Messages in this thread | | | Date | Mon, 5 Oct 2015 13:53:55 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] string: Improve the generic strlcpy() implementation |
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* Ingo Molnar <mingo@kernel.org> wrote:
> 2) > > Another problem is that strlcpy() will also happily do bad stuff if we pass > it a negative size. Instead of that we will from now on print a (one time) > warning and return safely.
Hm, so this check is buggy, as 'size_t' is unsigned - and for some reason GCC didn't warn about the never-met comparison and the resulting unreachable dead code here:
> + /* Overflow check: */ > + if (unlikely(dest_size < 0)) { > + WARN_ONCE(1, "strlcpy(): dest_size < 0 underflow!"); > + return strlen(src); > + }
which is annoying.
Would people object to something like:
> + /* Overflow check: */ > + if (unlikely((ssize_t)dest_size < 0)) { > + WARN_ONCE(1, "strlcpy(): dest_size < 0 underflow!"); > + return strlen(src); > + }
?
As I doubt it's legit to have larger than 2GB strings.
Also, I'm wondering why GCC didn't warn.
Thanks,
Ingo
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