• aliguori's avatar
    Add SASL authentication support ("Daniel P. Berrange") · 2f9606b3
    aliguori authored
    This patch adds the new SASL authentication protocol to the VNC server.
    
    It is enabled by setting the 'sasl' flag when launching VNC. SASL can
    optionally provide encryption via its SSF layer, if a suitable mechanism
    is configured (eg, GSSAPI/Kerberos, or Digest-MD5).  If an SSF layer is
    not available, then it should be combined with the x509 VNC authentication
    protocol which provides encryption.
    
    eg, if using GSSAPI
    
       qemu -vnc localhost:1,sasl
    
    eg if using  TLS/x509 for encryption
    
       qemu -vnc localhost:1,sasl,tls,x509
    
    
    By default the Cyrus SASL library will look for its configuration in
    the file /etc/sasl2/qemu.conf.  For non-root users, this can be overridden
    by setting the SASL_CONF_PATH environment variable, eg to make it look in
    $HOME/.sasl2.  NB unprivileged users may not have access to the full range
    of SASL mechanisms, since some of them require some administrative privileges
    to configure. The patch includes an example SASL configuration file which
    illustrates config for GSSAPI and Digest-MD5, though it should be noted that
    the latter is not really considered secure any more.
    
    Most of the SASL authentication code is located in a separate source file,
    vnc-auth-sasl.c.  The main vnc.c file only contains minimal integration
    glue, specifically parsing of command line flags / setup, and calls to
    start the SASL auth process, to do encoding/decoding for data.
    
    There are several possible stacks for reading & writing of data, depending
    on the combo of VNC authentication methods in use
    
     - Clear.    read/write straight to socket
     - TLS.      read/write via GNUTLS helpers
     - SASL.     encode/decode via SASL SSF layer, then read/write to socket
     - SASL+TLS. encode/decode via SASL SSF layer, then read/write via GNUTLS
    
    Hence, the vnc_client_read & vnc_client_write methods have been refactored
    a little.
    
       vnc_client_read:  main entry point for reading, calls either
    
           - vnc_client_read_plain   reading, with no intermediate decoding
           - vnc_client_read_sasl    reading, with SASL SSF decoding
    
       These two methods, then call vnc_client_read_buf(). This decides
       whether to write to the socket directly or write via GNUTLS.
    
    The situation is the same for writing data. More extensive comments
    have been added in the code / patch. The vnc_client_read_sasl and
    vnc_client_write_sasl method implementations live in the separate
    vnc-auth-sasl.c file.
    
    The state required for the SASL auth mechanism is kept in a separate
    VncStateSASL struct, defined in vnc-auth-sasl.h and included in the
    main VncState.
    
    The configure script probes for SASL and automatically enables it
    if found, unless --disable-vnc-sasl was given to override it.
    
    
     Makefile            |    7 
     Makefile.target     |    5 
     b/qemu.sasl         |   34 ++
     b/vnc-auth-sasl.c   |  626 ++++++++++++++++++++++++++++++++++++++++++++++++++++
     b/vnc-auth-sasl.h   |   67 +++++
     configure           |   34 ++
     qemu-doc.texi       |   97 ++++++++
     vnc-auth-vencrypt.c |   12 
     vnc.c               |  249 ++++++++++++++++++--
     vnc.h               |   31 ++
     10 files changed, 1129 insertions(+), 33 deletions(-)
    Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
    Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
    
    
    git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6724 c046a42c-6fe2-441c-8c8c-71466251a162
    2f9606b3
qemu.sasl 1.26 KB