[78/90] eCryptfs: Return error when lower file pointer is NULL

[Greg KH]

3.0-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxx>

commit f61500e000eedc0c7a0201200a7f00ba5529c002 upstream.

When an eCryptfs inode's lower file has been closed, and the pointer has
been set to NULL, return an error when trying to do a lower read or
write rather than calling BUG().

https://bugzilla.kernel.org/show_bug.cgi?id=37292

Signed-off-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 fs/ecryptfs/read_write.c |   18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -39,15 +39,16 @@
 int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
 			 loff_t offset, size_t size)
 {
-	struct ecryptfs_inode_info *inode_info;
+	struct file *lower_file;
 	mm_segment_t fs_save;
 	ssize_t rc;
 
-	inode_info = ecryptfs_inode_to_private(ecryptfs_inode);
-	BUG_ON(!inode_info->lower_file);
+	lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file;
+	if (!lower_file)
+		return -EIO;
 	fs_save = get_fs();
 	set_fs(get_ds());
-	rc = vfs_write(inode_info->lower_file, data, size, &offset);
+	rc = vfs_write(lower_file, data, size, &offset);
 	set_fs(fs_save);
 	mark_inode_dirty_sync(ecryptfs_inode);
 	return rc;
@@ -225,15 +226,16 @@ out:
 int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
 			struct inode *ecryptfs_inode)
 {
-	struct ecryptfs_inode_info *inode_info =
-		ecryptfs_inode_to_private(ecryptfs_inode);
+	struct file *lower_file;
 	mm_segment_t fs_save;
 	ssize_t rc;
 
-	BUG_ON(!inode_info->lower_file);
+	lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file;
+	if (!lower_file)
+		return -EIO;
 	fs_save = get_fs();
 	set_fs(get_ds());
-	rc = vfs_read(inode_info->lower_file, data, size, &offset);
+	rc = vfs_read(lower_file, data, size, &offset);
 	set_fs(fs_save);
 	return rc;
 }


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