fix: convert '\' to '/' on windows

[harshavardhana]

Description

fix: convert '' to '/' on windows

Motivation and Context

This is to ensure on windows we avoid
arbitrary path escalation during PUT
operations.

How to test this PR?

Needs a windows machine to test

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Optimization (provides speedup with no functional changes)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• Fixes a regression (If yes, please add commit-id or PR # here)
• Unit tests added/updated
• Internal documentation updated
• Create a documentation update request here

[minio-trusted]

Mint Automation

Test	Result
mint-erasure.sh	✔️
mint-compress-encrypt-dist-erasure.sh	✔️
mint-pools.sh	✔️
Deleting image on docker hub
Deleting image locally

[klauspost]

@harshavardhana @kannappanr We should just reject objects with \ - at least just on Windows. TBH I assumed we already did.

[klauspost]

If we accept it, it will be a constant duality between / and \, which we shouldn't have. We should only allow /

[harshavardhana]

If we accept it, it will be a constant duality between / and \, which we shouldn't have. We should only allow /

The reason is we have seen keys with \ on Linux so we can't blindly disallow it, however, we could reject the \ key for windows separately.

[klauspost]

however, we could reject the \ key for windows separately.

Yeah, that was my thought. Otherwise \ gets converted to / on Windows, which IMO is worse than rejecting it from the start.

[harshavardhana]

Yeah, that was my thought. Otherwise \ gets converted to / on Windows, which IMO is worse than rejecting it from the start.

It won't get converted, it's only validated as a check to look for .. @klauspost - so it will reject the PUT on windows with \.. - however outrightly rejected situations like \/hello is also needed on Windows.

Sent a PR #16856