On Wed, Aug 10, 2022 at 7:01 PM Roberto Sassu roberto.sassu@huawei.com wrote:
Add the bpf_verify_pkcs7_signature() kfunc, to give eBPF security modules the ability to check the validity of a signature against supplied data, by using user-provided or system-provided keys as trust anchor.
The new kfunc makes it possible to enforce mandatory policies, as eBPF programs might be allowed to make security decisions only based on data sources the system administrator approves.
The caller should provide the data to be verified and the signature as eBPF dynamic pointers (to minimize the number of parameters) and a bpf_key structure containing a reference to the keyring with keys trusted for signature verification, obtained from bpf_lookup_user_key() or bpf_lookup_system_key().
For bpf_key structures obtained from the former lookup function, bpf_verify_pkcs7_signature() completes the permission check deferred by that function by calling key_validate(). key_task_permission() is already called by the PKCS#7 code.
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com
Acked-by: KP Singh kpsingh@kernel.org