F49 pax-record-empty-lineAn empty line between two pax records.
Reject(draft) A strict parser must reject this archive.
F49-pax-record-empty-line.tar |
test archive, 3,072 bytes
sha256 e3465a4410c80b83de54eb10a1c79825f1dc8f8ce226a41bdb014a92eb4dae4a |
F49-pax-record-empty-line.json | expected result |
F49-pax-record-empty-line.txt | annotated blocks |
F49-pax-record-empty-line.py | generator script |
The archive has a file whose pax header has the record comment=x, followed by a newline, followed by the record path=renamed. Its header has the name header-name.
In POSIX, an extended header consists of records, each of which starts with its length, so a newline between two of them is not a record. This case is ambiguous because a reader can handle the empty line in one of three ways. A reader that skips it reads path=renamed, and the file is renamed. One that stops there, or ignores the extended header, keeps header-name. One that takes the newline for the start of the next record reads its length from one byte too early, and cuts the name to rename.
Decision point: whether a pax header may have bytes between its records.
Seen in: none of the scanned tarballs.
Every block of 512 bytes, to scale, with its offset. Hover over a field for its bytes.
F49-pax-record-empty-line: must reject
An empty line between two pax records.
The archive has a file whose pax header has the record `comment=x`, followed by a newline,
followed by the record `path=renamed`. Its header has the name `header-name`.
In POSIX, an extended header consists of records, each of which starts with its
length, so a newline between two of them is not a record. This case is ambiguous
because a reader can handle the empty line in one of three ways. A reader that skips it reads
`path=renamed`, and the file is `renamed`. One that stops there, or ignores the extended header,
keeps `header-name`. One that takes the newline for the start of the next record reads its length
from one byte too early, and cuts the name to `rename`.
Decision point: whether a pax header may have bytes between its records.
Seen in: none of the scanned tarballs.
See also: F36, a record length that is one short.
0x000000 header: pax extended header, two records, with a newline between them
name [ 0,100) "PaxHeader" + 91 NUL
mode [100,108) "0000644" + NUL 644 (octal)
uid [108,116) "0000000" + NUL 0
gid [116,124) "0000000" + NUL 0
size [124,136) "00000000036" + NUL 30
mtime [136,148) "00000000000" + NUL 0
chksum [148,156) "011100\0 " 4672: the unsigned sum of the header, this field as spaces
typeflag [156,157) "x" pax extended header
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 data: a comment, an empty line, and a path
30 bytes, then 482 NUL
"13 comment=x\n\n16 path=renamed\n"
0x000400 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) "011271\0 " 4793: 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" + 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 data
12 bytes, then 500 NUL to the end of the block
"which name?\n"
0x000800 2 zero blocks: the end-of-archive marker
0x000c00 end of file
As xxd writes it: xxd -r makes the archive of it.
00000000: 5061 7848 6561 6465 7200 0000 0000 0000 PaxHeader....... 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 3033 3600 3030 3030 3030 3030 0000036.00000000 00000090: 3030 3000 3031 3131 3030 0020 7800 0000 000.011100. x... 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: 3133 2063 6f6d 6d65 6e74 3d78 0a0a 3136 13 comment=x..16 00000210: 2070 6174 683d 7265 6e61 6d65 640a 0000 path=renamed... 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 0000 0000 0000 0000 0000 0000 ................ 00000270: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000280: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000290: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 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: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 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 0000 0000 0000 0000 ................ 00000350: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 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: 6865 6164 6572 2d6e 616d 6500 0000 0000 header-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 3030 3030 3634 3400 3030 3030 ....0000644.0000 00000470: 3030 3000 3030 3030 3030 3000 3030 3030 000.0000000.0000 00000480: 3030 3030 3031 3400 3030 3030 3030 3030 0000014.00000000 00000490: 3030 3000 3031 3132 3731 0020 3000 0000 000.011271. 0... 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: 7768 6963 6820 6e61 6d65 3f0a 0000 0000 which name?..... 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 ................ 00000a00: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000a10: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000a20: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000a30: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000a40: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000a50: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000a60: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000a70: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000a80: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000a90: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000aa0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000ab0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000ac0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000ad0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000ae0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000af0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000b00: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000b10: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000b20: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000b30: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000b40: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000b50: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000b60: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000b70: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000b80: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000b90: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000ba0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000bb0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000bc0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000bd0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000be0: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000bf0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
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: Malformed extended header: missing length tar: Exiting with failure status due to previous errors |
| bsdtar | bsdtar 3.8.11 - libarchive 3.8.11 | ✅ rejects | error: bsdtar: Ignoring malformed pax attributes: malformed attribute size field bsdtar: Error exit delayed from previous errors |
| BusyBox tar | BusyBox v1.38.0, defconfig | ⚠️ accepts | tree A: header-name (12 B, a578eb49) |
| 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: ReadError: file could not be opened successfully: - method gz: ReadError('not a gzip file') - method bz2: ReadError('not a bzip2 file') - method xz: ReadError('not an lzma file') - method zst: ReadEr… |
| Python tarfile, filter=tar | CPython 3.15.2 | ✅ rejects | error: ReadError: file could not be opened successfully: - method gz: ReadError('not a gzip file') - method bz2: ReadError('not a bzip2 file') - method xz: ReadError('not an lzma file') - method zst: ReadEr… |
| Python tarfile, filter=fully_trusted | CPython 3.15.2 | ✅ rejects | error: ReadError: file could not be opened successfully: - method gz: ReadError('not a gzip file') - method bz2: ReadError('not a bzip2 file') - method xz: ReadError('not an lzma file') - method zst: ReadEr… |
| node-tar | tar 7.5.22 | ⚠️ accepts | tree B: renamed (12 B, a578eb49) |
| node-tar, strict | tar 7.5.22 | ⚠️ accepts | tree B: renamed (12 B, a578eb49) |
| tar-fs | tar-fs 3.1.3, on tar-stream 3.2.2 | ⚠️ accepts | tree C: rename (12 B, a578eb49) |
| Java Commons Compress | Commons Compress 1.28.0, Expander, on Java 27.0.1.0.2 | ⚠️ accepts | tree B: renamed (12 B, a578eb49) |
| .NET System.Formats.Tar | System.Formats.Tar of .NET 10.0.14, ExtractToDirectory | ✅ rejects | error: InvalidDataException: The extended header contains invalid records. |
| PHP PharData, as in Composer | PharData of PHP 8.5.12, as Composer's TarDownloader calls it | ⚠️ accepts | tree A: header-name (12 B, a578eb49) |
| Go containerd archive.Apply | containerd v2.4.2, archive.Apply, of go1.27.3 | ✅ rejects | error: archive/tar: invalid tar header |
| Rust tar | tar 0.4.46, unpack | ⚠️ accepts | tree A: header-name (12 B, a578eb49) |
| Rust astral-tokio-tar | astral-tokio-tar 0.7.1, unpack | ✅ rejects | error: failed to iterate over archive |
| Rust tar-codec, as in uv | tar-codec 0.0.16, with the policies of uv 0.13 | ✅ rejects | error: at byte 0: invalid pax records: record length is not a valid decimal integer |
| 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" | ⚠️ accepts | tree B: renamed (12 B, a578eb49) |
| Perl Archive::Tar | Archive::Tar 3.12 of Perl v5.44.0 | ⚠️ accepts | tree A: header-name (12 B, a578eb49) |
| Haskell tar | tar 0.7.2.0, extract, of GHC 9.14 | ⚠️ accepts | tree A: header-name (12 B, a578eb49) |
| Julia Tar.jl | Tar 1.10.0 of Julia 1.13.3 | ✅ rejects | error: malformed extended header metadata: "13 comment=x\n\n16 path=renamed\n" |
| live-bootstrap untar | mescc-tools-extra a151c245e512, as live-bootstrap pins it | ⚠️ accepts | tree D: PaxHeader (30 B, c4cbcc5a), header-name (12 B, a578eb49) |
| live-bootstrap untar, --non-strict | mescc-tools-extra a151c245e512, as live-bootstrap pins it | ⚠️ accepts | tree D: PaxHeader (30 B, c4cbcc5a), header-name (12 B, a578eb49) |
The table below shows how many release tarballs have the features of this test case.
| ecosystem | tarballs | with it | share |
|---|---|---|---|
| Spack | 37,553 | 0 | none |
| nixpkgs | 18,990 | 0 | none |
| Guix | 10,168 | 0 | none |
| PyPI | 10,000 | 0 | none |
| crates.io | 5,000 | 0 | none |
| RubyGems | 5,000 | 0 | none |
| live-bootstrap | 171 | 0 | none |
| total (distinct) | 82,586 | 0 | none |
F36: a record length that is one short.