net_sched: Fix qdisc_notify()
Ben Pfaff reported a kernel oops and provided a test program to
reproduce it.
https://kerneltrap.org/mailarchive/linux-netdev/2010/5/21/6277805
tc_fill_qdisc() should not be called for builtin qdisc, or it
dereference a NULL pointer to get device ifindex.
Fix is to always use tc_qdisc_dump_ignore() before calling
tc_fill_qdisc().
Reported-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index fe35c1f..b9e8c3b 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1195,6 +1195,11 @@
return -1;
}
+static bool tc_qdisc_dump_ignore(struct Qdisc *q)
+{
+ return (q->flags & TCQ_F_BUILTIN) ? true : false;
+}
+
static int qdisc_notify(struct net *net, struct sk_buff *oskb,
struct nlmsghdr *n, u32 clid,
struct Qdisc *old, struct Qdisc *new)
@@ -1206,11 +1211,11 @@
if (!skb)
return -ENOBUFS;
- if (old && old->handle) {
+ if (old && !tc_qdisc_dump_ignore(old)) {
if (tc_fill_qdisc(skb, old, clid, pid, n->nlmsg_seq, 0, RTM_DELQDISC) < 0)
goto err_out;
}
- if (new) {
+ if (new && !tc_qdisc_dump_ignore(new)) {
if (tc_fill_qdisc(skb, new, clid, pid, n->nlmsg_seq, old ? NLM_F_REPLACE : 0, RTM_NEWQDISC) < 0)
goto err_out;
}
@@ -1223,11 +1228,6 @@
return -EINVAL;
}
-static bool tc_qdisc_dump_ignore(struct Qdisc *q)
-{
- return (q->flags & TCQ_F_BUILTIN) ? true : false;
-}
-
static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
struct netlink_callback *cb,
int *q_idx_p, int s_q_idx)