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Subject[PATCH v0] mctp: fix netdev reference bug
Date
In extended addressing mode, function mctp_local_output() fetch netdev
through dev_get_by_index_rcu, which won't increase netdev's reference
counter. Hence, the reference may underflow when mctp_local_output calls
dev_put(), results in possible use after free.

This patch adds dev_hold() to fix the reference bug.

Fixes: 99ce45d5e7db ("mctp: Implement extended addressing")
Signed-off-by: Lin Ma <linma@zju.edu.cn>
---
net/mctp/route.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/mctp/route.c b/net/mctp/route.c
index e52cef750500..a9e5d6c40c65 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -817,6 +817,7 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt,
return rc;
}

+ dev_hold(dev);
rt->dev = __mctp_dev_get(dev);
rcu_read_unlock();

--
2.35.1
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