From: Jeremy Compostella <jeremy.compostella@intel.com>
Date: Tue, 10 May 2016 11:10:20 +0000 (+0200)
Subject: ANDROID: dm verity fec: pack the fec_header structure
X-Git-Tag: firefly_0821_release~176^2~340
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8c07f4332955923c5ad64dbfa36a30c781c2fd05;p=firefly-linux-kernel-4.4.55.git

ANDROID: dm verity fec: pack the fec_header structure

The fec_header structure is generated build time and stored on disk.
The fec_header might be build on a 64 bits machine while it is read
per a 32 bits device or the other way around.  In such situations, the
fec_header fields are not aligned as expected by the device and it
fails to read the fec_header structure.

This patch makes the fec_header packed.

Change-Id: Idb84453e70cc11abd5ef3a0adfbb16f8b5feaf06
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
---

diff --git a/drivers/md/dm-android-verity.h b/drivers/md/dm-android-verity.h
index 782e1c815c67..f43b02fbb475 100644
--- a/drivers/md/dm-android-verity.h
+++ b/drivers/md/dm-android-verity.h
@@ -72,9 +72,6 @@
  * if fec is not present
  * <data_blocks> <verity_tree> <verity_metdata_32K>
  */
-/* TODO: rearrange structure to reduce memory holes
- * depends on userspace change.
- */
 struct fec_header {
 	__le32 magic;
 	__le32 version;
@@ -83,7 +80,7 @@ struct fec_header {
 	__le32 fec_size;
 	__le64 inp_size;
 	u8 hash[SHA256_DIGEST_SIZE];
-};
+} __attribute__((packed));
 
 struct android_metadata_header {
 	__le32 magic_number;