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Message-Id: <4766E5FA-4D3F-4A1B-B3C7-C1BE976A240B@linux.vnet.ibm.com>
Date: Fri, 1 Oct 2010 13:35:16 -0300
From: Rajiv Andrade <srajiv@...ux.vnet.ibm.com>
To: Christophe Henri RICARD <christophe-h.ricard@...com>
Cc: James Morris <jmorris@...ei.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"joe@...ches.com" <joe@...ches.com>
Subject: Re: [PATCH 1/3] TPM: new stm i2c device driver
Hi Christophe,
On 01/10/2010, at 12:44, Christophe Henri RICARD wrote:
> Hi Rajiv,
>
> I had implemented the ioctl function with TPMIOC_CANCEL/TPMIOC_TRANSMIT because I have seen that when I was trying to run a TSS tcsd(trousers) process some errors or warning messages were displayed.
> I have just checked the trousers source code I have and it use this way in src/tddl/tddl.c .
>
Trousers supports both methods, device read/write or through ioctl, the warning just notifies that the second isn't going to be used due the device driver's lack of support.
> For your information also, the 2 buffers tpm_i2c_buffer instead of the data buffer in my driver was because I found what I suppose to be an error with the allocation of chip->data_buffer in the tpm_open function.
> When I have done the following test with the tpm_tis driver for example on a pc platform (x86) with a TPM:
> - No TPM application launch such as TSS (trousers).
> - Put the platform in standby
> - Wake up the platform
> dmesg will shows an error during suspend/resume functions execution.
> My understanding is that in that specific case, no buffer is allocated and the driver couldn't save the TPM context (TPM_SaveState).
Sounds like an issue, thanks for reporting, I'll double check/debug this.
> In the case the platform generate a RESET on the LPC bus or on the TPM during standby all the TPM volatile context will be cleared
> (all the PCR's for example). I think this could be a problem.
> Only for my information, I would like to know if this scenario (TPM RESET during standby) could happen and if it could be a TPM/security issue.
As long as it implies in occurring a full power cycle, it isn't a TPM problem.
>
> I suppose what you are calling security-next tree is linux-next tree on www.kernel.org or are you referring to another tree ?
> I will try to provide you a patch for the ioctl function asap.
>
I'm using this one as security-next:
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/jamesm-security-next.git
Thanks,
Rajiv
>
>
> -----Original Message-----
> From: Rajiv Andrade [mailto:srajiv@...ux.vnet.ibm.com]
> Sent: Friday, October 01, 2010 10:26 AM
> To: Christophe Henri RICARD
> Cc: James Morris; linux-kernel@...r.kernel.org; joe@...ches.com
> Subject: Re: [PATCH 1/3] TPM: new stm i2c device driver
>
> Hi Christophe,
>
> The code must be applied and compiled against the security-next tree, that currently doesn't provide the locked ioctl anymore. Can you implement the locking inside tpm_st19_i2c_ioctl() and set it at the unlocked_ioctl field? Shouldn't be too hard, you can get tpm_write() as an example.
>
> By the way, I may be missing something, but why the tpm command transmission (TPMIOC_TRANSMIT) should be handled through ioctl instead of a modified tpm_write() that can send the commands through i2c?
>
> Thanks,
> Rajiv
>
> On 01/10/2010, at 11:27, Christophe Henri RICARD wrote:
>
>> Hi James,
>>
>> Which kernel are you using ?
>> I have made my testing with a 2.6.35.4 kernel.
>> As far as I know kernel 2.6.36 will not provide any ioctl field any more.
>> May be this is the reason ?
>>
>> Please let me know.
>> Thanks
>> Christophe
>>
>> -----Original Message-----
>> From: James Morris [mailto:jmorris@...ei.org]
>> Sent: Thursday, September 30, 2010 7:51 PM
>> To: Rajiv Andrade
>> Cc: linux-kernel@...r.kernel.org; joe@...ches.com; Christophe Henri RICARD
>> Subject: Re: [PATCH 1/3] TPM: new stm i2c device driver
>>
>> On Thu, 30 Sep 2010, Rajiv Andrade wrote:
>>
>>> From: Christophe Henri RICARD <christophe-h.ricard@...com>
>>>
>>> This driver uses the Linux I2C, TPM and generic gpio interfaces.
>>>
>>> Signed-off-by: Christophe Henri RICARD <christophe-h.ricard@...com>
>>> Signed-off-by: Rajiv Andrade <srajiv@...ux.vnet.ibm.com>
>>
>> This does not look to have been compile tested against my tree:
>>
>> CC [M] drivers/char/tpm/tpm_stm_st19_i2c.o
>> drivers/char/tpm/tpm_stm_st19_i2c.c:574: error: unknown field ioctl specified in initializer
>> drivers/char/tpm/tpm_stm_st19_i2c.c:574: warning: initialization from incompatible pointer type
>> make[1]: *** [drivers/char/tpm/tpm_stm_st19_i2c.o] Error 1
>>
>> The locked ioctl was removed in commit
>> b19dd42faf413b4705d4adb38521e82d73fa4249
>>
>>
>>
>> - James
>> --
>> James Morris
>> <jmorris@...ei.org>
>> --
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