On Tuesday 13 August 2013 12:23 PM, Joe wrote:
Is there any way at all to say which is the original file and which is
the hard link? I'll bet there isn't, although I' m not an internals guy
at all. If so, this would be impossible to do. The inode is the
"original", but all the file table entries to it are hard links (if
they're not symlinks.)
I guess the question is, what do you really want to accomplish?
The fact that more than one hard link exists probably means it really
does need to be backed up - or that the hard link shouldn't be there in
the original file system.
Joe
On 08/13/2013 01:11 AM, Sherin A wrote:
Can some one create a patch for excluding "hard link regular file"
from copying ?. May be like a command flag , rsync
--no-hardlink-copy ....
Hello Jose,
I think it is possible to check whether a file is regular file or
having more than one links, ( you can check it with stat system call )
The situation is we have an rsync command in a server which will copy
files of local users into a remote server / filesystem . Also have
ability to restore it , it is simple backup. But if a user create a
hard link to /etc/shadow from his home dir , and he request a restore ,
then he can read the shadow files and decrypt it .
So if there is an option to avoid hardlinks during copy process , it
is will add and extra security , it only need to add the following check
condition ,
1) Check the file that are going to copy is a regular file or having
more than 1 links
Also we have checked a lot of other thridparty software that use this
rsync too, which all have this race condition exploit running on .
let me know if you need a POC
--
--------------------------------------
Regards
Sherin A
http://www.sherin.co.in/
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