1 .\" Copyright (c) 2013 The FreeBSD Foundation
2 .\" All rights reserved.
4 .\" This documentation was written by Pawel Jakub Dawidek under sponsorship
5 .\" from the FreeBSD Foundation.
7 .\" Redistribution and use in source and binary forms, with or without
8 .\" modification, are permitted provided that the following conditions
10 .\" 1. Redistributions of source code must retain the above copyright
11 .\" notice, this list of conditions and the following disclaimer.
12 .\" 2. Redistributions in binary form must reproduce the above copyright
13 .\" notice, this list of conditions and the following disclaimer in the
14 .\" documentation and/or other materials provided with the distribution.
16 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46 .Nd "library for handling application capabilities"
55 .Fn cap_wrap "int sock"
57 .Fn cap_unwrap "cap_channel_t *chan"
59 .Fn cap_sock "const cap_channel_t *chan"
61 .Fn cap_clone "const cap_channel_t *chan"
63 .Fn cap_close "cap_channel_t *chan"
65 .Fn cap_limit_get "const cap_channel_t *chan" "nvlist_t **limitsp"
67 .Fn cap_limit_set "const cap_channel_t *chan" "nvlist_t *limits"
69 .Fn cap_send_nvlist "const cap_channel_t *chan" "const nvlist_t *nvl"
71 .Fn cap_recv_nvlist "const cap_channel_t *chan" "int flags"
73 .Fn cap_xfer_nvlist "const cap_channel_t *chan" "nvlist_t *nvl" "int flags"
75 .Fn cap_service_open "const cap_channel_t *chan" "const char *name"
79 library allows to manage application capabilities through the casper process.
81 The application capability (represented by the
83 type) is a communication channel between the caller and the casper process
84 daemon or an instance of one of its services.
85 A capability to the casper process obtained with the
87 function allows to create capabilities to casper's services via the
93 function opens capability to the casper process.
99 based on the given socket.
100 The function is used when capability is inherited through
104 domain socket as a regular file descriptor and has to be represented as
110 function is the opposite of the
115 structure and returns
117 domain socket associated with it.
121 function clones the given capability.
125 function closes the given capability.
131 domain socket descriptor associated with the given capability for use with
140 function stores current limits of the given capability in the
143 If the function return
149 it means there are no limits set.
153 function sets limits for the given capability.
154 The limits are provided as nvlist.
155 The exact format depends on the service the capability represents.
159 function sends the given nvlist over the given capability.
160 This is low level interface to communicate with casper services.
161 Most services should provide higher level API.
165 function receives the given nvlist over the given capability.
168 argument defines what type the top nvlist is expected to be.
169 If the nvlist flags do not match the flags passed to
170 .Fn cap_recv_nvlist ,
171 the nvlist will not be returned.
175 function sends the given nvlist, destroys it and receives new nvlist in
176 response over the given capability.
179 argument defines what type the top nvlist is expected to be.
180 If the nvlist flags do not match the flags passed to
181 .Fn cap_xfer_nvlist ,
182 the nvlist will not be returned.
183 It does not matter if the function succeeds or fails, the nvlist given
184 for sending will always be destroyed once the function returns.
188 function opens casper service of the given name through casper capability
192 The function returns capability that provides access to opened service.
197 .Fn cap_recv_nvlist ,
198 .Fn cap_service_open ,
224 functions always succeed.
226 The following example first opens capability to the casper then using this
227 capability creates new capability to the
229 casper service and uses the latter capability to resolve IP address.
231 cap_channel_t *capcas, *capdns;
233 const char *ipstr = "127.0.0.1";
237 /* Open capability to the Casper. */
240 err(1, "Unable to contact Casper");
242 /* Enter capability mode sandbox. */
243 if (cap_enter() < 0 && errno != ENOSYS)
244 err(1, "Unable to enter capability mode");
246 /* Use Casper capability to create capability to the system.dns service. */
247 capdns = cap_service_open(capcas, "system.dns");
249 err(1, "Unable to open system.dns service");
251 /* Close Casper capability, we don't need it anymore. */
254 /* Limit system.dns to reverse DNS lookups and IPv4 addresses. */
255 limits = nvlist_create(0);
256 nvlist_add_string(limits, "type", "ADDR");
257 nvlist_add_number(limits, "family", (uint64_t)AF_INET);
258 if (cap_limit_set(capdns, limits) < 0)
259 err(1, "Unable to limit access to the system.dns service");
261 /* Convert IP address in C-string to in_addr. */
262 if (!inet_aton(ipstr, &ip))
263 errx(1, "Unable to parse IP address %s.", ipstr);
265 /* Find hostname for the given IP address. */
266 hp = cap_gethostbyaddr(capdns, (const void *)&ip, sizeof(ip), AF_INET);
268 errx(1, "No name associated with %s.", ipstr);
270 printf("Name associated with %s is %s.\\n", ipstr, hp->h_name);
278 .Xr cap_gethostbyaddr 3 ,
280 .Xr gethostbyaddr 3 ,
288 library was implemented by
289 .An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net
290 under sponsorship from the FreeBSD Foundation.
293 new architecture was implemented by
294 .An Mariusz Zaborski Aq Mt oshogbo@FreeBSD.org