fc9ec5d88f
CSE FW uses an AEK (Attestation keybox Encryption Key) to encrypt the keybox with AES-256-GCM algorithm before sending it to Android/Trusty. This key is derived from the latest platform Seed by CSE FW with KDF (key derivation function) HMAC-SHA256. After Trusty retrieves this encrypted keybox over HECI/MEI driver, Trusty needs the same AEKkey to decrypt it. Hence, before Trusty launches, Hypervisor derives the same AEK key from Platform Seed with the same algorithm and the same derivation parameters, then sends this AEK along with Trusty vSeed to Trusty world memory. Since Platform Seed is only visible to Hypervisor and it must not be sent to any guest VM, only Hypervisor can derive this AEK from this Platform Seed, just like previous per-Trusty virtual Seed derivation. Please note that Android Attestation Keybox is shared in a single hardware platform, so all the Trusty instance/world can get the same AEK for decryption even if there are multiple Android User OS/VMs running on top of Hypervisor. v1 --> v2: Add detailed description why we need the patch to derive an extra key v2 --> v3: Convert API descriptions to Doxygen Tracked-On: #1812 Reviewed-by: Bing Zhu <bing.zhu@intel.com> Reviewed-by: Kai Wang <kai.z.wang@intel.com> Signed-off-by: Chen Gang G <gang.g.chen@intel.com> Acked-by: Bing Zhu <bing.zhu@intel.com> |
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| .. | ||
| arch/x86 | ||
| common | ||
| debug | ||
| dm | ||
| lib | ||
| public | ||
| hv_debug.h | ||
| hypervisor.h | ||