[Bug-tar] Circular symlinks lead to segfault

[Florian Oppermann]

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Dear developers,

tar doesn't detect circular symlinks in all cases which leads to endless
iterations (stopped by the OS) when using the -h switch.

The following example reproduces the error:

mkdir a
ln -s ../a a/link
tar -chf a.tar a

Switching on verbose mode shows output like:

> a/link/link/link/link/link/link/link/[…]

The output file actually gets quite large as every iteration adds
another folder.

Note that the following shows an error but doesn't loop endlessly:

mkdir b
ln -s ./a b/b
ln -s ./b b/a
tar -chf b.tar b

> tar: b/a: Cannot stat: Too many levels of symbolic links tar: b/b: 
> Cannot stat: Too many levels of symbolic links tar: Exiting with 
> failure status due to previous errors

I didn't find any report of this bug with a short search.

Best regards,
Florian
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