Re: [PATCH] cryptodev: Handle unexpected request to avoid crash

[Lei He]

> On Apr 27, 2023, at 16:05, zhenwei pi <pizhenwei@bytedance.com> wrote:
> 
> 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>
> ---
> backends/cryptodev.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
> 
> 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);
> -- 
> 2.34.1
> 

Reviewed-by: Lei He <helei.sig11@bytedance.com>


Best regards,
Lei He
--
helei.sig11@bytedance.com