* Alan Cox ([EMAIL PROTECTED]) wrote: > > + r = !memcmp(old_digest, sha1_item->sha1val, SHA1_DIGEST_SIZE); > > + mutex_unlock(&sha1_lock); > > + if (r) { > > + char *old_addr, *new_addr; > > + old_addr = kmap_atomic(oldpage, KM_USER0); > > + new_addr = kmap_atomic(newpage, KM_USER1); > > + r = !memcmp(old_addr+PAGEHASH_LEN, new_addr+PAGEHASH_LEN, > > + PAGE_SIZE-PAGEHASH_LEN); > > NAK - this isn't guaranteed to be robust so you could end up merging > different pages one provided by a malicious attacker.
I presume you're referring to the digest comparison. While there's theoretical concern of hash collision, it's mitigated by hmac(sha1) so the attacker can't brute force for known collisions. thanks, -chris -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html