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Re: [PATCH] string: Add tests for zero length string inputs
- From: Will Newton <will dot newton at linaro dot org>
- To: OndÅej BÃlka <neleai at seznam dot cz>
- Cc: libc-alpha <libc-alpha at sourceware dot org>
- Date: Fri, 19 Sep 2014 10:09:59 -0700
- Subject: Re: [PATCH] string: Add tests for zero length string inputs
- Authentication-results: sourceware.org; auth=none
- References: <1410910830-20900-1-git-send-email-will dot newton at linaro dot org> <20140919112302 dot GA2912 at domone>
On 19 September 2014 04:23, OndÅej BÃlka <email@example.com> wrote:
> On Tue, Sep 16, 2014 at 04:40:30PM -0700, Will Newton wrote:
>> For the string functions that take string lengths as an argument we
>> should ensure that no data is read or written if a length of zero is
>> specified. Pointers to PROT_NONE memory are used to ensure that any
>> reads or writes will cause a fault.
> You do not need these. C standard requires arguments to be valid
> pointers for most string functions, and they are already marked nonnull
> in header.
> Just adding size 0 to inputs would suffice.
These tests are not testing null pointers, they are testing that when
given a zero length the functions actually read/write zero bytes.
Whether the specification demands that behaviour is arguable but I
believe that it is the most sane behaviour.
Toolchain Working Group, Linaro