Re: bug in [ -f file ] test

[Reuti]

> Am 27.07.2016 um 18:13 schrieb László Házy <hazy_l@yahoo.com>:
> 
> Yes, SELinux is active.

Fine.

Can you please provide:

$ ls -Z /home/user1
$ ls -Z /home/user1/file

-- Reuti


> On Wed, 2016-07-27 at 17:55 +0200, Reuti wrote:
>>> 
>>> Am 27.07.2016 um 17:36 schrieb László Házy <
>>> hazy_l@yahoo.com
>>> >:
>>> 
>>> Yes, user2 has rx access to /home/user1. This is done by the first command 
>>> in the list of commands, namely: "[user1]$ chmod g+rx /home/user1". The two 
>>> users are part of the same group.
>>> 
>>> An even more troublesome variation, involving root, is the following:
>>> 
>>> [user1]$ touch file; ls -l file
>>> -rw-r--r--. 1 user1 users    0 Jul 26 15:24 file
>>> 
>> 
>> 
>> The dot at the end means SELinux ACL IIRC - are you running SELinux?
>> 
>> -- Reuti
>> 
>> 
>> 
>>> 
>>> [user1]$ ln -s /home/user1/file /var/tmp/link
>>> [user1]$ ls -l /var/tmp/link
>>> lrwxrwxrwx. 1 user1 users 17 Jul 26 15:26 /var/tmp/link -> /home/user1/file
>>> 
>>> [user1]$ [[ -f /var/tmp/link ]]; echo $?
>>> 0
>>> 
>>> [user1]$ su 
>>> [root]$ [[ -f /var/tmp/link ]]; echo $?
>>> 1
>>> 
>>> 
>>> On Tue, 2016-07-26 at 23:26 +0200, Reuti wrote:
>>> 
>>>> 
>>>> Am 26.07.2016 um 23:07 schrieb László Házy:
>>>> 
>>>> 
>>>> 
>>>>> 
>>>>> 
>>>>> Hmm, interesting. I can reproduce your results. Thanks.
>>>>> However, note the following:
>>>>> 
>>>>> [user1]$ chmod g+rx /home/user1
>>>>> [user1]$ touch file; ls -l file
>>>>> -rw-r--r--. 1 user1 users    0 Jul 26 15:24 file
>>>>> 
>>>>> [user1]$ su user2 -c "ln -s /home/user1/file /var/tmp/link"
>>>>> [user1]$ ls -l /var/tmp/link
>>>>> lrwxrwxrwx. 1 user2 users 17 Jul 26 15:26 /var/tmp/link -> 
>>>>> /home/user1/file
>>>>> 
>>>>> [user1]$ [[ -f /var/tmp/link ]]; echo $?
>>>>> 1
>>>>> 
>>>>> [user1]$ su user2
>>>>> [user2]$ [[ -f /var/tmp/link ]]; echo $?
>>>>> 0
>>>>> 
>>>>> Something does not add up.
>>>>> 
>>>>> 
>>>> 
>>>> 
>>>> 
>>>> Does user2 have rx access to /home/user1?
>>>> 
>>>> -- Reuti
>>>> 
>>>> 
>>>> 
>>>> 
>>>>> 
>>>>> 
>>>>> From experimenting, it appears that only the user who created the symlink 
>>>>> will get true for the file test.
>>>>> 
>>>>> Thank you.
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> On Tue, 2016-07-26 at 15:06 -0400, Grisha Levit wrote:
>>>>> 
>>>>> 
>>>>>> 
>>>>>> 
>>>>>> Are you sure "file" is a link to an actual file, not, say, a directory?
>>>>>> 
>>>>>> $ rpm -q bash; echo $BASH_VERSION; cat /etc/redhat-release
>>>>>> bash-4.3.42-3.fc23.x86_64
>>>>>> 4.3.42(1)-release
>>>>>> Fedora release 23 (Twenty Three)
>>>>>> 
>>>>>> $ touch file; ln -s file link; [[ -f link ]]; echo $?
>>>>>> 0
>>>>>> 
>>>>>> On Tue, Jul 26, 2016 at 12:58 PM, László Házy <
>>>>>> 
>>>>>> hazy_l@yahoo.com
>>>>>>> 
>>>>>>> wrote:
>>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> I am running bash 4.3.42-3 on Fedore Core 23.
>>>>>>> 
>>>>>>> I noticed that the [ -f file ] test returns false if "file" is a 
>>>>>>> symlink. Given the intended behavior (from a long time ago), this is 
>>>>>>> wrong as the symlinks are supposed to be followed. It certainly brakes 
>>>>>>> functionality in certain existing software.
>>>>>>> 
>>>>>>> Has the default behavior been changed somewhere along the time line and 
>>>>>>> I am not aware of it?
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>> 
>> 
>> 
>>