openpgp: Make armor parsing more robust.

  - ASCII Armor, designed to protect OpenPGP data in transit, has been
    a source of problems if the armor structure is damaged.  For
    example, copying data manually from one program to another might
    introduce or drop newlines.

  - This change introduces a heuristic that simply tries to detect the
    base64-encoded OpenPGP data.  This way, if the framing is in any
    way damaged, or even stripped, we can still recover the message.

  - Fixes #40.

1 files changed, 40 insertions, 0 deletions

diff --git a/openpgp/examples/wrap-literal.rs b/openpgp/examples/wrap-literal.rs
new file mode 100644
index 00000000..5d57d118
--- /dev/null
+++ b/openpgp/examples/wrap-literal.rs
@@ -0,0 +1,40 @@
+/// This program demonstrates how to wrap a stream into a literal data
+/// packet.
+///
+/// It is also used to generate test vectors for the armor subsystem.
+
+use std::env;
+use std::io;
+
+extern crate openpgp;
+use openpgp::armor;
+use openpgp::constants::DataFormat;
+use openpgp::serialize::stream::{wrap, LiteralWriter};
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    if args.len() != 1 {
+        panic!("A simple filter wrapping data into a literal data packet.\n\n\
+                Usage: {} <input >output\n", args[0]);
+    }
+
+    // Compose a writer stack corresponding to the output format and
+    // packet structure we want.  First, we want the output to be
+    // ASCII armored.
+    let sink = armor::Writer::new(io::stdout(), armor::Kind::Message, &[][..])
+        .expect("Failed to create armored writer.");
+
+    // Then, create a literal writer to wrap the data in a literal
+    // message packet.
+    let mut literal = LiteralWriter::new(wrap(sink), DataFormat::Binary,
+                                         None, None)
+        .expect("Failed to create literal writer");
+
+    // Finally, just copy all the data.
+    io::copy(&mut io::stdin(), &mut literal)
+        .expect("Failed to sign data");
+
+    // Teardown the stack to ensure all the data is written.
+    literal.finalize()
+        .expect("Failed to write data");
+}