platform: msm_shared: Size of decrypted signature should be equal to size of digest

For a successful boot image authentication, the RSA_public_decrypt() api returns
the size of the digest otherwise its a failure. This check avoids vulnerability due to
trailing data placed at the end of digest.

CRs-Fixed: 646385

Change-Id: I32c2d97d5c308d33146c509347915ca65fdd11ac
1 file changed