[RFC] Allow the wpa_ie to be updated when reassociating to a different AP

Helmut Schaa helmut.schaa at googlemail.com
Fri Mar 19 03:56:04 EDT 2010


Allow the wpa_ie to be updated when reassociating to a different AP. This
fixes issues when reassociating with a new AP we have preauthenticated
first.

The association with the first AP sets the appropriate wpa_ie. However,
when reassociating to a new AP within the same ESS (without prior
disassociation) wpa_sm_set_assoc_wpa_ie_default generates a correct wpa_ie
and returns it for use in the reassociation request but does not store it
in assoc_wpa_ie. Hence, the stored assoc_wpa_ie is still the one from the
previous association and won't contain the correct PMKID. As a result the
AP will refuse the second message of the 4-way handshake due to a
different wpa_ie (compared to the reassoc req).

Signed-off-by: Helmut Schaa <helmut.schaa at googlemail.com>
---

Since I'm not 100% sure to not create a different issue with this patch I'll
send it as RFC.

Jouni, if you want to see a logfile with -ddt for this issue I can reproduce
this behavior but I don't have the file from yesterday anymore :( and would
have to set my environment up again. Nevertheless the logfile clearly showed
that the wpa_ie's used in the reassoc request and in the 2nd message of the
4-way handshake were different.

Helmut

 src/rsn_supp/wpa.c |   22 ++++++++++------------
 1 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/src/rsn_supp/wpa.c b/src/rsn_supp/wpa.c
index df0688c..3264607 100644
--- a/src/rsn_supp/wpa.c
+++ b/src/rsn_supp/wpa.c
@@ -2225,19 +2225,17 @@ int wpa_sm_set_assoc_wpa_ie_default(struct wpa_sm *sm, u8 *wpa_ie,
 	wpa_hexdump(MSG_DEBUG, "WPA: Set own WPA IE default",
 		    wpa_ie, *wpa_ie_len);
 
-	if (sm->assoc_wpa_ie == NULL) {
-		/*
-		 * Make a copy of the WPA/RSN IE so that 4-Way Handshake gets
-		 * the correct version of the IE even if PMKSA caching is
-		 * aborted (which would remove PMKID from IE generation).
-		 */
-		sm->assoc_wpa_ie = os_malloc(*wpa_ie_len);
-		if (sm->assoc_wpa_ie == NULL)
-			return -1;
+	/*
+	 * Make a copy of the WPA/RSN IE so that 4-Way Handshake gets
+	 * the correct version of the IE even if PMKSA caching is
+	 * aborted (which would remove PMKID from IE generation).
+	 */
+	sm->assoc_wpa_ie = os_malloc(*wpa_ie_len);
+	if (sm->assoc_wpa_ie == NULL)
+		return -1;
 
-		os_memcpy(sm->assoc_wpa_ie, wpa_ie, *wpa_ie_len);
-		sm->assoc_wpa_ie_len = *wpa_ie_len;
-	}
+	os_memcpy(sm->assoc_wpa_ie, wpa_ie, *wpa_ie_len);
+	sm->assoc_wpa_ie_len = *wpa_ie_len;
 
 	return 0;
 }
-- 
1.6.4.2



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