TiDB-Lightning will print some sensitive message when it runs in server mode

[lichunzhu]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Run TiDB-Lightning in server mode and start an import task.

2. What did you expect to see? (Required)

Lightning's log doesn't contain sensitive information.

3. What did you see instead (Required)

Lightning's log contains sensitive information.

4. What is your TiDB version? (Required)

master

[niubell]

/remove-label affects-6.2

[kennytm]

I'm pretty sure #36375's regexp and test case are both written wrongly

tidb/br/pkg/utils/sensitive.go

Line 10 in a1b38f8

passwordPatterns = `(password[\s]*=[\s]*(\\")?)(.*?)((\\")?\\n)`

tidb/br/pkg/utils/sensitive_test.go

Line 17 in a1b38f8

`host = "127.0.0.1"\n user = "root"\n password = "/Q7B9DizNLLTTfiZHv9WoEAKamfpIUs="\n port = 3306\n`,

you don't need to escape the backslash inside the backquote-strings! `\n` will produce a literal \ followed by an n, not a newline character. The passwords are still visible in the log because the regexp isn't able to match any real text.