commit 7434b3111b80d2b84ddf656b66b7bf6591de5ab6
author Kenny Root <kroot@google.com> Fri Jun 14 11:29:53 2013 -0700
committer Kenny Root <kroot@google.com> Fri Jun 14 11:32:18 2013 -0700
tree c6c6f97cc113b38486c400706755a87ce078a2dd
parent 9caab76c6b5aefdeeb1715a3695491ca793b8c18

Change upgrade code to allow multiple versions

In the future, we'd like to have the ability to upgrade from any
supported version to any future version. Change the upgrade function
slightly to support this.

Change-Id: I3b20ccfff51c4c86f1e5e08690c263dc95ff5ce4

cryptfs.c

diff --git a/cryptfs.c b/cryptfs.c
index c86e712..c938402 100644
--- a/cryptfs.c
+++ b/cryptfs.c
@@ -250,46 +250,46 @@
  */
 static void upgrade_crypt_ftr(int fd, struct crypt_mnt_ftr *crypt_ftr, off64_t offset)
 {
-    struct crypt_persist_data *pdata;
-    off64_t pdata_offset = offset + CRYPT_FOOTER_TO_PERSIST_OFFSET;
+    int orig_major = crypt_ftr->major_version;
+    int orig_minor = crypt_ftr->minor_version;
 
-    /* This routine can currently only handle upgrading from 1.0 to 1.1.
-     * Do nothing if the passed structure is not version 1.0
-     */
+    if ((crypt_ftr->major_version == 1) && (crypt_ftr->minor_version == 0)) {
+        struct crypt_persist_data *pdata;
+        off64_t pdata_offset = offset + CRYPT_FOOTER_TO_PERSIST_OFFSET;
 
-    if ((crypt_ftr->major_version != 1) && (crypt_ftr->minor_version != 0)) {
-        return;
+        pdata = malloc(CRYPT_PERSIST_DATA_SIZE);
+        if (pdata == NULL) {
+            SLOGE("Cannot allocate persisent data\n");
+            return;
+        }
+        memset(pdata, 0, CRYPT_PERSIST_DATA_SIZE);
+
+        /* Need to initialize the persistent data area */
+        if (lseek64(fd, pdata_offset, SEEK_SET) == -1) {
+            SLOGE("Cannot seek to persisent data offset\n");
+            return;
+        }
+        /* Write all zeros to the first copy, making it invalid */
+        unix_write(fd, pdata, CRYPT_PERSIST_DATA_SIZE);
+
+        /* Write a valid but empty structure to the second copy */
+        init_empty_persist_data(pdata, CRYPT_PERSIST_DATA_SIZE);
+        unix_write(fd, pdata, CRYPT_PERSIST_DATA_SIZE);
+
+        /* Update the footer */
+        crypt_ftr->persist_data_size = CRYPT_PERSIST_DATA_SIZE;
+        crypt_ftr->persist_data_offset[0] = pdata_offset;
+        crypt_ftr->persist_data_offset[1] = pdata_offset + CRYPT_PERSIST_DATA_SIZE;
+        crypt_ftr->minor_version = 1;
     }
 
-    pdata = malloc(CRYPT_PERSIST_DATA_SIZE);
-    if (pdata == NULL) {
-        SLOGE("Cannot allocate persisent data\n");
-        return;
+    if ((orig_major != crypt_ftr->major_version) || (orig_minor != crypt_ftr->minor_version)) {
+        if (lseek64(fd, offset, SEEK_SET) == -1) {
+            SLOGE("Cannot seek to crypt footer\n");
+            return;
+        }
+        unix_write(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr));
     }
-    memset(pdata, 0, CRYPT_PERSIST_DATA_SIZE);
-
-    /* Need to initialize the persistent data area */
-    if (lseek64(fd, pdata_offset, SEEK_SET) == -1) {
-        SLOGE("Cannot seek to persisent data offset\n");
-        return;
-    }
-    /* Write all zeros to the first copy, making it invalid */
-    unix_write(fd, pdata, CRYPT_PERSIST_DATA_SIZE);
-
-    /* Write a valid but empty structure to the second copy */
-    init_empty_persist_data(pdata, CRYPT_PERSIST_DATA_SIZE);
-    unix_write(fd, pdata, CRYPT_PERSIST_DATA_SIZE);
-
-    /* Update the footer */
-    crypt_ftr->persist_data_size = CRYPT_PERSIST_DATA_SIZE;
-    crypt_ftr->persist_data_offset[0] = pdata_offset;
-    crypt_ftr->persist_data_offset[1] = pdata_offset + CRYPT_PERSIST_DATA_SIZE;
-    crypt_ftr->minor_version = 1;
-    if (lseek64(fd, offset, SEEK_SET) == -1) {
-        SLOGE("Cannot seek to crypt footer\n");
-        return;
-    }
-    unix_write(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr));
 }