p9_client_readdir() fix

BugLink: http://bugs.launchpad.net/bugs/1688499
commit 71d6ad08379304128e4bdfaf0b4185d54375423e upstream.

Don't assume that server is sane and won't return more data than
asked for.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

diff --git a/net/9p/client.c b/net/9p/client.c
index 3fc94a49ccd53c2dba661acb4d6b0433de9c393b..cf129fec73298c8ff424cdc2499a94550ed321bc 100644 (file)
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -2101,6 +2101,10 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
                trace_9p_protocol_dump(clnt, req->rc);
                goto free_and_error;
        }
+       if (rsize < count) {
+               pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
+               count = rsize;
+       }
 
        p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);