Destructive side-effect of "cg-status"

From: Wolfgang Denk <wd@denx.de>
Date: Sep 30, 2005, 16:03 UTC
Message-ID: <20050930160353.F025C352B7B@atlas.denx.de>

So far I thought "cg-status" is a harmless command which just displays some status information. It ain't so. One of our engineers reported a corrupted repository after I ran "cg-status" in his directory:

$ cg-status
Heads:
   >master      805f93e4ca96d0c0cb2d2f9532d9666b22961e88
  R origin      805f93e4ca96d0c0cb2d2f9532d9666b22961e88

error: open failed fatal: cache corrupted error: open failed ? COPYING ? CREDITS ? Documentation/00-INDEX ? Documentation/BUG-HUNTING ... error: open failed read_cache: Permission denied ... error: open failed read_cache: Permission denied ...

As mentioned before, all I did was running "cg-status" in his directory. Here is what happens:

Before:

	-> rpm -q cogito
	cogito-0.15.1-1
	-> id
	uid=500(wd) gid=500(wd) groups=200(gitmaster),400(denx),500(wd)
	-> umask
	0002
	-> ls -ld .git
	drwxrwxrwx  6 sr sr 80 Sep 30 17:49 .git
	-> ls -l .git/index
	-rw-r--r--  1 sr sr 1728032 Sep 30 17:17 .git/index

Then:

	-> cg-status
	Heads:
	   >master      805f93e4ca96d0c0cb2d2f9532d9666b22961e88
	  R origin      805f93e4ca96d0c0cb2d2f9532d9666b22961e88

	M arch/ppc/configs/bubinga_defconfig
	M arch/ppc/configs/walnut_defconfig
	-> ls -l .git/index
	-rw-------  1 wd wd 1728032 Sep 30 17:49 .git/index
	^^^^^^^^^^    ^^^^^

That means, that "cg-status" actually *rewrote* .git/index, with me (wd) as new owner, and - ignoring my umask - with permissions that prevent the original owner (sr) to access the file!

Arghhhh!!!

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
Generally speaking, there are other ways to accomplish whatever it is
that you think you need ...                               - Doug Gwyn