What do you propose....  This is free software.... Don't be a Jew.

   On 12/30/2013 7:11 PM, Matthew Thode wrote:
> On 12/30/2013 10:11 AM, Stephen Smalley wrote:
>> Calling *setfilecon() with a NULL context is a bug in the caller, just
>> like calling strlen() with a NULL string.
>> Fix the callers, please.
>>
>> On Wed, Dec 25, 2013 at 9:36 AM, Nicolas Iooss <nicolas.iooss@m4x.org> wrote:
>>> 2013/12/23 Daniel J Walsh wrote:
>>>> On 12/21/2013 09:27 AM, Nicolas Iooss wrote:
>>>>> My first message was not so clear. The check in
>>>>> libselinux/src/lsetfilecon.c line 35 [1] doesn't work because
>>>>> selinux_trans_to_raw_context(context, &rcontext) returns 0 and sets
>>>>> rcontext to NULL. This is why I'm asking to change the return value to
>>>>> something else if you want "cp -a" working. This fix is not to introduce a
>>>>> new feature but to fix an existing one.
>>>>>
>>>>> Nicolas
>>>>>
>>>> How about if we add a check on lsetfilecon_raw?  Changing the behaviour on
>>>> selinux_trans_to_raw_context might cause other problems.
>>> I agree. I've found
>>> http://selinuxproject.org/page/LibselinuxAPISummary which says
>>> precisely for selinux_trans_to_raw_context: "If passed NULL, sets the
>>> returned context to NULL and returns 0." As this feature is
>>> documented, callers may rely on it and changing this behavior is
>>> likely to break things.
>>>
>>> Moreover setfilecon_raw and fsetfilecon_raw have the same NULL-pointer
>>> dereference issue. Do these functions need a patch too?
>>>
>>> By the way, other callers of selinux_trans_to_raw_context may also
>>> share this bug: avc_context_to_sid, security_canonicalize_context,
>>> security_check_context, etc. Is doing a segmentation fault the
>>> expected way to tell the caller it used a NULL pointer and should have
>>> manually checked every parameter before calling any libselinux
>>> function?
>>>
>>> Thanks and merry Christmas!
>>>
>>> Nicolas
>>>
>>>>
>>>> diff --git a/libselinux/src/lsetfilecon.c b/libselinux/src/lsetfilecon.c
>>>> index 461e3f7..af3775e 100644
>>>> - --- a/libselinux/src/lsetfilecon.c
>>>> +++ b/libselinux/src/lsetfilecon.c
>>>> @@ -9,6 +9,10 @@
>>>>
>>>>   int lsetfilecon_raw(const char *path, const security_context_t context)
>>>>   {
>>>> +       if (! context) {
>>>> +               errno=EINVAL;
>>>> +               return -1;
>>>> +       }
>>>>          return lsetxattr(path, XATTR_NAME_SELINUX, context, strlen(context) + 1
>>>>                           0);
>>>>   }
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>>
> I think I may have hit this bug as well.
>
> https://bugs.gentoo.org/show_bug.cgi?id=495274
>
>
>
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