From 0805ec043ecb4f2b43782ec06779a27fa8d06d4a Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Wed, 1 Apr 2026 09:53:42 +0200 Subject: [PATCH] altsvc: cap the list at 5,000 entries Avoid never-ending growth. When adding more entries, it now deletes the first entry in the list, which is the oldest added entry still held in memory. I decided to avoid a Least Recently Used concept as I suspect with a list with this many entries most entries have not been used, and we don't save the timestamp of recent use anyway. The net effect might (no matter what) be that the removed entry might feel a bit "random" in the eyes of the user. Verify with test 1669. Reported-by: Geeknik Labs Fixes #21183 Closes #21189 --- lib/altsvc.c | 23 ++++++++++++---- lib/altsvc.h | 3 +++ tests/data/Makefile.am | 2 +- tests/data/test1669 | 37 ++++++++++++++++++++++++++ tests/unit/Makefile.inc | 2 +- tests/unit/unit1669.c | 58 +++++++++++++++++++++++++++++++++++++++++ 6 files changed, 118 insertions(+), 7 deletions(-) create mode 100644 tests/data/test1669 create mode 100644 tests/unit/unit1669.c diff --git a/lib/altsvc.c b/lib/altsvc.c index eb072bb49d..e0834cb663 100644 --- a/lib/altsvc.c +++ b/lib/altsvc.c @@ -144,6 +144,20 @@ static struct altsvc *altsvc_create(struct Curl_str *srchost, srcport, dstport); } +/* append the new entry to the list after possibly removing an old entry + first */ +static void altsvc_append(struct altsvcinfo *asi, struct altsvc *as) +{ + while(Curl_llist_count(&asi->list) >= MAX_ALTSVC_ENTRIES) { + /* It's full. Remove the first entry in the list */ + struct Curl_llist_node *e = Curl_llist_head(&asi->list); + struct altsvc *oldas = Curl_node_elem(e); + Curl_node_remove(e); + altsvc_free(oldas); + } + Curl_llist_append(&asi->list, as, &as->node); +} + /* only returns SERIOUS errors */ static CURLcode altsvc_add(struct altsvcinfo *asi, const char *line) { @@ -180,7 +194,6 @@ static CURLcode altsvc_add(struct altsvcinfo *asi, const char *line) curlx_str_newline(&line)) ; else { - struct altsvc *as; char dbuf[MAX_ALTSVC_DATELEN + 1]; time_t expires = 0; time_t now = time(NULL); @@ -192,12 +205,12 @@ static CURLcode altsvc_add(struct altsvcinfo *asi, const char *line) Curl_getdate_capped(dbuf, &expires); if(now < expires) { - as = altsvc_create(&srchost, &dsthost, &srcalpn, &dstalpn, - (size_t)srcport, (size_t)dstport); + struct altsvc *as = altsvc_create(&srchost, &dsthost, &srcalpn, &dstalpn, + (size_t)srcport, (size_t)dstport); if(as) { as->expires = expires; as->persist = persist ? 1 : 0; - Curl_llist_append(&asi->list, as, &as->node); + altsvc_append(asi, as); } else return CURLE_OUT_OF_MEMORY; @@ -594,7 +607,7 @@ CURLcode Curl_altsvc_parse(struct Curl_easy *data, else as->expires = maxage + secs; as->persist = persist; - Curl_llist_append(&asi->list, as, &as->node); + altsvc_append(asi, as); infof(data, "Added alt-svc: %.*s:%d over %s", (int)curlx_strlen(&dsthost), curlx_str(&dsthost), dstport, Curl_alpnid2str(dstalpnid)); diff --git a/lib/altsvc.h b/lib/altsvc.h index d1fed4fe1d..dc1740bce1 100644 --- a/lib/altsvc.h +++ b/lib/altsvc.h @@ -28,6 +28,9 @@ #if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_ALTSVC) #include "llist.h" +/* the maximum number of alt-svc entries kept in a single cache */ +#define MAX_ALTSVC_ENTRIES 5000 + struct althost { char *host; uint16_t port; diff --git a/tests/data/Makefile.am b/tests/data/Makefile.am index 78e3f26585..c3496b133f 100644 --- a/tests/data/Makefile.am +++ b/tests/data/Makefile.am @@ -221,7 +221,7 @@ test1638 test1639 test1640 test1641 test1642 test1643 test1644 \ \ test1650 test1651 test1652 test1653 test1654 test1655 test1656 test1657 \ test1658 test1659 test1660 test1661 test1662 test1663 test1664 test1665 \ -test1666 test1667 test1668 \ +test1666 test1667 test1668 test1669 \ \ test1670 test1671 test1672 test1673 \ \ diff --git a/tests/data/test1669 b/tests/data/test1669 new file mode 100644 index 0000000000..204b45b506 --- /dev/null +++ b/tests/data/test1669 @@ -0,0 +1,37 @@ + + + + +unittest +Alt-Svc + + + + + +unittest +alt-svc + + +# This date is exactly "20190124 22:34:21" UTC + +CURL_TIME=1548369261 + + +alt-svc load cache with >5000 entries + + +%LOGDIR/%TESTNUMBER + + +%repeat[5010 x h2 example.com 443 h3 shiny.example.com 8443 "20191231 00:00:00" 0 0%0a]% + + + + + +Allocations: 5100 +Maximum allocated: 600000 + + + diff --git a/tests/unit/Makefile.inc b/tests/unit/Makefile.inc index 459aee5f84..d8b2ed2d2e 100644 --- a/tests/unit/Makefile.inc +++ b/tests/unit/Makefile.inc @@ -41,7 +41,7 @@ TESTS_C = \ unit1636.c \ unit1650.c unit1651.c unit1652.c unit1653.c unit1654.c unit1655.c unit1656.c \ unit1657.c unit1658.c unit1660.c unit1661.c unit1663.c unit1664.c \ - unit1666.c unit1667.c unit1668.c \ + unit1666.c unit1667.c unit1668.c unit1669.c \ unit1979.c unit1980.c \ unit2600.c unit2601.c unit2602.c unit2603.c unit2604.c unit2605.c \ unit3200.c unit3205.c \ diff --git a/tests/unit/unit1669.c b/tests/unit/unit1669.c new file mode 100644 index 0000000000..625e004084 --- /dev/null +++ b/tests/unit/unit1669.c @@ -0,0 +1,58 @@ +/*************************************************************************** + * _ _ ____ _ + * Project ___| | | | _ \| | + * / __| | | | |_) | | + * | (__| |_| | _ <| |___ + * \___|\___/|_| \_\_____| + * + * Copyright (C) Daniel Stenberg, , et al. + * + * This software is licensed as described in the file COPYING, which + * you should have received as part of this distribution. The terms + * are also available at https://curl.se/docs/copyright.html. + * + * You may opt to use, copy, modify, merge, publish, distribute and/or sell + * copies of the Software, and permit persons to whom the Software is + * furnished to do so, under the terms of the COPYING file. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + * SPDX-License-Identifier: curl + * + ***************************************************************************/ +#include "unitcheck.h" + +#include "urldata.h" +#include "altsvc.h" + +static CURLcode test_unit1669(const char *arg) +{ + UNITTEST_BEGIN_SIMPLE + +#if !defined(CURL_DISABLE_HTTP) && !defined(CURL_DISABLE_ALTSVC) + char outname[256]; + CURL *curl; + CURLcode result; + struct altsvcinfo *asi = Curl_altsvc_init(); + abort_if(!asi, "Curl_altsvc_init"); + result = Curl_altsvc_load(asi, arg); + fail_if(result, "Curl_altsvc_load"); + if(result) + goto fail; + curl_global_init(CURL_GLOBAL_ALL); + curl = curl_easy_init(); + fail_if(!curl, "curl_easy_init"); + if(!curl) + goto fail; + fail_unless(Curl_llist_count(&asi->list) == MAX_ALTSVC_ENTRIES, + "wrong number of entries"); + curl_msnprintf(outname, sizeof(outname), "%s-out", arg); + + curl_easy_cleanup(curl); +fail: + Curl_altsvc_cleanup(&asi); +#endif + + UNITTEST_END(curl_global_cleanup()) +}