1.\" Copyright (c) 2016 Mariusz Zaborski <oshogbo@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.Dd May 16, 2024 26.Dt CAPSICUM_HELPERS 3 27.Os 28.Sh NAME 29.Nm caph_limit_stream , 30.Nm caph_limit_stdin , 31.Nm caph_limit_stderr , 32.Nm caph_limit_stdout , 33.Nm caph_limit_stdio , 34.Nm caph_stream_rights , 35.Nm caph_cache_tzdata , 36.Nm caph_cache_catpages , 37.Nm caph_enter , 38.Nm caph_enter_casper , 39.Nm caph_rights_limit , 40.Nm caph_ioctls_limit , 41.Nm caph_fcntls_limit 42.Nd "set of the capsicum helpers, part of the libcapsicum" 43.Sh LIBRARY 44.Lb libcapsicum 45.Sh SYNOPSIS 46.In capsicum_helpers.h 47.Ft int 48.Fn caph_enter "void" 49.Ft int 50.Fn caph_enter_casper "void" 51.Ft int 52.Fn caph_rights_limit "int fd" "const cap_rights_t *rights" 53.Ft int 54.Fn caph_ioctls_limit "int fd" "const unsigned long *cmds" "size_t ncmds" 55.Ft int 56.Fn caph_fcntls_limit "int fd" "uint32_t fcntlrights" 57.Ft int 58.Fn caph_limit_stream "int fd" "int flags" 59.Ft int 60.Fn caph_limit_stdin "void" 61.Ft int 62.Fn caph_limit_stderr "void" 63.Ft int 64.Fn caph_limit_stdout "void" 65.Ft int 66.Fn caph_limit_stdio "void" 67.Ft void 68.Fn caph_stream_rights "cap_rights_t *" "int flags" 69.Ft void 70.Fn caph_cache_tzdata "void" 71.Ft void 72.Fn caph_cache_catpages "void" 73.Sh DESCRIPTION 74The 75.Nm caph_enter , 76.Nm caph_rights_limit , 77.Nm caph_ioctls_limit 78and 79.Nm caph_fcntls_limit 80are respectively equivalent to 81.Xr cap_enter 2 , 82.Xr cap_rights_limit 2 , 83.Xr cap_ioctls_limit 2 84and 85.Xr cap_fcntls_limit 2 , 86it returns success when the kernel is built without support of the capability 87mode. 88.Pp 89The 90.Nm caph_enter_casper 91is equivalent to the 92.Nm caph_enter 93it returns success when the system is built without Casper support. 94.Pp 95The 96.Nm capsicum helpers 97are a set of a inline functions which simplify modifying programs to use 98Capsicum. 99The goal is to reduce duplicated code patterns. 100The 101.Nm capsicum helpers 102are part of 103.Nm libcapsicum 104but there is no need to link to the library. 105.Pp 106.Fn caph_limit_stream 107restricts capabilities on 108.Fa fd 109to only those needed by POSIX stream objects (that is, FILEs). 110.Pp 111These flags can be provided: 112.Pp 113.Bl -tag -width "CAPH_IGNORE_EBADF" -compact -offset indent 114.It Dv CAPH_IGNORE_EBADF 115Do not return an error if file descriptor is invalid. 116.It Dv CAPH_READ 117Set CAP_READ on limited descriptor. 118.It Dv CAPH_WRITE 119Set CAP_WRITE on limited descriptor. 120.El 121.Pp 122.Fn caph_limit_stdin , 123.Fn caph_limit_stderr 124and 125.Fn caph_limit_stdout 126limit standard descriptors using the 127.Nm caph_limit_stream 128function. 129.Pp 130.Fn caph_limit_stdio 131limits stdin, stderr and stdout. 132.Pp 133.Nm caph_stream_rights 134may be used to initialize 135.Fa rights 136with the same rights that a stream would be limited to, as if 137.Fn caph_limit_stream 138had been invoked using the same 139.Fa flags . 140.Pp 141.Fn caph_cache_tzdata 142precaches all timezone data needed to use 143.Li libc 144local time functions. 145.Pp 146.Fn caph_cache_catpages 147caches Native Language Support (NLS) data. 148NLS data is used for localized error printing by 149.Xr strerror 3 150and 151.Xr err 3 , 152among others. 153.Sh RETURN VALUES 154Upon successful completion, 155.Fn caph_enter , 156.Fn caph_enter_casper , 157.Fn caph_rights_limit , 158.Fn caph_ioctls_limit , 159.Fn caph_fcntls_limit , 160.Fn caph_limit_stream , 161.Fn caph_limit_stdin , 162.Fn caph_limit_stderr , 163.Fn caph_limit_stdout , 164and 165.Fn caph_limit_stdio 166return a value 167of 0. 168Otherwise, a value of -1 is returned and the global variable 169.Va errno 170is set to indicate the error. 171.Pp 172Functions 173.Fn caph_stream_rights , 174.Fn caph_cache_tzdata , 175and 176.Fn caph_cache_catpages 177can not fail. 178.Ed 179.Sh SEE ALSO 180.Xr cap_enter 2 , 181.Xr cap_rights_limit 2 , 182.Xr rights 4 183