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haproxyFreda-denoyelle
haproxyFred
authored and
a-denoyelle
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BUG/MEDIUM: quic: Possible crash during retransmissions and heavy load
This bug could be reproduced with -dMfail and dectected by libasan as follows: $ ASAN_OPTIONS=disable_coredump=0:unmap_shadow_on_exit=1:abort_on_error=f quic-freeze.cfg -dMfail -dMno-cache -dM0x55 ================================================================= ==82989==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7ffc 0x560790cc4749 bp 0x7fff8e0e8e30 sp 0x7fff8e0e8e28 WRITE of size 8 at 0x7fff8e0ea338 thread T0 #0 0x560790cc4748 in qc_frm_free src/quic_frame.c:1222 #1 0x560790cc5260 in qc_release_frm src/quic_frame.c:1261 #2 0x560790d1de99 in qc_treat_acked_tx_frm src/quic_rx.c:312 #3 0x560790d1e708 in qc_ackrng_pkts src/quic_rx.c:370 #4 0x560790d22a1d in qc_parse_ack_frm src/quic_rx.c:694 #5 0x560790d25daa in qc_parse_pkt_frms src/quic_rx.c:988 #6 0x560790d2a509 in qc_treat_rx_pkts src/quic_rx.c:1373 #7 0x560790c72d45 in quic_conn_io_cb src/quic_conn.c:906 #8 0x560791207847 in run_tasks_from_lists src/task.c:596 #9 0x5607912095f0 in process_runnable_tasks src/task.c:876 #10 0x560791135564 in run_poll_loop src/haproxy.c:2966 #11 0x5607911363af in run_thread_poll_loop src/haproxy.c:3165 #12 0x56079113938c in main src/haproxy.c:3862 #13 0x7f92606edd09 in __libc_start_main ../csu/libc-start.c:308 #14 0x560790bcd529 in _start (/home/flecaille/src/haproxy/haproxy+0x Address 0x7fff8e0ea338 is located in stack of thread T0 at offset 1032 i #0 0x560790d29b52 in qc_treat_rx_pkts src/quic_rx.c:1341 This frame has 2 object(s): [32, 48) 'ar' (line 1380) [64, 1088) '_msg' (line 1368) <== Memory access at offset 1032 is inable HINT: this may be a false positive if your program uses some custom stacnism, swapcontext or vfork (longjmp and C++ exceptions *are* supported) SUMMARY: AddressSanitizer: stack-use-after-scope src/quic_frame.c:1222 i Shadow bytes around the buggy address: 0x100071c15410: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 0x100071c15420: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 0x100071c15430: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 0x100071c15440: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 0x100071c15450: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 =>0x100071c15460: f8 f8 f8 f8 f8 f8 f8[f8]f8 f8 f8 f8 f8 f8 f3 f3 0x100071c15470: f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 00 00 0x100071c15480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x100071c15490: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x100071c154a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x100071c154b0: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 04 f3 f3 f3 Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb Shadow gap: cc ==82989==ABORTING AddressSanitizer:DEADLYSIGNAL AddressSanitizer:DEADLYSIGNAL AddressSanitizer:DEADLYSIGNAL AddressSanitizer:DEADLYSIGNAL AddressSanitizer:DEADLYSIGNAL AddressSanitizer:DEADLYSIGNAL Aborted (core dumped) Note that a coredump could not always be produced with all compilers. This was always the case with clang 11. When allocating frames to be retransmitted from qc_dgrams_retransmit(), if they could not be sent for any reason, they could remain attached to a local list to qc_dgrams_retransmit() and trigger a crash with libasan when releasing the original frames they were duplicated from. To fix this, always release the frames which could not be sent during retransmissions calling qc_free_frm_list() where needed. Must be backported as far as 2.6.
1 parent 34bc100 commit dc8a20b

1 file changed

Lines changed: 24 additions & 23 deletions

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‎src/quic_tx.c‎

Lines changed: 24 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -147,7 +147,7 @@ static void qc_dup_pkt_frms(struct quic_conn *qc,
147147
TRACE_DEVEL("built probing frame", QUIC_EV_CONN_PRSAFRM, qc, origin);
148148
if (origin->pkt) {
149149
TRACE_DEVEL("duplicated from packet", QUIC_EV_CONN_PRSAFRM,
150-
qc, NULL, &origin->pkt->pn_node.key);
150+
qc, dup_frm, &origin->pkt->pn_node.key);
151151
}
152152
else {
153153
/* <origin> is a frame which was sent from a packet detected as lost. */
@@ -1308,6 +1308,7 @@ int qc_send_hdshk_pkts(struct quic_conn *qc, int old_data,
13081308
int qc_dgrams_retransmit(struct quic_conn *qc)
13091309
{
13101310
int ret = 0;
1311+
int sret;
13111312
struct quic_pktns *ipktns = qc->ipktns;
13121313
struct quic_pktns *hpktns = qc->hpktns;
13131314
struct quic_pktns *apktns = qc->apktns;
@@ -1335,21 +1336,24 @@ int qc_dgrams_retransmit(struct quic_conn *qc)
13351336
qc->iel->retrans_frms = &ifrms;
13361337
if (qc->hel)
13371338
qc->hel->retrans_frms = &hfrms;
1338-
if (!qc_send_hdshk_pkts(qc, 1, qc->iel, qc->hel))
1339+
sret = qc_send_hdshk_pkts(qc, 1, qc->iel, qc->hel);
1340+
qc_free_frm_list(qc, &ifrms);
1341+
qc_free_frm_list(qc, &hfrms);
1342+
if (!sret)
13391343
goto leave;
1340-
/* Put back unsent frames in their packet number spaces */
1341-
LIST_SPLICE(&ipktns->tx.frms, &ifrms);
1342-
if (hpktns)
1343-
LIST_SPLICE(&hpktns->tx.frms, &hfrms);
13441344
}
13451345
else {
13461346
/* We are in the case where the anti-amplification limit will be
1347-
* reached after having sent this datagram. There is no need to
1348-
* send more than one datagram.
1347+
* reached after having sent this datagram or some handshake frames
1348+
* could not be allocated. There is no need to send more than one
1349+
* datagram.
13491350
*/
13501351
ipktns->tx.pto_probe = 1;
13511352
qc->iel->retrans_frms = &ifrms;
1352-
if (!qc_send_hdshk_pkts(qc, 0, qc->iel, NULL))
1353+
sret = qc_send_hdshk_pkts(qc, 0, qc->iel, NULL);
1354+
qc_free_frm_list(qc, &ifrms);
1355+
qc_free_frm_list(qc, &hfrms);
1356+
if (!sret)
13531357
goto leave;
13541358

13551359
break;
@@ -1374,11 +1378,10 @@ int qc_dgrams_retransmit(struct quic_conn *qc)
13741378
if (!LIST_ISEMPTY(&frms1)) {
13751379
hpktns->tx.pto_probe = 1;
13761380
qc->hel->retrans_frms = &frms1;
1377-
if (!qc_send_hdshk_pkts(qc, 1, qc->hel, NULL))
1381+
sret = qc_send_hdshk_pkts(qc, 1, qc->hel, NULL);
1382+
qc_free_frm_list(qc, &frms1);
1383+
if (!sret)
13781384
goto leave;
1379-
1380-
/* Put back unsent frames into their packet number spaces */
1381-
LIST_SPLICE(&hpktns->tx.frms, &frms1);
13821385
}
13831386
}
13841387
TRACE_STATE("no more need to probe Handshake packet number space",
@@ -1393,25 +1396,23 @@ int qc_dgrams_retransmit(struct quic_conn *qc)
13931396
qc_prep_fast_retrans(qc, apktns, &frms1, &frms2);
13941397
TRACE_PROTO("Avail. ack eliciting frames", QUIC_EV_CONN_FRMLIST, qc, &frms1);
13951398
TRACE_PROTO("Avail. ack eliciting frames", QUIC_EV_CONN_FRMLIST, qc, &frms2);
1399+
13961400
if (!LIST_ISEMPTY(&frms1)) {
13971401
apktns->tx.pto_probe = 1;
1398-
if (!qc_send_app_probing(qc, &frms1)) {
1399-
qc_free_frm_list(qc, &frms1);
1402+
sret = qc_send_app_probing(qc, &frms1);
1403+
qc_free_frm_list(qc, &frms1);
1404+
if (!sret) {
14001405
qc_free_frm_list(qc, &frms2);
14011406
goto leave;
14021407
}
1403-
1404-
/* Put back unsent frames into their packet number spaces */
1405-
LIST_SPLICE(&apktns->tx.frms, &frms1);
14061408
}
1409+
14071410
if (!LIST_ISEMPTY(&frms2)) {
14081411
apktns->tx.pto_probe = 1;
1409-
if (!qc_send_app_probing(qc, &frms2)) {
1410-
qc_free_frm_list(qc, &frms2);
1412+
sret = qc_send_app_probing(qc, &frms2);
1413+
qc_free_frm_list(qc, &frms2);
1414+
if (!sret)
14111415
goto leave;
1412-
}
1413-
/* Put back unsent frames into their packet number spaces */
1414-
LIST_SPLICE(&apktns->tx.frms, &frms2);
14151416
}
14161417
TRACE_STATE("no more need to probe 01RTT packet number space",
14171418
QUIC_EV_CONN_TXPKT, qc);

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