From:   Pietro Borrello <borrello@diag.uniroma1.it>
Date:   Sat, 28 Jan 2023 16:29:17 +0000
Subject: [PATCH net-next] net/tls: tls_is_tx_ready() checked list_entry
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Message-Id: <20230128-list-entry-null-check-tls-v1-1-525bbfe6f0d0@diag.uniroma1.it>
To:     Boris Pismenny <borisp@nvidia.com>,
        John Fastabend <john.fastabend@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Vakul Garg <vakul.garg@nxp.com>
Cc:     Cristiano Giuffrida <c.giuffrida@vu.nl>,
        "Bos, H.J." <h.j.bos@vu.nl>, Jakob Koschel <jkl820.git@gmail.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Pietro Borrello <borrello@diag.uniroma1.it>
Precedence: bulk

tls_is_tx_ready() checks that list_first_entry() does not return NULL.
This condition can never happen. For empty lists, list_first_entry()
returns the list_entry() of the head, which is a type confusion.
Use list_first_entry_or_null() which returns NULL in case of empty
lists.

Fixes: a42055e8d2c3 ("net/tls: Add support for async encryption of records for performance")
Signed-off-by: Pietro Borrello <borrello@diag.uniroma1.it>
---
 net/tls/tls_sw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 9ed978634125..a83d2b4275fa 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2427,7 +2427,7 @@ static bool tls_is_tx_ready(struct tls_sw_context_tx *ctx)
 {
 	struct tls_rec *rec;
 
-	rec = list_first_entry(&ctx->tx_list, struct tls_rec, list);
+	rec = list_first_entry_or_null(&ctx->tx_list, struct tls_rec, list);
 	if (!rec)
 		return false;
 

---
base-commit: 2241ab53cbb5cdb08a6b2d4688feb13971058f65
change-id: 20230128-list-entry-null-check-tls-92da3440d32e

Best regards,
-- 
Pietro Borrello <borrello@diag.uniroma1.it>