skvidal@phy.duke.edu (seth vidal) writes:
(BTW SHA please MD5 has flaws 8)
What flaws in particular?
md5 is not collision resistant. An attacker could create a bad and a good rpm-package. Both could be modified in such a way that they stay valid rpm-packages but differ at some places (e.g. in padding bits). When having e.g. 64 such bits, you could create 2^64 different but valid packages.
For the 128 bit md5sum, it is very likely (at least for common security purposes) that you can find a matching good-bad package-pair within this 2^64 possibilities (birthday attack). Now, attacker places good package into the QA-queue and waits for the review. Then, he replaces it with the bad package (with same md5sum) and fedora.us will have a malicious package...
This attack can be prevented by two ways:
* use better hash-function (e.g. 160 bit SHA1), or * speedup QA process so that it is faster than the dup-finding process;)
I do not know numbers about the duration of md5sum birthday attacks, but IMO they are *not* an issue for current QA process...
Enrico