From 3e6e38b7a37a7088c3b851b24beaef4e8caa4dad Mon Sep 17 00:00:00 2001
From: Eric Chiang <ericchiang@google.com>
Date: Mon, 16 Aug 2021 11:20:30 -0700
Subject: [PATCH] add OBJ_get0_data()

This allows encoding of an OBJECT IDENTIFIER, which uses complex base
128 encoding rules.

https://luca.ntop.org/Teaching/Appunti/asn1.html

Same as_slice() API as ASN1_STRING_get0_data().

Test data generated with the following Go program:
https://play.golang.org/p/vA1PBcx1R4v
---
 openssl-sys/src/object.rs |  4 ++++
 openssl/src/asn1.rs       | 26 ++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/openssl-sys/src/object.rs b/openssl-sys/src/object.rs
index fbc459bca..99abdebc9 100644
--- a/openssl-sys/src/object.rs
+++ b/openssl-sys/src/object.rs
@@ -18,4 +18,8 @@ extern "C" {
         -> c_int;
     pub fn OBJ_sn2nid(sn: *const libc::c_char) -> libc::c_int;
     pub fn OBJ_txt2obj(s: *const libc::c_char, no_name: libc::c_int) -> *mut ASN1_OBJECT;
+    #[cfg(ossl111)]
+    pub fn OBJ_length(obj: *const ASN1_OBJECT) -> libc::size_t;
+    #[cfg(ossl111)]
+    pub fn OBJ_get0_data(obj: *const ASN1_OBJECT) -> *const c_uchar;
 }
diff --git a/openssl/src/asn1.rs b/openssl/src/asn1.rs
index 9c066c556..5d7fd0fd6 100644
--- a/openssl/src/asn1.rs
+++ b/openssl/src/asn1.rs
@@ -626,6 +626,22 @@ impl Asn1Object {
             Ok(Asn1Object::from_ptr(obj))
         }
     }
+
+    /// Return the OID as an DER encoded array of bytes. This is the ASN.1
+    /// value, not including tag or length.
+    ///
+    /// This corresponds to [`OBJ_get0_data`].
+    ///
+    /// Requires OpenSSL 1.1.1 or newer.
+    ///
+    /// [`OBJ_get0_data`]: https://www.openssl.org/docs/man1.1.0/man3/OBJ_get0_data.html
+    #[cfg(ossl111)]
+    pub fn as_slice(&self) -> &[u8] {
+        unsafe {
+            let len = ffi::OBJ_length(self.as_ptr());
+            slice::from_raw_parts(ffi::OBJ_get0_data(self.as_ptr()), len)
+        }
+    }
 }
 
 impl Asn1ObjectRef {
@@ -765,4 +781,14 @@ mod tests {
             .map(|object| object.to_string())
             .expect_err("parsing invalid OID should fail");
     }
+
+    #[test]
+    #[cfg(ossl111)]
+    fn object_to_slice() {
+        let object = Asn1Object::from_str("2.16.840.1.101.3.4.2.1").unwrap();
+        assert_eq!(
+            object.as_slice(),
+            &[0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01],
+        );
+    }
 }
-- 
GitLab