On Wed, Jun 28, 2017 at 04:27:00PM +0200, Max Reitz wrote: > On 2017-06-27 19:09, Eric Blake wrote: > > On 06/11/2017 07:37 AM, Max Reitz wrote: > >> qemu proper has done so for 13 years > >> (8a7ddc38a60648257dc0645ab4a05b33d6040063), qemu-img and qemu-io have > >> done so for four years (526eda14a68d5b3596be715505289b541288ef2a). > >> Ignoring this signal is especially important in qemu-nbd because > >> otherwise a client can easily take down the qemu-nbd server by dropping > >> the connection when the server wants to send something, for example: > >> > >> $ qemu-nbd -x foo -f raw -t null-co:// & > >> [1] 12726 > >> $ qemu-io -c quit nbd://localhost/bar > >> can't open device nbd://localhost/bar: No export with name 'bar' available > >> [1] + 12726 broken pipe qemu-nbd -x foo -f raw -t null-co:// > >> > >> In this case, the client sends an NBD_OPT_ABORT and closes the > >> connection (because it is not required to wait for a reply), but the > >> server replies with an NBD_REP_ACK (because it is required to reply). > >> > >> Signed-off-by: Max Reitz <mre...@redhat.com> > >> --- > > > > As mentioned in another thread, I'm trying to figure out if this patch > > belongs as a third patch to fix CVE-2017-9524, or whether we want to > > open a second CVE by considering this a slightly different > > denial-of-service attack than what my patches fixed. > > I think nobody would rip our heads off if we added it to it... I think > it's similar in the regard that the NBD server tries to send something > to a client that is no longer there, so it crashes (aborting in the > original case, due to SIGPIPE here). > > But strictly speaking it's a different issue, even from the user's > perspective: In the original case you kill the server using nmap, here > you do so using a real NBD client. Hm, not sure, how hard is it to > assign a new CVE? O:-)
Have we issued a patch for CVE-2017-9524 yet ? If so, then we *must* request a new CVE, because vendors will need to track it as an additional fix to backport & ship, if they've already shipped the previous fix. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
