Resolves: RHEL-12737 - nginx:1.22/nginx: HTTP/2: Multiple HTTP/2 enabled web

servers are vulnerable to a DDoS attack (Rapid Reset Attack) (CVE-2023-44487)

0009-CVE-2023-44487-HTTP-2-per-iteration-stream-handling.patch

@@ -0,0 +1,76 @@
+From b6aa9504cdfb6391d895dcbddc87b9260ea6968c Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Lubo=C5=A1=20Uhliarik?= <luhliari@redhat.com>
+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 3611a2e..291677a 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;
+@@ -1320,6 +1321,14 @@ 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)
+@@ -1385,6 +1394,12 @@ 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 3492297..6a7aaa6 100644
+--- a/src/http/v2/ngx_http_v2.h
++++ b/src/http/v2/ngx_http_v2.h
+@@ -125,6 +125,8 @@ 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;
+-- 
+2.31.1
+

nginx.spec

@@ -56,7 +56,7 @@
 Name:              nginx
 Epoch:             1
 Version:           1.22.1
-Release:           4%{?dist}
+Release:           5%{?dist}
 
 Summary:           A high performance web server and reverse proxy server
 # BSD License (two clause)
@@ -111,6 +111,9 @@ Patch5:            0007-Enable-TLSv1.3-by-default.patch
 # https://bugzilla.redhat.com/show_bug.cgi?id=2170808
 Patch6:            0008-add-ssl-pass-phrase-dialog.patch
 
+# security fix - https://issues.redhat.com/browse/RHEL-12737
+Patch7:            0009-CVE-2023-44487-HTTP-2-per-iteration-stream-handling.patch
+
 BuildRequires:     make
 BuildRequires:     gcc
 BuildRequires:     gnupg2
@@ -623,6 +626,10 @@ fi
 
 
 %changelog
+* Mon Oct 16 2023 Luboš Uhliarik <luhliari@redhat.com> - 1:1.22.1-5
+- Resolves: RHEL-12737 - nginx:1.22/nginx: HTTP/2: Multiple HTTP/2 enabled web
+  servers are vulnerable to a DDoS attack (Rapid Reset Attack) (CVE-2023-44487)
+
 * Mon Aug 07 2023 Luboš Uhliarik <luhliari@redhat.com> - 1:1.22.1-4
 - Resolves: #2170808 - Running nginx with systemctl and entering ssl
   private key's pass phrase