[PATCH RFC 4/5] net/tls: Add support for PF_TLSH (a TLS handshake listener)

[Hannes Reinecke]

On 4/18/22 18:49, Chuck Lever wrote:
> In-kernel TLS consumers need a way to perform a TLS handshake. In
> the absence of a handshake implementation in the kernel itself, a
> mechanism to perform the handshake in user space, using an existing
> TLS handshake library, is necessary.
> 
> I've designed a way to pass a connected kernel socket endpoint to
> user space using the traditional listen/accept mechanism. accept(2)
> gives us a well-understood way to materialize a socket endpoint as a
> normal file descriptor in a specific user space process. Like any
> open socket descriptor, the accepted FD can then be passed to a
> library such as openSSL to perform a TLS handshake.
> 
> This prototype currently handles only initiating client-side TLS
> handshakes. Server-side handshakes and key renegotiation are left
> to do.
> 
> Security Considerations
> ~~~~~~~~ ~~~~~~~~~~~~~~
> 
> This prototype is net-namespace aware.
> 
> The kernel has no mechanism to attest that the listening user space
> agent is trustworthy.
> 
> Currently the prototype does not handle multiple listeners that
> overlap -- multiple listeners in the same net namespace that have
> overlapping bind addresses.
> 
> Signed-off-by: Chuck Lever <chuck.lever at oracle.com>
> ---
>   .../networking/tls-in-kernel-handshake.rst         |  103 ++
>   include/linux/socket.h                             |    1
>   include/net/sock.h                                 |    3
>   include/net/tls.h                                  |   15
>   include/net/tlsh.h                                 |   22
>   include/uapi/linux/tls.h                           |   16
>   net/core/sock.c                                    |    2
>   net/tls/Makefile                                   |    2
>   net/tls/af_tlsh.c                                  | 1040 ++++++++++++++++++++
>   net/tls/tls_main.c                                 |   10
>   10 files changed, 1213 insertions(+), 1 deletion(-)
>   create mode 100644 Documentation/networking/tls-in-kernel-handshake.rst
>   create mode 100644 include/net/tlsh.h
>   create mode 100644 net/tls/af_tlsh.c
> 
Reviewed-by: Hannes Reinecke <hare at suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare at suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer