Paul Moore <pmo...@redhat.com> writes:
> On Friday, June 08, 2012 05:38:12 PM Paul Moore wrote:
>> FIPS 140-2 requires disabling certain ciphers, including DES, which is used
>> by VNC to obscure passwords when they are sent over the network. The
>> solution for FIPS users is to disable the use of VNC password auth when the
>> host system is operating in FIPS mode.
>>
>> This patch causes QEMU to emit a message to stderr when the host system is
>> running in FIPS mode and a VNC password was specified on the commend line.
>> If the system is not running in FIPS mode, or is running in FIPS mode but
>> VNC password authentication was not requested, QEMU operates normally.
>>
>> Signed-off-by: Paul Moore <pmo...@redhat.com>
>
> Hi Anthony,
>
> Any word on this patch? Other than Daniel Berrange's reviewed-by tag, the
> discussion of the v4 patch has been quiet and I think we addressed all the
> other remaining issues in the discussion attached to the v2 patch
> posting.
I asked for the specific language in FIPS mandating this. I don't see
any other VNC server implementing a check like this. I would rather do
this in a more user friendly fashion like make it a config file option
that a user can set while in fips mode.
Regards,
Anthony Liguori
>
> -Paul
>
>> --
>> Changelog
>> * v4
>> - Removed the use of syslog
>> * v3
>> - Use fgetc() instead of fgets() in fips_enabled
>> - Only emit a syslog message if the caller tries to use VNC password auth
>> - Suggest alternative auth methods in the stderr notice
>> * v2
>> - Protected syslog with _WIN32
>> - Protected the guts of fips_enabled() with __linux__
>> - Converted fips_enabled() and the fips flag from int to bool
>> *v1
>> - Initial draft
>> ---
>> qemu-doc.texi | 8 +++++---
>> ui/vnc.c | 27 +++++++++++++++++++++++++++
>> ui/vnc.h | 1 +
>> 3 files changed, 33 insertions(+), 3 deletions(-)
>>
>> diff --git a/qemu-doc.texi b/qemu-doc.texi
>> index 0af0ff4..fe8d3df 100644
>> --- a/qemu-doc.texi
>> +++ b/qemu-doc.texi
>> @@ -1124,9 +1124,11 @@ the protocol limits passwords to 8 characters it
>> should not be considered to provide high security. The password can be
>> fairly easily brute-forced by a client making repeat connections. For this
>> reason, a VNC server using password authentication should be restricted to
>> only listen on the loopback interface -or UNIX domain sockets. Password
>> authentication is requested with the @code{password} -option, and then once
>> QEMU is running the password is set with the monitor. Until -the monitor is
>> used to set the password all clients will be rejected. +or UNIX domain
>> sockets. Password authentication is not supported when operating +in FIPS
>> 140-2 compliance mode as it requires the use of the DES cipher. Password
>> +authentication is requested with the @code{password} option, and then once
>> QEMU +is running the password is set with the monitor. Until the monitor is
>> used to +set the password all clients will be rejected.
>>
>> @example
>> qemu-system-i386 [...OPTIONS...] -vnc :1,password -monitor stdio
>> diff --git a/ui/vnc.c b/ui/vnc.c
>> index 54bc5ad..4bd816d 100644
>> --- a/ui/vnc.c
>> +++ b/ui/vnc.c
>> @@ -48,6 +48,21 @@ static DisplayChangeListener *dcl;
>> static int vnc_cursor_define(VncState *vs);
>> static void vnc_release_modifiers(VncState *vs);
>>
>> +static bool fips_enabled(void)
>> +{
>> + bool enabled = false;
>> +
>> +#ifdef __linux__
>> + FILE *fds = fopen("/proc/sys/crypto/fips_enabled", "r");
>> + if (fds != NULL) {
>> + enabled = (fgetc(fds) == '1');
>> + fclose(fds);
>> + }
>> +#endif /* __linux__ */
>> +
>> + return enabled;
>> +}
>> +
>> static void vnc_set_share_mode(VncState *vs, VncShareMode mode)
>> {
>> #ifdef _VNC_DEBUG
>> @@ -2748,6 +2763,9 @@ void vnc_display_init(DisplayState *ds)
>> dcl->idle = 1;
>> vnc_display = vs;
>>
>> + vs->fips = fips_enabled();
>> + VNC_DEBUG("FIPS mode %s\n", (vs->fips ? "enabled" : "disabled"));
>> +
>> vs->lsock = -1;
>>
>> vs->ds = ds;
>> @@ -2896,6 +2914,15 @@ int vnc_display_open(DisplayState *ds, const char
>> *display) while ((options = strchr(options, ','))) {
>> options++;
>> if (strncmp(options, "password", 8) == 0) {
>> + if (vs->fips) {
>> + fprintf(stderr,
>> + "VNC password auth disabled due to FIPS mode, "
>> + "consider using the VeNCrypt or SASL authentication
>> " + "methods as an alternative\n");
>> + g_free(vs->display);
>> + vs->display = NULL;
>> + return -1;
>> + }
>> password = 1; /* Require password auth */
>> } else if (strncmp(options, "reverse", 7) == 0) {
>> reverse = 1;
>> diff --git a/ui/vnc.h b/ui/vnc.h
>> index a851ebd..d41631b 100644
>> --- a/ui/vnc.h
>> +++ b/ui/vnc.h
>> @@ -160,6 +160,7 @@ struct VncDisplay
>> char *display;
>> char *password;
>> time_t expires;
>> + bool fips;
>> int auth;
>> bool lossy;
>> bool non_adaptive;
> --
> paul moore
> security and virtualization @ redhat
