Working draft

S14 tree-symlink-then-dir

A symlink to a directory, then a directory of the same name.

Reject(draft) A strict parser must reject this archive.

Category
order and state
Default policy
rejects it
Files
S14-tree-symlink-then-dir.tar test archive, 2,560 bytes sha256 7bacb404462ef3677492669d38ba79b8b3a7d1773c5d03e84262ae0477b7af0a
S14-tree-symlink-then-dir.jsonexpected result
S14-tree-symlink-then-dir.txtannotated blocks
S14-tree-symlink-then-dir.pygenerator script

The case

The archive has a directory target/, then a symlink a to target, then a directory a/.

The name a/ can be seen as a pathname that resolves through the symlink, as the name ends in a slash, to the directory target, which already exists, so extracting it changes nothing. It can also be seen as the name of a directory a, of the member's own type, which either replaces the symlink, or results in a failure, as it cannot be created where the symlink is.

Decision point: whether a directory member follows a symlink in its place.

Seen in: none of the scanned tarballs.

The archive

Every block of 512 bytes, to scale, with its offset. Hover over a field for its bytes.

S14-tree-symlink-then-dir: every block of the archive0x000000header: directoryname [0,100): "target/" + 93 NULnamemode [100,108): "0000755" + NUL, 755 (octal)uid [108,116): "0000000" + NUL, 0gid [116,124): "0000000" + NUL, 0size [124,136): "00000000000" + NUL, 0mtime [136,148): "00000000000" + NUL, 0chksum [148,156): "010473\0 ", 4411: the unsigned sum of the header, this field as spacestypeflag [156,157): "5", directorylinkname [157,257): 100 NULlinknamemagic [257,263): "ustar" + NULversion [263,265): "00"uname [265,297): 32 NULunamegname [297,329): 32 NULgnamedevmajor [329,337): "0000000" + NUL, 0devminor [337,345): "0000000" + NUL, 0prefix [345,500): 155 NULprefixpad [500,512): 12 NULname "target/" + 93 NUL0x000200header: symlinkname [0,100): "a" + 99 NULnamemode [100,108): "0000644" + NUL, 644 (octal)uid [108,116): "0000000" + NUL, 0gid [116,124): "0000000" + NUL, 0size [124,136): "00000000000" + NUL, 0mtime [136,148): "00000000000" + NUL, 0chksum [148,156): "010547\0 ", 4455: the unsigned sum of the header, this field as spacestypeflag [156,157): "2", symlinklinkname [157,257): "target" + 94 NULlinknamemagic [257,263): "ustar" + NULversion [263,265): "00"uname [265,297): 32 NULunamegname [297,329): 32 NULgnamedevmajor [329,337): "0000000" + NUL, 0devminor [337,345): "0000000" + NUL, 0prefix [345,500): 155 NULprefixpad [500,512): 12 NULname "a" + 99 NULlinkname "target" + 94 NUL0x000400header: directoryname [0,100): "a/" + 98 NULnamemode [100,108): "0000755" + NUL, 755 (octal)uid [108,116): "0000000" + NUL, 0gid [116,124): "0000000" + NUL, 0size [124,136): "00000000000" + NUL, 0mtime [136,148): "00000000000" + NUL, 0chksum [148,156): "007425\0 ", 3861: the unsigned sum of the header, this field as spacestypeflag [156,157): "5", directorylinkname [157,257): 100 NULlinknamemagic [257,263): "ustar" + NULversion [263,265): "00"uname [265,297): 32 NULunamegname [297,329): 32 NULgnamedevmajor [329,337): "0000000" + NUL, 0devminor [337,345): "0000000" + NUL, 0prefix [345,500): 155 NULprefixpad [500,512): 12 NULname "a/" + 98 NUL0x0006002 zero blocks: the end-of-archive markerbytes 0 to 512 of 1024: 512 NUL0x0008002 zero blocks, continuedbytes 512 to 1024 of 1024: 512 NUL0x000a00end of fileNULprintable ASCIIspacecontrol character, such as a newlinebyte over 0x7fwritten by the case itself
Every block, as text 
S14-tree-symlink-then-dir: must reject

A symlink to a directory, then a directory of the same name.

The archive has a directory `target/`, then a symlink `a` to `target`, then a directory `a/`.

The name `a/` can be seen as a pathname that resolves through the symlink, as
the name ends in a slash, to the directory `target`, which already exists, so
extracting it changes nothing. It can also be seen as the name of a directory `a`, of the member's
own type, which either replaces the symlink, or results in a failure, as it cannot be
created where the symlink is.

Decision point: whether a directory member follows a symlink in its place.
Seen in: none of the scanned tarballs.
See also: S10, a symlink, then a file of the same name.

0x000000  header: directory
          name     [  0,100)  "target/" + 93 NUL
          mode     [100,108)  "0000755" + NUL  755 (octal)
          uid      [108,116)  "0000000" + NUL  0
          gid      [116,124)  "0000000" + NUL  0
          size     [124,136)  "00000000000" + NUL  0
          mtime    [136,148)  "00000000000" + NUL  0
          chksum   [148,156)  "010473\0 "  4411: the unsigned sum of the header, this field as spaces
          typeflag [156,157)  "5"  directory
          linkname [157,257)  100 NUL
          magic    [257,263)  "ustar" + NUL
          version  [263,265)  "00"
          uname    [265,297)  32 NUL
          gname    [297,329)  32 NUL
          devmajor [329,337)  "0000000" + NUL  0
          devminor [337,345)  "0000000" + NUL  0
          prefix   [345,500)  155 NUL
          pad      [500,512)  12 NUL
0x000200  header: symlink
          name     [  0,100)  "a" + 99 NUL
          mode     [100,108)  "0000644" + NUL  644 (octal)
          uid      [108,116)  "0000000" + NUL  0
          gid      [116,124)  "0000000" + NUL  0
          size     [124,136)  "00000000000" + NUL  0
          mtime    [136,148)  "00000000000" + NUL  0
          chksum   [148,156)  "010547\0 "  4455: the unsigned sum of the header, this field as spaces
          typeflag [156,157)  "2"  symlink
          linkname [157,257)  "target" + 94 NUL
          magic    [257,263)  "ustar" + NUL
          version  [263,265)  "00"
          uname    [265,297)  32 NUL
          gname    [297,329)  32 NUL
          devmajor [329,337)  "0000000" + NUL  0
          devminor [337,345)  "0000000" + NUL  0
          prefix   [345,500)  155 NUL
          pad      [500,512)  12 NUL
0x000400  header: directory
          name     [  0,100)  "a/" + 98 NUL
          mode     [100,108)  "0000755" + NUL  755 (octal)
          uid      [108,116)  "0000000" + NUL  0
          gid      [116,124)  "0000000" + NUL  0
          size     [124,136)  "00000000000" + NUL  0
          mtime    [136,148)  "00000000000" + NUL  0
          chksum   [148,156)  "007425\0 "  3861: the unsigned sum of the header, this field as spaces
          typeflag [156,157)  "5"  directory
          linkname [157,257)  100 NUL
          magic    [257,263)  "ustar" + NUL
          version  [263,265)  "00"
          uname    [265,297)  32 NUL
          gname    [297,329)  32 NUL
          devmajor [329,337)  "0000000" + NUL  0
          devminor [337,345)  "0000000" + NUL  0
          prefix   [345,500)  155 NUL
          pad      [500,512)  12 NUL
0x000600  2 zero blocks: the end-of-archive marker
0x000a00  end of file
Every byte, as a hex dump

As xxd writes it: xxd -r makes the archive of it.

00000000: 7461 7267 6574 2f00 0000 0000 0000 0000  target/.........
00000010: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000020: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000030: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000040: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000050: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000060: 0000 0000 3030 3030 3735 3500 3030 3030  ....0000755.0000
00000070: 3030 3000 3030 3030 3030 3000 3030 3030  000.0000000.0000
00000080: 3030 3030 3030 3000 3030 3030 3030 3030  0000000.00000000
00000090: 3030 3000 3031 3034 3733 0020 3500 0000  000.010473. 5...
000000a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000000b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000000c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000000d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000000e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000000f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000100: 0075 7374 6172 0030 3000 0000 0000 0000  .ustar.00.......
00000110: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000120: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000130: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000140: 0000 0000 0000 0000 0030 3030 3030 3030  .........0000000
00000150: 0030 3030 3030 3030 0000 0000 0000 0000  .0000000........
00000160: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000170: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000180: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000190: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000001f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000200: 6100 0000 0000 0000 0000 0000 0000 0000  a...............
00000210: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000220: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000230: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000240: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000250: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000260: 0000 0000 3030 3030 3634 3400 3030 3030  ....0000644.0000
00000270: 3030 3000 3030 3030 3030 3000 3030 3030  000.0000000.0000
00000280: 3030 3030 3030 3000 3030 3030 3030 3030  0000000.00000000
00000290: 3030 3000 3031 3035 3437 0020 3274 6172  000.010547. 2tar
000002a0: 6765 7400 0000 0000 0000 0000 0000 0000  get.............
000002b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000002c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000002d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000002e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000002f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000300: 0075 7374 6172 0030 3000 0000 0000 0000  .ustar.00.......
00000310: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000320: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000330: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000340: 0000 0000 0000 0000 0030 3030 3030 3030  .........0000000
00000350: 0030 3030 3030 3030 0000 0000 0000 0000  .0000000........
00000360: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000370: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000380: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000390: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000003f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000400: 612f 0000 0000 0000 0000 0000 0000 0000  a/..............
00000410: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000420: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000430: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000440: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000450: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000460: 0000 0000 3030 3030 3735 3500 3030 3030  ....0000755.0000
00000470: 3030 3000 3030 3030 3030 3000 3030 3030  000.0000000.0000
00000480: 3030 3030 3030 3000 3030 3030 3030 3030  0000000.00000000
00000490: 3030 3000 3030 3734 3235 0020 3500 0000  000.007425. 5...
000004a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000004f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000500: 0075 7374 6172 0030 3000 0000 0000 0000  .ustar.00.......
00000510: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000520: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000530: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000540: 0000 0000 0000 0000 0030 3030 3030 3030  .........0000000
00000550: 0030 3030 3030 3030 0000 0000 0000 0000  .0000000........
00000560: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000570: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000580: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000590: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000005f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000600: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000610: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000620: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000630: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000640: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000650: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000660: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000670: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000680: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000690: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000006f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000700: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000710: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000720: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000730: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000740: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000750: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000760: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000770: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000780: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000790: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000007f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000800: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000810: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000820: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000830: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000840: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000850: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000860: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000870: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000880: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000890: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000008a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000008b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000008c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000008d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000008e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000008f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000900: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000910: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000920: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000930: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000940: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000950: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000960: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000970: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000980: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00000990: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000009a0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000009b0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000009c0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000009d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000009e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
000009f0: 0000 0000 0000 0000 0000 0000 0000 0000  ................

What implementations make of it

In the outcome column, ✅ means that the implementation follows the default policy.

implementationversionoutcomewhat it makes of it
GNU tartar (GNU tar) 1.35⚠️ acceptstree A: a/, target/
bsdtarbsdtar 3.8.11 - libarchive 3.8.11⚠️ acceptstree A: a/, target/
BusyBox tarBusyBox v1.38.0, defconfig⚠️ acceptstree B: a → target, target/
7-Zip7-Zip (z) 26.05 (x64)✅ rejectserror: ERROR: Cannot create folder : errno=17 : File exists : DEST/a
Python tarfile, filter=data, as in pipCPython 3.15.2⚠️ acceptstree B: a → target, target/
Python tarfile, filter=tarCPython 3.15.2⚠️ acceptstree B: a → target, target/
Python tarfile, filter=fully_trustedCPython 3.15.2⚠️ acceptstree B: a → target, target/
node-tartar 7.5.22⚠️ acceptstree A: a/, target/
node-tar, stricttar 7.5.22⚠️ acceptstree A: a/, target/
tar-fstar-fs 3.1.3, on tar-stream 3.2.2⚠️ acceptstree B: a → target, target/
Java Commons CompressCommons Compress 1.28.0, Expander, on Java 27.0.1.0.2✅ rejectserror: java.nio.file.FileAlreadyExistsException: DEST/a
.NET System.Formats.TarSystem.Formats.Tar of .NET 10.0.14, ExtractToDirectory⚠️ acceptstree B: a → target, target/
PHP PharData, as in ComposerPharData of PHP 8.5.12, as Composer's TarDownloader calls it⚠️ acceptstree C: nothing
Go containerd archive.Applycontainerd v2.4.2, archive.Apply, of go1.27.3⚠️ acceptstree A: a/, target/
Rust tartar 0.4.46, unpack✅ rejectserror: failed to unpack `DEST/a`
Rust astral-tokio-tarastral-tokio-tar 0.7.1, unpack✅ rejectserror: failed to unpack `DEST/a`
Rust tar-codec, as in uvtar-codec 0.0.16, with the policies of uv 0.13⚠️ acceptstree A: a/, target/
RubyGemsRubyGems 4.0.20 of Ruby 4.0.9, extract_tar_gz✅ rejectserror: Errno::EEXIST: File exists @ syserr_fail2_in - DEST/a
R untar, internalutils::untar of R 4.6.2, tar = "internal"⚠️ acceptstree A: a/, target/
Perl Archive::TarArchive::Tar 3.12 of Perl v5.44.0✅ rejectserror: Entry 'a/' is attempting to extract to a symlinked directory (DEST/a => target). This is considered a security vulnerability and not allowed under SECURE EXTRACT MODE at contrib/matrix/runners/perl/e…
Haskell tartar 0.7.2.0, extract, of GHC 9.14✅ rejectserror: createDirectoryLink:createSymbolicLink 'target' to 'DEST/a': already exists (File exists)
Julia Tar.jlTar 1.10.0 of Julia 1.13.3⚠️ acceptstree A: a/, target/
live-bootstrap untarmescc-tools-extra a151c245e512, as live-bootstrap pins it⚠️ acceptstree B: a → target, target/
live-bootstrap untar, --non-strictmescc-tools-extra a151c245e512, as live-bootstrap pins it⚠️ acceptstree B: a → target, target/

Prevalence in release tarballs

The table below shows how many release tarballs have the features of this test case.

ecosystemtarballswith itshare
Spack37,5530none
nixpkgs18,9900none
Guix10,1680none
PyPI10,0000none
crates.io5,0000none
RubyGems5,0000none
live-bootstrap1710none
total (distinct)82,5860none

See also