[Qemu-devel] [PATCH for-2.6] crypto: Avoid memory leak on failure

[Eric Blake <eblake@redhat.com>]

Commit 7836857 introduced a memory leak due to invalid use of
Error vs. visit_type_end().  If visiting the intermediate
members fails, we clear the error and unconditionally use
visit_end_struct() on the same error object; but if that
cleanup succeeds, we then skip the qapi_free call.

Until a later patch adds visit_check_struct(), the only safe
approach is to use two separate error objects.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/crypto.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/block/crypto.c b/block/crypto.c
index be34985..1903e84 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -196,6 +196,7 @@ block_crypto_open_opts_init(QCryptoBlockFormat format,
     OptsVisitor *ov;
     QCryptoBlockOpenOptions *ret = NULL;
     Error *local_err = NULL;
+    Error *end_err = NULL;

     ret = g_new0(QCryptoBlockOpenOptions, 1);
     ret->format = format;
@@ -218,10 +219,9 @@ block_crypto_open_opts_init(QCryptoBlockFormat format,
         error_setg(&local_err, "Unsupported block format %d", format);
         break;
     }
-    error_propagate(errp, local_err);
-    local_err = NULL;

-    visit_end_struct(opts_get_visitor(ov), &local_err);
+    visit_end_struct(opts_get_visitor(ov), &end_err);
+    error_propagate(&local_err, end_err);

  out:
     if (local_err) {
@@ -242,6 +242,7 @@ block_crypto_create_opts_init(QCryptoBlockFormat format,
     OptsVisitor *ov;
     QCryptoBlockCreateOptions *ret = NULL;
     Error *local_err = NULL;
+    Error *end_err = NULL;

     ret = g_new0(QCryptoBlockCreateOptions, 1);
     ret->format = format;
@@ -264,10 +265,9 @@ block_crypto_create_opts_init(QCryptoBlockFormat format,
         error_setg(&local_err, "Unsupported block format %d", format);
         break;
     }
-    error_propagate(errp, local_err);
-    local_err = NULL;

-    visit_end_struct(opts_get_visitor(ov), &local_err);
+    visit_end_struct(opts_get_visitor(ov), &end_err);
+    error_propagate(&local_err, end_err);

  out:
     if (local_err) {
-- 
2.5.5