From 673c5b95e5ead5b83cb81b208fe13a5352ccdafc Mon Sep 17 00:00:00 2001
From: OpenWrt community <openwrt-devel@lists.openwrt.org>
Date: Mon, 30 Oct 2023 14:51:36 +0100
Subject: [PATCH] fix: error to prevent unsigned overflow

---
 extract.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/extract.c b/extract.c
index ad8b3f7..17b201f 100644
--- a/extract.c
+++ b/extract.c
@@ -1257,8 +1257,17 @@ static int extract_or_test_entrylist(__G__ numchunk,
         if (G.lrec.compression_method == STORED) {
             zusz_t csiz_decrypted = G.lrec.csize;
 
-            if (G.pInfo->encrypted)
+            if (G.pInfo->encrypted) {
+                if (csiz_decrypted <= 12) {
+                    /* handle the error now to prevent unsigned overflow */
+                    Info(slide, 0x401, ((char *)slide,
+                      LoadFarStringSmall(ErrUnzipNoFile),
+                      LoadFarString(InvalidComprData),
+                      LoadFarStringSmall2(Inflate)));
+                    return PK_ERR;
+                }
                 csiz_decrypted -= 12;
+            }
             if (G.lrec.ucsize != csiz_decrypted) {
                 Info(slide, 0x401, ((char *)slide,
                   LoadFarStringSmall2(WrnStorUCSizCSizDiff),
--