CIFS: Fix possible buffer corruption in cifs_user_read()
If there was a short read in the middle of the rdata list,
we can end up with a corrupt output buffer.
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 3ea6fc8..c3390e2 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3049,7 +3049,9 @@
} else {
rc = cifs_readdata_to_iov(rdata, to);
}
-
+ /* if there was a short read -- discard anything left */
+ if (rdata->got_bytes && rdata->got_bytes < rdata->bytes)
+ rc = -ENODATA;
}
list_del_init(&rdata->list);
kref_put(&rdata->refcount, cifs_uncached_readdata_release);