[PATCH] ecryptfs: Use unaligned byteswapping helpers

From: Harvey Harrison
Date: Wed Jun 18 2008 - 21:06:43 EST


Rather than memcpy and cpu_to_be16/32.

Signed-off-by: Harvey Harrison <harvey.harrison@xxxxxxxxx>
---
fs/ecryptfs/crypto.c | 37 +++++++++++++++++--------------------
1 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index e2832bc..c6d4448 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -33,6 +33,7 @@
#include <linux/crypto.h>
#include <linux/file.h>
#include <linux/scatterlist.h>
+#include <asm/unaligned.h>
#include "ecryptfs_kernel.h"

static int
@@ -1032,10 +1033,9 @@ static int contains_ecryptfs_marker(char *data)
{
u32 m_1, m_2;

- memcpy(&m_1, data, 4);
- m_1 = be32_to_cpu(m_1);
- memcpy(&m_2, (data + 4), 4);
- m_2 = be32_to_cpu(m_2);
+ m_1 = get_unaligned_be32(data);
+ m_2 = get_unaligned_be32(data + 4);
+
if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
return 1;
ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
@@ -1073,8 +1073,8 @@ static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
int i;
u32 flags;

- memcpy(&flags, page_virt, 4);
- flags = be32_to_cpu(flags);
+ flags = get_unaligned_be32(page_virt);
+
for (i = 0; i < ((sizeof(ecryptfs_flag_map)
/ sizeof(struct ecryptfs_flag_map_elem))); i++)
if (flags & ecryptfs_flag_map[i].file_flag) {
@@ -1100,9 +1100,9 @@ static void write_ecryptfs_marker(char *page_virt, size_t *written)

get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
- m_1 = cpu_to_be32(m_1);
+ cpu_to_be32s(&m_1);
memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
- m_2 = cpu_to_be32(m_2);
+ cpu_to_be32s(&m_2);
memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2,
(MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
(*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
@@ -1121,8 +1121,7 @@ write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
flags |= ecryptfs_flag_map[i].file_flag;
/* Version is in top 8 bits of the 32-bit flag vector */
flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
- flags = cpu_to_be32(flags);
- memcpy(page_virt, &flags, 4);
+ put_unaligned_be32(flags, page_virt);
(*written) = 4;
}

@@ -1238,11 +1237,9 @@ ecryptfs_write_header_metadata(char *virt,
num_header_extents_at_front =
(u16)(crypt_stat->num_header_bytes_at_front
/ crypt_stat->extent_size);
- header_extent_size = cpu_to_be32(header_extent_size);
- memcpy(virt, &header_extent_size, 4);
+ put_unaligned_be32(header_extent_size, virt);
virt += 4;
- num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front);
- memcpy(virt, &num_header_extents_at_front, 2);
+ put_unaligned_be16(num_header_extents_at_front, virt);
(*written) = 6;
}

@@ -1410,15 +1407,15 @@ static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
u32 header_extent_size;
u16 num_header_extents_at_front;

- memcpy(&header_extent_size, virt, sizeof(u32));
- header_extent_size = be32_to_cpu(header_extent_size);
- virt += sizeof(u32);
- memcpy(&num_header_extents_at_front, virt, sizeof(u16));
- num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
+ header_extent_size = get_unaligned_be32(virt);
+ virt += sizeof(__be32);
+ num_header_extents_at_front = get_unaligned_be16(virt);
+ virt += sizeof(__be16);
+
crypt_stat->num_header_bytes_at_front =
(((size_t)num_header_extents_at_front
* (size_t)header_extent_size));
- (*bytes_read) = (sizeof(u32) + sizeof(u16));
+ (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
&& (crypt_stat->num_header_bytes_at_front
< ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
--
1.5.6.rc3.295.gdca2e



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