Re: Buffer overflows

"Reece Dunn" [off-list ref] writes:

Why is it easier? If you have a fixed-size buffer, why not use
strncpy, which is what a safe string API is essentially doing anyway?

I would not claim unchecked strcpy is good -- we obviously would
want to fix them.

But at the same time use of strncpy, strlcpy and friends solves
only half of the problem.  Often people say "use strncpy or
strlcpy then you would not overstep the buffer", but that does
not really solve anything, without additional logic to deal with
resulting truncation (barfing with "insanely long string" error
message and dying is the least impact).  Continuing the work on
data that the user did not intend to give you is just as wrong
as using corrupt data that overflowed your static buffer.

Does Timo's nonstandard API solve that issue?  Perhaps it does,
perhaps not.  Does it make easier to maintain our code?  I
highly doubt it in the current shape.

It is well and widely understood idiom to use strlcpy to a
fixed-sized buffer and checking the resulting length to make
sure the result would not have overflowed (and if it would have,
issue an error and die).  I would not have anything against a
set of patches to follow such a pattern.

But a patch to add a non-standard API that nobody else uses,
without any patch to show the changes to a few places that could
use the API to demonstrate that the use of API vastly cleans the
code up and makes it infinitely harder to make mistakes?

The API needs to justify itself to convince the people who needs
to learn and adjust to that the benefit far outweighes deviation
from better known patterns, and I do not see that happening in
Timo's patch.