autocrypt: Add ability to parse Autocrypt-Gossip headers.

  - Refactor parsing of Autocrypt headers into own function.

  - Key gossip uses the same format as specified in the spec [0].

  - Add tests from attached ticket.

  - Fixes #394.

[0]: https://autocrypt.org/level1.html#key-gossip

1 files changed, 155 insertions, 38 deletions

diff --git a/autocrypt/src/lib.rs b/autocrypt/src/lib.rs
index 6caa5a21..f336be9a 100644
--- a/autocrypt/src/lib.rs
+++ b/autocrypt/src/lib.rs
@@ -231,56 +231,70 @@ impl AutocryptHeaders {
             }
 
             const AUTOCRYPT : &str = "Autocrypt: ";
+            const AUTOCRYPT_GOSSIP : &str = "Autocrypt-Gossip: ";
             const FROM : &str = "From: ";
 
             if line.starts_with(FROM) {
                 headers.from
                     = Some(line[FROM.len()..].trim_matches(' ').into());
-            } else if line.starts_with(AUTOCRYPT) {
-                let ac_value = &line[AUTOCRYPT.len()..];
+            } else if line.starts_with(AUTOCRYPT) || line.starts_with(AUTOCRYPT_GOSSIP) {
+                headers.headers.push(Self::decode_autocrypt_like_header(&line));
+            }
+        }
 
-                let mut header = AutocryptHeader::empty(
-                    AutocryptHeaderType::Sender);
+        return Ok(headers)
+    }
 
-                for pair in ac_value.split(';') {
-                    let pair = pair
-                        .splitn(2, |c| c == '=')
-                        .collect::<Vec<&str>>();
+    /// Decode header that has the same format as the Autocrypt header.
+    /// This function should be called only on "Autocrypt" or "Autocrypt-Gossip"
+    /// headers.
+    fn decode_autocrypt_like_header(line: &str) -> AutocryptHeader {
+        let mut parts = line.splitn(2, ": ");
+        let header_name = parts.next().unwrap();
+        let ac_value = parts.next().unwrap();
+
+        let header_type = match header_name {
+            "Autocrypt" => AutocryptHeaderType::Sender,
+            "Autocrypt-Gossip" => AutocryptHeaderType::Gossip,
+            other => panic!("Expected Autocrypt header but found: {}", other)
+        };
 
-                    let (key, value) : (String, String) = if pair.len() == 1 {
-                        // No value...
-                        (pair[0].trim_matches(' ').into(), "".into())
-                    } else {
-                        (pair[0].trim_matches(' ').into(),
-                         pair[1].trim_matches(' ').into())
-                    };
-
-                    if key == "keydata" {
-                        if let Ok(decoded) = base64::decode(
-                            &value.replace(" ", "")[..]) {
-                            if let Ok(cert) = Cert::from_bytes(&decoded[..]) {
-                                header.key = Some(cert);
-                            }
-                        }
-                    }
+        let mut header = AutocryptHeader::empty(header_type);
 
-                    let critical = key.len() >= 1 && &key[0..1] == "_";
-                    header.attributes.push(Attribute {
-                        critical: critical,
-                        key: if critical {
-                            key[1..].to_string()
-                        } else {
-                            key
-                        },
-                        value,
-                    });
-                }
+        for pair in ac_value.split(';') {
+            let pair = pair
+                .splitn(2, |c| c == '=')
+                .collect::<Vec<&str>>();
 
-                headers.headers.push(header);
+            let (key, value) : (String, String) = if pair.len() == 1 {
+                // No value...
+                (pair[0].trim_matches(' ').into(), "".into())
+            } else {
+                (pair[0].trim_matches(' ').into(),
+                 pair[1].trim_matches(' ').into())
+            };
+
+            if key == "keydata" {
+                if let Ok(decoded) = base64::decode(
+                    &value.replace(" ", "")[..]) {
+                    if let Ok(cert) = Cert::from_bytes(&decoded[..]) {
+                        header.key = Some(cert);
+                    }
+                }
             }
-        }
 
-        return Ok(headers)
+            let critical = key.len() >= 1 && &key[0..1] == "_";
+            header.attributes.push(Attribute {
+                critical,
+                key: if critical {
+                    key[1..].to_string()
+                } else {
+                    key
+                },
+                value,
+            });
+        }
+        header
     }
 
     /// Parses an autocrypt header.
@@ -905,6 +919,7 @@ In the light of the Efail vulnerability I am asking myself if it's
         // We expect exactly one Autocrypt header.
         assert_eq!(ac.headers.len(), 1);
 
+        assert_eq!(ac.headers[0].header_type, AutocryptHeaderType::Sender);
         assert_eq!(ac.headers[0].get("addr").unwrap().value,
                    "holger@merlinux.eu");
 
@@ -969,6 +984,108 @@ In the light of the Efail vulnerability I am asking myself if it's
         assert_eq!(ac, ac2);
     }
 
+
+    #[test]
+    fn decode_gossip() {
+        const GOSSIP : &'static [u8] = b"\
+Autocrypt-Gossip: addr=dkg@fifthhorseman.net; keydata=
+ mDMEXEK/AhYJKwYBBAHaRw8BAQdAr/gSROcn+6m8ijTN0DV9AahoHGafy52RRkhCZVwxhEe0
+ K0RhbmllbCBLYWhuIEdpbGxtb3IgPGRrZ0BmaWZ0aGhvcnNlbWFuLm5ldD6ImQQTFggAQQIb
+ AQUJA8JnAAULCQgHAgYVCgkICwIEFgIDAQIeAQIXgBYhBMS8Lds4zOlkhevpwvIGkReQOOXG
+ BQJcQsbzAhkBAAoJEPIGkReQOOXG4fkBAO1joRxqAZY57PjdzGieXLpluk9RkWa3ufkt3YUV
+ EpH/AP9c+pgIxtyW+FwMQRjlqljuj8amdN4zuEqaCy4hhz/1DbgzBFxCv4sWCSsGAQQB2kcP
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+ ZfDvdhg512NIBfx+Mz9ls5kA/Rq97vz4z48MFuBdCuu0W/fVqVjnY7LN5n+CQJwGC0MIA7QA
+ /RyY7Sz2gFIOcrns0RpoHr+3WI+won3xCD8+sVXSHZvCAP98HCjDnw/b0lGuCR7coTXKLIM4
+ 4/LFWgXAdZjm1wjODbg4BFxCv50SCisGAQQBl1UBBQEBB0BG4iXnHX/fs35NWKMWQTQoRI7o
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+ y/qKAP0VuPQSCRxA7RKfcB/XrEphfUFkraL06Xn/xGwJ+D0hCw==
+Autocrypt-Gossip: addr=neal@walfield.org; keydata=
+ mQHhBFUjmukBDqCpmVI7Ve+2xTFSTG+mXMFHml63/Yai2nqxBk9gBfQfRFIjMt74whGG3LA1
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+
+...
+"
+;
+        let ac = AutocryptHeaders::from_bytes(&GOSSIP[..]).unwrap();
+        //eprintln!("ac: {:#?}", ac);
+
+        // We expect exactly two Autocrypt headers.
+        assert_eq!(ac.headers.len(), 2);
+
+        assert_eq!(ac.headers[0].header_type, AutocryptHeaderType::Gossip);
+        assert_eq!(ac.headers[0].get("addr").unwrap().value,
+                "dkg@fifthhorseman.net");
+
+        assert_eq!(ac.headers[1].get("addr").unwrap().value,
+                "neal@walfield.org");
+
+        let cert = ac.headers[0].key.as_ref()
+            .expect("Failed to parse key material.");
+        assert_eq!(cert.fingerprint(),
+                Fingerprint::from_hex(
+                    &"C4BC2DDB38CCE96485EBE9C2F20691179038E5C6"[..]).unwrap());
+        assert_eq!(cert.userids().next().unwrap().value(),
+                &b"Daniel Kahn Gillmor <dkg@fifthhorseman.net>"[..]);
+
+    }
+
     #[test]
     fn passcode_gen_test() {
         let mut dist = [0usize; 10];