add cargo-fuzz to the Github CI

.github/workflows/rust-fuzz.yml

@@ -0,0 +1,38 @@
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+name: Quick Fuzzing
+
+env:
+  CARGO_TERM_COLOR: always
+  RUST_BACKTRACE: 1
+
+jobs:
+  fuzzing:
+    name: Fuzzing
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Install nightly toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: nightly
+          override: true
+
+      - name: Install cargo-fuzz
+        uses: actions-rs/cargo@v1
+        with:
+          command: 'install'
+          args: 'cargo-fuzz'
+
+      - name: Run cargo-fuzz
+        uses: actions-rs/cargo@v1
+        with:
+          command: 'fuzz'
+          args: 'run parse_session -- -max_total_time=20'
+

examples/parse.rs

@@ -0,0 +1,40 @@
+use std::io::prelude::*;
+use std::{env, fs, process};
+
+fn main() -> process::ExitCode {
+    let mut args = env::args();
+    let _ = args.next().unwrap();
+    let Some(file) = args.next() else {
+        eprintln!("Usage: parse [file.sdp]");
+        return process::ExitCode::FAILURE;
+    };
+
+    let mut file = match fs::File::open(file) {
+        Ok(file) => file,
+        Err(err) => {
+            eprintln!("Failed to open file: {err}");
+            return process::ExitCode::FAILURE;
+        }
+    };
+
+    let mut content = Vec::new();
+    match file.read_to_end(&mut content) {
+        Ok(_) => {}
+        Err(err) => {
+            eprintln!("Failed to read file: {err}");
+            return process::ExitCode::FAILURE;
+        }
+    };
+
+    let sdp = match sdp_types::Session::parse(&content) {
+        Ok(sdp) => sdp,
+        Err(err) => {
+            eprintln!("Failed to parse SDP: {err}");
+            return process::ExitCode::FAILURE;
+        }
+    };
+
+    println!("{sdp:#?}");
+
+    process::ExitCode::SUCCESS
+}

fuzz/corpus/parse_session/crypto

@@ -0,0 +1,14 @@
+v=0
+o=jdoe 2890844526 2890842807 IN IP4 10.47.16.5
+s=SDP Seminar
+i=A Seminar on the session description protocol
+u=http://www.example.com/seminars/sdp.pdf
+e=j.doe@example.com (Jane Doe)
+c=IN IP4 161.44.17.12/127
+t=2873397496 2873404696
+m=video 51372 RTP/SAVP 31
+a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:d0RmdmcmVCspeEc3QGZiNWpVLFJhQX1cfHAwJSoj|2^20|1:32
+m=audio 49170 RTP/SAVP 0
+a=crypto:1 AES_CM_128_HMAC_SHA1_32 inline:NzB4d1BINUAvLEw6UzF3WSJ+PSdFcGdUJShpX1Zj|2^20|1:32
+m=application 32416 udp wb
+a=orient:portrait

fuzz/corpus/parse_session/simple

@@ -0,0 +1,12 @@
+v=0
+o=jdoe 2890844526 2890842807 IN IP4 10.47.16.5
+s=SDP Seminar
+i=A Seminar on the session description protocol
+u=http://www.example.com/seminars/sdp.pdf
+e=j.doe@example.com (Jane Doe)
+c=IN IP4 224.2.17.12/127
+t=2873397496 2873404696
+a=recvonly
+m=audio 49170 RTP/AVP 0
+m=video 51372 RTP/AVP 99
+a=rtpmap:99 h263-1998/90000

fuzz/fuzz_targets/parse_session.rs

@@ -2,5 +2,11 @@
 use libfuzzer_sys::fuzz_target;
 
 fuzz_target!(|data: &[u8]| {
-    let _ = sdp_types::Session::parse(data);
+    let session = sdp_types::Session::parse(data);
+
+    if let Ok (s) = session {
+        // serialize the parsed session
+        let mut written = vec![];
+        s.write(&mut written).unwrap();
+    };
 });

src/parser.rs

@@ -370,10 +370,10 @@ impl Media {
     ) -> Result<Option<Media>, ParserError> {
         let media = match lines.next()? {
             None => return Ok(None),
-            Some(line) => {
-                assert_eq!(line.key, b'm');
-                Media::parse_m_line(&line)?
-            }
+            Some(line) => match line.key {
+                b'm' => Media::parse_m_line(&line)?,
+                _ => return Err(ParserError::InvalidLineFormat(line.n, "line key not m")),
+            },
         };
 
         // As with Session::parse, be more permissive about order than RFC 8866.