CObey: Freeing the stack you execute in... ends badly

by gerph 4 years ago

macOS ◆ xterm-256color ◆ fish 1176 views

With Fortify enabled, the CObey module exits with a prefetch abort. This recording has the block tracking enabled, so the execution leading up to the exception can be reported on. You can see that it’s running a memset (which is used by Fortify to clear the block when they’re freed), and then tries to return… and blows up when trying to execute at &a9a9a9a9.

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