[PATCH v2] staging: rtl8723bs: fix remote heap information disclosure in issue_assocreq

[luka.gejak@linux.dev]

From: Luka Gejak <luka.gejak@linux.dev>

When building an association request frame, the driver copies the
ht capability ie using the attacker-controlled pIE->length from the
ap's beacon. If the ap provides a length greater than the size of
struct HT_caps_element (26 bytes), it causes an out-of-bounds read
of the adjacent heap memory (HT_info and network structures).
This uninitialized or sensitive memory is then transmitted over the air,
resulting in a remote heap information disclosure.

Fix this by clamping the length passed to rtw_set_ie() to the actual
size of struct HT_caps_element.

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable@vger.kernel.org
Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
---
---
Changes in v2:
- Refactored rtw_set_ie() alignment to follow "open parenthesis" style.
- Allowed the line length to exceed 100 characters for better readability as requested by Greg KH.

 drivers/staging/rtl8723bs/core/rtw_mlme_ext.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c b/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c
index 5f00fe282d1b..08e597bc0345 100644
--- a/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c
+++ b/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c
@@ -2954,7 +2954,9 @@ void issue_assocreq(struct adapter *padapter)
 			if (padapter->mlmepriv.htpriv.ht_option) {
 				if (!(is_ap_in_tkip(padapter))) {
 					memcpy(&(pmlmeinfo->HT_caps), pIE->data, sizeof(struct HT_caps_element));
-					pframe = rtw_set_ie(pframe, WLAN_EID_HT_CAPABILITY, pIE->length, (u8 *)(&(pmlmeinfo->HT_caps)), &(pattrib->pktlen));
+					pframe = rtw_set_ie(pframe, WLAN_EID_HT_CAPABILITY,
+							    min_t(uint, pIE->length, sizeof(struct HT_caps_element)),
+							    (u8 *)&pmlmeinfo->HT_caps, &pattrib->pktlen);
 				}
 			}
 			break;
-- 
2.53.0