[arch-general] Pointless to use non-md5 for makepkg INTEGRITY_CHECK

Dan McGee dpmcgee at gmail.com
Mon Jan 12 16:48:49 EST 2009


On Mon, Jan 12, 2009 at 3:45 PM, Aaron Griffin <aaronmgriffin at gmail.com> wrote:
> On Mon, Jan 12, 2009 at 3:23 PM, Aaron Schaefer <aaron at elasticdog.com> wrote:
>> On Mon, Jan 12, 2009 at 3:35 PM, Aaron Griffin <aaronmgriffin at gmail.com> wrote:
>>> Haven't we been over this like a hundred times? md5sums are not used
>>> for security. Not ever. Nope. Nada.
>>>
>>> We use them solely to detect whether or not the download completed as
>>> expected. And sha256 is going way overboard here.
>>
>> It has been discussed before, in fact, you said this back in November:
>>
>> "The checksums in pacman are only used for integrity, not security. I
>> agree that the first step towards super-omg-secure packages would be
>> switching to a different checksum, but sha1 might be deemed insecure
>> soon too. Why not jump over that one to something like sha256?"
>>
>> ...so a month ago you didn't think sha256 was going overboard, and now
>> you do? I'd also make a semantics argument and say that if the
>> "integrity" of the package could possibly be compromised by the
>> creation of a malicious package with the same md5 checksum, then that
>> absolutely effects the "security" of our system...the two ideas are
>> not completely separate.
>
> I do not recall my frame of mind at the time, but rereading that and
> knowing how I talk/write, I'd say that may have been tongue-in-cheek.
>
> I guess the point I was making was that simply bumping the checksum
> won't be the best solution because the NEXT choice may be labeled as
> insecure and then the next and the next.
>
> To put it in different terms: if you have some array that only holds
> 10 objects, and find out 10 isn't enough, you can bump it to 20. And
> when you find out 20 isn't enough, you can bump it to 100... and then
> 100 might not be enough... eventually, you're going to say "screw it"
> and tackle the problem differently (dynamically sized array).
>
> There has been lots and lots of work done to get GPG signed packages
> going on the pacman-dev list. Gerhard and Geoffroy, if I recall, kinda
> took the helm on this one. If we go with this solution, we won't have
> to play this game of cat-and-mouse with changing the checksums.

And remember makepkg source checksums are COMPLETELY different than
signed packages. I'm not even sure why these two are being mentioned
in the same light.

-Dan


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