eCryptfs: track header bytes rather than extents
Remove internal references to header extents; just keep track of header bytes
instead. Headers can easily span multiple pages with the recent persistent
file changes.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 5e7d018..4d1b2b4 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -379,8 +379,7 @@
static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
struct ecryptfs_crypt_stat *crypt_stat)
{
- (*offset) = ((crypt_stat->extent_size
- * crypt_stat->num_header_extents_at_front)
+ (*offset) = (crypt_stat->num_header_bytes_at_front
+ (crypt_stat->extent_size * extent_num));
}
@@ -842,15 +841,13 @@
set_extent_mask_and_shift(crypt_stat);
crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
- crypt_stat->num_header_extents_at_front = 0;
+ crypt_stat->num_header_bytes_at_front = 0;
else {
if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
- crypt_stat->num_header_extents_at_front =
- (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
- / crypt_stat->extent_size);
+ crypt_stat->num_header_bytes_at_front =
+ ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
else
- crypt_stat->num_header_extents_at_front =
- (PAGE_CACHE_SIZE / crypt_stat->extent_size);
+ crypt_stat->num_header_bytes_at_front = PAGE_CACHE_SIZE;
}
}
@@ -1236,7 +1233,8 @@
header_extent_size = (u32)crypt_stat->extent_size;
num_header_extents_at_front =
- (u16)crypt_stat->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);
virt += 4;
@@ -1311,40 +1309,16 @@
static int
ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
struct dentry *ecryptfs_dentry,
- char *page_virt)
+ char *virt)
{
- int current_header_page;
- int header_pages;
int rc;
- rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, page_virt,
- 0, PAGE_CACHE_SIZE);
- if (rc) {
+ rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
+ 0, crypt_stat->num_header_bytes_at_front);
+ if (rc)
printk(KERN_ERR "%s: Error attempting to write header "
"information to lower file; rc = [%d]\n", __FUNCTION__,
rc);
- goto out;
- }
- header_pages = ((crypt_stat->extent_size
- * crypt_stat->num_header_extents_at_front)
- / PAGE_CACHE_SIZE);
- memset(page_virt, 0, PAGE_CACHE_SIZE);
- current_header_page = 1;
- while (current_header_page < header_pages) {
- loff_t offset;
-
- offset = (((loff_t)current_header_page) << PAGE_CACHE_SHIFT);
- if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode,
- page_virt, offset,
- PAGE_CACHE_SIZE))) {
- printk(KERN_ERR "%s: Error attempting to write header "
- "information to lower file; rc = [%d]\n",
- __FUNCTION__, rc);
- goto out;
- }
- current_header_page++;
- }
-out:
return rc;
}
@@ -1370,15 +1344,13 @@
* retrieved via a prompt. Exactly what happens at this point should
* be policy-dependent.
*
- * TODO: Support header information spanning multiple pages
- *
* Returns zero on success; non-zero on error
*/
int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
{
struct ecryptfs_crypt_stat *crypt_stat =
&ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
- char *page_virt;
+ char *virt;
size_t size = 0;
int rc = 0;
@@ -1389,40 +1361,39 @@
goto out;
}
} else {
+ printk(KERN_WARNING "%s: Encrypted flag not set\n",
+ __FUNCTION__);
rc = -EINVAL;
- ecryptfs_printk(KERN_WARNING,
- "Called with crypt_stat->encrypted == 0\n");
goto out;
}
/* Released in this function */
- page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER);
- if (!page_virt) {
- ecryptfs_printk(KERN_ERR, "Out of memory\n");
+ virt = kzalloc(crypt_stat->num_header_bytes_at_front, GFP_KERNEL);
+ if (!virt) {
+ printk(KERN_ERR "%s: Out of memory\n", __FUNCTION__);
rc = -ENOMEM;
goto out;
}
- rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat,
- ecryptfs_dentry);
+ rc = ecryptfs_write_headers_virt(virt, &size, crypt_stat,
+ ecryptfs_dentry);
if (unlikely(rc)) {
- ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n");
- memset(page_virt, 0, PAGE_CACHE_SIZE);
+ printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
+ __FUNCTION__, rc);
goto out_free;
}
if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
- crypt_stat, page_virt,
- size);
+ crypt_stat, virt, size);
else
rc = ecryptfs_write_metadata_to_contents(crypt_stat,
- ecryptfs_dentry,
- page_virt);
+ ecryptfs_dentry, virt);
if (rc) {
- printk(KERN_ERR "Error writing metadata out to lower file; "
- "rc = [%d]\n", rc);
+ printk(KERN_ERR "%s: Error writing metadata out to lower file; "
+ "rc = [%d]\n", __FUNCTION__, rc);
goto out_free;
}
out_free:
- kmem_cache_free(ecryptfs_header_cache_0, page_virt);
+ memset(virt, 0, crypt_stat->num_header_bytes_at_front);
+ kfree(virt);
out:
return rc;
}
@@ -1442,16 +1413,16 @@
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);
- crypt_stat->num_header_extents_at_front =
- (int)num_header_extents_at_front;
+ 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));
if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
- && ((crypt_stat->extent_size
- * crypt_stat->num_header_extents_at_front)
+ && (crypt_stat->num_header_bytes_at_front
< ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
rc = -EINVAL;
- printk(KERN_WARNING "Invalid number of header extents: [%zd]\n",
- crypt_stat->num_header_extents_at_front);
+ printk(KERN_WARNING "Invalid header size: [%zd]\n",
+ crypt_stat->num_header_bytes_at_front);
}
return rc;
}
@@ -1466,7 +1437,8 @@
*/
static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
{
- crypt_stat->num_header_extents_at_front = 2;
+ crypt_stat->num_header_bytes_at_front =
+ ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
}
/**