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Bryan Steele @canadianbryan

Interesting technique by Todd Mortimer to reduce the number of gadgets on x86 even further: marc.info/?l=openbsd-tech&m=15

Bryan Steele @canadianbryan

Nice! Todd Mortimer has committed his patch for into -current.

"This change removes about 3% of total gadgets from the kernel, but about 6% of unique gadgets."

marc.info/?l=openbsd-cvs&m=151

Bryan Steele @canadianbryan

Follow-up x86 "ROP friendly" gadget reduction framework for , which can be extended. Impressive work by Todd Mortimer! 😎 marc.info/?l=openbsd-cvs&m=152

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Bryan Steele @canadianbryan

Todd Mortimer just landed his mitigation work (aka -fret-protector) into -current, and enabled by default.

marc.info/?l=openbsd-cvs&m=152

Bryan Steele @canadianbryan

"In this way RETGUARD is an improved stack protector, since the cookies are per-function."

"In the kernel, this has the effect of removing approximately 50% of total gadgets, and 15% of unique ROP gadgets compared to the 6.3 release kernel."

😎

Bryan Steele @canadianbryan

.

Bryan Steele @canadianbryan

This uses OpenBSD's random-data memory feature, which was used by the stack protector to provide per shared object cookies.

cvsweb.openbsd.org/cgi-bin/cvs
openbsd.org/innovations.html

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