From: Meenali Gupta <meenali.gu...@windriver.com> The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.
Signed-off-by: Meenali Gupta <meenali.gu...@windriver.com> --- .../nginx/files/CVE-2023-44487.patch | 80 +++++++++++++++++++ meta-webserver/recipes-httpd/nginx/nginx.inc | 1 + 2 files changed, 81 insertions(+) create mode 100644 meta-webserver/recipes-httpd/nginx/files/CVE-2023-44487.patch diff --git a/meta-webserver/recipes-httpd/nginx/files/CVE-2023-44487.patch b/meta-webserver/recipes-httpd/nginx/files/CVE-2023-44487.patch new file mode 100644 index 0000000000..02db1503d2 --- /dev/null +++ b/meta-webserver/recipes-httpd/nginx/files/CVE-2023-44487.patch @@ -0,0 +1,80 @@ +From 95d09cafae12d4b314df32027b97e828ecf798de Mon Sep 17 00:00:00 2001 +From: Maxim Dounin <mdou...@mdounin.ru> +Date: Tue, 10 Oct 2023 15:13:39 +0300 +Subject: [PATCH] nginx: 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. + +Upstream-Status: Backport [https://github.com/nginx/nginx/commit/6ceef192e7af1c507826ac38a2d43f08bf265fb9] +CVE: CVE-2023-44487 + +Signed-off-by: Meenali Gupta <meenali.gu...@windriver.com> +--- + 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 ea3f27c..1116e56 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 4e25293..b9daf92 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; +-- +2.40.0 diff --git a/meta-webserver/recipes-httpd/nginx/nginx.inc b/meta-webserver/recipes-httpd/nginx/nginx.inc index 8078b7621a..72a7bb0c1c 100644 --- a/meta-webserver/recipes-httpd/nginx/nginx.inc +++ b/meta-webserver/recipes-httpd/nginx/nginx.inc @@ -23,6 +23,7 @@ SRC_URI = " \ file://nginx.service \ file://nginx-fix-pidfile.patch \ file://0001-configure-libxslt-conf.patch \ + file://CVE-2023-44487.patch \ " inherit siteinfo update-rc.d useradd systemd -- 2.40.0
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