crypto: afalg: fix a NULL pointer dereference

Test-crypto-hash calls qcrypto_hash_bytesv/digest/base64 with
errp=NULL, this will cause a NULL pointer dereference if afalg_driver
doesn't support requested algos:

    ret = qcrypto_hash_afalg_driver.hash_bytesv(alg, iov, niov,
                                                result, resultlen,
                                                errp);
    if (ret == 0) {
        return ret;
    }

    error_free(*errp);  // <--- here

Because the error message is thrown away immediately, we should
just pass NULL to hash_bytesv(). There is also the same problem in
afalg-backend cipher & hmac, let's fix them together.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Longpeng <longpeng2@huawei.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

1 files changed, 1 insertions, 3 deletions

diff --git a/crypto/hmac.c b/crypto/hmac.c
index 82b0055adf..f6c2d8db60 100644
--- a/crypto/hmac.c
+++ b/crypto/hmac.c
@@ -90,11 +90,10 @@ QCryptoHmac *qcrypto_hmac_new(QCryptoHashAlgorithm alg,
 {
     QCryptoHmac *hmac;
     void *ctx = NULL;
-    Error *err2 = NULL;
     QCryptoHmacDriver *drv = NULL;
 
 #ifdef CONFIG_AF_ALG
-    ctx = qcrypto_afalg_hmac_ctx_new(alg, key, nkey, &err2);
+    ctx = qcrypto_afalg_hmac_ctx_new(alg, key, nkey, NULL);
     if (ctx) {
         drv = &qcrypto_hmac_afalg_driver;
     }
@@ -107,7 +106,6 @@ QCryptoHmac *qcrypto_hmac_new(QCryptoHashAlgorithm alg,
         }
 
         drv = &qcrypto_hmac_lib_driver;
-        error_free(err2);
     }
 
     hmac = g_new0(QCryptoHmac, 1);