path: root/net/qrtr/mhi.c
diff options
authorBjorn Andersson <>2021-04-21 10:40:07 -0700
committerDavid S. Miller <>2021-04-21 11:01:03 -0700
commit47a017f33943278570c072bc71681809b2567b3a (patch)
treec66d2abce9babf4914ff97d2e3b20b8cd76023b1 /net/qrtr/mhi.c
parent357a07c26697a770d39d28b6b111f978deb4017d (diff)
net: qrtr: Avoid potential use after free in MHI send
It is possible that the MHI ul_callback will be invoked immediately following the queueing of the skb for transmission, leading to the callback decrementing the refcount of the associated sk and freeing the skb. As such the dereference of skb and the increment of the sk refcount must happen before the skb is queued, to avoid the skb to be used after free and potentially the sk to drop its last refcount.. Fixes: 6e728f321393 ("net: qrtr: Add MHI transport layer") Signed-off-by: Bjorn Andersson <> Signed-off-by: David S. Miller <>
Diffstat (limited to 'net/qrtr/mhi.c')
1 files changed, 5 insertions, 3 deletions
diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c
index 2bf2b1943e61..fa611678af05 100644
--- a/net/qrtr/mhi.c
+++ b/net/qrtr/mhi.c
@@ -50,6 +50,9 @@ static int qcom_mhi_qrtr_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
struct qrtr_mhi_dev *qdev = container_of(ep, struct qrtr_mhi_dev, ep);
int rc;
+ if (skb->sk)
+ sock_hold(skb->sk);
rc = skb_linearize(skb);
if (rc)
goto free_skb;
@@ -59,12 +62,11 @@ static int qcom_mhi_qrtr_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
if (rc)
goto free_skb;
- if (skb->sk)
- sock_hold(skb->sk);
return rc;
+ if (skb->sk)
+ sock_put(skb->sk);
return rc;