Date: Fri, 19 Feb 2016 16:13:23 -0500 From: Daniel Micay <danielmicay@...il.com> To: oss-security@...ts.openwall.com Subject: Re: Address Sanitizer local root > As long as the aborts/faults happen at the earliest point where the > wrong program behavior can be detected, I see no way they are "more > painful to debug" than having ASan or similar introspectively print > crash info. Attaching a debugger should get you equally useful > information. The aborts and faults tend to happen later than the ASan detection would kick in though, other than the double-free case. For example, writes to freed memory only get detected when the junk data is validated later on (i.e. when an allocation is flushed from the FIFO quarantine), and it can be quite hard to debug from there. Use of freed memory often crashes right away with junk filling (pointer accesses) but it can end up causing subtler issues or crashes far away from the source. It's much easier to find the bugs than it would be without this, but if your goal is implementing hardening features, it's not very fun to need hundreds of fixes for use-after-frees across common software. It makes sense to go at it with ASan or Valgrind first to clear out the obvious problems and then worry about exploit mitigations. A surprising amount of software has all kinds of memory corruption in the *common* code paths. Download attachment "signature.asc" of type "application/pgp-signature" (820 bytes)
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