qcacld-3.0: Fix information leak in lim_process_auth_shared_system_algo()

cds_rand_get_bytes() fail may cause random kernel stack info to
use as challenge text which is an information leak. To avoid this
use send auth failure with status code REFUSED_TEMPORARILY
(try again later) when random number generation fail.

Change-Id: If1238343e0c911c7e1ead8b5de62c0315a701017
CRs-Fixed: 2248569

core/mac/src/pe/lim/lim_process_auth_frame.c

@@ -97,12 +97,12 @@ static void lim_process_auth_shared_system_algo(tpAniSirGlobal mac_ctx,
 		tpSirMacMgmtHdr mac_hdr,
 		tSirMacAuthFrameBody *rx_auth_frm_body,
 		tSirMacAuthFrameBody *auth_frame,
-		uint8_t *challenge_txt_arr,
 		tpPESession pe_session)
 {
 	uint32_t val;
-	uint8_t cfg_privacy_opt_imp, *challenge;
+	uint8_t cfg_privacy_opt_imp;
 	struct tLimPreAuthNode *auth_node;
+	uint8_t challenge_txt_arr[SIR_MAC_SAP_AUTH_CHALLENGE_LENGTH] = {0};
 
 	pe_debug("=======> eSIR_SHARED_KEY");
 	if (LIM_IS_AP_ROLE(pe_session))
@@ -183,19 +183,39 @@ static void lim_process_auth_shared_system_algo(tpAniSirGlobal mac_ctx,
 			lim_delete_pre_auth_node(mac_ctx, mac_hdr->sa);
 			return;
 		}
-		lim_activate_auth_rsp_timer(mac_ctx, auth_node);
-		auth_node->fTimerStarted = 1;
+
 		/*
 		 * get random bytes and use as challenge text.
-		 * If it fails we already have random stack bytes.
 		 */
-		if (!QDF_IS_STATUS_SUCCESS(cds_rand_get_bytes(0,
-				(uint8_t *) challenge_txt_arr,
-				SIR_MAC_SAP_AUTH_CHALLENGE_LENGTH)))
+		get_random_bytes(challenge_txt_arr,
+				 SIR_MAC_SAP_AUTH_CHALLENGE_LENGTH);
+		qdf_mem_zero(auth_node->challengeText,
+			     SIR_MAC_SAP_AUTH_CHALLENGE_LENGTH);
+		if (!qdf_mem_cmp(challenge_txt_arr,
+				 auth_node->challengeText,
+				 SIR_MAC_SAP_AUTH_CHALLENGE_LENGTH)) {
 			pe_err("Challenge text preparation failed");
-		challenge = auth_node->challengeText;
-		qdf_mem_copy(challenge, (uint8_t *)challenge_txt_arr,
-				sizeof(challenge_txt_arr));
+			lim_print_mac_addr(mac_ctx, mac_hdr->sa, LOGW);
+			auth_frame->authAlgoNumber =
+				rx_auth_frm_body->authAlgoNumber;
+			auth_frame->authTransactionSeqNumber =
+				rx_auth_frm_body->authTransactionSeqNumber + 1;
+			auth_frame->authStatusCode = eSIR_MAC_TRY_AGAIN_LATER;
+			lim_send_auth_mgmt_frame(mac_ctx,
+						 auth_frame,
+						 mac_hdr->sa,
+						 LIM_NO_WEP_IN_FC,
+						 pe_session);
+			lim_delete_pre_auth_node(mac_ctx, mac_hdr->sa);
+			return;
+		}
+
+		lim_activate_auth_rsp_timer(mac_ctx, auth_node);
+		auth_node->fTimerStarted = 1;
+
+		qdf_mem_copy(auth_node->challengeText,
+			     challenge_txt_arr,
+			     sizeof(challenge_txt_arr));
 		/*
 		 * Sending Authenticaton frame with challenge.
 		 */
@@ -303,7 +323,6 @@ static void lim_process_auth_frame_type1(tpAniSirGlobal mac_ctx,
 {
 	tpDphHashNode sta_ds_ptr = NULL;
 	struct tLimPreAuthNode *auth_node;
-	uint8_t challenge_txt_arr[SIR_MAC_SAP_AUTH_CHALLENGE_LENGTH];
 	uint32_t maxnum_preauth;
 	uint16_t associd = 0;
 
@@ -487,8 +506,7 @@ static void lim_process_auth_frame_type1(tpAniSirGlobal mac_ctx,
 
 		case eSIR_SHARED_KEY:
 			lim_process_auth_shared_system_algo(mac_ctx, mac_hdr,
-				rx_auth_frm_body, auth_frame,
-				challenge_txt_arr, pe_session);
+				rx_auth_frm_body, auth_frame, pe_session);
 			break;
 		default:
 			pe_err("rx Auth frm for unsupported auth algo %d "