4 ms·
Not a new attack. There is a decent history of an arms race in TOCTTOU races in access/open that leads to this type of algorithmic complexity attack against ba
by leif 14y ago
Not a new attack. There is a decent history of an arms race in TOCTTOU races in access/open that leads to this type of algorithmic complexity attack against bad hashing. Maybe btrfs does worse things if you do this but it's not alone.
See http://www.cs.stonybrook.edu/~xcai/races2.pdf http://www.cs.stonybrook.edu/~xcai/races2.pdf and some of its references.
- CJefferson 14y agoDoesn't the first paragraph of the article talk about the history of hash collision attacks? Or are you talking about some other way in which this is not a new attack? Also, looking at his numbers, btrfs is doing something very wrong, over simple hash collisions. A file system which takes over 5 seconds to make 61 files is simply broken (in this situation, not making general comments about btrfs).
- leif 14y agoYou're right, I skimmed and that's my fault. However, it's worth noting that these sorts of attacks can give privilege escalation, not just DoS.