[2/2] cryptodev: Handle unexpected request to avoid crash

Commit Message

zhenwei pi Aug. 3, 2023, 2:43 a.m. UTC

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 <[e-mail]>
Cc: Mauro Matteo Cascella <[e-mail]>
Cc: Xiao Lei <[e-mail]>
Cc: Yongkang Jia <[e-mail]>
Reported-by: Yiming Tao <[e-mail]>
Signed-off-by: zhenwei pi <[e-mail]>
---
 backends/cryptodev.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

Patch

diff --git a/backends/cryptodev.c b/backends/cryptodev.c
index 7d29517843..4d183f7237 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);