1.\" $NetBSD: paxctl.8,v 1.22 2023/08/21 00:41:49 dholland Exp $ 2.\" 3.\" Copyright 2006 Elad Efrat <elad@NetBSD.org> 4.\" Copyright 2008 Christos Zoulas <christos@NetBSD.org> 5.\" All rights reserved. 6.\" 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.\" 3. The name of the author may not be used to endorse or promote products 13.\" derived from this software without specific prior written permission. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" 26.Dd August 20, 2023 27.Dt PAXCTL 8 28.Os 29.Sh NAME 30.Nm paxctl 31.Nd list and modify PaX flags associated with an ELF program 32.Sh SYNOPSIS 33.Nm 34.Op Fl 0 | Ar flags 35.Ar program ... 36.Sh DESCRIPTION 37The 38.Nm 39utility is used to list and manipulate PaX flags associated with an ELF 40program. 41The PaX flags signify to the loader the privilege protections to be applied 42to mapped memory pages, and fuller explanations of the specific protections 43can be found in the 44.Xr security 7 45manpage. 46.Pp 47To view existing flags on a 48.Ar program , 49execute 50.Nm 51without any flags. 52.Pp 53If 54.Fl 0 55option is specified, all PaX flags 56.Pq including reserved bits 57are cleared. 58Otherwise, each flag can be prefixed either with a 59.Sq Cm + 60or a 61.Sq Fl 62sign to add or remove the flag, respectively. 63.Pp 64The following flags are available: 65.Pp 66.Bl -tag -width Ds -compact 67.It Cm a 68Explicitly disable PaX ASLR (Address Space Layout Randomization). 69.It Cm A 70Explicitly enable PaX ASLR. 71.Pp 72.It Cm g 73Explicitly disable PaX Segvguard. 74.It Cm G 75Explicitly enable PaX Segvguard. 76.Pp 77.It Cm m 78Explicitly disable PaX MPROTECT 79.Po Xr mprotect 2 80restrictions 81.Pc . 82.It Cm M 83Explicitly enable PaX MPROTECT. 84.El 85. 86.Sh SEE ALSO 87.Xr mprotect 2 , 88.Xr sysctl 3 , 89.Xr options 4 , 90.Xr elf 5 , 91.Xr security 7 , 92.Xr sysctl 8 , 93.Xr fileassoc 9 94.Sh HISTORY 95The 96.Nm 97utility first appeared in 98.Nx 4.0 . 99.Pp 100The 101.Nm 102utility is modeled after a tool of the same name available for Linux from the 103PaX project. 104.Sh AUTHORS 105.An Elad Efrat Aq Mt elad@NetBSD.org 106.An Christos Zoulas Aq Mt christos@NetBSD.org 107.Sh RESTRICTIONS 108The 109.Nm 110utility uses 111.Xr elf 5 112note sections to mark executables with PaX flags. 113This means that, as one might expect, the PaX settings do not persist 114if the program file is replaced. 115It also means that running 116.Nm 117changes the target executable, which can be undesirable in production. 118In general, 119.Nm 120settings should be applied to programs at build time. 121