force stdlib to define rand_s() */ +#if ! defined(_CRT_RAND_S) +# define _CRT_RAND_S +#endif + +// Workaround MinGW GCC trouble with recognizing `rand_s`, likely related +// to return type `error_t`; the symptom was: +// > error: implicit declaration of function ‘rand_s’ +#if defined(__MINGW32__) +# include <errno.h> +#endif + +#include <stdlib.h> // for rand_s +#include <string.h> // for memcpy + +// Help clang-tidy out with prototype of function `rand_s` +#if defined(XML_CLANG_TIDY) +int rand_s(unsigned int *); +#endif + +/* Provide declaration of rand_s() for MinGW-32 (not 64, which has it), + as it didn't declare it in its header prior to version 5.3.0 of its + runtime package (mingwrt, containing stdlib.h). The upstream fix + was introduced at https://osdn.net/projects/mingw/ticket/39658 . */ +#if defined(__MINGW32__) && defined(__MINGW32_VERSION) \ + && __MINGW32_VERSION < 5003000L && ! defined(__MINGW64_VERSION_MAJOR) +__declspec(dllimport) int rand_s(unsigned int *); +#endif + +/* Obtain entropy on Windows using the rand_s() function which + * generates cryptographically secure random numbers. Internally it + * uses RtlGenRandom API which is present in Windows XP and later. + */ +bool +writeRandomBytes_rand_s(void *target, size_t count) { + size_t bytesWrittenTotal = 0; + + while (bytesWrittenTotal < count) { + unsigned int random32 = 0; + + if (rand_s(&random32)) + return false; /* failure */ + + size_t toUse = count - bytesWrittenTotal; + if (toUse > sizeof(random32)) + toUse = sizeof(random32); + memcpy((char *)target + bytesWrittenTotal, &random32, toUse); + bytesWrittenTotal += toUse; + } + return true; /* success */ +} |