--- /dev/null
+From 8460e3230988ef2ec13ce6b69b687e941f6cdb32 Mon Sep 17 00:00:00 2001
+From: Jouni Malinen <jouni@codeaurora.org>
+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 <jouni@codeaurora.org>
+
+Upstream-Status: Acepted [https://w1.fi/cgit/hostap/commit/?id=8460e3230988ef2ec13ce6b69b687e941f6cdb32]
+CVE: CVE-2021-27803
+Signed-off-by: Minjae Kim <flowergom@gmail.com>
+---
+ 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
+
