TarReader doesn't read paths with spaces from Pax extended attributes

[prettybits]

Description

For tar archives with pax entries whose extended metadata contains a path with spaces that path is currently silently ignored and the standard name field used, which can lead to extraction errors when the names of headers aren't unique (e.g. I came across files that put "PaxHeader" as the name for every pax entry and their consecutive file entry.

Cannot create '/home/prettybits/tests/PaxHeader' because a file or directory with the 
same name already exists.

Spaces in values of extended metadata entries are explicitly treated as malformed here (introduced in #74281), but I can't see why. @stephentoub

Reproduction Steps

Given a tar file with multiple pax entries whose name field values for extended attribute and file entry each are "PaxHeader", and pax extended attributes which contain a path with spaces (e.g. 29 path=file with spaces.xml\n13 size=7720\n) :

using System.Formats.Tar;

TarFile.ExtractToDirectory(@"/home/prettybits/tests/paxheaders.tar", @"/home/prettybits/tests/", false);

=> Cannot create '/home/prettybits/tests/PaxHeader' because a file or directory with the same name already exists.

Expected behavior

Paths with spaces from pax extended attributes should be used as the name of the logical entry.

Actual behavior

Paths with spaces are ignored and the original name used, which might not be unique.

Regression?

Reading the diff, this likely worked correctly before #74281 was merged.

Known Workarounds

No response

Configuration

No response

Other information

No response

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Issue Details

---

Description

For tar archives with pax entries whose extended metadata contains a path with spaces that path is currently silently ignored and the standard name field used, which can lead to extraction errors when the names of headers aren't unique (e.g. I came across files that put "PaxHeader" as the name for every pax entry and their consecutive file entry.

Cannot create '/home/prettybits/tests/PaxHeader' because a file or directory with the 
same name already exists.

Spaces in values of extended metadata entries are explicitly treated as malformed here (introduced in #74281), but I can't see why.

Reproduction Steps

Given a tar file with multiple pax entries whose name field values for extended attribute and file entry each are "PaxHeader", and pax extended attributes which contain a path with spaces (e.g. 29 path=file with spaces.xml\n13 size=7720\n) :

using System.Formats.Tar;

TarFile.ExtractToDirectory(@"/home/prettybits/tests/paxheaders.tar", @"/home/prettybits/tests/", false);

=> Cannot create '/home/prettybits/tests/PaxHeader' because a file or directory with the same name already exists.

Expected behavior

Paths with spaces from pax extended attributes should be used as the name of the logical entry.

Actual behavior

Paths with spaces are ignored and the original name used, which might not be unique.

Regression?

Reading the diff, this likely worked correctly before #74281 was merged.

Known Workarounds

No response

Configuration

No response

Other information

No response

Author:	prettybits
Assignees:	-
Labels:	area-System.IO
Milestone:	-

[adamsitnik]

@jozkee @carlossanlop PTAL

Reading the diff, this likely worked correctly before #74281 was merged.

cc @stephentoub

[stephentoub]

introduced in #74281

Yup. I misread the Split call I was replacing, which is why I added that IndexOf, and there wasn't a test for paths with spaces to flag my mistake.