Avoid leading .. for temporary files from Filesystem recursive remove

[giosh94mhz]

Q	A
Branch?	5.4
Bug fix?	yes
New feature?	no
Deprecations?	no
Tickets
License	MIT
Doc PR

Method Filesystem::doRemove is using renaming of parent directory before recursive removal, in order to implement atomic remove.

This is a good thing, but to implement this is generating a random path name, with a modified base64 which replaces base64's = sign with .. This may lead to directory named as path/..8U6/ which freaked out our synchronization tools and security log scanner.

Since the leading . is already (correctly) hard-coded, I see no issue in using _ as a safer alternative.

[alexislefebvre]

This may lead to directory named as path/..8U6/ which freaked out our synchronization tools and security log scanner.

Are these tools right when they consider this path as risky? To my knowledge, there is no risk of accessing the parent directory here.

But this change looks good anyway, someone seeing a path like path/..8U6/ could be confused too.

[giosh94mhz]

Are these tools right when they consider this path as risky? To my knowledge, there is no risk of accessing the parent directory here.
But this change looks good anyway, someone seeing a path like path/..8U6/ could be confused too.

Precisely as you say.

The tools aren't right, strictly speaking, but usually when I find /a/path/..like/this, I verify that there are no fishy patterns, like a GET /?request=..like/this.

[nicolas-grekas]

Thank you @giosh94mhz.