[PATCH 4.19 092/120] staging: rtl8188eu: fix potential memory corruption in rtw_check_beacon_data()

[gregkh]

From: Greg Kroah-Hartman <gre...@linuxfoundation.org>

From: Dan Carpenter <dan.carpen...@oracle.com>

commit d4ac640322b06095128a5c45ba4a1e80929fe7f3 upstream.

The "ie_len" is a value in the 1-255 range that comes from the user.  We
have to cap it to ensure that it's not too large or it could lead to
memory corruption.

Fixes: 9a7fe54ddc3a ("staging: r8188eu: Add source files for new driver - part 
1")
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
Cc: stable <sta...@vger.kernel.org>
Link: https://lore.kernel.org/r/YEHyQCrFZKTXyT7J@mwanda
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/staging/rtl8188eu/core/rtw_ap.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/staging/rtl8188eu/core/rtw_ap.c
+++ b/drivers/staging/rtl8188eu/core/rtw_ap.c
@@ -794,6 +794,7 @@ int rtw_check_beacon_data(struct adapter
        /* SSID */
        p = rtw_get_ie(ie + _BEACON_IE_OFFSET_, _SSID_IE_, &ie_len, 
(pbss_network->ie_length - _BEACON_IE_OFFSET_));
        if (p && ie_len > 0) {
+               ie_len = min_t(int, ie_len, sizeof(pbss_network->Ssid.Ssid));
                memset(&pbss_network->Ssid, 0, sizeof(struct ndis_802_11_ssid));
                memcpy(pbss_network->Ssid.Ssid, (p + 2), ie_len);
                pbss_network->Ssid.SsidLength = ie_len;
@@ -812,6 +813,7 @@ int rtw_check_beacon_data(struct adapter
        /*  get supported rates */
        p = rtw_get_ie(ie + _BEACON_IE_OFFSET_, _SUPPORTEDRATES_IE_, &ie_len, 
(pbss_network->ie_length - _BEACON_IE_OFFSET_));
        if (p) {
+               ie_len = min_t(int, ie_len, NDIS_802_11_LENGTH_RATES_EX);
                memcpy(supportRate, p + 2, ie_len);
                supportRateNum = ie_len;
        }
@@ -819,6 +821,8 @@ int rtw_check_beacon_data(struct adapter
        /* get ext_supported rates */
        p = rtw_get_ie(ie + _BEACON_IE_OFFSET_, _EXT_SUPPORTEDRATES_IE_, 
&ie_len, pbss_network->ie_length - _BEACON_IE_OFFSET_);
        if (p) {
+               ie_len = min_t(int, ie_len,
+                              NDIS_802_11_LENGTH_RATES_EX - supportRateNum);
                memcpy(supportRate + supportRateNum, p + 2, ie_len);
                supportRateNum += ie_len;
        }
@@ -932,6 +936,7 @@ int rtw_check_beacon_data(struct adapter
 
                pht_cap->mcs.rx_mask[0] = 0xff;
                pht_cap->mcs.rx_mask[1] = 0x0;
+               ie_len = min_t(int, ie_len, sizeof(pmlmepriv->htpriv.ht_cap));
                memcpy(&pmlmepriv->htpriv.ht_cap, p+2, ie_len);
        }