On Wed, May 31, 2017 at 01:13:32PM -0500, Eric W. Biederman wrote: > Florian Westphal <fw@xxxxxxxxx> writes: > > > Quoting Joe Stringer: > > If a user loads nf_conntrack_ftp, sends FTP traffic through a network > > namespace, destroys that namespace then unloads the FTP helper module, > > then the kernel will crash. > > > > Events that lead to the crash: > > 1. conntrack is created with ftp helper in netns x > > 2. This netns is destroyed > > 3. netns destruction is scheduled > > 4. netns destruction wq starts, removes netns from global list > > 5. ftp helper is unloaded, which resets all helpers of the conntracks > > via for_each_net() > > > > but because netns is already gone from list the for_each_net() loop > > doesn't include it, therefore all of these conntracks are unaffected. > > > > 6. helper module unload finishes > > 7. netns wq invokes destructor for rmmod'ed helper > > > > CC: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > > Reported-by: Joe Stringer <joe@xxxxxxx> > > Signed-off-by: Florian Westphal <fw@xxxxxxxxx> > > --- > > Eric, I'd like an explicit (n)ack from you for this one. > > This doesn't look too scary but I have the impression we have addressed > this elsewhere with a different solution. Eric, so you hold your nose there and I take this ;-) Or let me know if you want a different path. Thanks ! -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
