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eCryptfs: Strip metadata in xattr flag in encrypted view

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The ecryptfs_encrypted_view mount option provides a unified way of
viewing encrypted eCryptfs files.  If the metadata is stored in a xattr,
the metadata is moved to the file header when the file is read inside
the eCryptfs mount.  Because of this, we should strip the
ECRYPTFS_METADATA_IN_XATTR flag from the header's flag section.  This
allows eCryptfs to treat the file as an eCryptfs file with a header
at the front.

Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
This commit is contained in:
Tyler Hicks 2010-02-11 00:02:32 -06:00
parent 1984c23f9e
commit f4e60e6b30
3 changed files with 22 additions and 4 deletions
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9
fs/ecryptfs/crypto.c
View file

@ -1107,9 +1107,9 @@ static void write_ecryptfs_marker(char *page_virt, size_t *written)
(*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
}
static void
write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
size_t *written)
void ecryptfs_write_crypt_stat_flags(char *page_virt,
struct ecryptfs_crypt_stat *crypt_stat,
size_t *written)
{
u32 flags = 0;
int i;
@ -1290,7 +1290,8 @@ static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
offset = ECRYPTFS_FILE_SIZE_BYTES;
write_ecryptfs_marker((page_virt + offset), &written);
offset += written;
write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
&written);
offset += written;
ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
&written);

3
fs/ecryptfs/ecryptfs_kernel.h
View file

@ -659,6 +659,9 @@ int ecryptfs_decrypt_page(struct page *page);
int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry);
int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry);
int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);
void ecryptfs_write_crypt_stat_flags(char *page_virt,
struct ecryptfs_crypt_stat *crypt_stat,
size_t *written);
int ecryptfs_read_and_validate_header_region(char *data,
struct inode *ecryptfs_inode);
int ecryptfs_read_and_validate_xattr_region(char *page_virt,

14
fs/ecryptfs/mmap.c
View file

@ -82,6 +82,19 @@ static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
return rc;
}
static void strip_xattr_flag(char *page_virt,
struct ecryptfs_crypt_stat *crypt_stat)
{
if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
size_t written;
crypt_stat->flags &= ~ECRYPTFS_METADATA_IN_XATTR;
ecryptfs_write_crypt_stat_flags(page_virt, crypt_stat,
&written);
crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
}
}
/**
* Header Extent:
* Octets 0-7: Unencrypted file size (big-endian)
@ -136,6 +149,7 @@ ecryptfs_copy_up_encrypted_with_header(struct page *page,
rc = ecryptfs_read_xattr_region(
page_virt, page->mapping->host);
strip_xattr_flag(page_virt + 16, crypt_stat);
ecryptfs_write_header_metadata(page_virt + 20,
crypt_stat,
&written);