From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
The pointer opt has a null check however before for this check opt is
dereferenced when len is initialized, hence we potentially have a null
pointer deference on opt. Avoid this by checking for a null opt before
dereferencing it.
Detected by CoverityScan, CID#1458234 ("Dereference before null check")
Fixes: 4e8b86c06269 ("mqprio: Introduce new hardware offload mode and shaper in mqprio")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
net/sched/sch_mqprio.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/sched/sch_mqprio.c b/net/sched/sch_mqprio.c
index f1ae9be83934..37d5fd9b617c 100644
--- a/net/sched/sch_mqprio.c
+++ b/net/sched/sch_mqprio.c
@@ -142,7 +142,7 @@ static int mqprio_init(struct Qdisc *sch, struct nlattr *opt)
struct nlattr *tb[TCA_MQPRIO_MAX + 1];
struct nlattr *attr;
int rem;
- int len = nla_len(opt) - NLA_ALIGN(sizeof(*qopt));
+ int len;
BUILD_BUG_ON(TC_MAX_QUEUE != TC_QOPT_MAX_QUEUE);
BUILD_BUG_ON(TC_BITMASK != TC_QOPT_BITMASK);
@@ -160,6 +160,7 @@ static int mqprio_init(struct Qdisc *sch, struct nlattr *opt)
if (mqprio_parse_opt(dev, qopt))
return -EINVAL;
+ len = nla_len(opt) - NLA_ALIGN(sizeof(*qopt));
if (len > 0) {
err = parse_attr(tb, TCA_MQPRIO_MAX, opt, mqprio_policy,
sizeof(*qopt));
--
2.14.1
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