Message ID | 1309796566-2645-2-git-send-email-paolo.pisati@canonical.com |
---|---|
State | New |
Headers | show |
On Mon, Jul 04, 2011 at 05:22:41PM +0100, paolo.pisati@canonical.com wrote: > From: Eric Dumazet <eric.dumazet@gmail.com> > > CVE-2010-4249 > > BugLink: http://bugs.launchpad.net/bugs/769182 > > commit upstream 9915672d41273f5b77f1b3c29b391ffb7732b84b > > Vegard Nossum found a unix socket OOM was possible, posting an exploit > program. > > My analysis is we can eat all LOWMEM memory before unix_gc() being > called from unix_release_sock(). Moreover, the thread blocked in > unix_gc() can consume huge amount of time to perform cleanup because of > huge working set. > > One way to handle this is to have a sensible limit on unix_tot_inflight, > tested from wait_for_unix_gc() and to force a call to unix_gc() if this > limit is hit. > > This solves the OOM and also reduce overall latencies, and should not > slowdown normal workloads. > > Reported-by: Vegard Nossum <vegard.nossum@gmail.com> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> > Signed-off-by: David S. Miller <davem@davemloft.net> > Signed-off-by: Brad Figg <brad.figg@canonical.com> > Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com> > --- > net/unix/garbage.c | 7 +++++++ > 1 files changed, 7 insertions(+), 0 deletions(-) > > diff --git a/net/unix/garbage.c b/net/unix/garbage.c > index 07499a5..dc2cb61 100644 > --- a/net/unix/garbage.c > +++ b/net/unix/garbage.c > @@ -269,9 +269,16 @@ static void inc_inflight_move_tail(struct unix_sock *u) > } > > static bool gc_in_progress = false; > +#define UNIX_INFLIGHT_TRIGGER_GC 16000 > > void wait_for_unix_gc(void) > { > + /* > + * If number of inflight sockets is insane, > + * force a garbage collect right now. > + */ > + if (unix_tot_inflight > UNIX_INFLIGHT_TRIGGER_GC && !gc_in_progress) > + unix_gc(); > wait_event(unix_gc_wait, gc_in_progress == false); > } Appears identicle to the upstream fix. Looks to do what it claims. Acked-by: Andy Whitcroft <apw@canonical.com> -apw
diff --git a/net/unix/garbage.c b/net/unix/garbage.c index 07499a5..dc2cb61 100644 --- a/net/unix/garbage.c +++ b/net/unix/garbage.c @@ -269,9 +269,16 @@ static void inc_inflight_move_tail(struct unix_sock *u) } static bool gc_in_progress = false; +#define UNIX_INFLIGHT_TRIGGER_GC 16000 void wait_for_unix_gc(void) { + /* + * If number of inflight sockets is insane, + * force a garbage collect right now. + */ + if (unix_tot_inflight > UNIX_INFLIGHT_TRIGGER_GC && !gc_in_progress) + unix_gc(); wait_event(unix_gc_wait, gc_in_progress == false); }