From 39aef60cc5c9fd870dd4fc26cec4ff5a49e8c559 Mon Sep 17 00:00:00 2001
From: OpenWrt community <openwrt-devel@lists.openwrt.org>
Date: Mon, 30 Oct 2023 14:53:08 +0100
Subject: [PATCH] fix: buffer overflow in the zi_short function

https://nvd.nist.gov/vuln/detail/CVE-2016-9844

CVE: CVE-2016-9844
---
 zipinfo.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/zipinfo.c b/zipinfo.c
index a92bca9..0148255 100644
--- a/zipinfo.c
+++ b/zipinfo.c
@@ -1921,7 +1921,18 @@ static int zi_short(__G)   /* return PK-type error code */
         ush  dnum=(ush)((G.crec.general_purpose_bit_flag>>1) & 3);
         methbuf[3] = dtype[dnum];
     } else if (methnum >= NUM_METHODS) {   /* unknown */
-        sprintf(&methbuf[1], "%03u", G.crec.compression_method);
+        /* 2016-12-05 SMS.
+         * https://launchpad.net/bugs/1643750
+         * Unexpectedly large compression methods overflow
+         * &methbuf[].  Use the old, three-digit decimal format
+         * for values which fit.  Otherwise, sacrifice the "u",
+         * and use four-digit hexadecimal.
+         */
+        if (G.crec.compression_method <= 999) {
+            sprintf( &methbuf[ 1], "%03u", G.crec.compression_method);
+        } else {
+            sprintf( &methbuf[ 0], "%04X", G.crec.compression_method);
+        }
     }
 
     for (k = 0;  k < 15;  ++k)
--