Why is the kernel stack such an issue with eCryptfs?
eCryptfs is a stacked filesystem. This implies that eCryptfs adds on top of whatever call stack exists with current filesystems. Each process in the Linux kernel has a fixed maximum stack size (4k+4k or 8k). Some filesystems (such as XFS) push the limit of the stack by themselves; adding eCryptfs on top may cause a stack overflow on these filesystems. If you wish to use eCryptfs on XFS, I recommend that you first perform stress tests to help determine whether your specific configuration will lead to a kernel process stack overflow. Q. Can I mount eCryptfs with a public key? You can mount eCryptfs with a public key if you have public key support (pubkey) in your kernel. You first need to generate a public/private keypair. Run ecryptfs-manager, follow the prompts to generate the keypair for the key module of your choosing, start the ecryptfsd daemon, and then specify the key module when mounting. For instance, for the OpenSSL key module, assuming you created your key in /usb-drive/mykey.
