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Avoid a theoretical use-after-free in WPA auth sm init

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wpa_sm_step() could theoretically free the statemachine, but it does
not do it in this particular case. Anyway, the code can be cleaned to
verify whether the state machine data is still available after the
wpa_sm_step() call.
This commit is contained in:
Jouni Malinen 2010-01-10 18:54:41 +02:00
parent 097c5802da
commit e4a6ea1d9c
1 changed files with 8 additions and 5 deletions
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13
src/ap/wpa_auth.c
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@ -38,7 +38,7 @@
static void wpa_send_eapol_timeout(void *eloop_ctx, void *timeout_ctx); static void wpa_send_eapol_timeout(void *eloop_ctx, void *timeout_ctx);
static void wpa_sm_step(struct wpa_state_machine *sm); static int wpa_sm_step(struct wpa_state_machine *sm);
static int wpa_verify_key_mic(struct wpa_ptk *PTK, u8 *data, size_t data_len); static int wpa_verify_key_mic(struct wpa_ptk *PTK, u8 *data, size_t data_len);
static void wpa_sm_call_step(void *eloop_ctx, void *timeout_ctx); static void wpa_sm_call_step(void *eloop_ctx, void *timeout_ctx);
static void wpa_group_sm_step(struct wpa_authenticator *wpa_auth, static void wpa_group_sm_step(struct wpa_authenticator *wpa_auth,
@ -520,7 +520,8 @@ void wpa_auth_sta_associated(struct wpa_authenticator *wpa_auth,
sm->started = 1; sm->started = 1;
sm->Init = TRUE; sm->Init = TRUE;
wpa_sm_step(sm); if (wpa_sm_step(sm) == 1)
return; /* should not really happen */
sm->Init = FALSE; sm->Init = FALSE;
sm->AuthenticationRequest = TRUE; sm->AuthenticationRequest = TRUE;
wpa_sm_step(sm); wpa_sm_step(sm);
@ -2059,17 +2060,17 @@ static void wpa_group_sm_step(struct wpa_authenticator *wpa_auth,
} }
static void wpa_sm_step(struct wpa_state_machine *sm) static int wpa_sm_step(struct wpa_state_machine *sm)
{ {
if (sm == NULL) if (sm == NULL)
return; return 0;
if (sm->in_step_loop) { if (sm->in_step_loop) {
/* This should not happen, but if it does, make sure we do not /* This should not happen, but if it does, make sure we do not
* end up freeing the state machine too early by exiting the * end up freeing the state machine too early by exiting the
* recursive call. */ * recursive call. */
wpa_printf(MSG_ERROR, "WPA: wpa_sm_step() called recursively"); wpa_printf(MSG_ERROR, "WPA: wpa_sm_step() called recursively");
return; return 0;
} }
sm->in_step_loop = 1; sm->in_step_loop = 1;
@ -2094,7 +2095,9 @@ static void wpa_sm_step(struct wpa_state_machine *sm)
wpa_printf(MSG_DEBUG, "WPA: Completing pending STA state " wpa_printf(MSG_DEBUG, "WPA: Completing pending STA state "
"machine deinit for " MACSTR, MAC2STR(sm->addr)); "machine deinit for " MACSTR, MAC2STR(sm->addr));
wpa_free_sta_sm(sm); wpa_free_sta_sm(sm);
return 1;
} }
return 0;
} }