Bluetooth: controller: Check minimum sizes of adv PDUs

While the maximum sizes were already correctly checked by the code, the
minimum sizes of the PDUs were not. This meant that PDUs smaller than
the minimum required length (typically 6 bytes for AdvA) were
incorrectly forwarded up to the Host.

Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>
(cherry picked from commit 3f0d701)

subsys/bluetooth/controller/ll_sw/nordic/lll/lll_scan.c

@@ -1267,6 +1267,7 @@ static inline int isr_rx_pdu(struct lll_scan *lll, struct pdu_adv *pdu_adv_rx,
 	/* Active scanner */
 	} else if (((pdu_adv_rx->type == PDU_ADV_TYPE_ADV_IND) ||
 		    (pdu_adv_rx->type == PDU_ADV_TYPE_SCAN_IND)) &&
+		   (pdu_adv_rx->len >= offsetof(struct pdu_adv_adv_ind, data)) &&
 		   (pdu_adv_rx->len <= sizeof(struct pdu_adv_adv_ind)) &&
 		   lll->type && !lll->state &&
 #if defined(CONFIG_BT_CENTRAL)
@@ -1359,6 +1360,7 @@ static inline int isr_rx_pdu(struct lll_scan *lll, struct pdu_adv *pdu_adv_rx,
 	else if (((((pdu_adv_rx->type == PDU_ADV_TYPE_ADV_IND) ||
 		    (pdu_adv_rx->type == PDU_ADV_TYPE_NONCONN_IND) ||
 		    (pdu_adv_rx->type == PDU_ADV_TYPE_SCAN_IND)) &&
+		   (pdu_adv_rx->len >= offsetof(struct pdu_adv_adv_ind, data)) &&
 		   (pdu_adv_rx->len <= sizeof(struct pdu_adv_adv_ind))) ||
 		  ((pdu_adv_rx->type == PDU_ADV_TYPE_DIRECT_IND) &&
 		   (pdu_adv_rx->len == sizeof(struct pdu_adv_direct_ind)) &&
@@ -1373,6 +1375,7 @@ static inline int isr_rx_pdu(struct lll_scan *lll, struct pdu_adv *pdu_adv_rx,
 						       &dir_report)) ||
 #endif /* CONFIG_BT_CTLR_ADV_EXT */
 		  ((pdu_adv_rx->type == PDU_ADV_TYPE_SCAN_RSP) &&
+		   (pdu_adv_rx->len >= offsetof(struct pdu_adv_scan_rsp, data)) &&
 		   (pdu_adv_rx->len <= sizeof(struct pdu_adv_scan_rsp)) &&
 		   (lll->state != 0U) &&
 		   isr_scan_rsp_adva_matches(pdu_adv_rx))) &&
@@ -1423,6 +1426,7 @@ static inline bool isr_scan_init_check(const struct lll_scan *lll,
 		lll_scan_adva_check(lll, pdu->tx_addr, pdu->adv_ind.addr,
 				    rl_idx)) &&
 		(((pdu->type == PDU_ADV_TYPE_ADV_IND) &&
+		  (pdu->len >= offsetof(struct pdu_adv_adv_ind, data)) &&
 		  (pdu->len <= sizeof(struct pdu_adv_adv_ind))) ||
 		 ((pdu->type == PDU_ADV_TYPE_DIRECT_IND) &&
 		  (pdu->len == sizeof(struct pdu_adv_direct_ind)) &&