oss-sec mailing list archives
Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files
From: Michael Gilbert <mgilbert () debian org>
Date: Fri, 21 Sep 2012 17:19:40 -0400
On Fri, Sep 21, 2012 at 3:30 PM, Kurt Seifried
Think about it this way. I open a file with mode 600 in vim, edit it, save it, and find it with mode 644? That would be an exposure, would it not?Not if it respects your umask.
Editing does not invoke a umask because the program already knows what umask you really wanted for that file, and didn't need a default to guess at it. $ umask 0077 $ touch test $ ls -l test -rw------- 1 a a 5 Sep 21 17:09 test $ umask 022 $ echo test > test $ ls -l test -rw------- 1 a a 5 Sep 21 17:09 test
If you want privacy set your umask correctly. Programs can't know what they're supposed to do unless you tell them. And we tell the system using umask.
Sure, umask applies a default set of permissions to new files, and the process of decrypting a file with gpg certainly creates a new file. But in this case, we can be more intelligent than the umask because we know the permissions of the original encrypted file, and don't need to guess at them using the umask.
I'm confused. It's not exposed unless you configure umask wrong and run this in a public viewable directory. If you want a CVE for every single program that doesn't ensure it's (potentially sensitive) output is mode 0600 than that's basically, well, all the programs on a system.
So, the point is that umask is more meant more as a fallback only when there isn't better info available to make the right permissions decision. Best wishes, Mike
Current thread:
- CVE request(?): gpg: improper file permssions set when en/de-crypting files Matthias Weckbecker (Sep 21)
- Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Dan Rosenberg (Sep 21)
- Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Matthias Weckbecker (Sep 21)
- Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Tomas Mraz (Sep 21)
- Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Michael Gilbert (Sep 21)
- Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Kurt Seifried (Sep 21)
- Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Michael Gilbert (Sep 21)
- Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Kurt Seifried (Sep 21)
- Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Michael Gilbert (Sep 21)
- Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Michael Gilbert (Sep 21)
- Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Matthias Weckbecker (Sep 24)
- Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Tavis Ormandy (Sep 24)
- Re: Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Michael Gilbert (Sep 24)
- Re: Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Tavis Ormandy (Sep 24)
- Re: Re: Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Michael Gilbert (Sep 24)
- Re: Re: Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Tavis Ormandy (Sep 24)
- Re: Re: Re: Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Michael Gilbert (Sep 24)
- Re: Re: Re: Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Michael Gilbert (Sep 24)
- Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Michael Gilbert (Sep 21)
- Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Dan Rosenberg (Sep 21)
- Re: Re: Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Steven M. Christey (Sep 24)