Date: Mon, 24 Sep 2012 11:21:54 -0600 From: Kurt Seifried <kseifried@...hat.com> To: oss-security@...ts.openwall.com CC: Tavis Ormandy <taviso@...xchg8b.com> Subject: Re: Re: Re: CVE request(?): gpg: improper file permssions set when en/de-crypting files -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 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). > > Personally I think applying file permissions at the program level > is in general (outside of some highly specific instances like > encryption key generation and storage in a file) a very very bad > place to do this. Moving it up a layer to the OS (e.g. umask, home > dir permissions, etc.) makes way more sense I think. > > However if people want to go ahead with this then a short list > would be: > > OpenSSH/any SSH or encrypted connection client OpenSSL/anything > that generates certificates/keys/etc. GPG/PGP/anything that > provides file encryption/decryption Email clients (email is almost > always sensitive, stored passwords/certs) Web clients (cached web > pages are sensitive, stored passwords/certs) Chat programs (IRC, > MSN, etc.) (stored passwords/certs) Any programs storing > financial/accounting data (GnuCash, etc.). Any programs storing > health related data (GnuHealth, etc.). File editing programs were > previously mentioned > > I'm sure I've missed a few. Sorry I forgot to include this: Also trying to fix this in a lot of programs has a major downside: systems with bad umasks/home directory permissions/etc. remain hidden to the user potentially. E.g. if programs start policing its file output permissions this works great until the user uses a program that doesn't do this (which they will do, probably sooner than later). Now that's not to say that some specific instances of data that by definition MUST be secret (e.g. secret passwords, certificate keys, etc.) should have their permissions policed by their respective program (due to the fact that they are quite often used on shared systems/etc.), but this is a vastly smaller set of programs and much more manageable. - -- Kurt Seifried Red Hat Security Response Team (SRT) PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQIcBAEBAgAGBQJQYJayAAoJEBYNRVNeJnmT8k0P/RDFbswvng9A/PzbYKEiXS/2 K2NFUK0EWDTbynzj8h6LtHvFmuUBE+n+xwDkKhrTtGcXken2VaTVeW4FtYN6qOlt aOeskXXnsu/WNoCC2AYFFX+CYPpX9idk7WnytzU2jjeEOVmqikm/FubzBKqe79yN hnBSYQGBhsN0xIMjGPij9uNv9kpRAMrhKOXEV6A8oKszSrMzbyrt8hy9DniBNnws rNDRdb5GzUQ+2mDa42odaqZWSZLdEk2eVEDjXpEqtkzwAHRoAi+iLBm7LOp5b1XL WJ3HsEIp8CtkjQpMbHWeh5sz+UEIT9MR405+2+koc2wpmKE0/TZpEOxXk0oncDvg GEwfsqZppRoj3+/Y/E8BunV+M/HYfRmFXsOg8KZlPJXoPMnDuVQkcGZKE8NtiMvX i+tDNzsjfTv7nvWWYyAmH88XRCtoYdmCdZRKMNjR2cLLD/Qek96N+pX8i2Uod1VI k+Sb+R8p4V9b4LbQMAaOq12YE6WFDs6J1RGkWpQcPb07Dmt00DFBDsNWMLKTIWml 6mcKW9FgNDuSAoYmGaCzLyLLEaKJC5PhmFsE7gXXbM+VvRV8PjhtnA4m7Ml7Kwf2 kOs5keypHb5CxzF+KvGdHLWlQOwFLQVHuh8zl88tqxoTXcgk9gph7OtGkpMYDwXN q9ovFUUMRUp+cNiaPJ22 =bUip -----END PGP SIGNATURE-----
Powered by blists - more mailing lists
Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.