Hi James,
Some comments below on how you are using the crypto API.
On 22 October 2018 at 04:36, James Bottomley
wrote:
> This code adds true session based HMAC authentication plus parameter
> decryption and response encryption using AES.
>
> The basic design of this code is to segregate all the
This runs through a preset sequence using sessions to demonstrate that
the session handling code functions. It does both HMAC, encryption
and decryption by testing an encrypted sealing operation with
authority and proving that the same sealed data comes back again via
an HMAC and response
This is the last component of encrypted tpm2 session handling that
allows us to verify from userspace that the key derived from the NULL
seed genuinely belongs to the TPM and has not been spoofed.
The procedure for doing this involves creating an attestation identity
key (which requires
If some entity is snooping the TPM bus, the can see the data going in
to be sealed and the data coming out as it is unsealed. Add parameter
and response encryption to these cases to ensure that no secrets are
leaked even if the bus is snooped.
As part of doing this conversion it was discovered
If some entity is snooping the TPM bus, they can see the random
numbers we're extracting from the TPM and do prediction attacks
against their consumers. Foil this attack by using response
encryption to prevent the attacker from seeing the random sequence.
Signed-off-by: James Bottomley
---
We use tpm2_pcr_extend() in trusted keys to extend a PCR to prevent a
key from being re-loaded until the next reboot. To use this
functionality securely, that extend must be protected by a session
hmac.
Signed-off-by: James Bottomley
---
v3: add error handling to sessions
---
This code adds true session based HMAC authentication plus parameter
decryption and response encryption using AES.
The basic design of this code is to segregate all the nasty crypto,
hash and hmac code into tpm2-sessions.c and export a usable API.
The API first of all starts off by gaining a
This separates out the old tpm_buf_... handling functions from static
inlines into tpm.h and makes them their own tpm-buf.c file. It also
adds handling for tpm2b structures and also incremental pointer
advancing parsers.
Signed-off-by: James Bottomley
---
v2: added this patch to separate out
By now, everybody knows we have a problem with the TPM2_RS_PW easy
button on TPM2 in that transactions on the TPM bus can be intercepted
and altered. The way to fix this is to use real sessions for HMAC
capabilities to ensure integrity and to use parameter and response
encryption to ensure
