details: https://hg.nginx.org/nginx/rev/b19cd299f37c
branches: stable-1.16
changeset: 7554:b19cd299f37c
user: Sergey Kandaurov <pluknet@nginx.com>
date: Tue Aug 13 15:43:32 2019 +0300
description:
HTTP/2: reject zero length headers with PROTOCOL_ERROR.

Fixed uncontrolled memory growth if peer sends a stream of
headers with a 0-length header name and 0-length header value.
Fix is to reject headers with zero name length.

diffstat:

src/http/v2/ngx_http_v2.c | 12 ++++++++----
1 files changed, 8 insertions(+), 4 deletions(-)

diffs (29 lines):

diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
--- a/src/http/v2/ngx_http_v2.c
+++ b/src/http/v2/ngx_http_v2.c
@@ -1546,6 +1546,14 @@ ngx_http_v2_state_process_header(ngx_htt
header->name.len = h2c->state.field_end - h2c->state.field_start;
header->name.data = h2c->state.field_start;

+ if (header->name.len == 0) {
+ ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0,
+ "client sent zero header name length");
+
+ return ngx_http_v2_connection_error(h2c,
+ NGX_HTTP_V2_PROTOCOL_ERROR);
+ }
+
return ngx_http_v2_state_field_len(h2c, pos, end);
}

@@ -3249,10 +3257,6 @@ ngx_http_v2_validate_header(ngx_http_req
ngx_uint_t i;
ngx_http_core_srv_conf_t *cscf;

- if (header->name.len == 0) {
- return NGX_ERROR;
- }
-
r->invalid_header = 0;

cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);
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