From 327b6d780f2667e99e9b74d4c064531c0208b22b Mon Sep 17 00:00:00 2001 From: Mathy Vanhoef Date: Fri, 29 Sep 2017 04:22:51 +0200 Subject: [PATCH 4/8] Prevent installation of an all-zero TK Properly track whether a PTK has already been installed to the driver and the TK part cleared from memory. This prevents an attacker from trying to trick the client into installing an all-zero TK. This fixes the earlier fix in commit ad00d64e7d8827b3cebd665a0ceb08adabf15e1e ('Fix TK configuration to the driver in EAPOL-Key 3/4 retry case') which did not take into account possibility of an extra message 1/4 showing up between retries of message 3/4. Signed-off-by: Mathy Vanhoef --- src/common/wpa_common.h | 1 + src/rsn_supp/wpa.c | 6 +++--- src/rsn_supp/wpa_i.h | 1 - 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/src/common/wpa_common.h b/src/common/wpa_common.h index 0872b12..8411686 100644 --- a/src/common/wpa_common.h +++ b/src/common/wpa_common.h @@ -219,6 +219,7 @@ struct wpa_ptk { size_t kck_len; size_t kek_len; size_t tk_len; + int installed; /* 1 if key has already been installed to driver */ }; struct wpa_gtk { diff --git a/src/rsn_supp/wpa.c b/src/rsn_supp/wpa.c index 3c8871d..cf9bf1c 100644 --- a/src/rsn_supp/wpa.c +++ b/src/rsn_supp/wpa.c @@ -594,7 +594,6 @@ static void wpa_supplicant_process_1_of_4(struct wpa_sm *sm, os_memset(buf, 0, sizeof(buf)); } sm->tptk_set = 1; - sm->tk_to_set = 1; kde = sm->assoc_wpa_ie; kde_len = sm->assoc_wpa_ie_len; @@ -701,7 +700,7 @@ static int wpa_supplicant_install_ptk(struct wpa_sm *sm, enum wpa_alg alg; const u8 *key_rsc; - if (!sm->tk_to_set) { + if (sm->ptk.installed) { wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, "WPA: Do not re-install same PTK to the driver"); return 0; @@ -745,7 +744,7 @@ static int wpa_supplicant_install_ptk(struct wpa_sm *sm, /* TK is not needed anymore in supplicant */ os_memset(sm->ptk.tk, 0, WPA_TK_MAX_LEN); - sm->tk_to_set = 0; + sm->ptk.installed = 1; if (sm->wpa_ptk_rekey) { eloop_cancel_timeout(wpa_sm_rekey_ptk, sm, NULL); @@ -4183,6 +4182,7 @@ int fils_process_assoc_resp(struct wpa_sm *sm, const u8 *resp, size_t len) * takes care of association frame encryption/decryption. */ /* TK is not needed anymore in supplicant */ os_memset(sm->ptk.tk, 0, WPA_TK_MAX_LEN); + sm->ptk.installed = 1; /* FILS HLP Container */ fils_process_hlp_container(sm, ie_start, end - ie_start); diff --git a/src/rsn_supp/wpa_i.h b/src/rsn_supp/wpa_i.h index 156e6cb..3b42245 100644 --- a/src/rsn_supp/wpa_i.h +++ b/src/rsn_supp/wpa_i.h @@ -24,7 +24,6 @@ struct wpa_sm { struct wpa_ptk ptk, tptk; int ptk_set, tptk_set; unsigned int msg_3_of_4_ok:1; - unsigned int tk_to_set:1; u8 snonce[WPA_NONCE_LEN]; u8 anonce[WPA_NONCE_LEN]; /* ANonce from the last 1/4 msg */ int renew_snonce; -- 2.7.4