Date: Mon, 24 Sep 2012 20:54:31 +0200 From: Tavis Ormandy <taviso@...xchg8b.com> To: oss-security@...ts.openwall.com Subject: Re: Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files Kurt Seifried <kseifried@...hat.com> wrote: > On 09/24/2012 11:15 AM, Kurt Seifried wrote: > > On 09/24/2012 02:42 AM, Tavis Ormandy wrote: > > > Matthias Weckbecker <mweckbecker@...e.de> wrote: > > > > > > On Friday 21 September 2012 23:47:48 Michael Gilbert wrote: [...] > >>>> > > > > > So anyway, I suppose this creates more questions than answers, but > > > > > I guess its worth thinking about. After all, what did the user > > > > > really expect? If they had intended that original file to be > > > > > private, and now its not, is that appropriate? Is it more > > > > > appropriate to assume all users know how to use umask > > > > > appropriately? > >>>> > >>> > > > > IMO if one bothers to encrypt a file at all it was certainly > > > > intended to be private and only supposed to be readable by a certain > > > > user / user group and not by just everyone. Otherwise encryption > > > > would be pointless, or are there any other reasons for encrypting a > > > > file? > >>> > > > > > Best wishes, Mike > >>> > > > > Thanks, Matthias > >>> > > > > > I agree. Users do know how to use umask properly, but this isn't what > > > umask is for. The umask for the low order bits are only applied if the > > > program requested 0666, it's still the responsibility of the program > > > to choose the appropriate permissions. > > > > > Creating sensitive files with 0666 and then saying "set your umask" is > > > just wrong. > > > > > Tavis. > > > > So where do we draw the line? tar? By this definition any program that > > has stores sensitive data (passwords/etc.) or has potentially sensitive > > output (so email, web clients, chat clients, file downloaders, text > > editors, etc.) needs to internally pick some "safe" default and apply it > > and/or umask (whichever is more secure I guess). > > Then lets just remove umask, because you're saying it's useless. The purpose of umask is to apply a *mask* to what applications request as default, not as a universal "set these permissions" command. If it was, it would be called uperms. And yes, I think that any program that creates files with sensitive contents and requests 0666 is broken. Tavis. -- ------------------------------------- taviso@...xchg8b.com | pgp encrypted mail preferred -------------------------------------------------------
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