CIFS: Fix NULL pointer deref on SMB2_tcon() failure

If SendReceive2() fails rsp is set to NULL but is dereferenced in the
error handling code.

Cc: stable@vger.kernel.org
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index fa17caa..3efcd96 100644 (file)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1255,7 +1255,7 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
        struct smb2_tree_connect_req *req;
        struct smb2_tree_connect_rsp *rsp = NULL;
        struct kvec iov[2];
-       struct kvec rsp_iov;
+       struct kvec rsp_iov = { NULL, 0 };
        int rc = 0;
        int resp_buftype;
        int unc_path_len;
@@ -1372,7 +1372,7 @@ tcon_exit:
        return rc;
 
 tcon_error_exit:
-       if (rsp->hdr.sync_hdr.Status == STATUS_BAD_NETWORK_NAME) {
+       if (rsp && rsp->hdr.sync_hdr.Status == STATUS_BAD_NETWORK_NAME) {
                cifs_dbg(VFS, "BAD_NETWORK_NAME: %s\n", tree);
        }
        goto tcon_exit;