[Emacs-bug-tracker] bug#8752: closed (cp: fchown called before fchmod, unable to set file mode)

[GNU bug Tracking System]

Your message dated Wed, 1 Jun 2011 13:17:28 -0600
with message-id <address@hidden>
and subject line Re: bug#8752: cp: fchown called before fchmod, unable to set 
file mode
has caused the GNU bug report #8752,
regarding cp: fchown called before fchmod, unable to set file mode
to be marked as done.

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8752: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=8752
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--- Begin Message --- Subject: cp: fchown called before fchmod, unable to set file mode Date: Sat, 28 May 2011 15:10:21 +0200

Hello, 

I believe that cp uses wrong order of syscalls when applying target file attributes; fchown(2) is called before fchmod(2). 
As a result it looses access to target file and is unable to apply file mode correctly; error message is as follows 
"cp: preserving permissions for `target': Not owner" 

The problem arises when -p (preserve attributes) is present and file owner is different from user doing the copy. 

Same operation using cp on hp-ux 11.31 is successfull, since hp-ux cp calls chmod(2) before chown(2). 

Please let me know what do you think about changing order of fchown(2) <=> fchmod(2). 

Kind Regards, 
Milan 

--- 

address@hidden:/home/hp/coreutils $ id 
uid=1058(hp) gid=20(users) groups=65535(last) 
address@hidden:/home/hp/coreutils $ ll source target 
target not found 
-rwxrwxrwx 1 elzu radia 32 May 20 15:50 source 
address@hidden:/home/hp/coreutils $ tusc -o tusc_hpuxcp.out /usr/bin/cp -p source target; echo $? ; ll source target 
0 
-rwxrwxrwx 1 elzu radia 32 May 20 15:50 source 
-rwxrwxrwx 1 elzu radia 32 May 20 15:50 target 
address@hidden:/home/hp/coreutils $ rm -f target 

address@hidden:/home/hp/coreutils $ tusc -o tusc_gnucp.out coreutils-8.11/src/cp -p source target; echo $? ; ll source target 
coreutils-8.11/src/cp: preserving permissions for `target': Not owner #>>>> ERROR 
1 
-rwxrwxrwx 1 elzu radia 32 May 20 15:50 source 
-rwx------ 1 elzu radia 32 May 20 15:50 target #>>> already owned by user elzu, so chmod executed as user hp fails 

address@hidden:/home/hp/coreutils $ coreutils-8.11/src/cp --version | head -1 
cp (GNU coreutils) 8.11 

address@hidden:/home/hp/coreutils $ uname -a 
HP-UX mtest B.11.31 U ia64 2263078376 unlimited-user license 

address@hidden:/home/hp/coreutils $ egrep "target|chown|chmod|exit" tusc_* 
tusc_hpuxcp.out:stat64("target", 0x7fffeec0) ............................................ ERR#2 ENT 
tusc_hpuxcp.out:stat64("target", 0x40021110) ............................................ ERR#2 ENT 
tusc_hpuxcp.out:stat64("target", 0x40021110) ............................................ ERR#2 ENT 
tusc_hpuxcp.out:access("target", F_OK) .................................................. ERR#2 ENT 
tusc_hpuxcp.out:open("target", O_WRONLY|O_CREAT|O_TRUNC|0x800, 0) ....................... = 6 
tusc_hpuxcp.out:utime("target", 0x7fffe5f0) ............................................. = 0 
tusc_hpuxcp.out:chmod("target", 0100777) ................................................ = 0 
tusc_hpuxcp.out:chown("target", 1021, 1005) ............................................. = 0 
tusc_hpuxcp.out:chmod("target", 0100777) ................................................ ERR#1 EPM 
tusc_hpuxcp.out:exit(0) ................................................................. WIFE) 

tusc_gnucp.out:stat64("target", 0x7fffedf0) ............................................ ERR#2T 
tusc_gnucp.out:stat64("target", 0x7fffeac0) ............................................ ERR#2T 
tusc_gnucp.out:open("target", O_WRONLY|O_CREAT|O_EXCL|0x800, 0700) ..................... = 5 
tusc_gnucp.out:utime("target", 0x7fffe7a8) ............................................. = 0 
tusc_gnucp.out:fchown(5, 1021, 1005) ................................................... = 0     #>>> the problem is HERE, CHOWN goes before CHMOD; 
tusc_gnucp.out:fchmod(5, 0100777) ...................................................... ERR#1M     #>>> this fails, since user hp is not the owner of the file anymore 
tusc_gnucp.out:exit(1) ................................................................. WIFEX) 

--- End Message ---

> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#8752: cp: fchown called before fchmod, unable to set file mode
>
>
>
>
> Date: 
>
> Wed, 1 Jun 2011 13:17:28 -0600
>
>
>
>
> User-agent: 
>
> Mutt/1.5.21 (2010-09-15)
>
>
>
>
> Paul Eggert wrote:
> > Paul Eggert wrote:
> > > # echo "-n CHOWN" >>/etc/privgrp
> > > # setprivgrp -f /etc/privgroup
> > 
> > Whoops, obviously I misspelled one of those two file names.
> > I think the second one is right.  But you should read the
> > manuals and check before trying it (I haven't used HP-UX
> > in years).
>
> The first was the misspelling, the second was the correct name.
>
> Just to be clear, this next command will set it interactively.  You
> can test the behavior without having made any permanent changes.  But
> if you reboot the change will be gone.
>
>   # setprivgrp -n CHOWN
>
> Setting this file /etc/privgroup with the following contents will make
> it persistent at boot time:
>
>   -n CHOWN
>
> See 'man 1m setprivgrp' for the HP-UX documentation.
>
> And since I think this completely resolves the issue I am going to
> close the ticket on it.  Please feel free to add additional comments.
> If needed the ticket can be reopened at any time.
>
> Bob
>
>
> --- End Message ---