bug#30534: cp - Possible bugs when not preserving mode (explicit) and when copying special files

[Pádraig Brady]

On 20/02/18 00:04, Declercq Laurent wrote:
> Le 20/02/2018 à 04:26, Pádraig Brady a écrit :
>>> 2. Non-permission bits are preserved, even when the --no-preserve=mode
>>> option is involved.
>>>
>>> Original file to copy: prwSrw-rw- 1 root staff 0 févr. 18 18:59 spfile
>>> cp(1) command (run as root user): cp -r --no-preserve=mode spfile
>>> spfile_copy
>>>
>>> Current result:
>>>
>>> prwsr-xr-x 1 root staff 0 févr. 18 22:05 spfile_copy
>> I'm not seeing this. I get 'x' rather than 's' here (and '-' with the fix)
>>
>>> Expected result (considering UMASK 0022 and without the first bug above):
>>>
>>> prw-r--r-- 1 root staff 0 févr. 18 22:05 spfile_copy
>> thanks!
>> Pádraig
>>
> 
> I'll make a new try, providing you relevant STRACE(1) output if necessary.
> 
> Thank you for your fast reaction.
> 

I've pushed this fix.

Whether setuid is cleared may be file system dependent.
set_acl() corresponds to a setxattr() here,
and that was enough to clear the setuid perm on various
file systems here at least.

We can expand on this in future if needed,
which would be better as a separate patch anyway.

cheers,
Pádraig.