[08/12] qcrypto-luks: extract store and load header

diff --git a/crypto/block-luks.c b/crypto/block-luks.c
index ba63e9b442..c3f3488222 100644
--- a/crypto/block-luks.c
+++ b/crypto/block-luks.c
@@ -409,6 +409,97 @@  qcrypto_block_luks_essiv_cipher(QCryptoCipherAlgorithm cipher,
     }
 }
 
+/*
+ * Stores the main LUKS header, taking care of endianess
+ */
+static int
+qcrypto_block_luks_store_header(QCryptoBlock *block,
+                                QCryptoBlockWriteFunc writefunc,
+                                void *opaque,
+                                Error **errp)
+{
+    const QCryptoBlockLUKS *luks = block->opaque;
+    Error *local_err = NULL;
+    size_t i;
+    g_autofree QCryptoBlockLUKSHeader *hdr_copy = NULL;
+
+    /* Create a copy of the header */
+    hdr_copy = g_new0(QCryptoBlockLUKSHeader, 1);
+    memcpy(hdr_copy, &luks->header, sizeof(QCryptoBlockLUKSHeader));
+
+    /*
+     * Everything on disk uses Big Endian (tm), so flip header fields
+     * before writing them
+     */
+    cpu_to_be16s(&hdr_copy->version);
+    cpu_to_be32s(&hdr_copy->payload_offset_sector);
+    cpu_to_be32s(&hdr_copy->master_key_len);
+    cpu_to_be32s(&hdr_copy->master_key_iterations);
+
+    for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
+        cpu_to_be32s(&hdr_copy->key_slots[i].active);
+        cpu_to_be32s(&hdr_copy->key_slots[i].iterations);
+        cpu_to_be32s(&hdr_copy->key_slots[i].key_offset_sector);
+        cpu_to_be32s(&hdr_copy->key_slots[i].stripes);
+    }
+
+    /* Write out the partition header and key slot headers */
+    writefunc(block, 0, (const uint8_t *)hdr_copy, sizeof(*hdr_copy),
+              opaque, &local_err);
+
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return -1;
+    }
+    return 0;
+}
+
+/*
+ * Loads the main LUKS header,and byteswaps it to native endianess
+ * And run basic sanity checks on it
+ */
+static int
+qcrypto_block_luks_load_header(QCryptoBlock *block,
+                                QCryptoBlockReadFunc readfunc,
+                                void *opaque,
+                                Error **errp)
+{
+    ssize_t rv;
+    size_t i;
+    QCryptoBlockLUKS *luks = block->opaque;
+
+    /*
+     * Read the entire LUKS header, minus the key material from
+     * the underlying device
+     */
+    rv = readfunc(block, 0,
+                  (uint8_t *)&luks->header,
+                  sizeof(luks->header),
+                  opaque,
+                  errp);
+    if (rv < 0) {
+        return rv;
+    }
+
+    /*
+     * The header is always stored in big-endian format, so
+     * convert everything to native
+     */
+    be16_to_cpus(&luks->header.version);
+    be32_to_cpus(&luks->header.payload_offset_sector);
+    be32_to_cpus(&luks->header.master_key_len);
+    be32_to_cpus(&luks->header.master_key_iterations);
+
+    for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
+        be32_to_cpus(&luks->header.key_slots[i].active);
+        be32_to_cpus(&luks->header.key_slots[i].iterations);
+        be32_to_cpus(&luks->header.key_slots[i].key_offset_sector);
+        be32_to_cpus(&luks->header.key_slots[i].stripes);
+    }
+
+    return 0;
+}
+
 /*
  * Given a key slot, and user password, this will attempt to unlock
  * the master encryption key from the key slot.
@@ -623,8 +714,6 @@  qcrypto_block_luks_open(QCryptoBlock *block,
     QCryptoBlockLUKS *luks = NULL;
     Error *local_err = NULL;
     int ret = 0;
-    size_t i;
-    ssize_t rv;
     g_autofree uint8_t *masterkey = NULL;
     char *ivgen_name, *ivhash_name;
     g_autofree char *password = NULL;
@@ -646,31 +735,11 @@  qcrypto_block_luks_open(QCryptoBlock *block,
     luks = g_new0(QCryptoBlockLUKS, 1);
     block->opaque = luks;
 
-    /* Read the entire LUKS header, minus the key material from
-     * the underlying device */
-    rv = readfunc(block, 0,
-                  (uint8_t *)&luks->header,
-                  sizeof(luks->header),
-                  opaque,
-                  errp);
-    if (rv < 0) {
-        ret = rv;
+    ret = qcrypto_block_luks_load_header(block, readfunc, opaque, errp);
+    if (ret < 0) {
         goto fail;
     }
 
-    /* The header is always stored in big-endian format, so
-     * convert everything to native */
-    be16_to_cpus(&luks->header.version);
-    be32_to_cpus(&luks->header.payload_offset_sector);
-    be32_to_cpus(&luks->header.master_key_len);
-    be32_to_cpus(&luks->header.master_key_iterations);
-
-    for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
-        be32_to_cpus(&luks->header.key_slots[i].active);
-        be32_to_cpus(&luks->header.key_slots[i].iterations);
-        be32_to_cpus(&luks->header.key_slots[i].key_offset_sector);
-        be32_to_cpus(&luks->header.key_slots[i].stripes);
-    }
 
     if (memcmp(luks->header.magic, qcrypto_block_luks_magic,
                QCRYPTO_BLOCK_LUKS_MAGIC_LEN) != 0) {
@@ -1235,46 +1304,7 @@  qcrypto_block_luks_create(QCryptoBlock *block,
         goto error;
     }
 
-    /* Everything on disk uses Big Endian, so flip header fields
-     * before writing them */
-    cpu_to_be16s(&luks->header.version);
-    cpu_to_be32s(&luks->header.payload_offset_sector);
-    cpu_to_be32s(&luks->header.master_key_len);
-    cpu_to_be32s(&luks->header.master_key_iterations);
-
-    for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
-        cpu_to_be32s(&luks->header.key_slots[i].active);
-        cpu_to_be32s(&luks->header.key_slots[i].iterations);
-        cpu_to_be32s(&luks->header.key_slots[i].key_offset_sector);
-        cpu_to_be32s(&luks->header.key_slots[i].stripes);
-    }
-
-
-    /* Write out the partition header and key slot headers */
-    writefunc(block, 0,
-              (const uint8_t *)&luks->header,
-              sizeof(luks->header),
-              opaque,
-              &local_err);
-
-    /* Delay checking local_err until we've byte-swapped */
-
-    /* Byte swap the header back to native, in case we need
-     * to read it again later */
-    be16_to_cpus(&luks->header.version);
-    be32_to_cpus(&luks->header.payload_offset_sector);
-    be32_to_cpus(&luks->header.master_key_len);
-    be32_to_cpus(&luks->header.master_key_iterations);
-
-    for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) {
-        be32_to_cpus(&luks->header.key_slots[i].active);
-        be32_to_cpus(&luks->header.key_slots[i].iterations);
-        be32_to_cpus(&luks->header.key_slots[i].key_offset_sector);
-        be32_to_cpus(&luks->header.key_slots[i].stripes);
-    }
-
-    if (local_err) {
-        error_propagate(errp, local_err);
+    if (qcrypto_block_luks_store_header(block,  writefunc, opaque, errp) < 0) {
         goto error;
     }