FTP server with vsftpd
I read the manual of vsftpd.conf, and it says "If chroot_local_user set to YES, local users will be (by default) placed in a chroot() jail in their home directory after login". I think this means if I enable this directive to Yes, when users connect to my FTP server, they only can access to their home folder.
But the manual warns me "Warning: This option has security implications, especially if the users have upload permission, or shell access. Only enable if you know what you are doing". Why it says so? I permit my users to upload files, but when they are restricted in their home directory, where is the problem?