[Stable-8.0.4 55/63] cryptodev: Handle unexpected request to avoid crash

[Michael Tokarev]

From: zhenwei pi <pizhenwei@bytedance.com>

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 94ca393cee..d3fe92d8c0 100644
--- 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);
-- 
2.39.2