[PATCH] virtio-crypto: fix NULL pointer dereference in virtio_crypto_free_request

[Mauro Matteo Cascella <mcascell@redhat.com>]

Ensure op_info is not NULL in case of QCRYPTODEV_BACKEND_ALG_SYM algtype.

Fixes: 02ed3e7c ("virtio-crypto: zeroize the key material before free")
Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com>
Reported-by: Yiming Tao <taoym@zju.edu.cn>
---
 hw/virtio/virtio-crypto.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/hw/virtio/virtio-crypto.c b/hw/virtio/virtio-crypto.c
index 2fe804510f..c729a1f79e 100644
--- a/hw/virtio/virtio-crypto.c
+++ b/hw/virtio/virtio-crypto.c
@@ -476,15 +476,17 @@ static void virtio_crypto_free_request(VirtIOCryptoReq *req)
         size_t max_len;
         CryptoDevBackendSymOpInfo *op_info = req->op_info.u.sym_op_info;
 
-        max_len = op_info->iv_len +
-                  op_info->aad_len +
-                  op_info->src_len +
-                  op_info->dst_len +
-                  op_info->digest_result_len;
-
-        /* Zeroize and free request data structure */
-        memset(op_info, 0, sizeof(*op_info) + max_len);
-        g_free(op_info);
+        if (op_info) {
+            max_len = op_info->iv_len +
+                      op_info->aad_len +
+                      op_info->src_len +
+                      op_info->dst_len +
+                      op_info->digest_result_len;
+
+            /* Zeroize and free request data structure */
+            memset(op_info, 0, sizeof(*op_info) + max_len);
+            g_free(op_info);
+        }
     } else if (req->flags == QCRYPTODEV_BACKEND_ALG_ASYM) {
         CryptoDevBackendAsymOpInfo *op_info = req->op_info.u.asym_op_info;
         if (op_info) {
-- 
2.40.1