On Thu, Dec 02, 2021 at 04:55:06PM -0500, Mimi Zohar wrote: > case IMA_VERITY_DIGSIG: > - fallthrough; > + set_bit(IMA_DIGSIG, &iint->atomic_flags); > + > + /* > + * The IMA signature is based on a hash of IMA_VERITY_DIGSIG > + * and the fs-verity file digest, not directly on the > + * fs-verity file digest. Both digests should probably be > + * included in the IMA measurement list, but for now this > + * digest is only used for verifying the IMA signature. > + */ > + verity_digest[0] = IMA_VERITY_DIGSIG; > + memcpy(verity_digest + 1, iint->ima_hash->digest, > + iint->ima_hash->length); > + > + hash.hdr.algo = iint->ima_hash->algo; > + hash.hdr.length = iint->ima_hash->length; This is still wrong because the bytes being signed don't include the hash algorithm. Unless you mean for it to be implicitly always SHA-256? fs-verity supports SHA-512 too, and it may support other hash algorithms in the future. - Eric
