From 7eec5e4b9a4b6efea5ef5f6b793a6cbef40e980d Mon Sep 17 00:00:00 2001
From: Jakub Martisko <jamartis@redhat.com>
Date: Wed, 23 May 2018 10:15:07 +0200
Subject: [PATCH] fix: CVE-2018-7726

---
 zzip/zip.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/zzip/zip.c b/zzip/zip.c
index a574b24..a6c7ced 100644
--- a/zzip/zip.c
+++ b/zzip/zip.c
@@ -323,6 +323,8 @@ __zzip_fetch_disk_trailer(int fd, zzip_off_t filesize,
                     trailer->zz_rootseek = zzip_disk_trailer_rootseek(orig);
                     trailer->zz_rootsize = zzip_disk_trailer_rootsize(orig);
 #                  endif
+                    if (trailer->zz_rootseek < 0 || trailer->zz_rootsize < 0)
+                       return(ZZIP_CORRUPTED); // forged value
 
                     __fixup_rootseek(offset + tail - mapped, trailer);
                     { return(0); }
@@ -343,6 +345,14 @@ __zzip_fetch_disk_trailer(int fd, zzip_off_t filesize,
                         zzip_disk64_trailer_finalentries(orig);
                     trailer->zz_rootseek = zzip_disk64_trailer_rootseek(orig);
                     trailer->zz_rootsize = zzip_disk64_trailer_rootsize(orig);
+                    if (trailer->zz_rootseek < 0 || trailer->zz_rootsize < 0)
+                       return(ZZIP_CORRUPTED); // forged value
+                    /*
+ 		     * "extract data from files archived in a single zip file."
+ 		     * So the file offsets must be within the current ZIP archive!
+		     */
+                    if (trailer->zz_rootseek >= filesize || (trailer->zz_rootseek + trailer->zz_rootsize) >= filesize)
+                        return(ZZIP_CORRUPTED);
                     { return(0); }
 #                  endif
                 }
@@ -410,6 +420,8 @@ __zzip_parse_root_directory(int fd,
     zzip_off64_t zz_rootsize = _disk_trailer_rootsize(trailer);
     zzip_off64_t zz_rootseek = _disk_trailer_rootseek(trailer);
     __correct_rootseek(zz_rootseek, zz_rootsize, trailer);
+    if (zz_entries < 0 || zz_rootseek < 0 || zz_rootsize < 0) 
+        return ZZIP_CORRUPTED;    
 
     hdr0 = (struct zzip_dir_hdr *) malloc(zz_rootsize);
     if (! hdr0)
-- 
2.14.3