net/9p: Return error on read with NULL buffer

This patch ensures that a read(fd, NULL, 10) returns  EFAULT on a 9p file.

Signed-off-by: Sanchit Garg <sancgarg@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

1 files changed, 1 insertions, 4 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index 8df80fb86f23..a848bca9fbff 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -1286,16 +1286,13 @@ p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
 
         if (data) {
                 memmove(data, dataptr, count);
-        }
-
-        if (udata) {
+        } else {
                 err = copy_to_user(udata, dataptr, count);
                 if (err) {
                         err = -EFAULT;
                         goto free_and_error;
                 }
         }
-
         p9_free_req(clnt, req);
         return count;