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authorMaxim Mikityanskiy <maximmi@nvidia.com>2021-03-11 16:42:05 +0200
committerDavid S. Miller <davem@davemloft.net>2021-03-11 18:30:32 -0800
commit93bde210c4341e79f0cd9cb160d889f4577e40b1 (patch)
tree6d79a62ca47853b088e41d919a71b3489cf8f5c4 /net
parent7a1468ba0e02eee24ae1353e8933793a27198e20 (diff)
downloadlinux-93bde210c4341e79f0cd9cb160d889f4577e40b1.tar.gz
sch_htb: Fix select_queue for non-offload mode
htb_select_queue assumes it's always the offload mode, and it ends up in
calling ndo_setup_tc without any checks. It may lead to a NULL pointer
dereference if ndo_setup_tc is not implemented, or to an error returned
from the driver, which will prevent attaching qdiscs to HTB classes in
the non-offload mode.

This commit fixes the bug by adding the missing check to
htb_select_queue. In the non-offload mode it will return sch->dev_queue,
mimicking tc_modify_qdisc's behavior for the case where select_queue is
not implemented.

Reported-by: syzbot+b53a709f04722ca12a3c@syzkaller.appspotmail.com
Fixes: d03b195b5aa0 ("sch_htb: Hierarchical QoS hardware offload")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sched/sch_htb.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index dff3adf5a915..b23203159996 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1340,8 +1340,12 @@ htb_select_queue(struct Qdisc *sch, struct tcmsg *tcm)
 {
 	struct net_device *dev = qdisc_dev(sch);
 	struct tc_htb_qopt_offload offload_opt;
+	struct htb_sched *q = qdisc_priv(sch);
 	int err;
 
+	if (!q->offload)
+		return sch->dev_queue;
+
 	offload_opt = (struct tc_htb_qopt_offload) {
 		.command = TC_HTB_LEAF_QUERY_QUEUE,
 		.classid = TC_H_MIN(tcm->tcm_parent),