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

From: Lee Gibson <lee...@gmail.com>

commit b93c1e3981af19527beee1c10a2bef67a228c48c upstream.

Function r8712_sitesurvey_cmd calls memcpy without checking the length.
A user could control that length and trigger a buffer overflow.
Fix by checking the length is within the maximum allowed size.

Signed-off-by: Lee Gibson <lee...@gmail.com>
Link: https://lore.kernel.org/r/20210301132648.420296-1-lee...@gmail.com
Cc: stable <sta...@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/staging/rtl8712/rtl871x_cmd.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/staging/rtl8712/rtl871x_cmd.c
+++ b/drivers/staging/rtl8712/rtl871x_cmd.c
@@ -192,8 +192,10 @@ u8 r8712_sitesurvey_cmd(struct _adapter
        psurveyPara->ss_ssidlen = 0;
        memset(psurveyPara->ss_ssid, 0, IW_ESSID_MAX_SIZE + 1);
        if (pssid && pssid->SsidLength) {
-               memcpy(psurveyPara->ss_ssid, pssid->Ssid, pssid->SsidLength);
-               psurveyPara->ss_ssidlen = cpu_to_le32(pssid->SsidLength);
+               int len = min_t(int, pssid->SsidLength, IW_ESSID_MAX_SIZE);
+
+               memcpy(psurveyPara->ss_ssid, pssid->Ssid, len);
+               psurveyPara->ss_ssidlen = cpu_to_le32(len);
        }
        set_fwstate(pmlmepriv, _FW_UNDER_SURVEY);
        r8712_enqueue_cmd(pcmdpriv, ph2c);


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