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Re: Networking Pearl Harbor in the Making
- From: Edward B. Dreger
- Date: Fri Nov 11 09:18:46 2005
RB> Date: Mon, 7 Nov 2005 14:43:54 -0600 (CST)
RB> From: Robert Bonomi
RB> Re-coding to eliminate all 'possible' buffer overflow situations is a *big*
RB> job. The required field-length checking for every multi-byte copy/move
RB> operation does have a significant negative impact on performance, as well.
Getting "owned" can also have a significant negative impact on
performance. Of course, maybe the attacker will be benevolent, so
perhaps all will be okay...
Correctness before speed. Who wants a machine that just gives bad
RB> Merely _identifying_ the 'tainted' (by being in contact -- directly or in-
RB> directly -- with 'user-supplied' data) data-structures is a task measured
RB> in man-years. As is isolating _all_ the points where such tainting occurs.
Sounds like a pretty good argument for "do it right the first time".
RB> Then, and only then, can you begin to -plan- how to remove the taint, whether
RB> by sanity-based bounds-checking, 'clipping' to known limits, explicit length
RB> checks, or whatever else is appropriate.
Hopefully the code is modular. e.g., running cscope and searching for
strcpy(3) invocations is easier than tracking down implemented-in-place
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