File bsc1227178-fetch_disk_trailer-Don-t-truncate-the-size-verif.patch of Package zziplib.35221

diff -Ppdru zziplib-0.13.67-orig/zzip/zip.c zziplib-0.13.67/zzip/zip.c
--- zziplib-0.13.67-orig/zzip/zip.c	2024-08-12 15:03:56.051553001 +0200
+++ zziplib-0.13.67/zzip/zip.c	2024-08-12 15:18:07.862841275 +0200
@@ -287,6 +287,10 @@ __zzip_fetch_disk_trailer(int fd, zzip_o
             HINT5("offs=$%lx len=%li filesize=%li pagesize=%i",
                   (long) offset, (long) maplen, (long) filesize, ZZIP_BUFSIZ);
         }
+       /* if the file-comment is not present, it happens that the z_comment field
+          often isn't either. The actual zip_disk_trailer is a bit shorter then,
+          with __sizeof(((struct zzip_disk_trailer*)(0))->z_comment) == 2 */
+#define __sizeof_z_comment 2
 
         {                       /* now, check for the trailer-magic, hopefully near the end of file */
             register unsigned char *end = mapped + maplen;
@@ -294,18 +298,16 @@ __zzip_fetch_disk_trailer(int fd, zzip_o
             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) - __sizeof_z_comment &&
                     zzip_disk_trailer_check_magic(tail))
                 {
 #                  ifndef ZZIP_DISK64_TRAILER
-                    /* if the file-comment is not present, it happens
-                       that the z_comment field often isn't either */
                     if (end - tail >= __sizeof(*trailer))
                     {
                         memcpy(trailer, tail, sizeof(*trailer));
                     } else
                     {
-                        memcpy(trailer, tail, sizeof(*trailer) - 2);
+                        memcpy(trailer, tail, sizeof(*trailer) - __sizeof_z_comment);
                         trailer->z_comment[0] = 0;
                         trailer->z_comment[1] = 0;
                     }
@@ -330,7 +332,7 @@ __zzip_fetch_disk_trailer(int fd, zzip_o
                     { return(0); }
                 } else if ((*tail == 'P') &&
                            end - tail >=
-                           __sizeof(struct zzip_disk64_trailer) - 2
+                           __sizeof(struct zzip_disk64_trailer)
                            && zzip_disk64_trailer_check_magic(tail))
                 {
 #                  ifndef ZZIP_DISK64_TRAILER