[Tcllib-bugs] [Tcllib] (umlaeute) tkt (New): zipfile::decode::unzip permissions bug with some zips

[<no...@tc...>]

Automated mail by fx, on behalf of no...@tc...

Ticket Change [6d407ad805b12e7d5d0414c375626744901d273b23989a3bde9b009684698c64]
  [zipfile::decode::unzip permissions bug with some zips]
  By      umlaeute
  For     Tcllib
  On      2025-03-06T16:40:22.060
  Details https://core.tcl-lang.org/tcllib/tinfo?name=6d407ad805b12e7d5d0414c375626744901d273b23989a3bde9b009684698c64
  Ticket  https://core.tcl-lang.org/tcllib/tktview/a0cbdc7e6f4a977e4c24b5a1a5c0f578c334958d

Changed Fields
  assignee:        nobody
  closer:          nobody
  comment:         Some ZIP-files generated on Windows cannot be properly extracted: the
                   extracted files end up with a permission of `0o000`

                   One such ZIP-file can be downloaded via
                   https://github.com/user-attachments/files/19111907/iem_vanilla.zip

                   `zipinfo -v` tells me something like this:

                   ```  Central directory entry #1:  ---------------------------

                   iem_vanilla/0.INTRO.txt

                   offset of local header from start of archive: 0  (0000000000000000h)
                   bytes  file system or operating system of origin: MS-DOS, OS/2 or NT
                   FAT  version of encoding software: 2.0  minimum file system
                   compatibility required: MS-DOS, OS/2 or NT FAT  minimum software
                   version required to extract: 2.0  compression method: deflated
                   compression sub-type (deflation): normal  file security status: not
                   encrypted  extended local header: no  file last modified on (DOS
                   date/time): 2020 Oct 30 15:42:26  32-bit CRC value (hex): bda8cbfe
                   compressed size: 1861 bytes  uncompressed size: 4899 bytes  length of
                   filename: 23 characters  length of extra field: 0 bytes  length of
                   file comment: 0 characters  disk number on which file begins: disk 1
                   apparent file type: text  non-MSDOS external file attributes: 000000
                   hex  MS-DOS file attributes (20 hex): arc

                   There is no file comment.  ```

                   The problem is apparently, that the `efattr` field for the file is
                   something like `32`, which tcllib takes as an invitation to change the
                   permissions, but then calculates the permissions as `0`.  Cf this code
                   for
                   [::zipfile::decode::CopyFile](https://core.tcl-lang.org/tcllib/file?ci
                   =tip&name=modules/zip/decode.tcl&ln=220-234):  ```  if {
                   ($::tcl_platform(platform) ne "windows") &&  ($fd(efattr) != 0)  } {
                   file attributes $dst -permissions \\  [string map {0 --- 1 --x 2 -w- 3
                   -wx 4 r-- 5 r-x 6 rw- 7 rwx} \\  [format %03o [expr {($fd(efattr) >>
                   16) & 0x1ff}]]]  }  ```

                   (obviously, `(32>>16)&0x1ff` evaluates to `0`.
  foundin:         2.0
  is_private:      0
  login:           umlaeute
  priority:        5 Medium
  private_contact: 25d17d5d6504beca5be732fc23fc1776440fca23
  resolution:      None
  severity:        Minor
  status:          Open
  submitter:       umlaeute
  subsystem:       zip
  title:           zipfile::decode::unzip permissions bug with some zips
  type:            Bug

------------------------------------------------------------
See Tcl/Tk development @ http://core.tcl-lang.org/
------------------------------------------------------------