From bd150334fb4084f5555a6be26b015a0671cb5b74 Mon Sep 17 00:00:00 2001
From: Kamil Dudka <[email protected]>
Date: Tue, 22 Sep 2015 18:52:23 +0200
Subject: [PATCH] extract: prevent unsigned overflow on invalid input
Bug-Debian: https://bugs.debian.org/802162
Bug-RedHat: https://bugzilla.redhat.com/show_bug.cgi?id=1260944
Origin: https://bugzilla.redhat.com/attachment.cgi?id=1075942

Suggested-by: Stefan Cornelius
---
 extract.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/extract.c b/extract.c
index 29db027..b9ae667 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),
-- 
2.5.2