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.
Use struct_group() in struct hfa384x_tx_frame around members frame_control, duration_id, address[1-4], and sequence_control, so they can be referenced together. This will allow memcpy() and sizeof() to more easily reason about sizes, improve readability, and avoid future warnings about writing beyond the end of frame_control.
"pahole" shows no size nor member offset changes to struct hfa384x_tx_frame. "objdump -d" shows no meaningful object code changes (i.e. only source line number induced differences.)
Signed-off-by: Kees Cook keescook@chromium.org --- drivers/staging/wlan-ng/hfa384x.h | 16 +++++++++------- drivers/staging/wlan-ng/hfa384x_usb.c | 4 +++- 2 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/drivers/staging/wlan-ng/hfa384x.h b/drivers/staging/wlan-ng/hfa384x.h index 88e894dd3568..87eb87e3beab 100644 --- a/drivers/staging/wlan-ng/hfa384x.h +++ b/drivers/staging/wlan-ng/hfa384x.h @@ -476,13 +476,15 @@ struct hfa384x_tx_frame {
/*-- 802.11 Header Information --*/
- u16 frame_control; - u16 duration_id; - u8 address1[6]; - u8 address2[6]; - u8 address3[6]; - u16 sequence_control; - u8 address4[6]; + struct_group(p80211, + u16 frame_control; + u16 duration_id; + u8 address1[6]; + u8 address2[6]; + u8 address3[6]; + u16 sequence_control; + u8 address4[6]; + ); __le16 data_len; /* little endian format */
/*-- 802.3 Header Information --*/ diff --git a/drivers/staging/wlan-ng/hfa384x_usb.c b/drivers/staging/wlan-ng/hfa384x_usb.c index f2a0e16b0318..38aaae7a2d69 100644 --- a/drivers/staging/wlan-ng/hfa384x_usb.c +++ b/drivers/staging/wlan-ng/hfa384x_usb.c @@ -2516,7 +2516,9 @@ int hfa384x_drvr_txframe(struct hfa384x *hw, struct sk_buff *skb, cpu_to_le16s(&hw->txbuff.txfrm.desc.tx_control);
/* copy the header over to the txdesc */ - memcpy(&hw->txbuff.txfrm.desc.frame_control, p80211_hdr, + BUILD_BUG_ON(sizeof(hw->txbuff.txfrm.desc.p80211) != + sizeof(union p80211_hdr)); + memcpy(&hw->txbuff.txfrm.desc.p80211, p80211_hdr, sizeof(union p80211_hdr));
/* if we're using host WEP, increase size by IV+ICV */