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: Tue, 18 Apr 2017 09:52:06 +0200 From: Nicolas Dichtel <nicolas.dichtel@...nd.com> To: David Ahern <dsa@...ulusnetworks.com>, vyasevic@...hat.com, Roopa Prabhu <roopa@...ulusnetworks.com> Cc: netdev@...r.kernel.org, davem@...emloft.net Subject: Re: [PATCH net-next 1/8] rtnetlink: Do not generate notifications for MTU events Le 15/04/2017 à 06:26, David Ahern a écrit : > +Nicolas > > On 4/14/17 7:51 PM, Vlad Yasevich wrote: >> On 04/10/2017 11:49 AM, David Ahern wrote: >>> On 4/10/17 9:39 AM, Vlad Yasevich wrote: >>>> OK, so this will work for the events that are generated as a result of device state change >>>> (like mtu, address, and others). >>>> >>>> However, the original event data may be needed for other events that may be >>>> of use to userspace like NETDEV_NOTIFY_PEERS and NETDEV_RESEND_IGMP (possibly others...) >>> >>> sure. My objection is to multiple messages with identical content. >>> >>> I think the rtnetlink_event message is unique for those 2 netdev events, >>> so no objections if it has value. >>> >> >> So, I've been looking at adding a bitmap and collecting all modification, however >> I ran into an interesting issue in do_setlink. >> >> Currently the notifications from do_setlink() don't appear to work as one would >> expect and it's somewhat confusing upon deeper inspection. >> >> We have 2 values DO_SETLINK_MODIFIED (1) and DO_SETLINK_NOTIFY (3). These 2 'attempt' >> to do different jobs, but really fail at it. The function will generate notifications >> regardless of which of the above values is used. >> >> Those changes were done in commit ba9989069f4e426b1e0ed7018eacc9e1ba607095 (cc Nicolas >> just in case he remembers the history) >> >> I am not sure which changes should really trigger a call netdev_state_change(), thus this >> message. Right now, all changes done in this function trigger them. If that's how that >> should function, that I can simplify the code. If not, then some of the changes may >> require us to export the event to the user. If I remember well, the goal was to trigger a netlink event as soon as 'something' changed. It was not the case before that patch, some updates (I don't remember which one) were not advertised via netlink. >> >> To use the dreaded NETDEV_CHANGEMTU event as an example, we used to generate 3 messages >> (PRECHANGEMTU, CHANGEMTU, and a message from netdev_state_change). With recent changes, >> we now only generate a message from netdev_state_change. However, mtu change is tagged >> with DO_SETLINK_MODIFIED which doesn't include the notify bit. So, should there be a >> NETDEV_CHANGE event associated with this change and a rtnl message (as it is now) or not? The rtnl msg is mandatory. Regards, Nicolas
Powered by blists - more mailing lists