Re: [librsync-devel] librsync and rsync vulnerability to maliciously crafted data. was Re: MD4 checksum_seed

2004-04-11 Thread Donovan Baarda
G'day, From: "Wayne Davison" <[EMAIL PROTECTED]> > On Thu, Apr 08, 2004 at 03:50:48PM +1000, Donovan Baarda wrote: > > I think I've just realised what you were getting at; if the > > checksum_seed is based on something like the whole file md4sum, it > > becomes repeatable, but unpredictable. > > No

Re: [librsync-devel] librsync and rsync vulnerability to maliciously crafted data. was Re: MD4 checksum_seed

2004-04-08 Thread Wayne Davison
On Thu, Apr 08, 2004 at 03:50:48PM +1000, Donovan Baarda wrote: > I think I've just realised what you were getting at; if the > checksum_seed is based on something like the whole file md4sum, it > becomes repeatable, but unpredictable. Not so. Copy the file once, and you'd get all the data you'd

Re: [librsync-devel] librsync and rsync vulnerability to maliciously crafted data. was Re: MD4 checksum_seed

2004-04-08 Thread Eran Tromer
Ahoy, On 2004/04/08 14:16, Donovan Baarda wrote: >>Nice indeed, but the cost is enormous: you'll have to read the file >>twice. When syncing a mostly-unchanged file that's larger than the disk >>cache, that means doubling the runtime (and disk load) on the receiver's >>side. Also, it means 'rdiff

Re: [librsync-devel] librsync and rsync vulnerability to maliciously crafted data. was Re: MD4 checksum_seed

2004-04-08 Thread Donovan Baarda
G'day again, From: "Eran Tromer" <[EMAIL PROTECTED]> [...] > > if the > > checksum_seed is based on something like the whole file md4sum, it > > becomes repeatable, but unpredictable. You can't manipulate individual > > blocks without it affecting every other blocksum, but the signature for > > th

Re: [librsync-devel] librsync and rsync vulnerability to maliciously crafted data. was Re: MD4 checksum_seed

2004-04-08 Thread Eran Tromer
On 2004/04/08 08:50, Donovan Baarda wrote: >>In some cases you might prefer to actually store an signed signature >>using something like GPG. I think librsync should act as a black box that guarantees file integrity (which, apparently, requires a whole file checksum). If someone wants to add authe

Re: [librsync-devel] librsync and rsync vulnerability to maliciously crafted data. was Re: MD4 checksum_seed

2004-04-07 Thread Donovan Baarda
On Thu, 2004-04-08 at 12:36, Martin Pool wrote: > On 5 Apr 2004, Donovan Baarda <[EMAIL PROTECTED]> wrote: > > > librsync needs a whole file checksum. Without it, it silently fails for > > case 1), 3), and 4). > > Yes, a whole-file checksum should be used with it. Presumably > something stronge