Messages in this thread | | | From | Rickard Strandqvist <> | Date | Thu, 16 Oct 2014 23:28:59 +0200 | Subject | Re: [PATCH v2] lib: string.c: Added a funktion function strzcpy |
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2014-10-16 23:17 GMT+02:00 Andrew Morton <akpm@linux-foundation.org>: > On Thu, 16 Oct 2014 23:09:00 +0200 Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se> wrote: > >> 2014-10-16 0:15 GMT+02:00 Andrew Morton <akpm@linux-foundation.org>: >> > On Sun, 5 Oct 2014 15:06:17 +0200 Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se> wrote: >> > >> >> Added a function strzcpy which works the same as strncpy, >> >> but guaranteed to produce the trailing null character. >> >> >> >> There are many places in the code where strncpy used although it >> >> must be zero terminated, and switching to strlcpy is not an option >> >> because the string must nonetheless be fyld with zero characters. >> > >> > As I mentioned last time, I think this patch would be better if it came >> > with follow-on patches which convert at least some of those callsites. >> > As it stands, this function has no callers and hence it won't get >> > tested. Plus those follow-on patches will demonstrate the value of >> > this patch and will provide example usages. >> >> >> Hi >> >> Sure I can do that! I have saved some patches just to be able to use >> this new feature. >> But should I submit everything as one patch then? >> Or is there some kind of dependency thing I can use... > > [patch 1/N] lib/string.c: add strzcpy() > [patch 2/N] foo/bar/zot.c: use strzcpy() > [patch 3/N] fooz/barz/zot.c: use strzcpy() > ... > >> I have also e-mailed with Dan about this, he pointed out the same as >> some of my tests indicate that strzcpy maybe just should use strncpy >> and add a null character instead because strncpy is optimized >> depending on the hardware it runs on. >> What do you think about that? > > Sounds like strzcpy() should be used in places where the entire buffer > will be copied out to userspace, or in other situations where we want to > zero it out for security reasons?
Hi
So that's how you write it, ok I will send them this weekend when I have some more time.
Yes it was the safety aspect I was most yelled at when I start swapping strncpy with strlcpy, although much of it was justified!
Even Linus was getting into the debate. See more: https://plus.google.com/111049168280159033135/posts/1amLbuhWbh5
Kind regards Rickard Strandqvist
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