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 May 5, 2020 .Dt CAP_SYSCTL 3 .Os .Sh NAME .Nm cap_sysctlbyname .Nd "library for getting or setting system information in capability mode" .Sh LIBRARY .Lb libcap_sysctl .Sh SYNOPSIS n sys/nv.h n libcasper.h n casper/cap_sysctl.h .Ft int .Fn cap_sysctlbyname "cap_channel_t *chan" " const char *name" " void *oldp" " size_t *oldlenp" " const void *newp" " size_t newlen" .Sh DESCRIPTION The function .Fn cap_sysctlbyname is equivalent to .Xr sysctlbyname 3 except that the connection to the .Nm system.sysctl service needs to be provided. .Sh LIMITS The service can be limited using .Xr cap_limit_set 3 function. The .Xr nvlist 9 for that function can contain the following values and types: l -ohang -offset indent t ( NV_TYPE_NUMBER ) The name of the element with type number will be treated as the limited sysctl. The value of the element will describe the access rights for given sysctl. There are four different rights .Dv CAP_SYSCTL_READ , .Dv CAP_SYSCTL_WRITE , .Dv CAP_SYSCTL_RDWR , and .Dv CAP_SYSCTL_RECURSIVE . The .Dv CAP_SYSCTL_READ flag allows to fetch the value of a given sysctl. The .Dv CAP_SYSCTL_WIRTE flag allows to override the value of a given sysctl. The .Dv CAP_SYSCTL_RDWR is combination of the .Dv CAP_SYSCTL_WIRTE and .Dv CAP_SYSCTL_READ and allows to read and write the value of a given sysctl. The .Dv CAP_SYSCTL_RECURSIVE allows access to all children of a given sysctl. This right must be combined with at least one other right. .Sh EXAMPLES The following example first opens a capability to casper and then uses this capability to create the .Nm system.sysctl casper service and uses it to get the value of .Dv kern.trap_enotcap . d -literal cap_channel_t *capcas, *capsysctl; const char *name = "kern.trap_enotcap"; nvlist_t *limits; int value; size_t size; /* 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.sysctl service. */ capsysctl = cap_service_open(capcas, "system.sysctl"); if (capsysctl == NULL) err(1, "Unable to open system.sysctl service"); /* Close Casper capability, we don't need it anymore. */ cap_close(capcas); /* Create limit for one MIB with read access only. */ limits = nvlist_create(0); nvlist_add_number(limits, name, CAP_SYSCTL_READ); /* Limit system.sysctl. */ if (cap_limit_set(capsysctl, limits) < 0) err(1, "Unable to set limits"); /* Fetch value. */ if (cap_sysctlbyname(capsysctl, name, &value, &size, NULL, 0) < 0) err(1, "Unable to get value of sysctl"); printf("The value of %s is %d.\\n", name, value); cap_close(capsysctl); .Ed .Sh SEE ALSO .Xr cap_enter 2 , .Xr err 3 , .Xr sysctlbyname 3 , .Xr capsicum 4 , .Xr nv 9 .Sh HISTORY The .Nm cap_sysctl service first appeared in .Fx 10.3 . .Sh AUTHORS The .Nm cap_sysctl service was implemented by .An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net under sponsorship from the FreeBSD Foundation.
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 May 5, 2020 .Dt CAP_SYSCTL 3 .Os .Sh NAME .Nm cap_sysctlbyname .Nd "library for getting or setting system information in capability mode" .Sh LIBRARY .Lb libcap_sysctl .Sh SYNOPSIS n sys/nv.h n libcasper.h n casper/cap_sysctl.h .Ft int .Fn cap_sysctlbyname "cap_channel_t *chan" " const char *name" " void *oldp" " size_t *oldlenp" " const void *newp" " size_t newlen" .Sh DESCRIPTION The function .Fn cap_sysctlbyname is equivalent to .Xr sysctlbyname 3 except that the connection to the .Nm system.sysctl service needs to be provided. .Sh LIMITS The service can be limited using .Xr cap_limit_set 3 function. The .Xr nvlist 9 for that function can contain the following values and types: l -ohang -offset indent t ( NV_TYPE_NUMBER ) The name of the element with type number will be treated as the limited sysctl. The value of the element will describe the access rights for given sysctl. There are four different rights .Dv CAP_SYSCTL_READ , .Dv CAP_SYSCTL_WRITE , .Dv CAP_SYSCTL_RDWR , and .Dv CAP_SYSCTL_RECURSIVE . The .Dv CAP_SYSCTL_READ flag allows to fetch the value of a given sysctl. The .Dv CAP_SYSCTL_WIRTE flag allows to override the value of a given sysctl. The .Dv CAP_SYSCTL_RDWR is combination of the .Dv CAP_SYSCTL_WIRTE and .Dv CAP_SYSCTL_READ and allows to read and write the value of a given sysctl. The .Dv CAP_SYSCTL_RECURSIVE allows access to all children of a given sysctl. This right must be combined with at least one other right. .Sh EXAMPLES The following example first opens a capability to casper and then uses this capability to create the .Nm system.sysctl casper service and uses it to get the value of .Dv kern.trap_enotcap . d -literal cap_channel_t *capcas, *capsysctl; const char *name = "kern.trap_enotcap"; nvlist_t *limits; int value; size_t size; /* 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.sysctl service. */ capsysctl = cap_service_open(capcas, "system.sysctl"); if (capsysctl == NULL) err(1, "Unable to open system.sysctl service"); /* Close Casper capability, we don't need it anymore. */ cap_close(capcas); /* Create limit for one MIB with read access only. */ limits = nvlist_create(0); nvlist_add_number(limits, name, CAP_SYSCTL_READ); /* Limit system.sysctl. */ if (cap_limit_set(capsysctl, limits) < 0) err(1, "Unable to set limits"); /* Fetch value. */ if (cap_sysctlbyname(capsysctl, name, &value, &size, NULL, 0) < 0) err(1, "Unable to get value of sysctl"); printf("The value of %s is %d.\\n", name, value); cap_close(capsysctl); .Ed .Sh SEE ALSO .Xr cap_enter 2 , .Xr err 3 , .Xr sysctlbyname 3 , .Xr capsicum 4 , .Xr nv 9 .Sh HISTORY The .Nm cap_sysctl service first appeared in .Fx 10.3 . .Sh AUTHORS The .Nm cap_sysctl service was implemented by .An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net under sponsorship from the FreeBSD Foundation.
p This manual page was written by .An Mariusz Zaborski Aq Mt oshogbo@FreeBSD.org .