add ability export PKCS7 to DER

resources/crypto.h

@@ -1,3 +1,5 @@
+void CRYPTO_free(void *addr);
+
 typedef struct crypto_ex_data_st CRYPTO_EX_DATA;
 struct crypto_ex_data_st {
   struct stack_st_void *sk;

resources/openssl.h

@@ -6,4 +6,4 @@ void OPENSSL_add_all_algorithms_conf(void);
 void OPENSSL_add_all_algorithms_noconf(void);
 
 void ERR_load_crypto_strings(void);
-void ERR_free_strings(void);
+void ERR_free_strings(void);

src/OpenSSL/PKCS7.php

@@ -36,8 +36,20 @@ class PKCS7 extends OpenSSL\C\CBackedObjectWithOwner
         if (!in_array($type, [PKCS7::NID_DIGEST, self::NID_SIGNED, self::NID_SIGNED_AND_ENVELOPED])) {
             throw new \RuntimeException("Can only verify signed or digested data");
         }
+    }
 
+    public function toDER(): string
+    {
+        $buf = $this->ffi->new("uint8_t*");
+        $ptr = FFI::addr($buf);
+        $len = $this->ffi->i2d_PKCS7($this->cObj, $ptr);
+        if ($len < 0) {
+            throw new \RuntimeException("Failed to create DER from PKCS7 object");
+        }
 
+        $val = FFI::string($buf, $len);
+        $this->ffi->CRYPTO_free($buf);
+        return $val;
     }
 
     public function freeObject()
@@ -54,16 +66,16 @@ class PKCS7 extends OpenSSL\C\CBackedObjectWithOwner
 
     public static function loadFromDER(string $der): PKCS7
     {
-        $pkcs = static::new();
-        $pkcs->loadDER($der);
-        return $pkcs;
-    }
-
-    private function loadDER(string $der)
-    {
+        $ffi = OpenSSL::getFFI();
         $derLen = strlen($der);
         $mem = Memory::buffer($der);
-        $this->ffi->d2i_PKCS7(FFI::addr($this->cObj), $mem->pointer(), $derLen);
+        $res = $ffi->d2i_PKCS7(null, $mem->pointer(), $derLen);
+
+        if ($res === null) {
+            throw new \RuntimeException("Failed loading DER");
+        }
+
         $mem->freed();
+        return new static($ffi, $res);
     }
 }

tests/PKCS7Test.php

@@ -4,6 +4,7 @@ namespace Cijber\OpenSSL\Tests;
 
 use Cijber\OpenSSL\PKCS7;
 use PHPUnit\Framework\TestCase;
+use RuntimeException;
 
 class PKCS7Test extends TestCase
 {
@@ -14,9 +15,20 @@ class PKCS7Test extends TestCase
         unset($pkcs7);
     }
 
-    public function testLoadDER() {
+    public function testLoadDER()
+    {
         $der = file_get_contents(__DIR__ . "/data/pkcs7/1.RSA");
         $pkcs7 = PKCS7::loadFromDER($der);
+        $newDer = $pkcs7->toDER();
+        $this->assertEquals($der, $newDer);
         $this->assertEquals(PKCS7::NID_SIGNED, $pkcs7->getType());
     }
+
+    public function testLoadingGarbageDER()
+    {
+        $this->expectException(RuntimeException::class);
+        $this->expectExceptionMessage("Failed loading DER");
+
+        PKCS7::loadFromDER("blaat");
+    }
 }