160 lines
4.3 KiB
Groff
160 lines
4.3 KiB
Groff
.\"
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.\" Copyright (c) 2012 The FreeBSD Foundation
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.\" All rights reserved.
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.\"
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.\" This documentation was written by Pawel Jakub Dawidek under sponsorship
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.\" the FreeBSD Foundation.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd March 6, 2015
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.Dt CAP_IOCTLS_LIMIT 2
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.Os
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.Sh NAME
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.Nm cap_ioctls_limit ,
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.Nm cap_ioctls_get
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.Nd manage allowed ioctl commands
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/capsicum.h
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.Ft int
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.Fn cap_ioctls_limit "int fd" "const unsigned long *cmds" "size_t ncmds"
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.Ft ssize_t
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.Fn cap_ioctls_get "int fd" "unsigned long *cmds" "size_t maxcmds"
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.Sh DESCRIPTION
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If a file descriptor is granted the
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.Dv CAP_IOCTL
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capability right, the list of allowed
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.Xr ioctl 2
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commands can be selectively reduced (but never expanded) with the
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.Fn cap_ioctls_limit
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system call.
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The
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.Fa cmds
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argument is an array of
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.Xr ioctl 2
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commands and the
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.Fa ncmds
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argument specifies the number of elements in the array.
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There can be up to
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.Va 256
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elements in the array.
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Including an element that has been previously revoked will generate an error.
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After a successful call only those listed in the array may be used.
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.Pp
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The list of allowed ioctl commands for a given file descriptor can be obtained
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with the
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.Fn cap_ioctls_get
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system call.
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The
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.Fa cmds
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argument points at memory that can hold up to
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.Fa maxcmds
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values.
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The function populates the provided buffer with up to
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.Fa maxcmds
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elements, but always returns the total number of ioctl commands allowed for the
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given file descriptor.
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The total number of ioctls commands for the given file descriptor can be
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obtained by passing
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.Dv NULL as the
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.Fa cmds
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argument and
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.Va 0
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as the
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.Fa maxcmds
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argument.
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If all ioctl commands are allowed
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.Dv ( CAP_IOCTL
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capability right is assigned to the file descriptor and the
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.Fn cap_ioctls_limit
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system call was never called for this file descriptor), the
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.Fn cap_ioctls_get
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system call will return
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.Dv CAP_IOCTLS_ALL
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and will not modify the buffer pointed to by the
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.Fa cmds
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argument.
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.Sh RETURN VALUES
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.Rv -std cap_ioctls_limit
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.Pp
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The
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.Fn cap_ioctls_get
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function, if successful, returns the total number of allowed ioctl commands or
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the value
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.Dv CAP_IOCTLS_ALL
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if all ioctls commands are allowed.
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On failure the value
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.Va -1
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is returned and the global variable errno is set to indicate the error.
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.Sh ERRORS
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.Fn cap_ioctls_limit
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succeeds unless:
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.Bl -tag -width Er
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.It Bq Er EBADF
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The
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.Fa fd
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argument is not a valid descriptor.
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.It Bq Er EFAULT
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The
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.Fa cmds
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argument points at an invalid address.
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.It Bq Er EINVAL
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The
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.Fa ncmds
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argument is greater than
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.Va 256 .
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.It Bq Er ENOTCAPABLE
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.Fa cmds
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would expand the list of allowed
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.Xr ioctl 2
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commands.
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.El
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.Pp
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.Fn cap_ioctls_get
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succeeds unless:
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.Bl -tag -width Er
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.It Bq Er EBADF
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The
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.Fa fd
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argument is not a valid descriptor.
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.It Bq Er EFAULT
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The
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.Fa cmds
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argument points at invalid address.
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.El
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.Sh SEE ALSO
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.Xr cap_fcntls_limit 2 ,
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.Xr cap_rights_limit 2 ,
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.Xr ioctl 2
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.Sh HISTORY
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Support for capabilities and capabilities mode was developed as part of the
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.Tn TrustedBSD
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Project.
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.Sh AUTHORS
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This function was created by
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.An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net
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under sponsorship of the FreeBSD Foundation.
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