From 8460e3230988ef2ec13ce6b69b687e941f6cdb32 Mon Sep 17 00:00:00 2001 From: Jouni Malinen Date: Tue, 8 Dec 2020 23:52:50 +0200 Subject: [PATCH] P2P: Fix a corner case in peer addition based on PD Request p2p_add_device() may remove the oldest entry if there is no room in the peer table for a new peer. This would result in any pointer to that removed entry becoming stale. A corner case with an invalid PD Request frame could result in such a case ending up using (read+write) freed memory. This could only by triggered when the peer table has reached its maximum size and the PD Request frame is received from the P2P Device Address of the oldest remaining entry and the frame has incorrect P2P Device Address in the payload. Fix this by fetching the dev pointer again after having called p2p_add_device() so that the stale pointer cannot be used. Fixes: 17bef1e97a50 ("P2P: Add peer entry based on Provision Discovery Request") Signed-off-by: Jouni Malinen --- src/p2p/p2p_pd.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/src/p2p/p2p_pd.c b/src/p2p/p2p_pd.c index 3994ec03f86b..05fd593494ef 100644 --- a/src/p2p/p2p_pd.c +++ b/src/p2p/p2p_pd.c @@ -595,14 +595,12 @@ void p2p_process_prov_disc_req(struct p2p_data *p2p, const u8 *sa, goto out; } + dev = p2p_get_device(p2p, sa); if (!dev) { - dev = p2p_get_device(p2p, sa); - if (!dev) { - p2p_dbg(p2p, - "Provision Discovery device not found " - MACSTR, MAC2STR(sa)); - goto out; - } + p2p_dbg(p2p, + "Provision Discovery device not found " + MACSTR, MAC2STR(sa)); + goto out; } } else if (msg.wfd_subelems) { wpabuf_free(dev->info.wfd_subelems); -- 2.25.1