[BUG] index out of range [0] with length 0 at modules/setting

[secsys-go]

Description

The function getPostgreSQLConnectionString in modules/setting/database.go parse the dbhost, and it works like:

host, port := parsePostgreSQLHostPort(dbHost)
if host[0] == '/' { // looks like a unix socket
...

but it just split host-string with :. If the provided host-string starts with :, the host will be "", and it will trigger an error like index out of range [0] with length 0

The poc is here:

package main

import "code.gitea.io/gitea/modules/setting"

func main() {
	setting.Database.Type = "postgres"
	setting.Database.Host = ":00000"
	_, _ = setting.DBConnStr()
}

And it crashed as :

panic: runtime error: index out of range [0] with length 0

goroutine 1 [running]:
code.gitea.io/gitea/modules/setting.getPostgreSQLConnectionString({0x744b0d, 0x0}, {0x0, 0x0}, {0x0, 0x0}, {0x0, 0x0}, {0x743130, 0x1}, ...)
        /home/zjx/workspace/gowork/src/go-fdg-exmaples/gitea/modules/setting/database.go:158 +0x410
code.gitea.io/gitea/modules/setting.DBConnStr()
        /home/zjx/workspace/gowork/src/go-fdg-exmaples/gitea/modules/setting/database.go:122 +0x5e9
main.main()
        /home/zjx/workspace/gowork/src/go-fdg-exmaples/gitea/modules/setting/pocTest_getPostgreSQL/main.go:8 +0x8a
exit status 2

Gitea Version

with git commit as ee769f7

Can you reproduce the bug on the Gitea demo site?

No

Log Gist

No response

Screenshots

No response

Git Version

No response

Operating System

No response

How are you running Gitea?

I test the API in Gitea through go-fuzz

Database

No response