[PATCH v6 5/5] net/tcp: Separate initialization of twsk

From: Dmitry Safonov
Date: Wed Nov 23 2022 - 12:40:09 EST


Convert BUG_ON() to WARN_ON_ONCE() and warn as well for unlikely
static key int overflow error-path.

Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
Acked-by: Jakub Kicinski <kuba@xxxxxxxxxx>
---
net/ipv4/tcp_minisocks.c | 61 +++++++++++++++++++++++-----------------
1 file changed, 35 insertions(+), 26 deletions(-)

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 6908812d50d3..e002f2e1d4f2 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -240,6 +240,40 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
}
EXPORT_SYMBOL(tcp_timewait_state_process);

+static void tcp_time_wait_init(struct sock *sk, struct tcp_timewait_sock *tcptw)
+{
+#ifdef CONFIG_TCP_MD5SIG
+ const struct tcp_sock *tp = tcp_sk(sk);
+ struct tcp_md5sig_key *key;
+
+ /*
+ * The timewait bucket does not have the key DB from the
+ * sock structure. We just make a quick copy of the
+ * md5 key being used (if indeed we are using one)
+ * so the timewait ack generating code has the key.
+ */
+ tcptw->tw_md5_key = NULL;
+ if (!static_branch_unlikely(&tcp_md5_needed.key))
+ return;
+
+ key = tp->af_specific->md5_lookup(sk, sk);
+ if (key) {
+ tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC);
+ if (!tcptw->tw_md5_key)
+ return;
+ if (!tcp_alloc_md5sig_pool())
+ goto out_free;
+ if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key))
+ goto out_free;
+ }
+ return;
+out_free:
+ WARN_ON_ONCE(1);
+ kfree(tcptw->tw_md5_key);
+ tcptw->tw_md5_key = NULL;
+#endif
+}
+
/*
* Move a socket to time-wait or dead fin-wait-2 state.
*/
@@ -282,32 +316,7 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
}
#endif

-#ifdef CONFIG_TCP_MD5SIG
- /*
- * The timewait bucket does not have the key DB from the
- * sock structure. We just make a quick copy of the
- * md5 key being used (if indeed we are using one)
- * so the timewait ack generating code has the key.
- */
- do {
- tcptw->tw_md5_key = NULL;
- if (static_branch_unlikely(&tcp_md5_needed.key)) {
- struct tcp_md5sig_key *key;
-
- key = tp->af_specific->md5_lookup(sk, sk);
- if (key) {
- tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC);
- if (!tcptw->tw_md5_key)
- break;
- BUG_ON(!tcp_alloc_md5sig_pool());
- if (!static_key_fast_inc_not_disabled(&tcp_md5_needed.key.key)) {
- kfree(tcptw->tw_md5_key);
- tcptw->tw_md5_key = NULL;
- }
- }
- }
- } while (0);
-#endif
+ tcp_time_wait_init(sk, tcptw);

/* Get the TIME_WAIT timeout firing. */
if (timeo < rto)
--
2.38.1