staging: rtl8188eu: fix potential memory corruption in rtw_check_beacon_data()

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.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/YEHyQCrFZKTXyT7J@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/rtl8188eu/core/rtw_ap.c b/drivers/staging/rtl8188eu/core/rtw_ap.c
index f5cedbbc552af39a9aae9e1ba6d6e8d8e4c262a6..d14a2313fccea32b0cbf2c6cf4c94ed88b7a27e6 100644 (file)
--- a/drivers/staging/rtl8188eu/core/rtw_ap.c
+++ b/drivers/staging/rtl8188eu/core/rtw_ap.c
@@ -921,6 +921,7 @@ int rtw_check_beacon_data(struct adapter *padapter, u8 *pbuf,  int len)
        /* SSID */
        p = rtw_get_ie(ie + _BEACON_IE_OFFSET_, _SSID_IE_, &ie_len, (pbss_network->IELength - _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;
@@ -939,6 +940,7 @@ int rtw_check_beacon_data(struct adapter *padapter, u8 *pbuf,  int len)
        /*  get supported rates */
        p = rtw_get_ie(ie + _BEACON_IE_OFFSET_, _SUPPORTEDRATES_IE_, &ie_len, (pbss_network->IELength - _BEACON_IE_OFFSET_));
        if (p !=  NULL) {
+               ie_len = min_t(int, ie_len, NDIS_802_11_LENGTH_RATES_EX);
                memcpy(supportRate, p+2, ie_len);
                supportRateNum = ie_len;
        }
@@ -946,6 +948,8 @@ int rtw_check_beacon_data(struct adapter *padapter, u8 *pbuf,  int len)
        /* get ext_supported rates */
        p = rtw_get_ie(ie + _BEACON_IE_OFFSET_, _EXT_SUPPORTEDRATES_IE_, &ie_len, pbss_network->IELength - _BEACON_IE_OFFSET_);
        if (p !=  NULL) {
+               ie_len = min_t(int, ie_len,
+                              NDIS_802_11_LENGTH_RATES_EX - supportRateNum);
                memcpy(supportRate+supportRateNum, p+2, ie_len);
                supportRateNum += ie_len;
        }
@@ -1061,6 +1065,7 @@ int rtw_check_beacon_data(struct adapter *padapter, u8 *pbuf,  int len)
                        pht_cap->supp_mcs_set[0] = 0xff;
                        pht_cap->supp_mcs_set[1] = 0x0;
                }
+               ie_len = min_t(int, ie_len, sizeof(pmlmepriv->htpriv.ht_cap));
                memcpy(&pmlmepriv->htpriv.ht_cap, p+2, ie_len);
        }