crypto: use auto cleanup for many stack variables

Simplify cleanup paths by using glib's auto cleanup macros for stack
variables, allowing several goto jumps / labels to be eliminated.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

1 files changed, 16 insertions, 23 deletions

diff --git a/crypto/secret.c b/crypto/secret.c
index a75d50ae0c..1cf0ad0ce8 100644
--- a/crypto/secret.c
+++ b/crypto/secret.c
@@ -72,10 +72,12 @@ static void qcrypto_secret_decrypt(QCryptoSecret *secret,
                                    size_t *outputlen,
                                    Error **errp)
 {
-    uint8_t *key = NULL, *ciphertext = NULL, *iv = NULL;
+    g_autofree uint8_t *key = NULL;
+    g_autofree uint8_t *ciphertext = NULL;
+    g_autofree uint8_t *iv = NULL;
     size_t keylen, ciphertextlen, ivlen;
-    QCryptoCipher *aes = NULL;
-    uint8_t *plaintext = NULL;
+    g_autoptr(QCryptoCipher) aes = NULL;
+    g_autofree uint8_t *plaintext = NULL;
 
     *output = NULL;
     *outputlen = 0;
@@ -83,27 +85,27 @@ static void qcrypto_secret_decrypt(QCryptoSecret *secret,
     if (qcrypto_secret_lookup(secret->keyid,
                               &key, &keylen,
                               errp) < 0) {
-        goto cleanup;
+        return;
     }
 
     if (keylen != 32) {
         error_setg(errp, "Key should be 32 bytes in length");
-        goto cleanup;
+        return;
     }
 
     if (!secret->iv) {
         error_setg(errp, "IV is required to decrypt secret");
-        goto cleanup;
+        return;
     }
 
     iv = qbase64_decode(secret->iv, -1, &ivlen, errp);
     if (!iv) {
-        goto cleanup;
+        return;
     }
     if (ivlen != 16) {
         error_setg(errp, "IV should be 16 bytes in length not %zu",
                    ivlen);
-        goto cleanup;
+        return;
     }
 
     aes = qcrypto_cipher_new(QCRYPTO_CIPHER_ALG_AES_256,
@@ -111,11 +113,11 @@ static void qcrypto_secret_decrypt(QCryptoSecret *secret,
                              key, keylen,
                              errp);
     if (!aes) {
-        goto cleanup;
+        return;
     }
 
     if (qcrypto_cipher_setiv(aes, iv, ivlen, errp) < 0) {
-        goto cleanup;
+        return;
     }
 
     if (secret->format == QCRYPTO_SECRET_FORMAT_BASE64) {
@@ -124,7 +126,7 @@ static void qcrypto_secret_decrypt(QCryptoSecret *secret,
                                     &ciphertextlen,
                                     errp);
         if (!ciphertext) {
-            goto cleanup;
+            return;
         }
         plaintext = g_new0(uint8_t, ciphertextlen + 1);
     } else {
@@ -136,8 +138,7 @@ static void qcrypto_secret_decrypt(QCryptoSecret *secret,
                                plaintext,
                                ciphertextlen,
                                errp) < 0) {
-        plaintext = NULL;
-        goto cleanup;
+        return;
     }
 
     if (plaintext[ciphertextlen - 1] > 16 ||
@@ -145,9 +146,7 @@ static void qcrypto_secret_decrypt(QCryptoSecret *secret,
         error_setg(errp, "Incorrect number of padding bytes (%d) "
                    "found on decrypted data",
                    (int)plaintext[ciphertextlen - 1]);
-        g_free(plaintext);
-        plaintext = NULL;
-        goto cleanup;
+        return;
     }
 
     /* Even though plaintext may contain arbitrary NUL
@@ -156,14 +155,8 @@ static void qcrypto_secret_decrypt(QCryptoSecret *secret,
     ciphertextlen -= plaintext[ciphertextlen - 1];
     plaintext[ciphertextlen] = '\0';
 
-    *output = plaintext;
+    *output = g_steal_pointer(&plaintext);
     *outputlen = ciphertextlen;
-
- cleanup:
-    g_free(ciphertext);
-    g_free(iv);
-    g_free(key);
-    qcrypto_cipher_free(aes);
 }