openpgp: Make crypto::Hash::digest fallible.

6 files changed, 37 insertions, 23 deletions

diff --git a/openpgp/src/crypto/backend/cng/hash.rs b/openpgp/src/crypto/backend/cng/hash.rs
index 33eeaeb9..22d8ae77 100644
--- a/openpgp/src/crypto/backend/cng/hash.rs
+++ b/openpgp/src/crypto/backend/cng/hash.rs
@@ -15,7 +15,7 @@ impl Digest for cng::Hash {
         let _ = self.hash(data);
     }
 
-    fn digest(&mut self, digest: &mut [u8]) {
+    fn digest(&mut self, digest: &mut [u8]) -> Result<()> {
         // TODO: Replace with CNG reusable hash objects, supported from Windows 8
         // This would allow us to not re-create the CNG hash object each time we
         // want to finish digest calculation
@@ -31,6 +31,7 @@ impl Digest for cng::Hash {
             .expect("CNG to not fail internally");
 
         digest.copy_from_slice(&buffer.as_slice()[..digest.len()]);
+        Ok(())
     }
 }
 
diff --git a/openpgp/src/crypto/backend/nettle/hash.rs b/openpgp/src/crypto/backend/nettle/hash.rs
index bf1d9cb5..acfdf3a8 100644
--- a/openpgp/src/crypto/backend/nettle/hash.rs
+++ b/openpgp/src/crypto/backend/nettle/hash.rs
@@ -2,20 +2,33 @@ use crate::crypto::hash::Digest;
 use crate::{Error, Result};
 use crate::types::{HashAlgorithm};
 
-impl<T: nettle::hash::Hash + Clone> Digest for T {
-    fn digest_size(&self) -> usize {
-        self.digest_size()
-    }
+macro_rules! impl_digest_for {
+    ($t: path) => {
+        impl Digest for $t {
+            fn digest_size(&self) -> usize {
+                nettle::hash::Hash::digest_size(self)
+            }
 
-    fn update(&mut self, data: &[u8]) {
-        self.update(data);
-    }
+            fn update(&mut self, data: &[u8]) {
+                nettle::hash::Hash::update(self, data);
+            }
 
-    fn digest(&mut self, digest: &mut [u8]) {
-        self.digest(digest);
+            fn digest(&mut self, digest: &mut [u8]) -> Result<()> {
+                nettle::hash::Hash::digest(self, digest);
+                Ok(())
+            }
+        }
     }
 }
 
+impl_digest_for!(nettle::hash::Sha224);
+impl_digest_for!(nettle::hash::Sha256);
+impl_digest_for!(nettle::hash::Sha384);
+impl_digest_for!(nettle::hash::Sha512);
+impl_digest_for!(nettle::hash::insecure_do_not_use::Sha1);
+impl_digest_for!(nettle::hash::insecure_do_not_use::Md5);
+impl_digest_for!(nettle::hash::insecure_do_not_use::Ripemd160);
+
 impl HashAlgorithm {
     /// Whether Sequoia supports this algorithm.
     pub fn is_supported(self) -> bool {
diff --git a/openpgp/src/crypto/ecdh.rs b/openpgp/src/crypto/ecdh.rs
index 8649753d..c203e397 100644
--- a/openpgp/src/crypto/ecdh.rs
+++ b/openpgp/src/crypto/ecdh.rs
@@ -131,7 +131,7 @@ fn kdf(x: &Protected, obits: usize, hash: HashAlgorithm, param: &[u8])
 
     // Providing a smaller buffer will truncate the digest.
     let mut key: Protected = vec![0; obits].into();
-    hash.digest(&mut key);
+    hash.digest(&mut key)?;
     Ok(key)
 }
 
diff --git a/openpgp/src/crypto/hash.rs b/openpgp/src/crypto/hash.rs
index c7a8b248..5643a30a 100644
--- a/openpgp/src/crypto/hash.rs
+++ b/openpgp/src/crypto/hash.rs
@@ -45,7 +45,7 @@ pub(crate) trait Digest: DynClone {
     ///
     /// `digest` must be at least `self.digest_size()` bytes large,
     /// otherwise the digest will be truncated.
-    fn digest(&mut self, digest: &mut [u8]);
+    fn digest(&mut self, digest: &mut [u8]) -> Result<()>;
 }
 
 dyn_clone::clone_trait_object!(Digest);
@@ -110,8 +110,8 @@ impl Context {
     /// otherwise the digest will be truncated.
     ///
     ///   [`self.digest_size()`]: #method.digest_size
-    pub fn digest<D: AsMut<[u8]>>(&mut self, mut digest: D) {
-        self.ctx.digest(digest.as_mut());
+    pub fn digest<D: AsMut<[u8]>>(&mut self, mut digest: D) -> Result<()> {
+        self.ctx.digest(digest.as_mut())
     }
 }
 
@@ -206,8 +206,8 @@ impl Digest for HashDumper {
         self.sink.write_all(data).unwrap();
         self.written += data.len();
     }
-    fn digest(&mut self, digest: &mut [u8]) {
-        self.hasher.digest(digest);
+    fn digest(&mut self, digest: &mut [u8]) -> Result<()> {
+        self.hasher.digest(digest)
     }
 }
 
@@ -386,7 +386,7 @@ impl Signature {
         sig.hash(&mut h);
 
         let mut digest = vec![0u8; h.digest_size()];
-        h.digest(&mut digest);
+        h.digest(&mut digest)?;
         Ok(digest)
     }
 
@@ -411,7 +411,7 @@ impl Signature {
         sig.hash(&mut h);
 
         let mut digest = vec![0u8; h.digest_size()];
-        h.digest(&mut digest);
+        h.digest(&mut digest)?;
         Ok(digest)
     }
 
@@ -431,7 +431,7 @@ impl Signature {
         sig.hash(&mut h);
 
         let mut digest = vec![0u8; h.digest_size()];
-        h.digest(&mut digest);
+        h.digest(&mut digest)?;
         Ok(digest)
     }
 
@@ -462,7 +462,7 @@ impl Signature {
         sig.hash(&mut h);
 
         let mut digest = vec![0u8; h.digest_size()];
-        h.digest(&mut digest);
+        h.digest(&mut digest)?;
         Ok(digest)
     }
 
@@ -482,7 +482,7 @@ impl Signature {
         sig.hash(&mut h);
 
         let mut digest = vec![0u8; h.digest_size()];
-        h.digest(&mut digest);
+        h.digest(&mut digest)?;
         Ok(digest)
     }
 }
diff --git a/openpgp/src/crypto/mem.rs b/openpgp/src/crypto/mem.rs
index 038d12c6..96f80483 100644
--- a/openpgp/src/crypto/mem.rs
+++ b/openpgp/src/crypto/mem.rs
@@ -279,7 +279,7 @@ mod has_access_to_prekey {
                 .expect("Mandatory algorithm unsupported");
             PREKEY.iter().for_each(|page| ctx.update(page));
             let mut sk: SessionKey = vec![0; 256/8].into();
-            ctx.digest(&mut sk);
+            let _ = ctx.digest(&mut sk);
             sk
         }
 
diff --git a/openpgp/src/crypto/s2k.rs b/openpgp/src/crypto/s2k.rs
index 4eee84d8..ecc6313e 100644
--- a/openpgp/src/crypto/s2k.rs
+++ b/openpgp/src/crypto/s2k.rs
@@ -228,7 +228,7 @@ impl S2K {
                             unreachable!(),
                     }
 
-                    hash.digest(data);
+                    let _ = hash.digest(data);
                     zeros.push(0);
                 }