[PATCH] staging: rtl8723bs: Avoid field-overflowing memcpy()

Kees Cook keescook at chromium.org
Fri Aug 6 20:14:22 UTC 2021

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.

Adjust memcpy() destination to be the named structure itself, rather than
the first member, allowing memcpy() to correctly reason about the size.

"objdump -d" shows no object code changes.

Cc: Ross Schmidt <ross.schm.dev at gmail.com>
Cc: Joe Perches <joe at perches.com>
Cc: devel at driverdev.osuosl.org
Signed-off-by: Kees Cook <keescook at chromium.org>
Hi Greg, since I've split out some other patches from my series, it made
sense to send this one directly too. You originally Acked it here:
But since it has no dependencies on my tree, you can take it directly. :)
 drivers/staging/rtl8723bs/core/rtw_mlme.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_mlme.c b/drivers/staging/rtl8723bs/core/rtw_mlme.c
index 5ed13bf765d2..e0cee51224ff 100644
--- a/drivers/staging/rtl8723bs/core/rtw_mlme.c
+++ b/drivers/staging/rtl8723bs/core/rtw_mlme.c
@@ -2389,7 +2389,7 @@ unsigned int rtw_restructure_ht_ie(struct adapter *padapter, u8 *in_ie, u8 *out_
 	/* fill default supported_mcs_set */
-	memcpy(ht_capie.mcs.rx_mask, pmlmeext->default_supported_mcs_set, 16);
+	memcpy(&ht_capie.mcs, pmlmeext->default_supported_mcs_set, 16);
 	/* update default supported_mcs_set */
 	rtw_hal_get_hwreg(padapter, HW_VAR_RF_TYPE, (u8 *)(&rf_type));

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