Date: Sat, 27 Jan 2018 22:49:34 +0000 (UTC) From: Mariusz Zaborski <oshogbo@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r328494 - head/lib/libcasper/services/cap_random Message-ID: <201801272249.w0RMnYdL072408@repo.freebsd.org>
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Author: oshogbo Date: Sat Jan 27 22:49:34 2018 New Revision: 328494 URL: https://svnweb.freebsd.org/changeset/base/328494 Log: Document the random Casper service. Reviewed by: bcr@ Differential Revision: https://reviews.freebsd.org/D14072 Added: head/lib/libcasper/services/cap_random/cap_random.3 (contents, props changed) Added: head/lib/libcasper/services/cap_random/cap_random.3 ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/lib/libcasper/services/cap_random/cap_random.3 Sat Jan 27 22:49:34 2018 (r328494) @@ -0,0 +1,98 @@ +.\" Copyright (c) 2018 Mariusz Zaborski <oshogbo@FreeBSD.org> +.\" All rights reserved. +.\" +.\" 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 AUTHORS 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 AUTHORS 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. +.\" +.\" $FreeBSD$ +.\" +.Dd January 27, 2018 +.Dt CAP_RANDOM 3 +.Os +.Sh NAME +.Nm cap_random_buf +.Nd "library for getting entropy in capability mode" +.Sh LIBRARY +.Lb libcap_random +.Sh SYNOPSIS +.In sys/nv.h +.In libcasper.h +.In casper/cap_random.h +.Ft "int" +.Fn cap_random_buf "cap_channel_t *chan" "void *buf" "size_t nbytes" +.Sh DESCRIPTION +The function +.Fn cap_random_buf +is equivalent to +.Xr arc4random_buf 3 +except that the connection to the +.Nm system.random +service needs to be provided. +.Sh EXAMPLES +The following example first opens a capability to casper and then uses this +capability to create the +.Nm system.random +casper service to obtain entropy. +.Bd -literal +cap_channel_t *capcas, *caprandom; +unsigned char buf[16]; +int i; + +/* Open capability to Casper. */ +capcas = cap_init(); +if (capcas == NULL) + err(1, "Unable to contact Casper"); + +/* Enter capability mode sandbox. */ +if (cap_enter() < 0 && errno != ENOSYS) + err(1, "Unable to enter capability mode"); + +/* Use Casper capability to create capability to the system.random service. */ +caprandom = cap_service_open(capcas, "system.random"); +if (caprandom == NULL) + err(1, "Unable to open system.random service"); + +/* Close Casper capability, we don't need it anymore. */ +cap_close(capcas); + +/* Obtain entropy. */ +if (cap_random_buf(caprandom, buf, sizeof(buf)) < 0) + err(1, "Unable to obtain entropy"); + +for (i = 0; i < sizeof(buf); i++) + printf("%.2x ", buf[i]); +printf("\\n"); +.Ed +.Sh SEE ALSO +.Xr cap_enter 2 , +.Xr arc4random_buf 3 , +.Xr err 3 , +.Xr nv 3 , +.Xr capsicum 4 +.Sh AUTHORS +The +.Nm cap_random +service was implemented by +.An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net +under sponsorship from the FreeBSD Foundation. +.Pp +This manual page was written by +.An Mariusz Zaborski Aq Mt oshogbo@FreeBSD.org .
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