shared: split random and hash utils

"nm-utils/nm-shared-utils.h" shall contain utility function without other
dependencies. It is intended to be used by other projects as-is.

nm_utils_random_bytes() requires getrandom() and a HAVE_GETRANDOM configure
check. That makes it more cumbersome to re-use "nm-shared-utils.h", in
cases where you don't care about nm_utils_random_bytes().

Split nm_utils_random_bytes() out to a separate file.

Same for hash utils, which depend on nm_utils_random_bytes(). Also, hash
utils will eventually be extended to use siphash24.

Makefile.am

@@ -421,7 +421,9 @@ libnm_core_lib_h_priv = \
 	shared/nm-utils/c-list-util.h \
 	shared/nm-utils/nm-dedup-multi.h \
 	shared/nm-utils/nm-enum-utils.h \
+	shared/nm-utils/nm-hash-utils.h \
 	shared/nm-utils/nm-shared-utils.h \
+	shared/nm-utils/nm-random-utils.h \
 	shared/nm-utils/nm-udev-utils.h \
 	shared/nm-meta-setting.h \
 	libnm-core/crypto.h \
@@ -437,7 +439,9 @@ libnm_core_lib_c_real = \
 	shared/nm-utils/c-list-util.c \
 	shared/nm-utils/nm-dedup-multi.c \
 	shared/nm-utils/nm-enum-utils.c \
+	shared/nm-utils/nm-hash-utils.c \
 	shared/nm-utils/nm-shared-utils.c \
+	shared/nm-utils/nm-random-utils.c \
 	shared/nm-utils/nm-udev-utils.c \
 	shared/nm-meta-setting.c \
 	libnm-core/crypto.c \

libnm-core/nm-utils.c

@@ -38,6 +38,7 @@
 #endif
 
 #include "nm-utils/nm-enum-utils.h"
+#include "nm-utils/nm-hash-utils.h"
 #include "nm-common-macros.h"
 #include "nm-utils-private.h"
 #include "nm-setting-private.h"

shared/nm-utils/nm-dedup-multi.c

@@ -23,6 +23,8 @@
 
 #include "nm-dedup-multi.h"
 
+#include "nm-hash-utils.h"
+
 /*****************************************************************************/
 
 typedef struct {

shared/nm-utils/nm-hash-utils.c

@@ -0,0 +1,50 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
+/* NetworkManager -- Network link manager
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ * (C) Copyright 2017 Red Hat, Inc.
+ */
+
+#include "nm-default.h"
+
+#include "nm-hash-utils.h"
+
+#include "nm-shared-utils.h"
+#include "nm-random-utils.h"
+
+/*****************************************************************************/
+
+guint
+NM_HASH_INIT (guint seed)
+{
+	static volatile guint global_seed = 0;
+	guint g, s;
+
+	/* we xor @seed with a random @global_seed. This is to make the hashing behavior
+	 * less predictable and harder to exploit collisions. */
+	g = global_seed;
+	if (G_UNLIKELY (g == 0)) {
+		nm_utils_random_bytes (&s, sizeof (s));
+		if (s == 0)
+			s = 42;
+		g_atomic_int_compare_and_exchange ((int *) &global_seed, 0, s);
+		g = global_seed;
+		nm_assert (g);
+	}
+
+	return g ^ seed;
+}

shared/nm-utils/nm-hash-utils.h

@@ -0,0 +1,47 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
+/* NetworkManager -- Network link manager
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ * (C) Copyright 2017 Red Hat, Inc.
+ */
+
+#ifndef __NM_HASH_UTILS_H__
+#define __NM_HASH_UTILS_H__
+
+guint NM_HASH_INIT (guint seed);
+
+static inline guint
+NM_HASH_COMBINE (guint h, guint val)
+{
+	/* see g_str_hash() for reasons */
+	return (h << 5) + h + val;
+}
+
+static inline guint
+NM_HASH_COMBINE_UINT64 (guint h, guint64 val)
+{
+	return NM_HASH_COMBINE (h, (((guint) val) & 0xFFFFFFFFu) + ((guint) (val >> 32)));
+}
+
+static inline guint
+NM_HASH_POINTER (gconstpointer ptr)
+{
+	/* same as g_direct_hash(), but inline. */
+	return GPOINTER_TO_UINT (ptr);
+}
+
+#endif /* __NM_HASH_UTILS_H__ */

shared/nm-utils/nm-random-utils.c

@@ -0,0 +1,165 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
+/* NetworkManager -- Network link manager
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ * (C) Copyright 2017 Red Hat, Inc.
+ */
+
+#include "nm-default.h"
+
+#include "nm-random-utils.h"
+
+#include <fcntl.h>
+
+#if USE_SYS_RANDOM_H
+#include <sys/random.h>
+#else
+#include <linux/random.h>
+#endif
+
+#include "nm-shared-utils.h"
+
+/*****************************************************************************/
+
+/**
+ * nm_utils_random_bytes:
+ * @p: the buffer to fill
+ * @n: the number of bytes to write to @p.
+ *
+ * Uses getrandom() or reads /dev/urandom to fill the buffer
+ * with random data. If all fails, as last fallback it uses
+ * GRand to fill the buffer with pseudo random numbers.
+ * The function always succeeds in writing some random numbers
+ * to the buffer. The return value of FALSE indicates that the
+ * obtained bytes are probably not of good randomness.
+ *
+ * Returns: whether the written bytes are good. If you
+ * don't require good randomness, you can ignore the return
+ * value.
+ *
+ * Note that if calling getrandom() fails because there is not enough
+ * entroy (at early boot), the function will read /dev/urandom.
+ * Which of course, still has low entropy, and cause kernel to log
+ * a warning.
+ */
+gboolean
+nm_utils_random_bytes (void *p, size_t n)
+{
+	int fd;
+	int r;
+	gboolean has_high_quality = TRUE;
+	gboolean urandom_success;
+	guint8 *buf = p;
+	gboolean avoid_urandom = FALSE;
+
+	g_return_val_if_fail (p, FALSE);
+	g_return_val_if_fail (n > 0, FALSE);
+
+#if HAVE_GETRANDOM
+	{
+		static gboolean have_syscall = TRUE;
+
+		if (have_syscall) {
+			r = getrandom (buf, n, GRND_NONBLOCK);
+			if (r > 0) {
+				if ((size_t) r == n)
+					return TRUE;
+
+				/* no or partial read. There is not enough entropy.
+				 * Fill the rest reading from urandom, and remember that
+				 * some bits are not hight quality. */
+				nm_assert (r < n);
+				buf += r;
+				n -= r;
+				has_high_quality = FALSE;
+
+				/* At this point, we don't want to read /dev/urandom, because
+				 * the entropy pool is low (early boot?), and asking for more
+				 * entropy causes kernel messages to be logged.
+				 *
+				 * We use our fallback via GRand. Note that g_rand_new() also
+				 * tries to seed itself with data from /dev/urandom, but since
+				 * we reuse the instance, it shouldn't matter. */
+				avoid_urandom = TRUE;
+			} else {
+				if (errno == ENOSYS) {
+					/* no support for getrandom(). We don't know whether
+					 * we urandom will give us good quality. Assume yes. */
+					have_syscall = FALSE;
+				} else {
+					/* unknown error. We'll read urandom below, but we don't have
+					 * high-quality randomness. */
+					has_high_quality = FALSE;
+				}
+			}
+		}
+	}
+#endif
+
+	urandom_success = FALSE;
+	if (!avoid_urandom) {
+fd_open:
+		fd = open ("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOCTTY);
+		if (fd < 0) {
+			r = errno;
+			if (r == EINTR)
+				goto fd_open;
+		} else {
+			r = nm_utils_fd_read_loop_exact (fd, buf, n, TRUE);
+			close (fd);
+			if (r >= 0)
+				urandom_success = TRUE;
+		}
+	}
+
+	if (!urandom_success) {
+		static _nm_thread_local GRand *rand = NULL;
+		gsize i;
+		int j;
+
+		/* we failed to fill the bytes reading from urandom.
+		 * Fill the bits using GRand pseudo random numbers.
+		 *
+		 * We don't have good quality.
+		 */
+		has_high_quality = FALSE;
+
+		if (G_UNLIKELY (!rand))
+			rand = g_rand_new ();
+
+		nm_assert (n > 0);
+		i = 0;
+		for (;;) {
+			const union {
+				guint32 v32;
+				guint8 v8[4];
+			} v = {
+				.v32 = g_rand_int (rand),
+			};
+
+			for (j = 0; j < 4; ) {
+				buf[i++] = v.v8[j++];
+				if (i >= n)
+					goto done;
+			}
+		}
+done:
+		;
+	}
+
+	return has_high_quality;
+}

shared/nm-utils/nm-random-utils.h

@@ -0,0 +1,27 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
+/* NetworkManager -- Network link manager
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ * (C) Copyright 2017 Red Hat, Inc.
+ */
+
+#ifndef __NM_RANDOM_UTILS_H__
+#define __NM_RANDOM_UTILS_H__
+
+gboolean nm_utils_random_bytes (void *p, size_t n);
+
+#endif /* __NM_RANDOM_UTILS_H__ */

shared/nm-utils/nm-shared-utils.c

@@ -28,12 +28,6 @@
 #include <poll.h>
 #include <fcntl.h>
 
-#if USE_SYS_RANDOM_H
-#include <sys/random.h>
-#else
-#include <linux/random.h>
-#endif
-
 /*****************************************************************************/
 
 const void *const _NM_PTRARRAY_EMPTY[1] = { NULL };
@@ -863,29 +857,6 @@ nm_g_object_class_find_property_from_gtype (GType gtype,
 
 /*****************************************************************************/
 
-guint
-NM_HASH_INIT (guint seed)
-{
-	static volatile guint global_seed = 0;
-	guint g, s;
-
-	/* we xor @seed with a random @global_seed. This is to make the hashing behavior
-	 * less predictable and harder to exploit collisions. */
-	g = global_seed;
-	if (G_UNLIKELY (g == 0)) {
-		nm_utils_random_bytes (&s, sizeof (s));
-		if (s == 0)
-			s = 42;
-		g_atomic_int_compare_and_exchange ((int *) &global_seed, 0, s);
-		g = global_seed;
-		nm_assert (g);
-	}
-
-	return g ^ seed;
-}
-
-/*****************************************************************************/
-
 static void
 _str_append_escape (GString *s, char ch)
 {
@@ -1118,134 +1089,3 @@ nm_utils_fd_read_loop_exact (int fd, void *buf, size_t nbytes, bool do_poll)
 
 	return 0;
 }
-
-/*****************************************************************************/
-
-/**
- * nm_utils_random_bytes:
- * @p: the buffer to fill
- * @n: the number of bytes to write to @p.
- *
- * Uses getrandom() or reads /dev/urandom to fill the buffer
- * with random data. If all fails, as last fallback it uses
- * GRand to fill the buffer with pseudo random numbers.
- * The function always succeeds in writing some random numbers
- * to the buffer. The return value of FALSE indicates that the
- * obtained bytes are probably not of good randomness.
- *
- * Returns: whether the written bytes are good. If you
- * don't require good randomness, you can ignore the return
- * value.
- *
- * Note that if calling getrandom() fails because there is not enough
- * entroy (at early boot), the function will read /dev/urandom.
- * Which of course, still has low entropy, and cause kernel to log
- * a warning.
- */
-gboolean
-nm_utils_random_bytes (void *p, size_t n)
-{
-	int fd;
-	int r;
-	gboolean has_high_quality = TRUE;
-	gboolean urandom_success;
-	guint8 *buf = p;
-	gboolean avoid_urandom = FALSE;
-
-	g_return_val_if_fail (p, FALSE);
-	g_return_val_if_fail (n > 0, FALSE);
-
-#if HAVE_GETRANDOM
-	{
-		static gboolean have_syscall = TRUE;
-
-		if (have_syscall) {
-			r = getrandom (buf, n, GRND_NONBLOCK);
-			if (r > 0) {
-				if ((size_t) r == n)
-					return TRUE;
-
-				/* no or partial read. There is not enough entropy.
-				 * Fill the rest reading from urandom, and remember that
-				 * some bits are not hight quality. */
-				nm_assert (r < n);
-				buf += r;
-				n -= r;
-				has_high_quality = FALSE;
-
-				/* At this point, we don't want to read /dev/urandom, because
-				 * the entropy pool is low (early boot?), and asking for more
-				 * entropy causes kernel messages to be logged.
-				 *
-				 * We use our fallback via GRand. Note that g_rand_new() also
-				 * tries to seed itself with data from /dev/urandom, but since
-				 * we reuse the instance, it shouldn't matter. */
-				avoid_urandom = TRUE;
-			} else {
-				if (errno == ENOSYS) {
-					/* no support for getrandom(). We don't know whether
-					 * we urandom will give us good quality. Assume yes. */
-					have_syscall = FALSE;
-				} else {
-					/* unknown error. We'll read urandom below, but we don't have
-					 * high-quality randomness. */
-					has_high_quality = FALSE;
-				}
-			}
-		}
-	}
-#endif
-
-	urandom_success = FALSE;
-	if (!avoid_urandom) {
-fd_open:
-		fd = open ("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOCTTY);
-		if (fd < 0) {
-			r = errno;
-			if (r == EINTR)
-				goto fd_open;
-		} else {
-			r = nm_utils_fd_read_loop_exact (fd, buf, n, TRUE);
-			close (fd);
-			if (r >= 0)
-				urandom_success = TRUE;
-		}
-	}
-
-	if (!urandom_success) {
-		static _nm_thread_local GRand *rand = NULL;
-		gsize i;
-		int j;
-
-		/* we failed to fill the bytes reading from urandom.
-		 * Fill the bits using GRand pseudo random numbers.
-		 *
-		 * We don't have good quality.
-		 */
-		has_high_quality = FALSE;
-
-		if (G_UNLIKELY (!rand))
-			rand = g_rand_new ();
-
-		nm_assert (n > 0);
-		i = 0;
-		for (;;) {
-			const union {
-				guint32 v32;
-				guint8 v8[4];
-			} v = {
-				.v32 = g_rand_int (rand),
-			};
-
-			for (j = 0; j < 4; ) {
-				buf[i++] = v.v8[j++];
-				if (i >= n)
-					goto done;
-			}
-		}
-done:
-		;
-	}
-
-	return has_high_quality;
-}

shared/nm-utils/nm-shared-utils.h

@@ -378,30 +378,6 @@ GParamSpec *nm_g_object_class_find_property_from_gtype (GType gtype,
 
 /*****************************************************************************/
 
-guint NM_HASH_INIT (guint seed);
-
-static inline guint
-NM_HASH_COMBINE (guint h, guint val)
-{
-	/* see g_str_hash() for reasons */
-	return (h << 5) + h + val;
-}
-
-static inline guint
-NM_HASH_COMBINE_UINT64 (guint h, guint64 val)
-{
-	return NM_HASH_COMBINE (h, (((guint) val) & 0xFFFFFFFFu) + ((guint) (val >> 32)));
-}
-
-static inline guint
-NM_HASH_POINTER (gconstpointer ptr)
-{
-	/* same as g_direct_hash(), but inline. */
-	return GPOINTER_TO_UINT (ptr);
-}
-
-/*****************************************************************************/
-
 typedef enum {
 	NM_UTILS_STR_UTF8_SAFE_FLAG_NONE                = 0,
 	NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL         = 0x0001,
@@ -430,8 +406,4 @@ int nm_utils_fd_read_loop_exact (int fd, void *buf, size_t nbytes, bool do_poll)
 
 /*****************************************************************************/
 
-gboolean nm_utils_random_bytes (void *p, size_t n);
-
-/*****************************************************************************/
-
 #endif /* __NM_SHARED_UTILS_H__ */

src/dhcp/nm-dhcp-client.c

@@ -32,6 +32,7 @@
 #include <linux/rtnetlink.h>
 
 #include "nm-utils/nm-dedup-multi.h"
+#include "nm-utils/nm-random-utils.h"
 
 #include "NetworkManagerUtils.h"
 #include "nm-utils.h"

src/nm-core-utils.c

@@ -36,6 +36,7 @@
 #include <linux/if_infiniband.h>
 #include <net/ethernet.h>
 
+#include "nm-utils/nm-random-utils.h"
 #include "nm-utils.h"
 #include "nm-core-internal.h"
 #include "nm-setting-connection.h"

src/nm-core-utils.h

@@ -25,6 +25,8 @@
 #include <stdio.h>
 #include <arpa/inet.h>
 
+#include "nm-utils/nm-hash-utils.h"
+
 #include "nm-connection.h"
 
 /*****************************************************************************/