Add a small bit of belt and suspenders around ERR_V_OK with X509_STORE_ctx

and X509_verify_cert - We at least make it so an an init'ed ctx is not
"valid" until X509_verify_cert has actually been called, And we make it
impossible to return success without having the error set to ERR_V_OK.
ok jsing@

1 files changed, 20 insertions, 2 deletions

diff --git a/src/lib/libcrypto/x509/x509_vfy.c b/src/lib/libcrypto/x509/x509_vfy.c
index 3d4121ed2a..f555941587 100644
--- a/src/lib/libcrypto/x509/x509_vfy.c
+++ b/src/lib/libcrypto/x509/x509_vfy.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: x509_vfy.c,v 1.53 2017/01/03 05:34:48 beck Exp $ */
+/* $OpenBSD: x509_vfy.c,v 1.54 2017/01/03 05:52:28 beck Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -242,6 +242,16 @@ X509_verify_cert(X509_STORE_CTX *ctx)
                 ctx->error = X509_V_ERR_INVALID_CALL;
                 return -1;
         }
+        if (ctx->error != X509_V_ERR_UNSPECIFIED) {
+                /*
+                 * This X509_STORE_CTX has not been properly initialized.
+                 */
+                X509err(X509_F_X509_VERIFY_CERT,
+                    ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
+                ctx->error = X509_V_ERR_INVALID_CALL;
+                return -1;
+        }
+        ctx->error = X509_V_OK; /* Initialize to OK */
 
         cb = ctx->verify_cb;
 
@@ -538,7 +548,9 @@ X509_verify_cert(X509_STORE_CTX *ctx)
         /* Safety net, error returns must set ctx->error */
         if (ok <= 0 && ctx->error == X509_V_OK)
                 ctx->error = X509_V_ERR_UNSPECIFIED;
-        return ok;
+
+        /* Ensure we only return success with ctx->error of X509_V_OK */
+        return (ctx->error == X509_V_OK);
 }
 
 /* Given a STACK_OF(X509) find the issuer of cert (if any)
@@ -2168,6 +2180,12 @@ X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store, X509 *x509,
         memset(ctx, 0, sizeof(*ctx));
 
         /*
+         * Start with this set to not valid - it will be set to valid
+         * in X509_verify_cert.
+         */
+        ctx->error = X509_V_ERR_UNSPECIFIED;
+
+        /*
          * Set values other than 0.  Keep this in the same order as
          * X509_STORE_CTX except for values that may fail.  All fields that
          * may fail should go last to make sure 'ctx' is as consistent as