From: Dmitry Volyntsev <xeioex@nginx.com>
Date: Tue, 22 Sep 2026 03:28:29 +0000 (-0700)
Subject: CHB: avoid overflow when enforcing the chain limit
X-Git-Tag: 1.0.2~18
X-Git-Url: https://git.kaiwu.me/ngx_http_auth_basic_module.html?a=commitdiff_plain;h=6611698b90464d395ee6715b910682d83f1101c1;p=njs.git

CHB: avoid overflow when enforcing the chain limit

Check the requested size against the remaining chain capacity instead of
adding it to the current total.  This prevents the size check from wrapping
and bypassing the configured chain limit.
---

diff --git a/src/njs_chb.c b/src/njs_chb.c
index eace09fe..ece3aeb0 100644
--- a/src/njs_chb.c
+++ b/src/njs_chb.c
@@ -68,7 +68,8 @@ njs_chb_reserve(njs_chb_t *chain, size_t size)
     }
 
     if (njs_slow_path(chain->max_size != 0
-                      && chain->total_size + size > chain->max_size))
+                      && (chain->total_size > chain->max_size
+                          || size > chain->max_size - chain->total_size)))
     {
         chain->error = NJS_CHB_ERR_OVERFLOW;
         return NULL;