N38 gnu-long-name-empty · Tar file extraction test suite

N38 gnu-long-name-empty

An empty GNU long name: the name in the header, or none?

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

Category

name

Default policy

rejects it

Files

`N38-gnu-long-name-empty.tar`	test archive, 2,560 bytes sha256 `3f2d690c72a4a6244e1c434d236c34c59eb8091a1ccd7c9f92ef64625cfffb55`
`N38-gnu-long-name-empty.json`	expected result
`N38-gnu-long-name-empty.txt`	annotated blocks
`N38-gnu-long-name-empty.py`	generator script

The case¶

The archive has a GNU long name header of size 0, then a file whose header has GNU's magic and the name header-name.

A GNU long name replaces the name of the next member, and GNU's format does not say what an empty one means. If it applies, the pathname of the member is empty, and in POSIX an empty pathname does not resolve. This case is ambiguous because a reader can take the empty long name in one of three ways. A reader that ignores it extracts header-name. One that applies it gives the member an empty name, which is skipped, rejected or taken for .. One that takes the name of the long name header itself extracts the member as ././@LongLink. To a reader that does not know typeflag L, the member is header-name, after an empty file @LongLink.

Decision point: whether an empty GNU long name replaces the name in the header.

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.

N38-gnu-long-name-empty: must reject An empty GNU long name: the name in the header, or none? The archive has a GNU long name header of size 0, then a file whose header has GNU's magic and the name `header-name`. A GNU long name replaces the name of the next member, and GNU's format does not say what an empty one means. If it applies, the pathname of the member is empty, and in POSIX an empty pathname does not resolve. This case is ambiguous because a reader can take the empty long name in one of three ways. A reader that ignores it extracts `header-name`. One that applies it gives the member an empty name, which is skipped, rejected or taken for `.`. One that takes the name of the long name header itself extracts the member as `././@LongLink`. To a reader that does not know typeflag `L`, the member is `header-name`, after an empty file `@LongLink`. Decision point: whether an empty GNU long name replaces the name in the header. Seen in: none of the scanned tarballs. See also: N17, an empty name, and N22, an empty pax `path`. 0x000000 header: GNU long name, an empty long name name [ 0,100) "././@LongLink" + 87 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) "011221\0 " 4753: the unsigned sum of the header, this field as spaces typeflag [156,157) "L" GNU long name linkname [157,257) 100 NUL magic [257,263) "ustar " version [263,265) " " + NUL 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: regular file name [ 0,100) "header-name" + 89 NUL mode [100,108) "0000644" + NUL 644 (octal) uid [108,116) "0000000" + NUL 0 gid [116,124) "0000000" + NUL 0 size [124,136) "00000000014" + NUL 12 mtime [136,148) "00000000000" + NUL 0 chksum [148,156) "011231\0 " 4761: the unsigned sum of the header, this field as spaces typeflag [156,157) "0" regular file linkname [157,257) 100 NUL magic [257,263) "ustar " version [263,265) " " + NUL 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 data 12 bytes, then 500 NUL to the end of the block "which name?\n" 0x000600 2 zero blocks: the end-of-archive marker 0x000a00 end of file

00000000: 2e2f 2e2f 404c 6f6e 674c 696e 6b00 0000 ././@LongLink... 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 3634 3400 3030 3030 ....0000644.0000 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 3132 3231 0020 4c00 0000 000.011221. L... 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 2020 0000 0000 0000 0000 .ustar ........ 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: 6865 6164 6572 2d6e 616d 6500 0000 0000 header-name..... 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 3031 3400 3030 3030 3030 3030 0000014.00000000 00000290: 3030 3000 3031 3132 3331 0020 3000 0000 000.011231. 0... 000002a0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 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 2020 0000 0000 0000 0000 .ustar ........ 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: 7768 6963 6820 6e61 6d65 3f0a 0000 0000 which name?..... 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 0000 0000 0000 0000 0000 0000 ................ 00000470: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000480: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000490: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 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: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 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 0000 0000 0000 0000 ................ 00000550: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 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.

implementation	version	outcome	what it makes of it
GNU tar	tar (GNU tar) 1.35	✅ rejects	error: tar: Substituting `.' for empty member name tar: .: Cannot open: File exists tar: Exiting with failure status due to previous errors
bsdtar	bsdtar 3.8.11 - libarchive 3.8.11	⚠️ accepts	tree A: `header-name` (12 B, a578eb49)
BusyBox tar	BusyBox v1.38.0, defconfig	✅ rejects	error: tar: can't open '': No such file or directory
7-Zip	7-Zip (z) 26.05 (x64)	⚠️ accepts	tree A: `header-name` (12 B, a578eb49)
Python tarfile, filter=data, as in pip	CPython 3.15.2	✅ rejects	error: IsADirectoryError: [Errno 21] Is a directory: 'DEST'
Python tarfile, filter=tar	CPython 3.15.2	✅ rejects	error: IsADirectoryError: [Errno 21] Is a directory: 'DEST'
Python tarfile, filter=fully_trusted	CPython 3.15.2	✅ rejects	error: IsADirectoryError: [Errno 21] Is a directory: 'DEST'
node-tar	tar 7.5.22	⚠️ accepts	tree A: `header-name` (12 B, a578eb49)
node-tar, strict	tar 7.5.22	⚠️ accepts	tree A: `header-name` (12 B, a578eb49)
tar-fs	tar-fs 3.1.3, on tar-stream 3.2.2	✅ rejects	error: Error: Unexpected end of data
Java Commons Compress	Commons Compress 1.28.0, Expander, on Java 27.0.1.0.2	✅ rejects	error: java.nio.file.FileSystemException: DEST: Is a directory
.NET System.Formats.Tar	System.Formats.Tar of .NET 10.0.14, ExtractToDirectory	⚠️ accepts	tree B: `@LongLink` (12 B, a578eb49)
PHP PharData, as in Composer	PharData of PHP 8.5.12, as Composer's TarDownloader calls it	✅ rejects	error: UnexpectedValueException: phar error: "suite/archives/N38-gnu-long-name-empty.tar" is a corrupted tar file (invalid entry size)
Go containerd archive.Apply	containerd v2.4.2, archive.Apply, of go1.27.3	⚠️ accepts	tree A: `header-name` (12 B, a578eb49)
Rust tar	tar 0.4.46, unpack	⚠️ accepts	tree C: nothing
Rust astral-tokio-tar	astral-tokio-tar 0.7.1, unpack	⚠️ accepts	tree C: nothing
Rust tar-codec, as in uv	tar-codec 0.0.16, with the policies of uv 0.13	✅ rejects	error: at byte 0: malformed GNU LongName metadata payload: declared payload size is zero
RubyGems	RubyGems 4.0.20 of Ruby 4.0.9, extract_tar_gz	⚠️ accepts	tree A: `header-name` (12 B, a578eb49)
R untar, internal	utils::untar of R 4.6.2, tar = "internal"	⚠️ crashes	argument must be coercible to non-negative integer Warning message: In max(which(block > 0)) : no non-missing arguments to max; returning -Inf
Perl Archive::Tar	Archive::Tar 3.12 of Perl v5.44.0	✅ rejects	error: status 1
Haskell tar	tar 0.7.2.0, extract, of GHC 9.14	✅ rejects	error: Invalid file name in tar archive: ""
Julia Tar.jl	Tar 1.10.0 of Julia 1.13.3	⚠️ crashes	BoundsError: attempt to access 0-element view(::Vector{UInt8}, 1:0) with eltype UInt8 at index [0]
live-bootstrap untar	mescc-tools-extra a151c245e512, as live-bootstrap pins it	✅ rejects	error: unable to create long symlink
live-bootstrap untar, --non-strict	mescc-tools-extra a151c245e512, as live-bootstrap pins it	✅ rejects	error: non-strict mode enabled, preparing for chaos unable to create long symlink

Prevalence in release tarballs¶

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

ecosystem	tarballs	share
Spack	37,553	none
nixpkgs	18,990	none
Guix	10,168	none
PyPI	10,000	none
crates.io	5,000	none
RubyGems	5,000	none
live-bootstrap	171	none
total (distinct)	82,586	none

ecosystem

tarballs

with it

Spack

37,553

none

nixpkgs

18,990

none

Guix

10,168

none

PyPI

10,000

none

crates.io

5,000

none

RubyGems

5,000

none

live-bootstrap

171

none

total (distinct)

82,586

none

`N38` gnu-long-name-empty

The case¶

The archive¶

What implementations make of it¶

Prevalence in release tarballs¶

See also¶