Fixed chunk size parsing.

src/http/ngx_http_parse.c

diff --git a/src/http/ngx_http_parse.c b/src/http/ngx_http_parse.c
index 34b3b85..3c168aa 100644
--- a/src/http/ngx_http_parse.c
+++ b/src/http/ngx_http_parse.c
@@ -2209,6 +2209,10 @@
 
     }
 
+    if (ctx->size < 0 || ctx->length < 0) {
+        goto invalid;
+    }
+
     return rc;
 
 done: