tls – TLS and SSL3 record layer
bind -a #a /net
The TLS device implements the record layer protocols
of Transport Layer Security version 1.0-1.2 and Secure Sockets Layer version 3.0.
It does not implement the handshake protocols, which are responsible for
mutual authentication and key exchange.
device can be thought of as filters providing optional encryption and anti-tampering.
The top level directory contains a
file and subdirectories numbered from zero through at least the last active filter.
file reserves a filter.
The file descriptor returned from the
will point to the control file,
of the newly allocated filter.
file returns a text string containing the number of the filter directory.
The filter initially cannot be used to pass messages
and will not encrypt or digest messages.
It is configured and controlled by writing commands to
The following commands are supported:
fd open-fd vers
Pass record messages over the communications channel
Initially, outgoing messages use version
format records, but incoming messages of either version are accepted.
Valid versions are
for SSLv3.0 and
for TLSv1.0 (which could be known as SSLv3.01), TLSv1.1 and TLSv1.2.
This command must be issued before any other command
and before reading or writing any messages;
it may only be executed once.
format records for all future records,
both outgoing and incoming.
This command may only be executed once.
secret hashalg encalg isclient secretdata
Set up the digesting and encryption algorithms and secrets.
must be algorithm names returned by the corresponding files.
is the base-64 encoded (see
secret data used for the algorithms.
It must contain at least enough data to populate the
secrets for digesting and encrypting.
These secrets are divided into three categories: digest secrets, keys, and initialization vectors.
The secrets are packed in this order, with no extra padding.
Within each category, the secret for data traveling from the client to the server comes first.
The incoming and outgoing secrets are automatically selected by devtls based on the
argument, which must be non-zero for the client of the TLS handshake,
and zero for the server.
This command must be issued after
and may be issued more than once.
At least one new
command must be issued before each
command; similarly, at least one new
must precede each incoming changecipher message.
Enable outgoing encryption and digesting as configured by the previous
This command sends a
Enable data messages.
This command may be issued any number of times,
although only the first is significant.
It must follow at least one successful
Send an alert message.
may be a valid alert code for either SSLv3.0 or TLS,
and is mapped to an appropriate code for the protocol in use.
If it is a fatal alert, the filter is set into an error state.
Application messages and handshake messages are communicated using
is allowed at a time.
Any record layer headers and trailers are inserted and
stripped automatically, and are not visible from the outside.
The device tries to synchronize record boundaries with reads and writes.
Each read will return data from exactly one record,
and will return all of the data from the record as long as
the buffer is big enough.
Each write will be converted into an integral number of records,
with all but potentially the last being maximal size.
The maximum record length supported is 16384 bytes.
This behavior is not specified in the protocols,
and may not be followed by other implementations.
If a fatal alert message is received, or a fatal
command issued, the filter is set into an error state.
All further correspondence is halted,
although some pending operations may not be terminated.
will fail with a
’tls error’ ,
and operations on
will fail with a textual decoding of the alert.
The current non-fatal alert messages are
’close notify’ ,
’no renegotiation’ ,
’handshake canceled by user’ .
Receipt of one of these alerts cause the next read on
to terminate with an error.
If the alert is
all future reads will terminate with a
command will terminate all future writes or reads from
If an error is encountered while reading or writing
the underlying communications channel, the error is returned
to the offending operation.
If the error is not
the filter is set into the error state.
In this case, all future operations on
will fail with a
’channel error’ .
When all file descriptors for a filter have been closed,
the session is terminated and the filter reclaimed for future use.
alert will be sent on the underlying communications channel
unless one has already been sent or the filter is in the error state.
returns information about the filter.
Each datum is returned on a single line of the form
tag: data .
returns the number of bytes communicated by the
The four lines returned are tagged by, in order,
returns lines following tags:
value is a string describing the status of the connection,
and is one of the following:
give the hexadecimal record layer version in use.
fields return name of the current algorithms in use
or ready to be used, if any.
will give the space-separated list of algorithms implemented.
This will always include
meaning no encryption or digesting.
Currently implemented encryption algorithms for use with TLSv1.0 and TLSv1.1 are:
For TLSv1.2, which adds support for authenticated encryption with
associated data (AEAD), the following ciphers are supported:
Currently implemented hashing algorithms are:
For an AEAD cipher, the hashing algorithm should be set to