The builtin keyring was exported prior to this which allowed
android-verity to simply lookup the key in the builtin keyring and
verify the signature of the verity metadata.
This is now broken as the kernel expects the signature to be
in pkcs#7 format (same used for module signing). Obviously, this doesn't
work with the verity metadata as we just append the raw signature in the
metadata .. sigh.
*This one time*, add an API to accept arbitrary signature and verify
that with a key from system's trusted keyring.
Bug: 72722987
Test:
$ adb push verity_fs.img /data/local/tmp/
$ adb root && adb shell
> cd /data/local/tmp
> losetup /dev/block/loop0 verity_fs.img
> dmctl create verity-fs android-verity 0 4200 Android:#7e4333f9bba00adfe0ede979e28ed1920492b40f 7:0
> mount -t ext4 /dev/block/dm-0 temp/
> cat temp/foo.txt temp/bar.txt
Change-Id: I0c14f3cb2b587b73a4c75907367769688756213e
Signed-off-by: Sandeep Patil <sspatil@google.com>
Make the determination of the trustworthiness of a key dependent on whether
a key that can verify it is present in the supplied ring of trusted keys
rather than whether or not the verifying key has KEY_FLAG_TRUSTED set.
verify_pkcs7_signature() will return -ENOKEY if the PKCS#7 message trust
chain cannot be verified.
Signed-off-by: David Howells <dhowells@redhat.com>
Generalise system_verify_data() to provide access to internal content
through a callback. This allows all the PKCS#7 stuff to be hidden inside
this function and removed from the PE file parser and the PKCS#7 test key.
If external content is not required, NULL should be passed as data to the
function. If the callback is not required, that can be set to NULL.
The function is now called verify_pkcs7_signature() to contrast with
verify_pefile_signature() and the definitions of both have been moved into
linux/verification.h along with the key_being_used_for enum.
Signed-off-by: David Howells <dhowells@redhat.com>
