eCryptfs: Strip metadata in xattr flag in encrypted view
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>
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 4d9db0e..fad5bf6 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1107,9 +1107,9 @@
(*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 @@
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);
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index d031efd..bc71154 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -659,6 +659,9 @@
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,
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 270f42a..bea998a 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -82,6 +82,19 @@
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 @@
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);
