Subject: [PATCH 15/31] net/tls: Fix sk_psock refcnt leak when in tls_data_ready()

From: Xiyu Yang <[email-masked]>
Date: Sat, 25 Apr 2020 21:10:23 +0800

[ Upstream commit 62b4011fa7bef9fa00a6aeec26e69685dc1cc21e ]

tls_data_ready() invokes sk_psock_get(), which returns a reference of
the specified sk_psock object to "psock" with increased refcnt.

When tls_data_ready() returns, local variable "psock" becomes invalid,
so the refcount should be decreased to keep refcount balanced.

The reference counting issue happens in one exception handling path of
tls_data_ready(). When "psock->ingress_msg" is empty but "psock" is not
NULL, the function forgets to decrease the refcnt increased by
sk_psock_get(), causing a refcnt leak.

Fix this issue by calling sk_psock_put() on all paths when "psock" is
not NULL.

Signed-off-by: Xiyu Yang <[email-masked]>
Signed-off-by: Xin Tan <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/tls/tls_sw.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 7e646b2f04af..5513a08a4308 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2078,8 +2078,9 @@ static void tls_data_ready(struct sock *sk)
 	strp_data_ready(&ctx->strp);
 
 	psock = sk_psock_get(sk);
-	if (psock && !list_empty(&psock->ingress_msg)) {
-		ctx->saved_data_ready(sk);
+	if (psock) {
+		if (!list_empty(&psock->ingress_msg))
+			ctx->saved_data_ready(sk);
 		sk_psock_put(sk, psock);
 	}
 }
-- 
2.26.2