From 2a84ae73e93b0c1f4f12f2c58104f8327d10e41b Mon Sep 17 00:00:00 2001
From: vlefebvre <valentin.lefebvre@suse.com>
Date: Wed, 7 Aug 2024 11:10:05 +0200
Subject: [PATCH] fetch_disk_trailer: Don't truncate the size verif
Reference:https://github.com/gdraheim/zziplib/commit/2a84ae73e93b0c1f4f12f2c58104f8327d10e41b

* We must check if the tail obtained have the size of the zzip_disk_trailer
  struct. end - tail should be at least >= of the size but not size - 2.
  Where truncated by 2 was good for pre-C99 compilers.
* Fix gdraheim#165

---
 zzip/zip.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/zzip/zip.c b/zzip/zip.c
index dfa1c2f..8d9bc9b 100644
--- a/zzip/zip.c
+++ b/zzip/zip.c
@@ -293,7 +293,7 @@ __zzip_fetch_disk_trailer(int fd, zzip_off_t filesize,
             for (tail = end - 1; (tail >= mapped); tail--)
             {
                 if ((*tail == 'P') &&   /* quick pre-check for trailer magic */
-                    end - tail >= __sizeof(struct zzip_disk_trailer) - 2 &&
+                    end - tail >= __sizeof(struct zzip_disk_trailer) &&				
                     zzip_disk_trailer_check_magic(tail))
                 {
 #                  ifndef ZZIP_DISK64_TRAILER
@@ -329,10 +329,9 @@ __zzip_fetch_disk_trailer(int fd, zzip_off_t filesize,
 		    if (trailer->zz_rootseek >= filesize || (trailer->zz_rootseek + trailer->zz_rootsize) >= filesize)
 		        return(ZZIP_CORRUPTED);
                     { return(0); }
-                } else if ((*tail == 'P') &&
-                           end - tail >=
-                           __sizeof(struct zzip_disk64_trailer) - 2
-                           && zzip_disk64_trailer_check_magic(tail))
+	        }
+	        else if ((*tail == 'P') && end - tail >= __sizeof(struct zzip_disk64_trailer) &&
+                           zzip_disk64_trailer_check_magic(tail))
                 {
 #                  ifndef ZZIP_DISK64_TRAILER
                     return (ZZIP_DIR_LARGEFILE);
-- 
2.27.0

