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    SubjectRe: [PATCH 0/12: eCryptfs] eCryptfs version 0.1.6
    Phillip Hellewell wrote:
    > This patch set constitutes the 0.1.6 release of the eCryptfs
    > cryptographic filesystem:

    Great work!
    I just want to make some notes about the user mode interface.

    I think that current security and encryption solutions that
    come out these days without a proper smart card support
    create a false sense of security for users. So solutions
    should first be designed so that a smart card can be used,
    and only then provide a passphrase alternative.

    This is the first time I've looked on the user mode
    keyutils, and it looks quite good. I think that the eCryptfs
    should use it more ?correctly? so that keys stored on smart
    card may be used.

    For example, you can publish a text format of the key data
    so that any application can easily and independently
    construct this.

    A simple example of key content is:

    You can modify the mount options:
    mount -o keytype=type,keydesc=desc,keydata=data

    So that any specific key may be provided, and not only keys
    derived from a passphrase. And a proper key may be
    instantiate from the kernel.

    User may already have this key available using keyctl. The
    key may be available from any place.

    But if the key is not available, the following
    request-key.conf this may be written:

    create user eCryptfs:p11-data:*
    |/usr/bin/eCryptfs-key-p11-data /etc/eCryptfs-key-p11-data.conf

    create user eCryptfs:pass:* |/usr/bin/eCryptfs-key-pass

    This will construct the key from the data if the key is not

    For PKCS#11 the providers listed in the conf file, key may
    be stored as a data object, and data may be:
    slot - slot id
    name - slot name
    label - token label

    ?Calling without a PIN may allow prompt for dialog
    via a named pipe to a running daemon by uid?

    For passphrase the data may be the cipher:passphrase.

    Another issue is a multi user access without a shared
    secret. This may be done by encrypting the symmetric key in
    several asymmetric ones. Again this can be done in user
    mode... But there is a need to support reencrypting the
    whole filesystem with a new symmetric key so that a user may
    be removed from the list.

    In order to support this mode using smart cards when key is
    unavailable, the following request-key.conf may be written:

    create user eCryptfs:p11-multi:*

    Now the data may be:
    slot - slot id
    name - slot name
    label - token label
    id - CKA_ID
    label - CKA_LABEL
    subject - certificate subject

    I hope I understood correctly the various components.

    If you like, I will be happy to help you with the user mode
    stuff, and implement the smart card access.

    Best Regards,
    Alon Bar-Lev

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