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Diffstat (limited to 'static/freebsd/man2/cap_rights_limit.2')
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diff --git a/static/freebsd/man2/cap_rights_limit.2 b/static/freebsd/man2/cap_rights_limit.2 new file mode 100644 index 00000000..8372d07f --- /dev/null +++ b/static/freebsd/man2/cap_rights_limit.2 @@ -0,0 +1,164 @@ +.\" +.\" Copyright (c) 2008-2010 Robert N. M. Watson +.\" Copyright (c) 2012-2013 The FreeBSD Foundation +.\" All rights reserved. +.\" +.\" This software was developed at the University of Cambridge Computer +.\" Laboratory with support from a grant from Google, Inc. +.\" +.\" Portions of this documentation were written by Pawel Jakub Dawidek +.\" under sponsorship from the FreeBSD Foundation. +.\" +.\" 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 AUTHOR 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 AUTHOR 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 April 27, 2024 +.Dt CAP_RIGHTS_LIMIT 2 +.Os +.Sh NAME +.Nm cap_rights_limit +.Nd limit capability rights +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In sys/capsicum.h +.Ft int +.Fn cap_rights_limit "int fd" "const cap_rights_t *rights" +.Sh DESCRIPTION +When a file descriptor is created by a function such as +.Xr fhopen 2 , +.Xr kqueue 2 , +.Xr mq_open 2 , +.Xr open 2 , +.Xr pdfork 2 , +.Xr pipe 2 , +.Xr shm_open 2 , +.Xr socket 2 +or +.Xr socketpair 2 , +it is assigned all capability rights; for +.Xr accept 2 , +.Xr accept4 2 +or +.Xr openat 2 , +it inherits capability rights from the "parent" file descriptor. +Those rights can be reduced (but never expanded) by using the +.Fn cap_rights_limit +system call. +Once capability rights are reduced, operations on the file descriptor will be +limited to those permitted by +.Fa rights . +.Pp +The +.Fa rights +argument should be prepared using +.Xr cap_rights_init 3 +family of functions. +.Pp +Capability rights assigned to a file descriptor can be obtained with the +.Xr cap_rights_get 3 +function. +.Pp +The complete list of the capability rights can be found in the +.Xr rights 4 +manual page. +.Sh RETURN VALUES +.Rv -std +.Sh EXAMPLES +The following example demonstrates how to limit file descriptor capability +rights to allow reading only. +.Bd -literal +cap_rights_t setrights; +char buf[1]; +int fd; + +fd = open("/tmp/foo", O_RDWR); +if (fd < 0) + err(1, "open() failed"); + +if (cap_enter() < 0) + err(1, "cap_enter() failed"); + +cap_rights_init(&setrights, CAP_READ); +if (cap_rights_limit(fd, &setrights) < 0) + err(1, "cap_rights_limit() failed"); + +buf[0] = 'X'; + +if (write(fd, buf, sizeof(buf)) > 0) + errx(1, "write() succeeded!"); + +if (read(fd, buf, sizeof(buf)) < 0) + err(1, "read() failed"); +.Ed +.Sh ERRORS +.Fn cap_rights_limit +succeeds unless: +.Bl -tag -width Er +.It Bq Er EBADF +The +.Fa fd +argument is not a valid active descriptor. +.It Bq Er EINVAL +An invalid right has been requested in +.Fa rights . +.It Bq Er ENOSYS +The running kernel was compiled without +.Cd "options CAPABILITY_MODE" . +.It Bq Er ENOTCAPABLE +The +.Fa rights +argument contains capability rights not present for the given file descriptor. +Capability rights list can only be reduced, never expanded. +.El +.Sh SEE ALSO +.Xr accept 2 , +.Xr accept4 2 , +.Xr cap_enter 2 , +.Xr fhopen 2 , +.Xr kqueue 2 , +.Xr mq_open 2 , +.Xr open 2 , +.Xr openat 2 , +.Xr pdfork 2 , +.Xr pipe 2 , +.Xr read 2 , +.Xr shm_open 2 , +.Xr socket 2 , +.Xr socketpair 2 , +.Xr write 2 , +.Xr cap_rights_get 3 , +.Xr cap_rights_init 3 , +.Xr err 3 , +.Xr capsicum 4 , +.Xr rights 4 +.Sh HISTORY +The +.Fn cap_rights_limit +function first appeared in +.Fx 8.3 . +Support for capabilities and capabilities mode was developed as part of the +.Tn TrustedBSD +Project. +.Sh AUTHORS +This function was created by +.An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net +under sponsorship of the FreeBSD Foundation. |