From 15bf6d8cc950d3aec2d1c3152b39f62be4939025 Mon Sep 17 00:00:00 2001
From: Maxim Dounin <mdounin@mdounin.ru>
Date: Tue, 31 Aug 2021 16:44:13 +0300
Subject: [PATCH] HTTP/2: avoid memcpy() with NULL source and zero length.

Prodded by Clang Static Analyzer.
---
 src/http/v2/ngx_http_v2.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
index 5ccb36360..79c4f17c2 100644
--- a/src/http/v2/ngx_http_v2.c
+++ b/src/http/v2/ngx_http_v2.c
@@ -4241,7 +4241,9 @@ ngx_http_v2_process_request_body(ngx_http_request_t *r, u_char *pos,
                 n = size;
             }
 
-            rb->buf->last = ngx_cpymem(rb->buf->last, pos, n);
+            if (n > 0) {
+                rb->buf->last = ngx_cpymem(rb->buf->last, pos, n);
+            }
 
             ngx_log_debug1(NGX_LOG_DEBUG_HTTP, fc->log, 0,
                            "http2 request body recv %uz", n);