diff mbox series

[PULL,5/5] crypto/tls-cipher-suites: Produce fw_cfg consumable blob

Message ID 20200704163927.28188-6-philmd@redhat.com (mailing list archive)
State New, archived
Headers show
Series [PULL,1/5] crypto: Add tls-cipher-suites object | expand

Commit Message

Philippe Mathieu-Daudé July 4, 2020, 4:39 p.m. UTC
Since our format is consumable by the fw_cfg device,
we can implement the FW_CFG_DATA_GENERATOR interface.

Example of use to dump the cipher suites (if tracing enabled):

  $ qemu-system-x86_64 -S \
    -object tls-cipher-suites,id=mysuite1,priority=@SYSTEM \
    -fw_cfg name=etc/path/to/ciphers,gen_id=mysuite1 \
    -trace qcrypto\*
  1590664444.197123:qcrypto_tls_cipher_suite_priority priority: @SYSTEM
  1590664444.197219:qcrypto_tls_cipher_suite_info data=[0x13,0x02] version=TLS1.3 name=TLS_AES_256_GCM_SHA384
  1590664444.197228:qcrypto_tls_cipher_suite_info data=[0x13,0x03] version=TLS1.3 name=TLS_CHACHA20_POLY1305_SHA256
  1590664444.197233:qcrypto_tls_cipher_suite_info data=[0x13,0x01] version=TLS1.3 name=TLS_AES_128_GCM_SHA256
  1590664444.197236:qcrypto_tls_cipher_suite_info data=[0x13,0x04] version=TLS1.3 name=TLS_AES_128_CCM_SHA256
  1590664444.197240:qcrypto_tls_cipher_suite_info data=[0xc0,0x30] version=TLS1.2 name=TLS_ECDHE_RSA_AES_256_GCM_SHA384
  1590664444.197245:qcrypto_tls_cipher_suite_info data=[0xcc,0xa8] version=TLS1.2 name=TLS_ECDHE_RSA_CHACHA20_POLY1305
  1590664444.197250:qcrypto_tls_cipher_suite_info data=[0xc0,0x14] version=TLS1.0 name=TLS_ECDHE_RSA_AES_256_CBC_SHA1
  1590664444.197254:qcrypto_tls_cipher_suite_info data=[0xc0,0x2f] version=TLS1.2 name=TLS_ECDHE_RSA_AES_128_GCM_SHA256
  1590664444.197258:qcrypto_tls_cipher_suite_info data=[0xc0,0x13] version=TLS1.0 name=TLS_ECDHE_RSA_AES_128_CBC_SHA1
  1590664444.197261:qcrypto_tls_cipher_suite_info data=[0xc0,0x2c] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_GCM_SHA384
  1590664444.197266:qcrypto_tls_cipher_suite_info data=[0xcc,0xa9] version=TLS1.2 name=TLS_ECDHE_ECDSA_CHACHA20_POLY1305
  1590664444.197270:qcrypto_tls_cipher_suite_info data=[0xc0,0xad] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_CCM
  1590664444.197274:qcrypto_tls_cipher_suite_info data=[0xc0,0x0a] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_256_CBC_SHA1
  1590664444.197278:qcrypto_tls_cipher_suite_info data=[0xc0,0x2b] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_GCM_SHA256
  1590664444.197283:qcrypto_tls_cipher_suite_info data=[0xc0,0xac] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_CCM
  1590664444.197287:qcrypto_tls_cipher_suite_info data=[0xc0,0x09] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_128_CBC_SHA1
  1590664444.197291:qcrypto_tls_cipher_suite_info data=[0x00,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_GCM_SHA384
  1590664444.197296:qcrypto_tls_cipher_suite_info data=[0xc0,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_CCM
  1590664444.197300:qcrypto_tls_cipher_suite_info data=[0x00,0x35] version=TLS1.0 name=TLS_RSA_AES_256_CBC_SHA1
  1590664444.197304:qcrypto_tls_cipher_suite_info data=[0x00,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_GCM_SHA256
  1590664444.197308:qcrypto_tls_cipher_suite_info data=[0xc0,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_CCM
  1590664444.197312:qcrypto_tls_cipher_suite_info data=[0x00,0x2f] version=TLS1.0 name=TLS_RSA_AES_128_CBC_SHA1
  1590664444.197316:qcrypto_tls_cipher_suite_info data=[0x00,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_GCM_SHA384
  1590664444.197320:qcrypto_tls_cipher_suite_info data=[0xcc,0xaa] version=TLS1.2 name=TLS_DHE_RSA_CHACHA20_POLY1305
  1590664444.197325:qcrypto_tls_cipher_suite_info data=[0xc0,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_CCM
  1590664444.197329:qcrypto_tls_cipher_suite_info data=[0x00,0x39] version=TLS1.0 name=TLS_DHE_RSA_AES_256_CBC_SHA1
  1590664444.197333:qcrypto_tls_cipher_suite_info data=[0x00,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_GCM_SHA256
  1590664444.197337:qcrypto_tls_cipher_suite_info data=[0xc0,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_CCM
  1590664444.197341:qcrypto_tls_cipher_suite_info data=[0x00,0x33] version=TLS1.0 name=TLS_DHE_RSA_AES_128_CBC_SHA1
  1590664444.197345:qcrypto_tls_cipher_suite_count count: 29

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200623172726.21040-6-philmd@redhat.com>
---
 crypto/tls-cipher-suites.c | 11 +++++++++++
 qemu-options.hx            | 18 ++++++++++++++++++
 2 files changed, 29 insertions(+)

Comments

Kevin Wolf Sept. 29, 2020, 3:46 p.m. UTC | #1
Am 04.07.2020 um 18:39 hat Philippe Mathieu-Daudé geschrieben:
> Since our format is consumable by the fw_cfg device,
> we can implement the FW_CFG_DATA_GENERATOR interface.
> 
> Example of use to dump the cipher suites (if tracing enabled):
> 
>   $ qemu-system-x86_64 -S \
>     -object tls-cipher-suites,id=mysuite1,priority=@SYSTEM \
>     -fw_cfg name=etc/path/to/ciphers,gen_id=mysuite1 \
>     -trace qcrypto\*
>   1590664444.197123:qcrypto_tls_cipher_suite_priority priority: @SYSTEM
>   1590664444.197219:qcrypto_tls_cipher_suite_info data=[0x13,0x02] version=TLS1.3 name=TLS_AES_256_GCM_SHA384
>   1590664444.197228:qcrypto_tls_cipher_suite_info data=[0x13,0x03] version=TLS1.3 name=TLS_CHACHA20_POLY1305_SHA256
>   1590664444.197233:qcrypto_tls_cipher_suite_info data=[0x13,0x01] version=TLS1.3 name=TLS_AES_128_GCM_SHA256
>   1590664444.197236:qcrypto_tls_cipher_suite_info data=[0x13,0x04] version=TLS1.3 name=TLS_AES_128_CCM_SHA256
>   1590664444.197240:qcrypto_tls_cipher_suite_info data=[0xc0,0x30] version=TLS1.2 name=TLS_ECDHE_RSA_AES_256_GCM_SHA384
>   1590664444.197245:qcrypto_tls_cipher_suite_info data=[0xcc,0xa8] version=TLS1.2 name=TLS_ECDHE_RSA_CHACHA20_POLY1305
>   1590664444.197250:qcrypto_tls_cipher_suite_info data=[0xc0,0x14] version=TLS1.0 name=TLS_ECDHE_RSA_AES_256_CBC_SHA1
>   1590664444.197254:qcrypto_tls_cipher_suite_info data=[0xc0,0x2f] version=TLS1.2 name=TLS_ECDHE_RSA_AES_128_GCM_SHA256
>   1590664444.197258:qcrypto_tls_cipher_suite_info data=[0xc0,0x13] version=TLS1.0 name=TLS_ECDHE_RSA_AES_128_CBC_SHA1
>   1590664444.197261:qcrypto_tls_cipher_suite_info data=[0xc0,0x2c] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_GCM_SHA384
>   1590664444.197266:qcrypto_tls_cipher_suite_info data=[0xcc,0xa9] version=TLS1.2 name=TLS_ECDHE_ECDSA_CHACHA20_POLY1305
>   1590664444.197270:qcrypto_tls_cipher_suite_info data=[0xc0,0xad] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_CCM
>   1590664444.197274:qcrypto_tls_cipher_suite_info data=[0xc0,0x0a] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_256_CBC_SHA1
>   1590664444.197278:qcrypto_tls_cipher_suite_info data=[0xc0,0x2b] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_GCM_SHA256
>   1590664444.197283:qcrypto_tls_cipher_suite_info data=[0xc0,0xac] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_CCM
>   1590664444.197287:qcrypto_tls_cipher_suite_info data=[0xc0,0x09] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_128_CBC_SHA1
>   1590664444.197291:qcrypto_tls_cipher_suite_info data=[0x00,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_GCM_SHA384
>   1590664444.197296:qcrypto_tls_cipher_suite_info data=[0xc0,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_CCM
>   1590664444.197300:qcrypto_tls_cipher_suite_info data=[0x00,0x35] version=TLS1.0 name=TLS_RSA_AES_256_CBC_SHA1
>   1590664444.197304:qcrypto_tls_cipher_suite_info data=[0x00,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_GCM_SHA256
>   1590664444.197308:qcrypto_tls_cipher_suite_info data=[0xc0,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_CCM
>   1590664444.197312:qcrypto_tls_cipher_suite_info data=[0x00,0x2f] version=TLS1.0 name=TLS_RSA_AES_128_CBC_SHA1
>   1590664444.197316:qcrypto_tls_cipher_suite_info data=[0x00,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_GCM_SHA384
>   1590664444.197320:qcrypto_tls_cipher_suite_info data=[0xcc,0xaa] version=TLS1.2 name=TLS_DHE_RSA_CHACHA20_POLY1305
>   1590664444.197325:qcrypto_tls_cipher_suite_info data=[0xc0,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_CCM
>   1590664444.197329:qcrypto_tls_cipher_suite_info data=[0x00,0x39] version=TLS1.0 name=TLS_DHE_RSA_AES_256_CBC_SHA1
>   1590664444.197333:qcrypto_tls_cipher_suite_info data=[0x00,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_GCM_SHA256
>   1590664444.197337:qcrypto_tls_cipher_suite_info data=[0xc0,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_CCM
>   1590664444.197341:qcrypto_tls_cipher_suite_info data=[0x00,0x33] version=TLS1.0 name=TLS_DHE_RSA_AES_128_CBC_SHA1
>   1590664444.197345:qcrypto_tls_cipher_suite_count count: 29
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
> Acked-by: Laszlo Ersek <lersek@redhat.com>
> Message-Id: <20200623172726.21040-6-philmd@redhat.com>

I noticed only now that this breaks '--object help' in
qemu-storage-daemon:

$ qemu-storage-daemon --object help
List of user creatable objects:
qemu-storage-daemon: missing interface 'fw_cfg-data-generator' for object 'tls-creds'
Aborted (core dumped)

The reason is that we don't (and can't) link hw/nvram/fw_cfg.c into the
storage daemon because it requires other system emulator stuff.

Kevin
Laszlo Ersek Oct. 1, 2020, 7:18 a.m. UTC | #2
On 09/29/20 17:46, Kevin Wolf wrote:
> Am 04.07.2020 um 18:39 hat Philippe Mathieu-Daudé geschrieben:
>> Since our format is consumable by the fw_cfg device,
>> we can implement the FW_CFG_DATA_GENERATOR interface.
>>
>> Example of use to dump the cipher suites (if tracing enabled):
>>
>>   $ qemu-system-x86_64 -S \
>>     -object tls-cipher-suites,id=mysuite1,priority=@SYSTEM \
>>     -fw_cfg name=etc/path/to/ciphers,gen_id=mysuite1 \
>>     -trace qcrypto\*
>>   1590664444.197123:qcrypto_tls_cipher_suite_priority priority: @SYSTEM
>>   1590664444.197219:qcrypto_tls_cipher_suite_info data=[0x13,0x02] version=TLS1.3 name=TLS_AES_256_GCM_SHA384
>>   1590664444.197228:qcrypto_tls_cipher_suite_info data=[0x13,0x03] version=TLS1.3 name=TLS_CHACHA20_POLY1305_SHA256
>>   1590664444.197233:qcrypto_tls_cipher_suite_info data=[0x13,0x01] version=TLS1.3 name=TLS_AES_128_GCM_SHA256
>>   1590664444.197236:qcrypto_tls_cipher_suite_info data=[0x13,0x04] version=TLS1.3 name=TLS_AES_128_CCM_SHA256
>>   1590664444.197240:qcrypto_tls_cipher_suite_info data=[0xc0,0x30] version=TLS1.2 name=TLS_ECDHE_RSA_AES_256_GCM_SHA384
>>   1590664444.197245:qcrypto_tls_cipher_suite_info data=[0xcc,0xa8] version=TLS1.2 name=TLS_ECDHE_RSA_CHACHA20_POLY1305
>>   1590664444.197250:qcrypto_tls_cipher_suite_info data=[0xc0,0x14] version=TLS1.0 name=TLS_ECDHE_RSA_AES_256_CBC_SHA1
>>   1590664444.197254:qcrypto_tls_cipher_suite_info data=[0xc0,0x2f] version=TLS1.2 name=TLS_ECDHE_RSA_AES_128_GCM_SHA256
>>   1590664444.197258:qcrypto_tls_cipher_suite_info data=[0xc0,0x13] version=TLS1.0 name=TLS_ECDHE_RSA_AES_128_CBC_SHA1
>>   1590664444.197261:qcrypto_tls_cipher_suite_info data=[0xc0,0x2c] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_GCM_SHA384
>>   1590664444.197266:qcrypto_tls_cipher_suite_info data=[0xcc,0xa9] version=TLS1.2 name=TLS_ECDHE_ECDSA_CHACHA20_POLY1305
>>   1590664444.197270:qcrypto_tls_cipher_suite_info data=[0xc0,0xad] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_CCM
>>   1590664444.197274:qcrypto_tls_cipher_suite_info data=[0xc0,0x0a] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_256_CBC_SHA1
>>   1590664444.197278:qcrypto_tls_cipher_suite_info data=[0xc0,0x2b] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_GCM_SHA256
>>   1590664444.197283:qcrypto_tls_cipher_suite_info data=[0xc0,0xac] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_CCM
>>   1590664444.197287:qcrypto_tls_cipher_suite_info data=[0xc0,0x09] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_128_CBC_SHA1
>>   1590664444.197291:qcrypto_tls_cipher_suite_info data=[0x00,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_GCM_SHA384
>>   1590664444.197296:qcrypto_tls_cipher_suite_info data=[0xc0,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_CCM
>>   1590664444.197300:qcrypto_tls_cipher_suite_info data=[0x00,0x35] version=TLS1.0 name=TLS_RSA_AES_256_CBC_SHA1
>>   1590664444.197304:qcrypto_tls_cipher_suite_info data=[0x00,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_GCM_SHA256
>>   1590664444.197308:qcrypto_tls_cipher_suite_info data=[0xc0,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_CCM
>>   1590664444.197312:qcrypto_tls_cipher_suite_info data=[0x00,0x2f] version=TLS1.0 name=TLS_RSA_AES_128_CBC_SHA1
>>   1590664444.197316:qcrypto_tls_cipher_suite_info data=[0x00,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_GCM_SHA384
>>   1590664444.197320:qcrypto_tls_cipher_suite_info data=[0xcc,0xaa] version=TLS1.2 name=TLS_DHE_RSA_CHACHA20_POLY1305
>>   1590664444.197325:qcrypto_tls_cipher_suite_info data=[0xc0,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_CCM
>>   1590664444.197329:qcrypto_tls_cipher_suite_info data=[0x00,0x39] version=TLS1.0 name=TLS_DHE_RSA_AES_256_CBC_SHA1
>>   1590664444.197333:qcrypto_tls_cipher_suite_info data=[0x00,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_GCM_SHA256
>>   1590664444.197337:qcrypto_tls_cipher_suite_info data=[0xc0,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_CCM
>>   1590664444.197341:qcrypto_tls_cipher_suite_info data=[0x00,0x33] version=TLS1.0 name=TLS_DHE_RSA_AES_128_CBC_SHA1
>>   1590664444.197345:qcrypto_tls_cipher_suite_count count: 29
>>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
>> Acked-by: Laszlo Ersek <lersek@redhat.com>
>> Message-Id: <20200623172726.21040-6-philmd@redhat.com>
> 
> I noticed only now that this breaks '--object help' in
> qemu-storage-daemon:
> 
> $ qemu-storage-daemon --object help
> List of user creatable objects:
> qemu-storage-daemon: missing interface 'fw_cfg-data-generator' for object 'tls-creds'
> Aborted (core dumped)
> 
> The reason is that we don't (and can't) link hw/nvram/fw_cfg.c into the
> storage daemon because it requires other system emulator stuff.

Ouch. I've been completely oblivious to "--object help" and how it
affects qemu-storage-daemon. Sorry about that.

Could you please include a backtrace about the abort()?

Grepping for the error message, I can find type_initialize() in
"qom/object.c", but my knowledge about QOM internals is practically nil.

The error message seems bogus FWIW -- why would
TYPE_FW_CFG_DATA_GENERATOR_INTERFACE be *required* from "tls-creds"?

TYPE_FW_CFG_DATA_GENERATOR_INTERFACE is implemented by
"tls-cipher-suites", and required by "-fw_cfg name=...,gen_id=...". If
that -fw_cfg switch is not used, then why would anything look for the
TYPE_FW_CFG_DATA_GENERATOR_INTERFACE interface? Especially under the
tls-creds object?

Thanks,
Laszlo
Philippe Mathieu-Daudé Oct. 5, 2020, 9:16 a.m. UTC | #3
Hi Laszlo,

On 10/1/20 9:18 AM, Laszlo Ersek wrote:
> On 09/29/20 17:46, Kevin Wolf wrote:
>> Am 04.07.2020 um 18:39 hat Philippe Mathieu-Daudé geschrieben:
>>> Since our format is consumable by the fw_cfg device,
>>> we can implement the FW_CFG_DATA_GENERATOR interface.
>>>
>>> Example of use to dump the cipher suites (if tracing enabled):
>>>
>>>   $ qemu-system-x86_64 -S \
>>>     -object tls-cipher-suites,id=mysuite1,priority=@SYSTEM \
>>>     -fw_cfg name=etc/path/to/ciphers,gen_id=mysuite1 \
>>>     -trace qcrypto\*
>>>   1590664444.197123:qcrypto_tls_cipher_suite_priority priority: @SYSTEM
>>>   1590664444.197219:qcrypto_tls_cipher_suite_info data=[0x13,0x02] version=TLS1.3 name=TLS_AES_256_GCM_SHA384
>>>   1590664444.197228:qcrypto_tls_cipher_suite_info data=[0x13,0x03] version=TLS1.3 name=TLS_CHACHA20_POLY1305_SHA256
>>>   1590664444.197233:qcrypto_tls_cipher_suite_info data=[0x13,0x01] version=TLS1.3 name=TLS_AES_128_GCM_SHA256
>>>   1590664444.197236:qcrypto_tls_cipher_suite_info data=[0x13,0x04] version=TLS1.3 name=TLS_AES_128_CCM_SHA256
>>>   1590664444.197240:qcrypto_tls_cipher_suite_info data=[0xc0,0x30] version=TLS1.2 name=TLS_ECDHE_RSA_AES_256_GCM_SHA384
>>>   1590664444.197245:qcrypto_tls_cipher_suite_info data=[0xcc,0xa8] version=TLS1.2 name=TLS_ECDHE_RSA_CHACHA20_POLY1305
>>>   1590664444.197250:qcrypto_tls_cipher_suite_info data=[0xc0,0x14] version=TLS1.0 name=TLS_ECDHE_RSA_AES_256_CBC_SHA1
>>>   1590664444.197254:qcrypto_tls_cipher_suite_info data=[0xc0,0x2f] version=TLS1.2 name=TLS_ECDHE_RSA_AES_128_GCM_SHA256
>>>   1590664444.197258:qcrypto_tls_cipher_suite_info data=[0xc0,0x13] version=TLS1.0 name=TLS_ECDHE_RSA_AES_128_CBC_SHA1
>>>   1590664444.197261:qcrypto_tls_cipher_suite_info data=[0xc0,0x2c] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_GCM_SHA384
>>>   1590664444.197266:qcrypto_tls_cipher_suite_info data=[0xcc,0xa9] version=TLS1.2 name=TLS_ECDHE_ECDSA_CHACHA20_POLY1305
>>>   1590664444.197270:qcrypto_tls_cipher_suite_info data=[0xc0,0xad] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_CCM
>>>   1590664444.197274:qcrypto_tls_cipher_suite_info data=[0xc0,0x0a] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_256_CBC_SHA1
>>>   1590664444.197278:qcrypto_tls_cipher_suite_info data=[0xc0,0x2b] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_GCM_SHA256
>>>   1590664444.197283:qcrypto_tls_cipher_suite_info data=[0xc0,0xac] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_CCM
>>>   1590664444.197287:qcrypto_tls_cipher_suite_info data=[0xc0,0x09] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_128_CBC_SHA1
>>>   1590664444.197291:qcrypto_tls_cipher_suite_info data=[0x00,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_GCM_SHA384
>>>   1590664444.197296:qcrypto_tls_cipher_suite_info data=[0xc0,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_CCM
>>>   1590664444.197300:qcrypto_tls_cipher_suite_info data=[0x00,0x35] version=TLS1.0 name=TLS_RSA_AES_256_CBC_SHA1
>>>   1590664444.197304:qcrypto_tls_cipher_suite_info data=[0x00,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_GCM_SHA256
>>>   1590664444.197308:qcrypto_tls_cipher_suite_info data=[0xc0,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_CCM
>>>   1590664444.197312:qcrypto_tls_cipher_suite_info data=[0x00,0x2f] version=TLS1.0 name=TLS_RSA_AES_128_CBC_SHA1
>>>   1590664444.197316:qcrypto_tls_cipher_suite_info data=[0x00,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_GCM_SHA384
>>>   1590664444.197320:qcrypto_tls_cipher_suite_info data=[0xcc,0xaa] version=TLS1.2 name=TLS_DHE_RSA_CHACHA20_POLY1305
>>>   1590664444.197325:qcrypto_tls_cipher_suite_info data=[0xc0,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_CCM
>>>   1590664444.197329:qcrypto_tls_cipher_suite_info data=[0x00,0x39] version=TLS1.0 name=TLS_DHE_RSA_AES_256_CBC_SHA1
>>>   1590664444.197333:qcrypto_tls_cipher_suite_info data=[0x00,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_GCM_SHA256
>>>   1590664444.197337:qcrypto_tls_cipher_suite_info data=[0xc0,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_CCM
>>>   1590664444.197341:qcrypto_tls_cipher_suite_info data=[0x00,0x33] version=TLS1.0 name=TLS_DHE_RSA_AES_128_CBC_SHA1
>>>   1590664444.197345:qcrypto_tls_cipher_suite_count count: 29
>>>
>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
>>> Acked-by: Laszlo Ersek <lersek@redhat.com>
>>> Message-Id: <20200623172726.21040-6-philmd@redhat.com>
>>
>> I noticed only now that this breaks '--object help' in
>> qemu-storage-daemon:
>>
>> $ qemu-storage-daemon --object help
>> List of user creatable objects:
>> qemu-storage-daemon: missing interface 'fw_cfg-data-generator' for object 'tls-creds'
>> Aborted (core dumped)
>>
>> The reason is that we don't (and can't) link hw/nvram/fw_cfg.c into the
>> storage daemon because it requires other system emulator stuff.
> 
> Ouch. I've been completely oblivious to "--object help" and how it
> affects qemu-storage-daemon. Sorry about that.
> 
> Could you please include a backtrace about the abort()?
> 
> Grepping for the error message, I can find type_initialize() in
> "qom/object.c", but my knowledge about QOM internals is practically nil.
> 
> The error message seems bogus FWIW -- why would
> TYPE_FW_CFG_DATA_GENERATOR_INTERFACE be *required* from "tls-creds"?
> 
> TYPE_FW_CFG_DATA_GENERATOR_INTERFACE is implemented by
> "tls-cipher-suites", and required by "-fw_cfg name=...,gen_id=...". If
> that -fw_cfg switch is not used, then why would anything look for the
> TYPE_FW_CFG_DATA_GENERATOR_INTERFACE interface? Especially under the
> tls-creds object?

Sorry for not updating Kevin's post in time (we have been discussing
over IRC).

What happens here is a QOM design flow, first triggered by fw_cfg as
we are now trying to have QEMU split into more components.

QOM interface/object type names are simple strings, so we don't get
any link failure in case of missing dependency (which are resolved at
runtime using strcmp).

"tls-cipher-suites" is a generic crypto object, it happens to implement
the fw_cfg-data-generator interface. The fw_cfg-data-generator interface
is registered as QOM type in hw/nvram/fw_cfg.c which is only built when
SOFTMMU is selected. qemu-storage-daemon doesn't select SOFTMMU.
We don't want to restrict "tls-cipher-suites" to SOFTMMU.

The simplest fix we discuss is to have a single C file to register the
fw_cfg-data-generator interface in QOM, and link with it if any of
CRYPTO / NVRAM kconfig is selected.

I'll send a patch.

Regards,

Phil.
Laszlo Ersek Oct. 6, 2020, 8:41 a.m. UTC | #4
On 10/05/20 11:16, Philippe Mathieu-Daudé wrote:
> Hi Laszlo,
> 
> On 10/1/20 9:18 AM, Laszlo Ersek wrote:
>> On 09/29/20 17:46, Kevin Wolf wrote:
>>> Am 04.07.2020 um 18:39 hat Philippe Mathieu-Daudé geschrieben:
>>>> Since our format is consumable by the fw_cfg device,
>>>> we can implement the FW_CFG_DATA_GENERATOR interface.
>>>>
>>>> Example of use to dump the cipher suites (if tracing enabled):
>>>>
>>>>   $ qemu-system-x86_64 -S \
>>>>     -object tls-cipher-suites,id=mysuite1,priority=@SYSTEM \
>>>>     -fw_cfg name=etc/path/to/ciphers,gen_id=mysuite1 \
>>>>     -trace qcrypto\*
>>>>   1590664444.197123:qcrypto_tls_cipher_suite_priority priority: @SYSTEM
>>>>   1590664444.197219:qcrypto_tls_cipher_suite_info data=[0x13,0x02] version=TLS1.3 name=TLS_AES_256_GCM_SHA384
>>>>   1590664444.197228:qcrypto_tls_cipher_suite_info data=[0x13,0x03] version=TLS1.3 name=TLS_CHACHA20_POLY1305_SHA256
>>>>   1590664444.197233:qcrypto_tls_cipher_suite_info data=[0x13,0x01] version=TLS1.3 name=TLS_AES_128_GCM_SHA256
>>>>   1590664444.197236:qcrypto_tls_cipher_suite_info data=[0x13,0x04] version=TLS1.3 name=TLS_AES_128_CCM_SHA256
>>>>   1590664444.197240:qcrypto_tls_cipher_suite_info data=[0xc0,0x30] version=TLS1.2 name=TLS_ECDHE_RSA_AES_256_GCM_SHA384
>>>>   1590664444.197245:qcrypto_tls_cipher_suite_info data=[0xcc,0xa8] version=TLS1.2 name=TLS_ECDHE_RSA_CHACHA20_POLY1305
>>>>   1590664444.197250:qcrypto_tls_cipher_suite_info data=[0xc0,0x14] version=TLS1.0 name=TLS_ECDHE_RSA_AES_256_CBC_SHA1
>>>>   1590664444.197254:qcrypto_tls_cipher_suite_info data=[0xc0,0x2f] version=TLS1.2 name=TLS_ECDHE_RSA_AES_128_GCM_SHA256
>>>>   1590664444.197258:qcrypto_tls_cipher_suite_info data=[0xc0,0x13] version=TLS1.0 name=TLS_ECDHE_RSA_AES_128_CBC_SHA1
>>>>   1590664444.197261:qcrypto_tls_cipher_suite_info data=[0xc0,0x2c] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_GCM_SHA384
>>>>   1590664444.197266:qcrypto_tls_cipher_suite_info data=[0xcc,0xa9] version=TLS1.2 name=TLS_ECDHE_ECDSA_CHACHA20_POLY1305
>>>>   1590664444.197270:qcrypto_tls_cipher_suite_info data=[0xc0,0xad] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_CCM
>>>>   1590664444.197274:qcrypto_tls_cipher_suite_info data=[0xc0,0x0a] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_256_CBC_SHA1
>>>>   1590664444.197278:qcrypto_tls_cipher_suite_info data=[0xc0,0x2b] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_GCM_SHA256
>>>>   1590664444.197283:qcrypto_tls_cipher_suite_info data=[0xc0,0xac] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_CCM
>>>>   1590664444.197287:qcrypto_tls_cipher_suite_info data=[0xc0,0x09] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_128_CBC_SHA1
>>>>   1590664444.197291:qcrypto_tls_cipher_suite_info data=[0x00,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_GCM_SHA384
>>>>   1590664444.197296:qcrypto_tls_cipher_suite_info data=[0xc0,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_CCM
>>>>   1590664444.197300:qcrypto_tls_cipher_suite_info data=[0x00,0x35] version=TLS1.0 name=TLS_RSA_AES_256_CBC_SHA1
>>>>   1590664444.197304:qcrypto_tls_cipher_suite_info data=[0x00,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_GCM_SHA256
>>>>   1590664444.197308:qcrypto_tls_cipher_suite_info data=[0xc0,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_CCM
>>>>   1590664444.197312:qcrypto_tls_cipher_suite_info data=[0x00,0x2f] version=TLS1.0 name=TLS_RSA_AES_128_CBC_SHA1
>>>>   1590664444.197316:qcrypto_tls_cipher_suite_info data=[0x00,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_GCM_SHA384
>>>>   1590664444.197320:qcrypto_tls_cipher_suite_info data=[0xcc,0xaa] version=TLS1.2 name=TLS_DHE_RSA_CHACHA20_POLY1305
>>>>   1590664444.197325:qcrypto_tls_cipher_suite_info data=[0xc0,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_CCM
>>>>   1590664444.197329:qcrypto_tls_cipher_suite_info data=[0x00,0x39] version=TLS1.0 name=TLS_DHE_RSA_AES_256_CBC_SHA1
>>>>   1590664444.197333:qcrypto_tls_cipher_suite_info data=[0x00,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_GCM_SHA256
>>>>   1590664444.197337:qcrypto_tls_cipher_suite_info data=[0xc0,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_CCM
>>>>   1590664444.197341:qcrypto_tls_cipher_suite_info data=[0x00,0x33] version=TLS1.0 name=TLS_DHE_RSA_AES_128_CBC_SHA1
>>>>   1590664444.197345:qcrypto_tls_cipher_suite_count count: 29
>>>>
>>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>>> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
>>>> Acked-by: Laszlo Ersek <lersek@redhat.com>
>>>> Message-Id: <20200623172726.21040-6-philmd@redhat.com>
>>>
>>> I noticed only now that this breaks '--object help' in
>>> qemu-storage-daemon:
>>>
>>> $ qemu-storage-daemon --object help
>>> List of user creatable objects:
>>> qemu-storage-daemon: missing interface 'fw_cfg-data-generator' for object 'tls-creds'
>>> Aborted (core dumped)
>>>
>>> The reason is that we don't (and can't) link hw/nvram/fw_cfg.c into the
>>> storage daemon because it requires other system emulator stuff.
>>
>> Ouch. I've been completely oblivious to "--object help" and how it
>> affects qemu-storage-daemon. Sorry about that.
>>
>> Could you please include a backtrace about the abort()?
>>
>> Grepping for the error message, I can find type_initialize() in
>> "qom/object.c", but my knowledge about QOM internals is practically nil.
>>
>> The error message seems bogus FWIW -- why would
>> TYPE_FW_CFG_DATA_GENERATOR_INTERFACE be *required* from "tls-creds"?
>>
>> TYPE_FW_CFG_DATA_GENERATOR_INTERFACE is implemented by
>> "tls-cipher-suites", and required by "-fw_cfg name=...,gen_id=...". If
>> that -fw_cfg switch is not used, then why would anything look for the
>> TYPE_FW_CFG_DATA_GENERATOR_INTERFACE interface? Especially under the
>> tls-creds object?
> 
> Sorry for not updating Kevin's post in time (we have been discussing
> over IRC).
> 
> What happens here is a QOM design flow, first triggered by fw_cfg as
> we are now trying to have QEMU split into more components.
> 
> QOM interface/object type names are simple strings, so we don't get
> any link failure in case of missing dependency (which are resolved at
> runtime using strcmp).
> 
> "tls-cipher-suites" is a generic crypto object, it happens to implement
> the fw_cfg-data-generator interface. The fw_cfg-data-generator interface
> is registered as QOM type in hw/nvram/fw_cfg.c which is only built when
> SOFTMMU is selected. qemu-storage-daemon doesn't select SOFTMMU.
> We don't want to restrict "tls-cipher-suites" to SOFTMMU.
> 
> The simplest fix we discuss is to have a single C file to register the
> fw_cfg-data-generator interface in QOM, and link with it if any of
> CRYPTO / NVRAM kconfig is selected.
> 
> I'll send a patch.

Thank you for the explanation!

(I suggest keeping such discussions *originally* on the list. IRC is
practically indistinguishable from the bit bucket, and you'll have to
write up a summary for others on the mailing list anyway. (In some cases
it could even require filing a ticket in some tracker, in the end.) Best
to have the discussion at once on the list. Just my suggestion of course.)

Thanks!
Laszlo
Philippe Mathieu-Daudé Oct. 6, 2020, 9:26 a.m. UTC | #5
On 10/6/20 10:41 AM, Laszlo Ersek wrote:
> On 10/05/20 11:16, Philippe Mathieu-Daudé wrote:
>> Hi Laszlo,
>>
>> On 10/1/20 9:18 AM, Laszlo Ersek wrote:
>>> On 09/29/20 17:46, Kevin Wolf wrote:
>>>> Am 04.07.2020 um 18:39 hat Philippe Mathieu-Daudé geschrieben:
>>>>> Since our format is consumable by the fw_cfg device,
>>>>> we can implement the FW_CFG_DATA_GENERATOR interface.
>>>>>
>>>>> Example of use to dump the cipher suites (if tracing enabled):
>>>>>
>>>>>   $ qemu-system-x86_64 -S \
>>>>>     -object tls-cipher-suites,id=mysuite1,priority=@SYSTEM \
>>>>>     -fw_cfg name=etc/path/to/ciphers,gen_id=mysuite1 \
>>>>>     -trace qcrypto\*
>>>>>   1590664444.197123:qcrypto_tls_cipher_suite_priority priority: @SYSTEM
>>>>>   1590664444.197219:qcrypto_tls_cipher_suite_info data=[0x13,0x02] version=TLS1.3 name=TLS_AES_256_GCM_SHA384
>>>>>   1590664444.197228:qcrypto_tls_cipher_suite_info data=[0x13,0x03] version=TLS1.3 name=TLS_CHACHA20_POLY1305_SHA256
>>>>>   1590664444.197233:qcrypto_tls_cipher_suite_info data=[0x13,0x01] version=TLS1.3 name=TLS_AES_128_GCM_SHA256
>>>>>   1590664444.197236:qcrypto_tls_cipher_suite_info data=[0x13,0x04] version=TLS1.3 name=TLS_AES_128_CCM_SHA256
>>>>>   1590664444.197240:qcrypto_tls_cipher_suite_info data=[0xc0,0x30] version=TLS1.2 name=TLS_ECDHE_RSA_AES_256_GCM_SHA384
>>>>>   1590664444.197245:qcrypto_tls_cipher_suite_info data=[0xcc,0xa8] version=TLS1.2 name=TLS_ECDHE_RSA_CHACHA20_POLY1305
>>>>>   1590664444.197250:qcrypto_tls_cipher_suite_info data=[0xc0,0x14] version=TLS1.0 name=TLS_ECDHE_RSA_AES_256_CBC_SHA1
>>>>>   1590664444.197254:qcrypto_tls_cipher_suite_info data=[0xc0,0x2f] version=TLS1.2 name=TLS_ECDHE_RSA_AES_128_GCM_SHA256
>>>>>   1590664444.197258:qcrypto_tls_cipher_suite_info data=[0xc0,0x13] version=TLS1.0 name=TLS_ECDHE_RSA_AES_128_CBC_SHA1
>>>>>   1590664444.197261:qcrypto_tls_cipher_suite_info data=[0xc0,0x2c] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_GCM_SHA384
>>>>>   1590664444.197266:qcrypto_tls_cipher_suite_info data=[0xcc,0xa9] version=TLS1.2 name=TLS_ECDHE_ECDSA_CHACHA20_POLY1305
>>>>>   1590664444.197270:qcrypto_tls_cipher_suite_info data=[0xc0,0xad] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_256_CCM
>>>>>   1590664444.197274:qcrypto_tls_cipher_suite_info data=[0xc0,0x0a] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_256_CBC_SHA1
>>>>>   1590664444.197278:qcrypto_tls_cipher_suite_info data=[0xc0,0x2b] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_GCM_SHA256
>>>>>   1590664444.197283:qcrypto_tls_cipher_suite_info data=[0xc0,0xac] version=TLS1.2 name=TLS_ECDHE_ECDSA_AES_128_CCM
>>>>>   1590664444.197287:qcrypto_tls_cipher_suite_info data=[0xc0,0x09] version=TLS1.0 name=TLS_ECDHE_ECDSA_AES_128_CBC_SHA1
>>>>>   1590664444.197291:qcrypto_tls_cipher_suite_info data=[0x00,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_GCM_SHA384
>>>>>   1590664444.197296:qcrypto_tls_cipher_suite_info data=[0xc0,0x9d] version=TLS1.2 name=TLS_RSA_AES_256_CCM
>>>>>   1590664444.197300:qcrypto_tls_cipher_suite_info data=[0x00,0x35] version=TLS1.0 name=TLS_RSA_AES_256_CBC_SHA1
>>>>>   1590664444.197304:qcrypto_tls_cipher_suite_info data=[0x00,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_GCM_SHA256
>>>>>   1590664444.197308:qcrypto_tls_cipher_suite_info data=[0xc0,0x9c] version=TLS1.2 name=TLS_RSA_AES_128_CCM
>>>>>   1590664444.197312:qcrypto_tls_cipher_suite_info data=[0x00,0x2f] version=TLS1.0 name=TLS_RSA_AES_128_CBC_SHA1
>>>>>   1590664444.197316:qcrypto_tls_cipher_suite_info data=[0x00,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_GCM_SHA384
>>>>>   1590664444.197320:qcrypto_tls_cipher_suite_info data=[0xcc,0xaa] version=TLS1.2 name=TLS_DHE_RSA_CHACHA20_POLY1305
>>>>>   1590664444.197325:qcrypto_tls_cipher_suite_info data=[0xc0,0x9f] version=TLS1.2 name=TLS_DHE_RSA_AES_256_CCM
>>>>>   1590664444.197329:qcrypto_tls_cipher_suite_info data=[0x00,0x39] version=TLS1.0 name=TLS_DHE_RSA_AES_256_CBC_SHA1
>>>>>   1590664444.197333:qcrypto_tls_cipher_suite_info data=[0x00,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_GCM_SHA256
>>>>>   1590664444.197337:qcrypto_tls_cipher_suite_info data=[0xc0,0x9e] version=TLS1.2 name=TLS_DHE_RSA_AES_128_CCM
>>>>>   1590664444.197341:qcrypto_tls_cipher_suite_info data=[0x00,0x33] version=TLS1.0 name=TLS_DHE_RSA_AES_128_CBC_SHA1
>>>>>   1590664444.197345:qcrypto_tls_cipher_suite_count count: 29
>>>>>
>>>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>>>> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
>>>>> Acked-by: Laszlo Ersek <lersek@redhat.com>
>>>>> Message-Id: <20200623172726.21040-6-philmd@redhat.com>
>>>>
>>>> I noticed only now that this breaks '--object help' in
>>>> qemu-storage-daemon:
>>>>
>>>> $ qemu-storage-daemon --object help
>>>> List of user creatable objects:
>>>> qemu-storage-daemon: missing interface 'fw_cfg-data-generator' for object 'tls-creds'
>>>> Aborted (core dumped)
>>>>
>>>> The reason is that we don't (and can't) link hw/nvram/fw_cfg.c into the
>>>> storage daemon because it requires other system emulator stuff.
>>>
>>> Ouch. I've been completely oblivious to "--object help" and how it
>>> affects qemu-storage-daemon. Sorry about that.
>>>
>>> Could you please include a backtrace about the abort()?
>>>
>>> Grepping for the error message, I can find type_initialize() in
>>> "qom/object.c", but my knowledge about QOM internals is practically nil.
>>>
>>> The error message seems bogus FWIW -- why would
>>> TYPE_FW_CFG_DATA_GENERATOR_INTERFACE be *required* from "tls-creds"?
>>>
>>> TYPE_FW_CFG_DATA_GENERATOR_INTERFACE is implemented by
>>> "tls-cipher-suites", and required by "-fw_cfg name=...,gen_id=...". If
>>> that -fw_cfg switch is not used, then why would anything look for the
>>> TYPE_FW_CFG_DATA_GENERATOR_INTERFACE interface? Especially under the
>>> tls-creds object?
>>
>> Sorry for not updating Kevin's post in time (we have been discussing
>> over IRC).
>>
>> What happens here is a QOM design flow, first triggered by fw_cfg as
>> we are now trying to have QEMU split into more components.
>>
>> QOM interface/object type names are simple strings, so we don't get
>> any link failure in case of missing dependency (which are resolved at
>> runtime using strcmp).
>>
>> "tls-cipher-suites" is a generic crypto object, it happens to implement
>> the fw_cfg-data-generator interface. The fw_cfg-data-generator interface
>> is registered as QOM type in hw/nvram/fw_cfg.c which is only built when
>> SOFTMMU is selected. qemu-storage-daemon doesn't select SOFTMMU.
>> We don't want to restrict "tls-cipher-suites" to SOFTMMU.
>>
>> The simplest fix we discuss is to have a single C file to register the
>> fw_cfg-data-generator interface in QOM, and link with it if any of
>> CRYPTO / NVRAM kconfig is selected.
>>
>> I'll send a patch.
> 
> Thank you for the explanation!
> 
> (I suggest keeping such discussions *originally* on the list. IRC is
> practically indistinguishable from the bit bucket, and you'll have to
> write up a summary for others on the mailing list anyway. (In some cases
> it could even require filing a ticket in some tracker, in the end.) Best
> to have the discussion at once on the list. Just my suggestion of course.)

There are so many discussions there... But you are right,
noted for the areas I'm co-maintaining, I'll summarize on
the list.

Regards,

Phil.
diff mbox series

Patch

diff --git a/crypto/tls-cipher-suites.c b/crypto/tls-cipher-suites.c
index a4e0f84307..0d305b684b 100644
--- a/crypto/tls-cipher-suites.c
+++ b/crypto/tls-cipher-suites.c
@@ -13,6 +13,7 @@ 
 #include "qom/object_interfaces.h"
 #include "crypto/tlscreds.h"
 #include "crypto/tls-cipher-suites.h"
+#include "hw/nvram/fw_cfg.h"
 #include "trace.h"
 
 /*
@@ -88,11 +89,20 @@  static void qcrypto_tls_cipher_suites_complete(UserCreatable *uc,
     }
 }
 
+static GByteArray *qcrypto_tls_cipher_suites_fw_cfg_gen_data(Object *obj,
+                                                             Error **errp)
+{
+    return qcrypto_tls_cipher_suites_get_data(QCRYPTO_TLS_CIPHER_SUITES(obj),
+                                              errp);
+}
+
 static void qcrypto_tls_cipher_suites_class_init(ObjectClass *oc, void *data)
 {
     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
+    FWCfgDataGeneratorClass *fwgc = FW_CFG_DATA_GENERATOR_CLASS(oc);
 
     ucc->complete = qcrypto_tls_cipher_suites_complete;
+    fwgc->get_data = qcrypto_tls_cipher_suites_fw_cfg_gen_data;
 }
 
 static const TypeInfo qcrypto_tls_cipher_suites_info = {
@@ -103,6 +113,7 @@  static const TypeInfo qcrypto_tls_cipher_suites_info = {
     .class_init = qcrypto_tls_cipher_suites_class_init,
     .interfaces = (InterfaceInfo[]) {
         { TYPE_USER_CREATABLE },
+        { TYPE_FW_CFG_DATA_GENERATOR_INTERFACE },
         { }
     }
 };
diff --git a/qemu-options.hx b/qemu-options.hx
index ecc4658e1f..b2cbbbf281 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4586,6 +4586,24 @@  SRST
         string as described at
         https://gnutls.org/manual/html_node/Priority-Strings.html.
 
+        An example of use of this object is to control UEFI HTTPS Boot.
+        The tls-cipher-suites object exposes the ordered list of permitted
+        TLS cipher suites from the host side to the guest firmware, via
+        fw_cfg. The list is represented as an array of IANA_TLS_CIPHER
+        objects. The firmware uses the IANA_TLS_CIPHER array for configuring
+        guest-side TLS.
+
+        In the following example, the priority at which the host-side policy
+        is retrieved is given by the ``priority`` property.
+        Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to
+        refer to /etc/crypto-policies/back-ends/gnutls.config.
+
+        .. parsed-literal::
+
+             # |qemu_system| \
+                 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \
+                 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0
+
     ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]``
         Interval t can't be 0, this filter batches the packet delivery:
         all packets arriving in a given interval on netdev netdevid are