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All pages All categories Search Index Introduction Explanation Shuffling .o files Shuffle the planet! A perfect task for Gentoo Patch every Makefile? shuffleld: A wrapper script for gcc Experiment and Analysis Conclusion Appendix: Gentoo environment 2023-01-26 Recently, I stumbled upon a OpenBSD effort that attempts to make it harder to perform a ROP-based exploitaiton against sshd: sshd random relinking at boot It comes down to this line in the Makefile: cc -o sshd `echo ${OBJS} | tr ' ' '\n' | sort -R` ${LDADD} The essence of the idea is to simply pass the .o files in a random order to the linker. Their order inside the sshd binary won't be predictable. On reboot, OpenBSD relinks the binary. This ensures that it'll differ between OpenBSD installations and thus, offsets for ROP gadgets will vary too. The idea is that this has the potential to make an attackers life harder,...

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