ACK manager must avoid infinite probe time when waiting handshake confirmation

According to RFC 9002, section 6.2.2.1 the client the client must keep PTO (probe
time out) armed if it has not seen HANDSHAKE_DONE quic message from server.
Not following RFC spec here may cause the QUIC session to stale during TLS handshake.

Fixes openssl/project#1266

Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/28023)

include/internal/quic_ackm.h

@@ -23,7 +23,7 @@ OSSL_ACKM *ossl_ackm_new(OSSL_TIME (*now)(void *arg),
                          void *now_arg,
                          OSSL_STATM *statm,
                          const OSSL_CC_METHOD *cc_method,
-                         OSSL_CC_DATA *cc_data);
+                         OSSL_CC_DATA *cc_data, char is_server);
 void ossl_ackm_free(OSSL_ACKM *ackm);
 
 void ossl_ackm_set_loss_detection_deadline_callback(OSSL_ACKM *ackm,

ssl/quic/quic_ackm.c

@@ -536,6 +536,9 @@ struct ossl_ackm_st {
     /* Set to 1 when the handshake is confirmed. */
     char            handshake_confirmed;
 
+    /* Set to 1 when attached to server channel */
+    char            is_server;
+
     /* Set to 1 when the peer has completed address validation. */
     char            peer_completed_addr_validation;
 
@@ -855,7 +858,13 @@ static OSSL_TIME ackm_get_pto_time_and_space(OSSL_ACKM *ackm, int *space)
     }
 
     for (i = QUIC_PN_SPACE_INITIAL; i < QUIC_PN_SPACE_NUM; ++i) {
-        if (ackm->ack_eliciting_bytes_in_flight[i] == 0)
+        /*
+         * RFC 9002 section 5.2.2.1 keep probe timeout armed until
+         * handshake is confirmed (client sees HANDSHAKE_DONE message
+         * from server(.
+         */
+        if (ackm->ack_eliciting_bytes_in_flight[i] == 0 &&
+            (ackm->handshake_confirmed == 1 || ackm->is_server == 1))
             continue;
 
         if (i == QUIC_PN_SPACE_APP) {
@@ -875,10 +884,18 @@ static OSSL_TIME ackm_get_pto_time_and_space(OSSL_ACKM *ackm, int *space)
             }
         }
 
-        t = ossl_time_add(ackm->time_of_last_ack_eliciting_pkt[i], duration);
+        /*
-        if (ossl_time_compare(t, pto_timeout) < 0) {
+         * Only re-arm timer if stack has sent at least one ACK eliciting frame.
-            pto_timeout = t;
+         * If stack has sent no ACK eliciting at given encryption level then
-            pto_space   = i;
+         * particular timer is zero and we must not attempt to set it. Timer time
+         * runs since epoch (Jan 1 1970 and we must not set timer to past.
+         */
+        if (!ossl_time_is_zero(ackm->time_of_last_ack_eliciting_pkt[i])) {
+	    t = ossl_time_add(ackm->time_of_last_ack_eliciting_pkt[i], duration);
+	    if (ossl_time_compare(t, pto_timeout) < 0) {
+		pto_timeout = t;
+		pto_space   = i;
+	    }
         }
     }
 
@@ -1021,7 +1038,8 @@ OSSL_ACKM *ossl_ackm_new(OSSL_TIME (*now)(void *arg),
                          void *now_arg,
                          OSSL_STATM *statm,
                          const OSSL_CC_METHOD *cc_method,
-                         OSSL_CC_DATA *cc_data)
+                         OSSL_CC_DATA *cc_data,
+                         char is_server)
 {
     OSSL_ACKM *ackm;
     int i;
@@ -1045,6 +1063,7 @@ OSSL_ACKM *ossl_ackm_new(OSSL_TIME (*now)(void *arg),
     ackm->statm     = statm;
     ackm->cc_method = cc_method;
     ackm->cc_data   = cc_data;
+    ackm->is_server = is_server;
 
     ackm->rx_max_ack_delay = ossl_ms2time(QUIC_DEFAULT_MAX_ACK_DELAY);
     ackm->tx_max_ack_delay = DEFAULT_TX_MAX_ACK_DELAY;

ssl/quic/quic_channel.c

@@ -242,7 +242,8 @@ static int ch_init(QUIC_CHANNEL *ch)
         goto err;
 
     if ((ch->ackm = ossl_ackm_new(get_time, ch, &ch->statm,
-                                  ch->cc_method, ch->cc_data)) == NULL)
+                                  ch->cc_method, ch->cc_data,
+                                  ch->is_server)) == NULL)
         goto err;
 
     if (!ossl_quic_stream_map_init(&ch->qsm, get_stream_limit, ch,

test/quic_ackm_test.c

@@ -104,7 +104,8 @@ static int helper_init(struct helper *h, size_t num_pkts)
 
     /* Initialise ACK manager. */
     h->ackm = ossl_ackm_new(fake_now, NULL, &h->statm,
-                            &ossl_cc_dummy_method, h->ccdata);
+                            &ossl_cc_dummy_method, h->ccdata,
+                            /* is_server */0);
     if (!TEST_ptr(h->ackm))
         goto err;
 

test/quic_fifd_test.c

@@ -329,7 +329,8 @@ static int test_fifd(int idx)
         || !TEST_ptr(info.ackm = ossl_ackm_new(fake_now, NULL,
                                                &info.statm,
                                                &ossl_cc_dummy_method,
-                                               info.ccdata))
+                                               info.ccdata,
+                                               /* is_server */0))
         || !TEST_true(ossl_ackm_on_handshake_confirmed(info.ackm))
         || !TEST_ptr(info.cfq = ossl_quic_cfq_new())
         || !TEST_ptr(info.txpim = ossl_quic_txpim_new())

test/quic_txp_test.c

@@ -182,7 +182,8 @@ static int helper_init(struct helper *h)
     if (!TEST_ptr(h->args.ackm = ossl_ackm_new(fake_now, NULL,
                                                &h->statm,
                                                h->cc_method,
-                                               h->cc_data)))
+                                               h->cc_data,
+                                               /* is_server */0)))
         goto err;
 
     if (!TEST_true(ossl_quic_stream_map_init(&h->qsm, NULL, NULL,