NAME
syd-mdwe - Run a program under Memory-Deny-Write-Execute protections
SYNOPSIS
syd-mdwe [-hms] {command [args...]}
DESCRIPTION
syd-mdwe utility runs a program under Memory-Deny-Write-Execute (MDWE) protections. The protections can be applied using prctl(2) and seccomp(2), These protections are identical to what Syd applies by default.
OPTIONS
| -h | Display help. |
| -m | Enable MDWE protections using prctl(2) PR_SET_MDWE (default: both). |
| -s | Enable MDWE protections using seccomp(2) (default: both). |
EXAMPLES
Running pax-test once standalone and once under syd-mdwe(1) on a 6.8 kernel we get the following differences:
| PaX Testcase | standalone | mdwe |
| Executable anonymous mapping | Killed | Killed |
| Executable bss | Killed | Killed |
| Executable data | Killed | Killed |
| Executable heap | Killed | Killed |
| Executable stack | Killed | Killed |
| Executable shared library bss | Killed | Killed |
| Executable shared library data | Killed | Killed |
| Executable anonymous mapping (mprotect) | Vulnerable | Killed |
| Executable bss (mprotect) | Vulnerable | Killed |
| Executable data (mprotect) | Vulnerable | Killed |
| Executable heap (mprotect) | Vulnerable | Killed |
| Executable stack (mprotect) | Vulnerable | Killed |
| Executable shared library bss (mprotect) | Vulnerable | Killed |
| Executable shared library data (mprotect): | Vulnerable | Killed |
| Writable text segments | Vulnerable | Killed |
The test was performed with paxtest-0.9.15:
PaXtest - Copyright(c) 2003-2016 by Peter Busser <[email protected]> and Brad Spengler <[email protected]> Released under the GNU Public Licence version 2 or later Mode: 1 Blackhat Kernel: Linux syd 6.8.0-syd-13213-g70293240c5ce #9 SMP PREEMPT_DYNAMIC Mon Mar 25 04:40:47 CET 2024 x86_64 GNU/Linux
EXIT STATUS
On clean exit, syd-mdwe exits with the same code as the child process. On unclean termination, exit code is set to 128 plus signal number. In case executing the child process fails syd-mdwe exits with the errno(3) number.
CAVEATS
By default, prctl(2) error setting PR_SET_MDWE(2const) is not fatal. Use the -m option to make this error fatal. This utility does not work on MIPS architectures where Linux requires executable stack.
SEE ALSO
syd(1), syd(2), syd(5), syd-lock(1), syd-ofd(1), syd-pds(1), syd-ring(1), syd-sec(1), syd-tsc(1), seccomp(2), prctl(2), PR_SET_MDWE(2const)
syd homepage: https://sydbox.exherbo.org/
AUTHORS
Maintained by Ali Polatel. Up-to-date sources can be found at https://gitlab.exherbo.org/sydbox/sydbox.git and on Radicle at rad:z38HCnbmcDegA2BMxuPaPRPMdp6wF. Bugs/patches can be submitted to https://gitlab.exherbo.org/groups/sydbox/-/issues. Discuss in #sydbox on Libera Chat or in #sydbox:mailstation.de on Matrix.