Adding upstream version 2.41.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

lib/randutils.c

@@ -0,0 +1,235 @@
+/*
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * General purpose random utilities. Based on libuuid code.
+ *
+ * This code is free software; you can redistribute it and/or modify it under
+ * the terms of the Modified BSD License. The complete text of the license is
+ * available in the Documentation/licenses/COPYING.BSD-3-Clause file.
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#ifdef HAVE_SYS_SYSCALL_H
+#include <sys/syscall.h>
+#endif
+#include "c.h"
+#include "randutils.h"
+#include "nls.h"
+
+
+#ifdef HAVE_GETRANDOM
+# include <sys/random.h>
+#elif defined (__linux__)
+# if !defined(SYS_getrandom) && defined(__NR_getrandom)
+   /* usable kernel-headers, but old glibc-headers */
+#  define SYS_getrandom __NR_getrandom
+# endif
+#endif
+
+#if !defined(HAVE_GETRANDOM) && defined(SYS_getrandom)
+/* libc without function, but we have syscall */
+#define GRND_NONBLOCK 0x01
+#define GRND_RANDOM 0x02
+static int getrandom(void *buf, size_t buflen, unsigned int flags)
+{
+	return (syscall(SYS_getrandom, buf, buflen, flags));
+}
+# define HAVE_GETRANDOM
+#endif
+
+#if defined(__linux__) && defined(__NR_gettid) && defined(HAVE_JRAND48)
+#define DO_JRAND_MIX
+THREAD_LOCAL unsigned short ul_jrand_seed[3];
+#endif
+
+int rand_get_number(int low_n, int high_n)
+{
+	return rand() % (high_n - low_n + 1) + low_n;
+}
+
+static void crank_random(void)
+{
+	int i;
+	struct timeval tv;
+	unsigned int n_pid, n_uid;
+
+	gettimeofday(&tv, NULL);
+	n_pid = getpid();
+	n_uid = getuid();
+	srand((n_pid << 16) ^ n_uid ^ tv.tv_sec ^ tv.tv_usec);
+
+#ifdef DO_JRAND_MIX
+	ul_jrand_seed[0] = getpid() ^ (tv.tv_sec & 0xFFFF);
+	ul_jrand_seed[1] = getppid() ^ (tv.tv_usec & 0xFFFF);
+	ul_jrand_seed[2] = (tv.tv_sec ^ tv.tv_usec) >> 16;
+#endif
+	/* Crank the random number generator a few times */
+	gettimeofday(&tv, NULL);
+	for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
+		rand();
+}
+
+int random_get_fd(void)
+{
+	int fd;
+
+	fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
+	if (fd == -1)
+		fd = open("/dev/random", O_RDONLY | O_NONBLOCK | O_CLOEXEC);
+	crank_random();
+	return fd;
+}
+
+/*
+ * Generate a stream of random nbytes into buf.
+ * Use /dev/urandom if possible, and if not,
+ * use glibc pseudo-random functions.
+ */
+#define UL_RAND_READ_ATTEMPTS	8
+#define UL_RAND_READ_DELAY	125000	/* microseconds */
+
+/*
+ * Write @nbytes random bytes into @buf.
+ *
+ * Returns 0 for good quality of random bytes or 1 for weak quality.
+ */
+int ul_random_get_bytes(void *buf, size_t nbytes)
+{
+	unsigned char *cp = (unsigned char *)buf;
+	size_t i, n = nbytes;
+	int lose_counter = 0;
+
+#ifdef HAVE_GETRANDOM
+	while (n > 0) {
+		int x;
+
+		errno = 0;
+		x = getrandom(cp, n, GRND_NONBLOCK);
+		if (x > 0) {			/* success */
+		       n -= x;
+		       cp += x;
+		       lose_counter = 0;
+		       errno = 0;
+		} else if (errno == ENOSYS) {	/* kernel without getrandom() */
+			break;
+
+		} else if (errno == EAGAIN && lose_counter < UL_RAND_READ_ATTEMPTS) {
+			xusleep(UL_RAND_READ_DELAY);	/* no entropy, wait and try again */
+			lose_counter++;
+		} else
+			break;
+	}
+
+	if (errno == ENOSYS)
+#endif
+	/*
+	 * We've been built against headers that support getrandom, but the
+	 * running kernel does not.  Fallback to reading from /dev/{u,}random
+	 * as before
+	 */
+	{
+		int fd = random_get_fd();
+
+		lose_counter = 0;
+		if (fd >= 0) {
+			while (n > 0) {
+				ssize_t x = read(fd, cp, n);
+				if (x <= 0) {
+					if (lose_counter++ > UL_RAND_READ_ATTEMPTS)
+						break;
+					xusleep(UL_RAND_READ_DELAY);
+					continue;
+				}
+				n -= x;
+				cp += x;
+				lose_counter = 0;
+			}
+
+			close(fd);
+		}
+	}
+	/*
+	 * We do this all the time, but this is the only source of
+	 * randomness if /dev/random/urandom is out to lunch.
+	 */
+	crank_random();
+	for (cp = buf, i = 0; i < nbytes; i++)
+		*cp++ ^= (rand() >> 7) & 0xFF;
+
+#ifdef DO_JRAND_MIX
+	{
+		unsigned short tmp_seed[3];
+
+		memcpy(tmp_seed, ul_jrand_seed, sizeof(tmp_seed));
+		ul_jrand_seed[2] = ul_jrand_seed[2] ^ syscall(__NR_gettid);
+		for (cp = buf, i = 0; i < nbytes; i++)
+			*cp++ ^= (jrand48(tmp_seed) >> 7) & 0xFF;
+		memcpy(ul_jrand_seed, tmp_seed,
+		       sizeof(ul_jrand_seed)-sizeof(unsigned short));
+	}
+#endif
+
+	return n != 0;
+}
+
+
+/*
+ * Tell source of randomness.
+ */
+const char *random_tell_source(void)
+{
+#ifdef HAVE_GETRANDOM
+	return _("getrandom() function");
+#else
+	size_t i;
+	static const char *const random_sources[] = {
+		"/dev/urandom",
+		"/dev/random"
+	};
+
+	for (i = 0; i < ARRAY_SIZE(random_sources); i++) {
+		if (!access(random_sources[i], R_OK))
+			return random_sources[i];
+	}
+#endif
+	return _("libc pseudo-random functions");
+}
+
+#ifdef TEST_PROGRAM_RANDUTILS
+#include <inttypes.h>
+
+int main(int argc, char *argv[])
+{
+	size_t i, n;
+	int64_t *vp, v;
+	char *buf;
+	size_t bufsz;
+
+	n = argc == 1 ? 16 : atoi(argv[1]);
+
+	printf("Multiple random calls:\n");
+	for (i = 0; i < n; i++) {
+		ul_random_get_bytes(&v, sizeof(v));
+		printf("#%02zu: %25"PRIu64"\n", i, v);
+	}
+
+
+	printf("One random call:\n");
+	bufsz = n * sizeof(*vp);
+	buf = malloc(bufsz);
+	if (!buf)
+		err(EXIT_FAILURE, "failed to allocate buffer");
+
+	ul_random_get_bytes(buf, bufsz);
+	for (i = 0; i < n; i++) {
+		vp = (int64_t *) (buf + (i * sizeof(*vp)));
+		printf("#%02zu: %25"PRIu64"\n", i, *vp);
+	}
+
+	return EXIT_SUCCESS;
+}
+#endif /* TEST_PROGRAM_RANDUTILS */