Hi, On 2004/04/05 07:21, Donovan Baarda wrote: [snip] > there are four ways crafted blocks can be use; > > 1) two crafted blocks in the "original" file > > 2) two crafted blocks in the "target" file > > 3) a crafted pair of "target" and "original" files with matching > block(s) > > 4) a block in the "target" crafted to match a block in the "original" [snip] > Summary; > > case 2) has no impact > > case 4) is of minimal impact in rsync, and sufficiently hard in > librsync. > > librsync needs a whole file checksum. Without it, it silently fails for > case 1), 3), and 4). > > librsync could benefit from a random checksum_seed. It would need to be > included in the signature. Without it librsync is vulnerable to cases 1) > and 3). [snip] > rsync shouldn't need a fixed seed for batch modes... just store the seed > in the signature. using a fixed seed makes it vulnerable to 1) and 3).
I fully agree with your analysis. I'll just note that in many situations, case 2 can be elevated to case 3 simply by transferring the file twice. Eran -- To unsubscribe or change options: http://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html
