tar: make error reporting more robust and use correct errno

[emaste]

As discussed in #1609.

[kientzle]

Thank you!

[sgammon]

Beat me to it. I'm very glad to see someone more qualified take this on @emaste ... thank you for your hard work on FreeBSD

[mcatanzaro]

One more note: this is particular usage is probably fine because bsdtar is a utility rather than part of the library component of libarchive, but you unfortunately can't use strerror() in libraries (or threaded applications) because it's not threadsafe. Awkward workarounds are generally required like this or this. So beware: it's one of those tempting APIs that's almost impossible to use correctly except in single-threaded programs.

[qwertychouskie]

Are there plans to backport this fix to older releases?

[gamer191]

this is particular usage is probably fine

That may well be the case (I don't know much about coding tbh), but it's highly suspicious, because it was added in #1609, created by a known bad actor (JiaT75 recently snuck a backdoor into XZ, over a series of commits, after contributing for over a year and eventually becoming a co-maintainer)

Once again, I don't know much about coding, and I definitely don't understand the specific change. I do wonder though whether it could have set the stage for an obfuscated attempt to insert malware (EDIT: or a vulnerability that a malicious program could then exploit)

[mcatanzaro]

I do wonder though whether it could have set the stage for an obfuscated attempt to insert malware (EDIT: or a vulnerability that a malicious program could then exploit)

Pretty unlikely; would too hard to abuse it.

[Scrumplex]

These changes have mixed whitespace. Someone should probably replace the new added spaces with tabs.

[emaste]

this follows FreeBSD style(9): tabs are 8, 2nd level indent is 4 spaces.
https://man.freebsd.org/cgi/man.cgi?query=style&sektion=9

[jmpalacios]

Are there OS-level patches going to be issued to distribute these corrections to the general public?

[EverStarck]

hell yeah

[udaya2899]

Thanks @emaste for the quick fix. Will there be a new release with this fix included soon?

[emaste]

Release plans aren't my call. IMO it would be good to get whatever we do for #2107 into a release (and not just #2101). If that's not imminent though I see there are a number of minor updates and bugfixes in the tree since v3.7.2 that would be good to release.