Test V4 apk_digest computation in apkverify
Bug: 239534874
Test: atest libapkverify.test
Change-Id: I73df9d67be0fdc922299968a56db7ed87dec171c
diff --git a/libs/apkverify/src/sigutil.rs b/libs/apkverify/src/sigutil.rs
index 7034527..72c5c1a 100644
--- a/libs/apkverify/src/sigutil.rs
+++ b/libs/apkverify/src/sigutil.rs
@@ -289,17 +289,20 @@
}
}
-/// Rank the signature algorithm according to the preferences of the v4 signing scheme.
-pub fn rank_signature_algorithm(algo: u32) -> Result<u32> {
- rank_content_digest_algorithm(to_content_digest_algorithm(algo)?)
-}
-
-fn rank_content_digest_algorithm(id: u32) -> Result<u32> {
- match id {
+/// This method is used to help pick v4 apk digest. According to APK Signature
+/// Scheme v4, apk digest is the first available content digest of the highest
+/// rank (rank N).
+///
+/// This rank was also used for step 3a of the v3 signature verification.
+///
+/// [v3 verification]: https://source.android.com/docs/security/apksigning/v3#v3-verification
+pub fn get_signature_algorithm_rank(algo: u32) -> Result<u32> {
+ let content_digest = to_content_digest_algorithm(algo)?;
+ match content_digest {
CONTENT_DIGEST_CHUNKED_SHA256 => Ok(0),
CONTENT_DIGEST_VERITY_CHUNKED_SHA256 => Ok(1),
CONTENT_DIGEST_CHUNKED_SHA512 => Ok(2),
- _ => bail!("Unknown digest algorithm: {}", id),
+ _ => bail!("Unknown digest algorithm: {}", content_digest),
}
}