Reimplement hash verification

This patch re-implements hashing using the "ring" crypto library and
implementing a streaming hashing with it.

This way, we stream the file to the hasher rather than reading the full file to
memory.

Signed-off-by: Matthias Beyer <matthias.beyer@atos.net>

1 files changed, 21 insertions, 24 deletions

diff --git a/src/package/source.rs b/src/package/source.rs
index 4d97365..4f8994b 100644
--- a/src/package/source.rs
+++ b/src/package/source.rs
@@ -1,3 +1,5 @@
+use std::io::Read;
+
 use anyhow::Result;
 use anyhow::anyhow;
 use getset::Getters;
@@ -33,9 +35,9 @@ pub struct SourceHash {
 }
 
 impl SourceHash {
-    pub fn matches_hash_of(&self, buf: &[u8]) -> Result<()> {
+    pub fn matches_hash_of<R: Read>(&self, reader: R) -> Result<()> {
         trace!("Hashing buffer with: {:?}", self.hashtype);
-        let h = self.hashtype.hash_buffer(&buf)?;
+        let h = self.hashtype.hash_from_reader(reader)?;
         trace!("Hashing buffer with: {} finished", self.hashtype);
 
         if h == self.value {
@@ -70,29 +72,24 @@ pub enum HashType {
 }
 
 impl HashType {
-    fn hash_buffer(&self, buffer: &[u8]) -> Result<HashValue> {
-        match self {
-            HashType::Sha1 => {
-                trace!("SHA1 hashing buffer");
-                let mut m = sha1::Sha1::new();
-                m.update(buffer);
-                Ok(HashValue(m.digest().to_string()))
-            },
-            HashType::Sha256 => {
-                trace!("SHA256 hashing buffer");
-                //let mut m = sha2::Sha256::new();
-                //m.update(buffer);
-                //Ok(HashValue(String::from(m.finalize())))
-                unimplemented!()
-            },
-            HashType::Sha512 => {
-                trace!("SHA512 hashing buffer");
-                //let mut m = sha2::Sha512::new();
-                //m.update(buffer);
-                //Ok(HashValue(String::from(m.finalize())))
-                unimplemented!()
-            },
+    fn hash_from_reader<R: Read>(&self, mut reader: R) -> Result<HashValue> {
+        use ring::digest::{Context, SHA1_FOR_LEGACY_USE_ONLY, SHA256, SHA512};
+        let mut context = match self {
+            HashType::Sha1   => Context::new(&SHA1_FOR_LEGACY_USE_ONLY),
+            HashType::Sha256 => Context::new(&SHA256),
+            HashType::Sha512 => Context::new(&SHA512),
+        };
+        let mut buffer = [0; 1024];
+
+        loop {
+            let count = reader.read(&mut buffer)?;
+            if count == 0 {
+                break;
+            }
+            context.update(&buffer[..count]);
         }
+
+        Ok(HashValue(data_encoding::HEXLOWER.encode(context.finish().as_ref())))
     }
 }