Add advisory for openssl ssl::select_next_proto UAF (#2217)

Author: sfackler

crates/openssl/RUSTSEC-0000-0000.md

@@ -0,0 +1,48 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "openssl"
+date = "2025-02-02"
+url = "https://github.com/sfackler/rust-openssl/security/advisories/GHSA-rpmj-rpgj-qmpm"
+references = ["https://github.com/sfackler/rust-openssl/pull/2360"]
+categories = ["memory-exposure"]
+keywords = ["ssl", "tls", "alpn"]
+aliases = ["GHSA-rpmj-rpgj-qmpm"]
+
+[affected.functions]
+"openssl::ssl::select_next_proto" = [">= 0.10.0, < 0.10.70"]
+
+[versions]
+patched = [">= 0.10.70"]
+```
+
+# ssl::select_next_proto use after free
+
+In `openssl` versions before `0.10.70`, `ssl::select_next_proto` can return a slice pointing into the `server` argument's buffer but with a lifetime bound to the `client` argument. In situations where the `server` buffer's lifetime is shorter than the `client` buffer's, this can cause a use after free. This could cause the server to crash or to return arbitrary memory contents to the client.
+
+`openssl` 0.10.70 fixes the signature of `ssl::select_next_proto` to properly constrain the output buffer's lifetime to that of both input buffers.
+
+In standard usage of `ssl::select_next_proto` in the callback passed to `SslContextBuilder::set_alpn_select_callback`, code is only affected if the `server` buffer is constructed *within* the callback. For example:
+
+Not vulnerable - the server buffer has a `'static` lifetime:
+```rust
+builder.set_alpn_select_callback(|_, client_protos| {
+    ssl::select_next_proto(b"\x02h2", client_protos).ok_or_else(AlpnError::NOACK)
+});
+```
+
+Not vulnerable - the server buffer outlives the handshake:
+```rust
+let server_protos = b"\x02h2".to_vec();
+builder.set_alpn_select_callback(|_, client_protos| {
+    ssl::select_next_proto(&server_protos, client_protos).ok_or_else(AlpnError::NOACK)
+});
+```
+
+Vulnerable - the server buffer is freed when the callback returns:
+```rust
+builder.set_alpn_select_callback(|_, client_protos| {
+    let server_protos = b"\x02h2".to_vec();
+    ssl::select_next_proto(&server_protos, client_protos).ok_or_else(AlpnError::NOACK)
+});
+```