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@chromium.org --- 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 9a19046217df..cea8a9ddc4da 100644 --- a/drivers/net/wireless/intersil/hostap/hostap_hw.c +++ b/drivers/net/wireless/intersil/hostap/hostap_hw.c @@ -1812,8 +1812,9 @@ 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.frame); + BUILD_BUG_ON(hdr_len != 24); + skb_copy_from_linear_data(skb, &txdesc.frame, 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..174735a137c5 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(frame, + __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;