From 021aed75f89e41890273b66f47e6b93fe713a8c5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lubo=C5=A1=20Uhliarik?= Date: Mon, 16 Oct 2023 13:32:20 +0200 Subject: [PATCH] Resolves: RHEL-12728 - nginx:1.22/nginx: HTTP/2: Multiple HTTP/2 enabled web servers are vulnerable to a DDoS attack (Rapid Reset Attack)(CVE-2023-44487) --- nginx-1.22-CVE-2023-44487.patch | 73 +++++++++++++++++++++++++++++++++ nginx.spec | 10 ++++- 2 files changed, 82 insertions(+), 1 deletion(-) create mode 100644 nginx-1.22-CVE-2023-44487.patch diff --git a/nginx-1.22-CVE-2023-44487.patch b/nginx-1.22-CVE-2023-44487.patch new file mode 100644 index 0000000..4b88fe4 --- /dev/null +++ b/nginx-1.22-CVE-2023-44487.patch @@ -0,0 +1,73 @@ +From b6aa9504cdfb6391d895dcbddc87b9260ea6968c Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Lubo=C5=A1=20Uhliarik?= +Date: Wed, 11 Oct 2023 09:59:23 +0200 +Subject: [PATCH] CVE-2023-44487 - HTTP/2: per-iteration stream handling limit. + +To ensure that attempts to flood servers with many streams are detected +early, a limit of no more than 2 * max_concurrent_streams new streams per one +event loop iteration was introduced. This limit is applied even if +max_concurrent_streams is not yet reached - for example, if corresponding +streams are handled synchronously or reset. + +Further, refused streams are now limited to maximum of max_concurrent_streams +and 100, similarly to priority_limit initial value, providing some tolerance +to clients trying to open several streams at the connection start, yet +low tolerance to flooding attempts. +--- + src/http/v2/ngx_http_v2.c | 15 +++++++++++++++ + src/http/v2/ngx_http_v2.h | 2 ++ + 2 files changed, 17 insertions(+) + +diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c +index 0e45a7b..253718f 100644 +--- a/src/http/v2/ngx_http_v2.c ++++ b/src/http/v2/ngx_http_v2.c +@@ -361,6 +361,7 @@ ngx_http_v2_read_handler(ngx_event_t *rev) + ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http2 read handler"); + + h2c->blocked = 1; ++ h2c->new_streams = 0; + + if (c->close) { + c->close = 0; +@@ -1321,6 +1322,14 @@ ngx_http_v2_state_headers(ngx_http_v2_connection_t *h2c, u_char *pos, + goto rst_stream; + } + ++ if (h2c->new_streams++ >= 2 * h2scf->concurrent_streams) { ++ ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, ++ "client sent too many streams at once"); ++ ++ status = NGX_HTTP_V2_REFUSED_STREAM; ++ goto rst_stream; ++ } ++ + if (!h2c->settings_ack + && !(h2c->state.flags & NGX_HTTP_V2_END_STREAM_FLAG) + && h2scf->preread_size < NGX_HTTP_V2_DEFAULT_WINDOW) +@@ -1386,6 +1395,12 @@ ngx_http_v2_state_headers(ngx_http_v2_connection_t *h2c, u_char *pos, + + rst_stream: + ++ if (h2c->refused_streams++ > ngx_max(h2scf->concurrent_streams, 100)) { ++ ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, ++ "client sent too many refused streams"); ++ return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_NO_ERROR); ++ } ++ + if (ngx_http_v2_send_rst_stream(h2c, h2c->state.sid, status) != NGX_OK) { + return ngx_http_v2_connection_error(h2c, NGX_HTTP_V2_INTERNAL_ERROR); + } +diff --git a/src/http/v2/ngx_http_v2.h b/src/http/v2/ngx_http_v2.h +index 70ee287..7593f1c 100644 +--- a/src/http/v2/ngx_http_v2.h ++++ b/src/http/v2/ngx_http_v2.h +@@ -124,6 +124,8 @@ struct ngx_http_v2_connection_s { + ngx_uint_t processing; + ngx_uint_t frames; + ngx_uint_t idle; ++ ngx_uint_t new_streams; ++ ngx_uint_t refused_streams; + ngx_uint_t priority_limit; + + ngx_uint_t pushing; diff --git a/nginx.spec b/nginx.spec index fa4914b..809408c 100644 --- a/nginx.spec +++ b/nginx.spec @@ -30,7 +30,7 @@ Name: nginx Epoch: 1 Version: 1.22.1 -Release: 1%{?dist} +Release: 2%{?dist} Summary: A high performance web server and reverse proxy server Group: System Environment/Daemons @@ -74,6 +74,9 @@ Patch4: nginx-1.20.0-enable-tls1v3-by-default.patch # https://bugzilla.redhat.com/show_bug.cgi?id=1668717 Patch5: nginx-1.18.0-pkcs11-cert.patch +# https://issues.redhat.com/browse/RHEL-12728 +Patch6: nginx-1.22-CVE-2023-44487.patch + %if 0%{?with_gperftools} BuildRequires: gperftools-devel %endif @@ -230,6 +233,7 @@ Requires: zlib-devel %patch3 -p1 %patch4 -p1 %patch5 -p1 +%patch6 -p1 cp %{SOURCE200} %{SOURCE210} %{SOURCE10} %{SOURCE12} . @@ -542,6 +546,10 @@ fi %{nginx_srcdir}/ %changelog +* Mon Oct 16 2023 Luboš Uhliarik - 1:1.22.1-2 +- Resolves: RHEL-12728 - nginx:1.22/nginx: HTTP/2: Multiple HTTP/2 enabled web + servers are vulnerable to a DDoS attack (Rapid Reset Attack)(CVE-2023-44487) + * Thu Dec 01 2022 Luboš Uhliarik - 1:1.22.1-1 - Resolves: #2112345 - nginx:1.22 for RHEL 8 - add stream_geoip_module and stream_realip_module