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-rw-r--r--lib/util/arc4random_buf.c70
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diff --git a/lib/util/arc4random_buf.c b/lib/util/arc4random_buf.c
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+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2020 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#ifndef HAVE_ARC4RANDOM_BUF
+
+#include <stdlib.h>
+#if defined(HAVE_STDINT_H)
+# include <stdint.h>
+#elif defined(HAVE_INTTYPES_H)
+# include <inttypes.h>
+#endif
+
+#include "sudo_compat.h"
+#include "sudo_rand.h"
+
+#define minimum(a, b) ((a) < (b) ? (a) : (b))
+
+/*
+ * Call arc4random() repeatedly to fill buf with n bytes of random data.
+ */
+void
+sudo_arc4random_buf(void *buf, size_t n)
+{
+ char *cp = buf;
+
+ while (n != 0) {
+ size_t m = minimum(n, 4);
+ uint32_t val = arc4random();
+
+ switch (m) {
+ case 4:
+ *cp++ = (val >> 24) & 0xff;
+ FALLTHROUGH;
+ case 3:
+ *cp++ = (val >> 16) & 0xff;
+ FALLTHROUGH;
+ case 2:
+ *cp++ = (val >> 8) & 0xff;
+ FALLTHROUGH;
+ case 1:
+ *cp++ = val & 0xff;
+ break;
+ }
+ n -= m;
+ }
+}
+
+#endif /* HAVE_ARC4RANDOM_BUF */