[PATCH] [OE-core] [meta-openembedded] hostapd: fix CVE-2021-27803

[PATCH] [OE-core] [meta-openembedded] hostapd: fix CVE-2021-27803

[Stefan Ghinea]

A vulnerability was discovered in how p2p/p2p_pd.c in wpa_supplicant
before 2.10 processes P2P (Wi-Fi Direct) provision discovery requests.
It could result in denial of service or other impact (potentially
execution of arbitrary code), for an attacker within radio range.

References:
https://nvd.nist.gov/vuln/detail/CVE-2021-27803

Upstream patches:
https://w1.fi/cgit/hostap/commit/?id=8460e3230988ef2ec13ce6b69b687e941f6cdb32

Signed-off-by: Stefan Ghinea <stefan.ghinea@windriver.com>
---
 .../hostapd/hostapd/CVE-2021-27803.patch      | 58 +++++++++++++++++++
 .../hostapd/hostapd_2.9.bb                    |  1 +
 2 files changed, 59 insertions(+)
 create mode 100644 meta-oe/recipes-connectivity/hostapd/hostapd/CVE-2021-27803.patch

diff --git a/meta-oe/recipes-connectivity/hostapd/hostapd/CVE-2021-27803.patch b/meta-oe/recipes-connectivity/hostapd/hostapd/CVE-2021-27803.patch
new file mode 100644
index 000000000..004b1dbd1
--- /dev/null
+++ b/meta-oe/recipes-connectivity/hostapd/hostapd/CVE-2021-27803.patch
@@ -0,0 +1,58 @@
+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: Backport
+CVE: CVE-2021-27803
+
+Reference to upstream patch:
+[https://w1.fi/cgit/hostap/commit/?id=8460e3230988ef2ec13ce6b69b687e941f6cdb32]
+
+Signed-off-by: Stefan Ghinea <stefan.ghinea@windriver.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 3994ec0..05fd593 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);
+-- 
+2.17.1
+
diff --git a/meta-oe/recipes-connectivity/hostapd/hostapd_2.9.bb b/meta-oe/recipes-connectivity/hostapd/hostapd_2.9.bb
index 68dc12370..ae497b6ae 100644
--- a/meta-oe/recipes-connectivity/hostapd/hostapd_2.9.bb
+++ b/meta-oe/recipes-connectivity/hostapd/hostapd_2.9.bb
@@ -12,6 +12,7 @@ SRC_URI = " \
     file://init \
     file://hostapd.service \
     file://CVE-2019-16275.patch \
+    file://CVE-2021-27803.patch \
 "
 
 SRC_URI[md5sum] = "f188fc53a495fe7af3b6d77d3c31dee8"
-- 
2.17.1