Bash gets shellshocked [LWN.net]

Bash gets shellshocked

Posted Oct 2, 2014 7:50 UTC (Thu) by andreashappe (subscriber, #4810)
Parent article: Bash gets shellshocked

Just a question: is systemd providing more security w.r.t. to shell-scripts within startup? From my (very naiive) understanding it would replace lots of shell scripts with ``declarative'' configuration files -- so resetting or checking the environment might be easier?

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Bash gets shellshocked

Posted Oct 2, 2014 8:56 UTC (Thu) by dtlin (subscriber, #36537) [Link]

I don't know whether security was among the motivations, but the systemd suite consistently avoids shelling out. Everything is done by stuff like libraries in-process, D-Bus calls, or direct exec of another binary; I believe it's possible to boot a system without /bin/sh at all? Also systemd launches everything with a clean environment.

Commands specified in unit files (e.g. ExecStart=...) just get word-splitting and some substitutions made, no shell processing. I believe the same is true for udev rules and RUN+="..." but it seems a little more complex.

In practical terms, most of these things probably aren't attackable, with the exception of systemd-networkd whose developer got to boast a bit noting that its in-process DHCP client is unaffected Shellshock (unlike dhclient and dhcpcd).