eCryptfs: Fix metadata in xattr feature regression

Fixes regression in 8faece5f906725c10e7a1f6caf84452abadbdc7b

When using the ecryptfs_xattr_metadata mount option, eCryptfs stores the
metadata (normally stored at the front of the file) in the user.ecryptfs
xattr.  This causes ecryptfs_crypt_stat.num_header_bytes_at_front to be
0, since there is no header data at the front of the file.  This results
in too much memory being requested and ENOMEM being returned from
ecryptfs_write_metadata().

This patch fixes the problem by using the num_header_bytes_at_front
variable for specifying the max size of the metadata, despite whether it
is stored in the header or xattr.

Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

4 files changed, 18 insertions, 18 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 7cb0a59f4b9d..c907f6f49351 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -381,8 +381,8 @@ out:
 static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
                                              struct ecryptfs_crypt_stat *crypt_stat)
 {
-        (*offset) = (crypt_stat->num_header_bytes_at_front
-                     + (crypt_stat->extent_size * extent_num));
+        (*offset) = ecryptfs_lower_header_size(crypt_stat)
+                    + (crypt_stat->extent_size * extent_num);
 }
 
 /**
@@ -834,7 +834,8 @@ void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
         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_bytes_at_front = 0;
+                crypt_stat->num_header_bytes_at_front =
+                                        ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
         else {
                 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
                         crypt_stat->num_header_bytes_at_front =
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 542f625312f3..8456f70606ad 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -464,6 +464,14 @@ struct ecryptfs_daemon {
 
 extern struct mutex ecryptfs_daemon_hash_mux;
 
+static inline size_t
+ecryptfs_lower_header_size(struct ecryptfs_crypt_stat *crypt_stat)
+{
+        if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+                return 0;
+        return crypt_stat->num_header_bytes_at_front;
+}
+
 static inline struct ecryptfs_file_info *
 ecryptfs_file_to_private(struct file *file)
 {
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 4a430ab4115c..1a739531b0dd 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -768,7 +768,7 @@ upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 {
         loff_t lower_size;
 
-        lower_size = crypt_stat->num_header_bytes_at_front;
+        lower_size = ecryptfs_lower_header_size(crypt_stat);
         if (upper_size != 0) {
                 loff_t num_extents;
 
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index df4ce99d0597..5a30e01547f1 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -97,19 +97,6 @@ out:
  *                        (big-endian)
  *     Octet  26:         Begin RFC 2440 authentication token packet set
  */
-static void set_header_info(char *page_virt,
-                            struct ecryptfs_crypt_stat *crypt_stat)
-{
-        size_t written;
-        size_t save_num_header_bytes_at_front =
-                crypt_stat->num_header_bytes_at_front;
-
-        crypt_stat->num_header_bytes_at_front =
-                ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
-        ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
-        crypt_stat->num_header_bytes_at_front =
-                save_num_header_bytes_at_front;
-}
 
 /**
  * ecryptfs_copy_up_encrypted_with_header
@@ -146,9 +133,13 @@ ecryptfs_copy_up_encrypted_with_header(struct page *page,
                         memset(page_virt, 0, PAGE_CACHE_SIZE);
                         /* TODO: Support more than one header extent */
                         if (view_extent_num == 0) {
+                                size_t written;
+
                                 rc = ecryptfs_read_xattr_region(
                                         page_virt, page->mapping->host);
-                                set_header_info(page_virt, crypt_stat);
+                                ecryptfs_write_header_metadata(page_virt + 20,
+                                                               crypt_stat,
+                                                               &written);
                         }
                         kunmap_atomic(page_virt, KM_USER0);
                         flush_dcache_page(page);