Date: Mon, 25 Jul 2016 11:49:28 +0200 From: Bálint Réczey <balint@...intreczey.hu> To: oss-security@...ts.openwall.com Cc: "Eric W. Biederman" <ebiederm@...ssion.com>, Shadow package maintainers <pkg-shadow-devel@...ts.alioth.debian.org> Subject: Re: Re: [Pkg-shadow-devel] subuid security patches for shadow package Hi, While this is not immediately clear from the Shadow homepage the development continued on GitHub where I have opened two issues for the two potential security problems: Incorrect integer handling CVE-2016-6252: https://github.com/shadow-maint/shadow/issues/27 Potentially unsafe use of getlogin CVE-2016-6251: https://github.com/shadow-maint/shadow/issues/28 Probably upstream's issue tracker would be the best place to discuss the fixes in detail. With upstream development happening on GitHub the pkg-shadow-devel list could host mostly Debian-packaging releated discussions and probably not all oss-security subscribers would like to get all the messages. Cheers, Balint 2016-07-25 10:39 GMT+02:00 Sebastian Krahmer <krahmer@...e.com>: > On Mon, Jul 25, 2016 at 10:03:31AM +0200, Sebastian Krahmer wrote: >> On Wed, Jul 20, 2016 at 11:48:52PM +0200, Nicolas François wrote: >> > Hi, >> > >> > The first point looks like a non issue to me. >> > >> > getlogin() is used to differentiate users with the same UID. >> > The result of getlogin() is checked: if it returns a username that do not >> > have the UID returned by getuid(), it will be ignored. >> > >> > >> > Best Regards, >> > -- >> > Nekral >> >> I agree that its not a severe issue. But its dubious code at best. >> I couldnt even imagine someone would have usernames with different UID's? >> Maybe such configs should not be encouraged and potential issues with >> that discussed. >> >> My understanding of secure coding is that getlogin() should not >> be trusted. Having same username with multiple UIDs is also to be avoided >> IMHO, since its asking for trouble (I dont know if thats some requirement >> of LSB or POSIX or so?) > > Err, sorry. Shared UID, different name (the other way around, thanks Alex). > But then you are open to GID hopping attacks (as also previously > pointed out) since you actually _do_ rely on getlogin() trust. > > Sebastian > > -- > > ~ perl self.pl > ~ $_='print"\$_=\47$_\47;eval"';eval > ~ krahmer@...e.com - SuSE Security Team >
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.