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[src/trunk]: src/lib/libc/include Add getentropy() to libc - a simple wrapper...
details: https://anonhg.NetBSD.org/src/rev/a85643634793
branches: trunk
changeset: 932393:a85643634793
user: nia <nia%NetBSD.org@localhost>
date: Wed May 06 16:17:36 2020 +0000
description:
Add getentropy() to libc - a simple wrapper to access the kernel CSPRNG.
Posted to tech-userlevel@ a week ago and reviewed by riastradh@.
GETENTROPY(3) Library Functions Manual GETENTROPY(3)
NAME
getentropy - fill a buffer with high quality random data
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
int
getentropy(void *buf, size_t buflen);
DESCRIPTION
The getentropy() function fills a buffer with high quality random data,
suitable for seeding cryptographically secure psuedorandom number
generators.
getentropy() is only intended for seeding random number generators and is
not intended for use by regular code which simply needs secure random
data. For this purpose, please use arc4random(3).
The maximum value for buflen is 256 bytes.
IMPLEMENTATION NOTES
getentropy() reads from the sysctl(7) variable kern.arandom.
RETURN VALUES
The getentropy() function returns 0 on success, and -1 if an error
occurred.
ERRORS
getentropy() will succeed unless:
[EFAULT] The buf argument points to an invalid memory address.
[EIO] Too many bytes were requested.
SEE ALSO
arc4random(3), rnd(4)
STANDARDS
The getentropy() function is non-standard.
HISTORY
The getentropy() function first appeared in OpenBSD 5.6, then in
FreeBSD 12.0, and NetBSD 10.
diffstat:
distrib/sets/lists/comp/mi | 5 +-
include/unistd.h | 3 +-
lib/libc/gen/Makefile.inc | 6 +-
lib/libc/gen/getentropy.3 | 93 ++++++++++++++++++++++++++++++++++++++++++++
lib/libc/gen/getentropy.c | 64 ++++++++++++++++++++++++++++++
lib/libc/include/namespace.h | 3 +-
6 files changed, 168 insertions(+), 6 deletions(-)
diffs (259 lines):
diff -r 7c1e8c06addb -r a85643634793 distrib/sets/lists/comp/mi
--- a/distrib/sets/lists/comp/mi Wed May 06 14:59:51 2020 +0000
+++ b/distrib/sets/lists/comp/mi Wed May 06 16:17:36 2020 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: mi,v 1.2324 2020/05/01 21:43:23 jdolecek Exp $
+# $NetBSD: mi,v 1.2325 2020/05/06 16:17:36 nia Exp $
#
# Note: don't delete entries from here - mark them as "obsolete" instead.
./etc/mtree/set.comp comp-sys-root
@@ -7273,6 +7273,7 @@
./usr/share/man/cat3/getdiskrawname.0 comp-c-catman .cat
./usr/share/man/cat3/getdomainname.0 comp-c-catman .cat
./usr/share/man/cat3/getdtablesize.0 comp-c-catman .cat
+./usr/share/man/cat3/getentropy.0 comp-c-catman .cat
./usr/share/man/cat3/getenv.0 comp-c-catman .cat
./usr/share/man/cat3/getenv_r.0 comp-c-catman .cat
./usr/share/man/cat3/getfsent.0 comp-c-catman .cat
@@ -15316,6 +15317,7 @@
./usr/share/man/html3/getdiskrawname.html comp-c-htmlman html
./usr/share/man/html3/getdomainname.html comp-c-htmlman html
./usr/share/man/html3/getdtablesize.html comp-c-htmlman html
+./usr/share/man/html3/getentropy.html comp-c-htmlman html
./usr/share/man/html3/getenv.html comp-c-htmlman html
./usr/share/man/html3/getenv_r.html comp-c-htmlman html
./usr/share/man/html3/getfsent.html comp-c-htmlman html
@@ -23297,6 +23299,7 @@
./usr/share/man/man3/getdiskrawname.3 comp-c-man .man
./usr/share/man/man3/getdomainname.3 comp-c-man .man
./usr/share/man/man3/getdtablesize.3 comp-c-man .man
+./usr/share/man/man3/getentropy.3 comp-c-man .man
./usr/share/man/man3/getenv.3 comp-c-man .man
./usr/share/man/man3/getenv_r.3 comp-c-man .man
./usr/share/man/man3/getfsent.3 comp-c-man .man
diff -r 7c1e8c06addb -r a85643634793 include/unistd.h
--- a/include/unistd.h Wed May 06 14:59:51 2020 +0000
+++ b/include/unistd.h Wed May 06 16:17:36 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: unistd.h,v 1.156 2020/03/31 16:50:31 kamil Exp $ */
+/* $NetBSD: unistd.h,v 1.157 2020/05/06 16:17:36 nia Exp $ */
/*-
* Copyright (c) 1998, 1999, 2008 The NetBSD Foundation, Inc.
@@ -338,6 +338,7 @@
int fdiscard(int, off_t, off_t);
int fsync_range(int, int, off_t, off_t);
int getdomainname(char *, size_t);
+int getentropy(void *, size_t);
int getgrouplist(const char *, gid_t, gid_t *, int *);
int getgroupmembership(const char *, gid_t, gid_t *, int, int *);
mode_t getmode(const void *, mode_t);
diff -r 7c1e8c06addb -r a85643634793 lib/libc/gen/Makefile.inc
--- a/lib/libc/gen/Makefile.inc Wed May 06 14:59:51 2020 +0000
+++ b/lib/libc/gen/Makefile.inc Wed May 06 16:17:36 2020 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile.inc,v 1.201 2020/04/22 23:32:25 joerg Exp $
+# $NetBSD: Makefile.inc,v 1.202 2020/05/06 16:17:36 nia Exp $
# from: @(#)Makefile.inc 8.6 (Berkeley) 5/4/95
# gen sources
@@ -15,7 +15,7 @@
errc.c errlist.c errno.c execl.c execle.c execlp.c execv.c execvp.c \
exect.c extattr.c fmtcheck.c fmtmsg.c fnmatch.c fstab.c ftok.c \
fts.c ftw.c getbsize.c getcap.c getcwd.c \
- getdevmajor.c getdomainname.c getgrent.c \
+ getdevmajor.c getdomainname.c getentropy.c getgrent.c \
getgrouplist.c getgroupmembership.c gethostname.c \
getloadavg.c getlogin.c getmntinfo.c \
getnetgrent.c getpagesize.c \
@@ -60,7 +60,7 @@
fmtcheck.3 fmtmsg.3 fnmatch.3 fpclassify.3 fpgetmask.3 \
ftok.3 fts.3 ftw.3 \
getbsize.3 cgetcap.3 getcwd.3 getdevmajor.3 \
- getdomainname.3 getdiskbyname.3 getfsent.3 \
+ getdomainname.3 getdiskbyname.3 getentropy.3 getfsent.3 \
getgrent.3 getgrouplist.3 gethostname.3 getlastlogx.3 getloadavg.3 \
getmntinfo.3 getnetgrent.3 getpagesize.3 getpass.3 \
getprogname.3 getpwent.3 getttyent.3 getusershell.3 glob.3 \
diff -r 7c1e8c06addb -r a85643634793 lib/libc/gen/getentropy.3
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/libc/gen/getentropy.3 Wed May 06 16:17:36 2020 +0000
@@ -0,0 +1,93 @@
+.\" $NetBSD: getentropy.3,v 1.1 2020/05/06 16:17:36 nia Exp $ $
+.\"
+.\" Copyright (c) 2020 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Nia Alarie.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd May 1, 2020
+.Dt GETENTROPY 3
+.Os
+.Sh NAME
+.Nm getentropy
+.Nd fill a buffer with high quality random data
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In unistd.h
+.Ft int
+.Fn getentropy "void *buf" "size_t buflen"
+.Sh DESCRIPTION
+.Pp
+The
+.Fn getentropy
+function fills a buffer with high quality random data, suitable for seeding
+cryptographically secure psuedorandom number generators.
+.Pp
+.Fn getentropy
+is only intended for seeding random number generators and is not intended
+for use by regular code which simply needs secure random data. For this
+purpose, please use
+.Xr arc4random 3 .
+.Pp
+The maximum value for
+.Li buflen
+is 256 bytes.
+.Sh IMPLEMENTATION NOTES
+.Fn getentropy
+reads from the
+.Xr sysctl 7
+variable
+.Li kern.arandom .
+.Sh RETURN VALUES
+The
+.Fn getentropy
+function returns 0 on success, and -1 if an error occurred.
+.Sh ERRORS
+.Fn getentropy
+will succeed unless:
+.Bl -tag -width Er
+.It Bq Er EFAULT
+The
+.Fa buf
+argument points to an invalid memory address.
+.It Bq Er EIO
+Too many bytes were requested.
+.Sh SEE ALSO
+.Xr arc4random 3 ,
+.Xr rnd 4
+.Sh STANDARDS
+The
+.Fn getentropy
+function is non-standard.
+.Sh HISTORY
+The
+.Fn getentropy
+function first appeared in
+.Ox 5.6 ,
+then in
+.Fx 12.0 ,
+and
+.Nx 10 .
diff -r 7c1e8c06addb -r a85643634793 lib/libc/gen/getentropy.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/libc/gen/getentropy.c Wed May 06 16:17:36 2020 +0000
@@ -0,0 +1,64 @@
+/* $NetBSD: getentropy.c,v 1.1 2020/05/06 16:17:36 nia Exp $ */
+
+/*-
+ * Copyright (c) 2020 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Nia Alarie.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__RCSID("$NetBSD: getentropy.c,v 1.1 2020/05/06 16:17:36 nia Exp $");
+
+#include "namespace.h"
+
+#include <sys/param.h>
+#include <sys/sysctl.h>
+
+#include <errno.h>
+#include <unistd.h>
+
+#ifdef __weak_alias
+__weak_alias(getentropy,_getentropy)
+#endif
+
+int
+getentropy(void *buf, size_t buflen)
+{
+ size_t len = buflen;
+ int name[2] = { CTL_KERN, KERN_ARND };
+
+ if (buf == NULL && buflen > 0) {
+ errno = EFAULT;
+ return -1;
+ }
+
+ if (buflen > 256) {
+ errno = EIO;
+ return -1;
+ }
+
+ return sysctl(name, 2, buf, &len, NULL, 0);
+}
diff -r 7c1e8c06addb -r a85643634793 lib/libc/include/namespace.h
--- a/lib/libc/include/namespace.h Wed May 06 14:59:51 2020 +0000
+++ b/lib/libc/include/namespace.h Wed May 06 16:17:36 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: namespace.h,v 1.198 2020/04/18 23:55:50 thorpej Exp $ */
+/* $NetBSD: namespace.h,v 1.199 2020/05/06 16:17:36 nia Exp $ */
/*-
* Copyright (c) 1997-2004 The NetBSD Foundation, Inc.
@@ -362,6 +362,7 @@
#define getdevmajor _getdevmajor
#define getdiskbyname _getdiskbyname
#define getdomainname _getdomainname
+#define getentropy _getentropy
#define getfsent _getfsent
#define getfsfile _getfsfile
#define getfsspec _getfsspec
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