cryptodev: Handle unexpected request to avoid crash

Generally guest side should discover which services the device is
able to offer, then do requests on device.

However it's also possible to break this rule in a guest. Handle
unexpected request here to avoid NULL pointer dereference.

Fixes: e7a775fd ('cryptodev: Account statistics')
Cc: Gonglei <arei.gonglei@huawei.com>
Cc: Mauro Matteo Cascella <mcascell@redhat.com>
Cc: Xiao Lei <nop.leixiao@gmail.com>
Cc: Yongkang Jia <kangel@zju.edu.cn>
Reported-by: Yiming Tao <taoym@zju.edu.cn>
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Message-Id: <20230803024314.29962-3-pizhenwei@bytedance.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 15b11a1da6a4b7c6b8bb37883f52b544dee2b8fd)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/backends/cryptodev.c b/backends/cryptodev.c
index 94ca393cee3b801ddaf44637bfffb06e59216e8f..d3fe92d8c09665e9e116909d4c8e1a06eb68ec9e 100644 (file)
--- a/backends/cryptodev.c
+++ b/backends/cryptodev.c
@@ -191,6 +191,11 @@ static int cryptodev_backend_account(CryptoDevBackend *backend,
     if (algtype == QCRYPTODEV_BACKEND_ALG_ASYM) {
         CryptoDevBackendAsymOpInfo *asym_op_info = op_info->u.asym_op_info;
         len = asym_op_info->src_len;
+
+        if (unlikely(!backend->asym_stat)) {
+            error_report("cryptodev: Unexpected asym operation");
+            return -VIRTIO_CRYPTO_NOTSUPP;
+        }
         switch (op_info->op_code) {
         case VIRTIO_CRYPTO_AKCIPHER_ENCRYPT:
             CryptodevAsymStatIncEncrypt(backend, len);
@@ -210,6 +215,11 @@ static int cryptodev_backend_account(CryptoDevBackend *backend,
     } else if (algtype == QCRYPTODEV_BACKEND_ALG_SYM) {
         CryptoDevBackendSymOpInfo *sym_op_info = op_info->u.sym_op_info;
         len = sym_op_info->src_len;
+
+        if (unlikely(!backend->sym_stat)) {
+            error_report("cryptodev: Unexpected sym operation");
+            return -VIRTIO_CRYPTO_NOTSUPP;
+        }
         switch (op_info->op_code) {
         case VIRTIO_CRYPTO_CIPHER_ENCRYPT:
             CryptodevSymStatIncEncrypt(backend, len);