staging: r8188eu: pass only ies to process_p2p_ps_ie

The process_p2p_ps_ie function parses the information elements of a beacon
message and extracts p2p-related info.

process_p2p_ps_ie does not receive a pointer to the information elements
as one would expect. Instead it receives a pointer to the timestamp field
in the beacon message. process_p2p_ps_ie increments this pointer by
_BEACON_IE_OFFSET_ to jump to the start of the information elements (and
decreases the buffer length accordingly).

This is clumsy and hard to understand. Rewrite this such that
process_p2p_ps_ie takes a pointer to the information elements and the
total length of all elements. Check up-front that the total length is
not negative.

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20221126160129.178697-5-martin@kaiser.cx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/r8188eu/core/rtw_mlme_ext.c b/drivers/staging/r8188eu/core/rtw_mlme_ext.c
index 5a31b20..07c57a2 100644 (file)
--- a/drivers/staging/r8188eu/core/rtw_mlme_ext.c
+++ b/drivers/staging/r8188eu/core/rtw_mlme_ext.c
@@ -556,6 +556,13 @@ static void OnBeacon(struct adapter *padapter, struct recv_frame *precv_frame)
        uint len = precv_frame->len;
        struct wlan_bssid_ex *pbss;
        int ret = _SUCCESS;
+       u8 *ie_ptr;
+       u32 ie_len;
+
+       ie_ptr = (u8 *)&mgmt->u.beacon.variable;
+       if (precv_frame->len < offsetof(struct ieee80211_mgmt, u.beacon.variable))
+               return;
+       ie_len = precv_frame->len - offsetof(struct ieee80211_mgmt, u.beacon.variable);
 
        if (pmlmeext->sitesurvey_res.state == SCAN_PROCESS) {
                report_survey_event(padapter, precv_frame);
@@ -598,7 +605,7 @@ static void OnBeacon(struct adapter *padapter, struct recv_frame *precv_frame)
                                /* todo: the timer is used instead of the number of the beacon received */
                                if ((sta_rx_pkts(psta) & 0xf) == 0)
                                        update_beacon_info(padapter, pframe, len, psta);
-                               process_p2p_ps_ie(padapter, (pframe + WLAN_HDR_A3_LEN), (len - WLAN_HDR_A3_LEN));
+                               process_p2p_ps_ie(padapter, ie_ptr, ie_len);
                        }
                } else if ((pmlmeinfo->state & 0x03) == WIFI_FW_ADHOC_STATE) {
                        psta = rtw_get_stainfo(pstapriv, mgmt->sa);

diff --git a/drivers/staging/r8188eu/core/rtw_p2p.c b/drivers/staging/r8188eu/core/rtw_p2p.c
index dc159e5..ce05458 100644 (file)
--- a/drivers/staging/r8188eu/core/rtw_p2p.c
+++ b/drivers/staging/r8188eu/core/rtw_p2p.c
@@ -1505,8 +1505,6 @@ void p2p_protocol_wk_hdl(struct adapter *padapter, int intCmdType)
 
 void process_p2p_ps_ie(struct adapter *padapter, u8 *IEs, u32 IELength)
 {
-       u8 *ies;
-       u32 ies_len;
        u8 *p2p_ie;
        u32     p2p_ielen = 0;
        u8      noa_attr[MAX_P2P_IE_LEN] = { 0x00 };/*  NoA length should be n*(13) + 2 */
@@ -1518,13 +1516,8 @@ void process_p2p_ps_ie(struct adapter *padapter, u8 *IEs, u32 IELength)
 
        if (rtw_p2p_chk_state(pwdinfo, P2P_STATE_NONE))
                return;
-       if (IELength <= _BEACON_IE_OFFSET_)
-               return;
 
-       ies = IEs + _BEACON_IE_OFFSET_;
-       ies_len = IELength - _BEACON_IE_OFFSET_;
-
-       p2p_ie = rtw_get_p2p_ie(ies, ies_len, NULL, &p2p_ielen);
+       p2p_ie = rtw_get_p2p_ie(IEs, IELength, NULL, &p2p_ielen);
 
        while (p2p_ie) {
                find_p2p = true;
@@ -1579,7 +1572,7 @@ void process_p2p_ps_ie(struct adapter *padapter, u8 *IEs, u32 IELength)
                }
 
                /* Get the next P2P IE */
-               p2p_ie = rtw_get_p2p_ie(p2p_ie + p2p_ielen, ies_len - (p2p_ie - ies + p2p_ielen), NULL, &p2p_ielen);
+               p2p_ie = rtw_get_p2p_ie(p2p_ie + p2p_ielen, IELength - (p2p_ie - IEs + p2p_ielen), NULL, &p2p_ielen);
        }
 
        if (find_p2p) {