Re: [PATCH v5 1/2] selinux: add brief info to policydb

From	Sebastien Buisson <sbuisson.ddn@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v5 1/2] selinux: add brief info to policydb
Date	2017-05-17 17:50 +0200
Message-ID	<tI9n3-4Ud-9@gated-at.bofh.it> (permalink)
References	(1 earlier) <tHRqa-1So-15@gated-at.bofh.it> <tI8Km-4GH-7@gated-at.bofh.it> <tI8Km-4GH-19@gated-at.bofh.it> <tI93I-4Nh-13@gated-at.bofh.it> <tI9dn-4QL-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

2017-05-17 17:34 GMT+02:00 William Roberts <bill.c.roberts@gmail.com>:
>>>>> Is there a particular reason to not just return policybrief_len here as
>>>>> well, for consistency in the interface?  How do you intend to use this
>>>>> value in the caller?
>>>>
>>>> As called in the other patch to expose policy brief via selinuxfs
>>>> (sel_read_policybrief), the intent is to provide the caller with the
>>>> length of the string returned.
>>>> Or should I set *len to policy brief_len here, and just make the
>>>> caller aware that the returned length is in fact the length of the
>>>> buffer (i.e. including terminating NUL byte)?
>>>
>>> What is the caller supposed to do with length? This interface seemed kind of
>>> odd. If it's guaranteed NUL byte terminated, do they even need length?
>>
>> The length is useful as an input parameter in case the caller provides
>> its own buffer (instead of letting the function allocate one), and as
>
> This is what I don't get, why doesn't the function just always allocate?

For performance reasons mainly. The caller would have a statically
allocated buffer, reused every time it needs to get the policy brief
info.

Thread

[PATCH v5 1/2] selinux: add brief info to policydb Sebastien Buisson <sbuisson.ddn@gmail.com> - 2017-05-16 12:00 +0200
  Re: [PATCH v5 1/2] selinux: add brief info to policydb Stephen Smalley <sds@tycho.nsa.gov> - 2017-05-16 22:40 +0200
    Re: [PATCH v5 1/2] selinux: add brief info to policydb Sebastien Buisson <sbuisson.ddn@gmail.com> - 2017-05-17 17:10 +0200
      Re: [PATCH v5 1/2] selinux: add brief info to policydb William Roberts <bill.c.roberts@gmail.com> - 2017-05-17 17:10 +0200
        Re: [PATCH v5 1/2] selinux: add brief info to policydb Sebastien Buisson <sbuisson.ddn@gmail.com> - 2017-05-17 17:30 +0200
          Re: [PATCH v5 1/2] selinux: add brief info to policydb William Roberts <bill.c.roberts@gmail.com> - 2017-05-17 17:40 +0200
            Re: [PATCH v5 1/2] selinux: add brief info to policydb Sebastien Buisson <sbuisson.ddn@gmail.com> - 2017-05-17 17:50 +0200
              Re: [PATCH v5 1/2] selinux: add brief info to policydb William Roberts <bill.c.roberts@gmail.com> - 2017-05-17 18:10 +0200
                Re: [PATCH v5 1/2] selinux: add brief info to policydb William Roberts <bill.c.roberts@gmail.com> - 2017-05-17 18:30 +0200
                Re: [PATCH v5 1/2] selinux: add brief info to policydb Sebastien Buisson <sbuisson.ddn@gmail.com> - 2017-05-17 19:10 +0200
                Re: [PATCH v5 1/2] selinux: add brief info to policydb William Roberts <bill.c.roberts@gmail.com> - 2017-05-17 20:30 +0200
      Re: [PATCH v5 1/2] selinux: add brief info to policydb Stephen Smalley <sds@tycho.nsa.gov> - 2017-05-17 17:40 +0200

csiph-web