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, addr1, addr2, addr3, and seq_ctrl, 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 object code changes.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
v1->v2: rename "frame" to "header"
---
drivers/net/wireless/intersil/hostap/hostap_hw.c | 5 +++--
drivers/net/wireless/intersil/hostap/hostap_wlan.h | 14 ++++++++------
2 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/drivers/net/wireless/intersil/hostap/hostap_hw.c b/drivers/net/wireless/intersil/hostap/hostap_hw.c
index e459e7192ae9..b74f4cb5d6d3 100644
--- a/drivers/net/wireless/intersil/hostap/hostap_hw.c
+++ b/drivers/net/wireless/intersil/hostap/hostap_hw.c
@@ -1815,8 +1815,9 @@ static int prism2_tx_80211(struct sk_buff *skb, struct net_device *dev)
memset(&txdesc, 0, sizeof(txdesc));
/* skb->data starts with txdesc->frame_control */
- hdr_len = 24;
- skb_copy_from_linear_data(skb, &txdesc.frame_control, hdr_len);
+ hdr_len = sizeof(txdesc.header);
+ BUILD_BUG_ON(hdr_len != 24);
+ skb_copy_from_linear_data(skb, &txdesc.header, hdr_len);
if (ieee80211_is_data(txdesc.frame_control) &&
ieee80211_has_a4(txdesc.frame_control) &&
skb->len >= 30) {
diff --git a/drivers/net/wireless/intersil/hostap/hostap_wlan.h b/drivers/net/wireless/intersil/hostap/hostap_wlan.h
index dd2603d9b5d3..c25cd21d18bd 100644
--- a/drivers/net/wireless/intersil/hostap/hostap_wlan.h
+++ b/drivers/net/wireless/intersil/hostap/hostap_wlan.h
@@ -115,12 +115,14 @@ struct hfa384x_tx_frame {
__le16 tx_control; /* HFA384X_TX_CTRL_ flags */
/* 802.11 */
- __le16 frame_control; /* parts not used */
- __le16 duration_id;
- u8 addr1[ETH_ALEN];
- u8 addr2[ETH_ALEN]; /* filled by firmware */
- u8 addr3[ETH_ALEN];
- __le16 seq_ctrl; /* filled by firmware */
+ struct_group(header,
+ __le16 frame_control; /* parts not used */
+ __le16 duration_id;
+ u8 addr1[ETH_ALEN];
+ u8 addr2[ETH_ALEN]; /* filled by firmware */
+ u8 addr3[ETH_ALEN];
+ __le16 seq_ctrl; /* filled by firmware */
+ );
u8 addr4[ETH_ALEN];
__le16 data_len;
--
2.30.2
