RT4175: Fix PKCS7_verify() regression with Authenticode signatures

This is a partial revert of commit c8491de39 ("GH354: Memory leak fixes"),
which was cherry-picked from commit 55500ea7c in OpenSSL 1.1.

That commit introduced a change in behaviour which is a regression for
software implementing Microsoft Authenticode — which requires a PKCS#7
signature to be validated against explicit external data, even though
it's a non-detached signature with its own embedded data.

The is fixed differently in OpenSSL 1.1 by commit 6b2ebe433 ("Add
PKCS7_NO_DUAL_CONTENT flag"), but that approach isn't viable in the
1.0.2 stable branch, so just comment the offending check back out again.

Signed-off-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Tim Hudson <tjh@openssl.org>

crypto/pkcs7/pk7_smime.c

@@ -274,12 +274,29 @@ int PKCS7_verify(PKCS7 *p7, STACK_OF(X509) *certs, X509_STORE *store,
         PKCS7err(PKCS7_F_PKCS7_VERIFY, PKCS7_R_NO_CONTENT);
         return 0;
     }
+#if 0
+    /*
+     * NB: this test commented out because some versions of Netscape
+     * illegally include zero length content when signing data. Also
+     * Microsoft Authenticode includes a SpcIndirectDataContent data
+     * structure which describes the content to be protected by the
+     * signature, rather than directly embedding that content. So
+     * Authenticode implementations are also expected to use
+     * PKCS7_verify() with explicit external data, on non-detached
+     * PKCS#7 signatures.
+     *
+     * In OpenSSL 1.1 a new flag PKCS7_NO_DUAL_CONTENT has been
+     * introduced to disable this sanity check. For the 1.0.2 branch
+     * this change is not acceptable, so the check remains completely
+     * commented out (as it has been for a long time).
+     */
 
     /* Check for data and content: two sets of data */
     if (!PKCS7_get_detached(p7) && indata) {
         PKCS7err(PKCS7_F_PKCS7_VERIFY, PKCS7_R_CONTENT_AND_DATA_PRESENT);
         return 0;
     }
+#endif
 
     sinfos = PKCS7_get_signer_info(p7);