Re: [Powertop] [PATCH v2 6/8] Stop buffer overflow

[Arjan van de Ven <arjan at linux.intel.com>]

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>>> yes, this is the reason behind this proposal. these patches a) don't check for
>>> overrun; b) don't handle overrun. they just shut up the compiler.
>>
>>
>> that's never a good tradeoff.
>> -D_FORTIFY_SOURCE-2 is an essential compiler feature that has a defined semantic/etc
>> patches that make behavior worse than that baseline, but shut up some warning, are damage
>> not value.
>>
>
> well, the macro handles overrun (should probably be snprintf(a, bsz - 1, ...) >= bsz)
> and replaces small part of the buffer with '...\0'. which is, imho, a bit better
> than `backtrace(); abort();' (I don't think we can benefit from compile-time checks
> of -D_FORTIFY_SOURCE=2, only run time ones) for developers that behaviour makes
> sense, for users it's just "seg fault/core dump/whatever"

well it's that or corruption....
the data is still truncated and partial.. and you keep running with it.

(this is why many people first think strlcpy is a good idea, and then they think more about it and realize it's not)