Being Sneaky in C

Re:Being Sneaky in C by kazinator on Friday June 12, 2015 @03:02PM (#9707892)

If your claim is that OpenBSD routes every call to malloc/free through mmap/munmap, it is simply not believable.

Do you have a URL to a git ... hahaha, pardon me, CVS repo?

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Re:Being Sneaky in C by marios on Friday June 12, 2015 @03:16PM (#9707967)

http://bxr.su/OpenBSD/lib/libc/stdlib/malloc.c#omalloc ^Not the CVS repo, but close enough for those who want to check OpenBSD's malloc implementation. The malloc.conf manpage is also an interesting read : http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man5/...

And some context around malloc and the various techniques OpenBSD implements to make exploitation of bugs more difficult: http://www.openbsd.org/papers/dev-sw-hostile-env.html

The tl;dr is : if your code compiles and runs on OpenBSD, chances are it will fine on other Unices. The opposite is not necessarily true though.

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Re:Being Sneaky in C by comex on Friday June 12, 2015 @04:08PM (#9708220)

I don't think that source refutes the parent's point: only large allocations go directly to mmap/munmap as opposed to being cached. Of course, there are other anti-exploitation measures too...

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Re:Being Sneaky in C by icebraining on Friday June 12, 2015 @03:18PM (#9707976)

Here's the CVS repo: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/lib/libc/stdlib...

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Re:Being Sneaky in C by kayamon on Friday June 12, 2015 @03:05PM (#9707916)

Well you could read the paper he just linked to.

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