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net_sched: Fix qdisc_notify()

Browse source 
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>
This commit is contained in:
Eric Dumazet 2010-05-22 20:37:44 +00:00 committed by David S. Miller
parent a6c0f8217c
commit 53b0f08042
1 changed files with 7 additions and 7 deletions
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14
net/sched/sch_api.c
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@ -1195,6 +1195,11 @@ static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
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 @@ static int qdisc_notify(struct net *net, struct sk_buff *oskb,
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 @@ static int qdisc_notify(struct net *net, struct sk_buff *oskb,
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)