tls: don't rely on tx_work during send()

With async crypto, we rely on tx_work to actually transmit records
once encryption completes. But while send() is running, both the
tx_lock and socket lock are held, so tx_work_handler cannot process
the queue of encrypted records, and simply reschedules itself. During
a large send(), this could last a long time, and use a lot of memory.

Transmit any pending encrypted records before restarting the main
loop of tls_sw_sendmsg_locked.

Fixes: a42055e8d2c3 ("net/tls: Add support for async encryption of records for performance")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://patch.msgid.link/8396631478f70454b44afb98352237d33f48d34d.1760432043.git.sd@queasysnail.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index e3d852091e7a43dbbf6ad7bc779c77e82c5dc34d..d171353699800eb05ca3b9538eb6fce92daf1fa5 100644 (file)
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -1152,6 +1152,13 @@ alloc_encrypted:
                                } else if (ret != -EAGAIN)
                                        goto send_end;
                        }
+
+                       /* Transmit if any encryptions have completed */
+                       if (test_and_clear_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask)) {
+                               cancel_delayed_work(&ctx->tx_work.work);
+                               tls_tx_records(sk, msg->msg_flags);
+                       }
+
                        continue;
 rollback_iter:
                        copied -= try_to_copy;
@@ -1207,6 +1214,12 @@ copied:
                                        goto send_end;
                                }
                        }
+
+                       /* Transmit if any encryptions have completed */
+                       if (test_and_clear_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask)) {
+                               cancel_delayed_work(&ctx->tx_work.work);
+                               tls_tx_records(sk, msg->msg_flags);
+                       }
                }
 
                continue;