lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 7 May 2014 19:49:10 +0200 From: Veaceslav Falico <vfalico@...hat.com> To: Vlad Yasevich <vyasevic@...hat.com> Cc: Jay Vosburgh <jay.vosburgh@...onical.com>, netdev@...r.kernel.org, Andy Gospodarek <andy@...yhouse.net>, Ding Tianhong <dingtianhong@...wei.com>, Patric McHardy <kaber@...sh.net> Subject: Re: [PATCH v2 net] bonding: Fix stacked device detection in arp monitoring On Wed, May 07, 2014 at 01:08:09PM -0400, Vlad Yasevich wrote: ...snip... >Yes. I verified that it works. The reason is that we are traversing >the all_adj_list.upper list which contains all of the upper devices at >each level. So, at vlan100 level, we will see vlan200 and all will be >well. Hrm, two scenarios, with the following config: bond0 -> whatever1 -> vlan1 -> whatever2 -> vlan2 -> whatever3_IP end == whatever3_IP 1) IIRC there are no guarantees on order of all_upper list, so, if whatever3_IP dev is the first in the list - bond_check_patch() will return true right away. I might be wrong, though, it's 8PM and my brain farts when trying to look at that code. That's fixable (from first sight) by introducing a variable upper_found: + netdev_for_each_all_upper_dev_rcu(start, upper, iter) { ... + if (upper == end) + upper_found = true; ... + } + return upper_found; This way it will first try to go through all nested vlans and, if none found, will return true. Basically, "return upper_found (=true)" has the meaning that upper was found and there are no vlans in between. The "wrong" order might be achieved by creating a bridge for whatever2, creating and linking vlan2 and whatever3_IP, and only *after* that adding vlan1 as a port to bridge whatever2. 2) (with the fix from #1 applied) bond_check_path start==bond0 idx=0 finds vlan1, tag[0] set, recursion start==vlan1 idx=1 bond_check_path start==vlan1 idx=1 finds vlan2, tag[1] set, recursion start==vlan2 idx=2 returns right away with false as idx >= 2. That's wrong as there might be vlan3 on top of whatever2, and tag[1] might be set to it, whilst vlan3 has nothing to do with whatever3_IP. The fix here would be to halt on idx > 2, or, rather, to NOT use recursion/vlan checks if idx == 2, thus leaving us with only upper_found logic. So, the end patch (not compiled, not tested...) would look something like (only the bond_check_path() is changed and copied here, everything else remains the same): + bool upper_found = false; + + netdev_for_each_all_upper_dev_rcu(start, upper, iter) { + if (upper == end) + upper_found = true; + + if (idx < 2 && is_vlan_dev(upper) && + bond_check_path(upper, end, tag, idx+1)) { + tag[idx].vlan_proto = vlan_dev_vlan_proto(upper); + tag[idx].vlan_id = vlan_dev_vlan_id(upper); + return true; + } + } + return upper_found; This way we'll collect the maximum ammount of stacked vlans on our trip from bond0 to whatever3_IP (the limit is 2, however it might be removed afterwards if needed, will still work with long enough tag[]). Hope that makes at least some sense. > >-vlad ...snip... -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists