staging: wlan-ng: Avoid duplicate header in tx/rx frames

Instead of open-coding the same header details in the tx/rx frames,
directly include the actual struct. Rename associated variables to the
more verbose of the two versions. This also has the benefit of being
able to replace a field-spanning memcpy() with a direct assignment,
helping clear the way for coming FORTIFY_SOURCE improvements.

"diffoscope" reports no object code differences after this change,
excepting the selection of different registers when switching from
memcpy() to direct assignment:

 --- drivers/staging/wlan-ng/prism2usb.o.before
 +++ drivers/staging/wlan-ng/prism2usb.o.after
├── objdump --line-numbers --disassemble --demangle --reloc --no-show-raw-insn --section=.text {}
│ @@ -4887,24 +4887,24 @@
│       sub    %rdi,%rcx
│       add    $0x3c,%ecx
│       shr    $0x3,%ecx
│       rep stos %rax,%es:(%rdi)
│       mov    $0x8,%eax
│       movl   $0x123,0x23e(%rbx)
│       mov    %ax,0x244(%rbx)
│ -     mov    (%rdx),%rcx
│ -     mov    %rcx,0x246(%rbx)
│ -     mov    0x8(%rdx),%rcx
│ -     mov    %rcx,0x24e(%rbx)
│ -     mov    0x10(%rdx),%rcx
│ -     mov    %rcx,0x256(%rbx)
│ -     mov    0x18(%rdx),%ecx
│ -     mov    %ecx,0x25e(%rbx)
│ -     movzwl 0x1c(%rdx),%edx
│ -     mov    %dx,0x262(%rbx)
│ +     mov    (%rdx),%rax
│ +     mov    %rax,0x246(%rbx)
│ +     mov    0x8(%rdx),%rax
│ +     mov    %rax,0x24e(%rbx)
│ +     mov    0x10(%rdx),%rax
│ +     mov    %rax,0x256(%rbx)
│ +     mov    0x18(%rdx),%eax
│ +     mov    %eax,0x25e(%rbx)
│ +     movzwl 0x1c(%rdx),%eax
│ +     mov    %ax,0x262(%rbx)
│       cmpq   $0x0,0x0(%rbp)
│       movzwl 0x70(%rsi),%eax
│       je     477a <hfa384x_drvr_txframe+0xba>
│       add    $0x8,%eax
│       mov    $0x44,%r12d
│       mov    %ax,0x264(%rbx)
│       mov    0x70(%r13),%edx

Cc: Romain Perier <romain.perier@gmail.com>
Cc: Allen Pais <apais@linux.microsoft.com>
Cc: Ivan Safonov <insafonov@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-staging@lists.linux.dev
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210819174537.3499227-3-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/wlan-ng/hfa384x.h b/drivers/staging/wlan-ng/hfa384x.h
index f1bc1f2..75ed8bc 100644 (file)
--- a/drivers/staging/wlan-ng/hfa384x.h
+++ b/drivers/staging/wlan-ng/hfa384x.h
@@ -475,14 +475,7 @@ struct hfa384x_tx_frame {
        u16 tx_control;
 
        /*-- 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 p80211_hdr hdr;
        __le16 data_len;                /* little endian format */
 
        /*-- 802.3 Header Information --*/
@@ -541,13 +534,7 @@ struct hfa384x_rx_frame {
        u16 reserved2;
 
        /*-- 802.11 Header Information (802.11 byte order) --*/
-       __le16 frame_control;
-       u16 duration_id;
-       u8 address1[6];
-       u8 address2[6];
-       u8 address3[6];
-       u16 sequence_control;
-       u8 address4[6];
+       struct p80211_hdr hdr;
        __le16 data_len;                /* hfa384x (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 0bf71f3..8c85246 100644 (file)
--- a/drivers/staging/wlan-ng/hfa384x_usb.c
+++ b/drivers/staging/wlan-ng/hfa384x_usb.c
@@ -2516,8 +2516,7 @@ 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,
-              sizeof(struct p80211_hdr));
+       hw->txbuff.txfrm.desc.hdr = *p80211_hdr;
 
        /* if we're using host WEP, increase size by IV+ICV */
        if (p80211_wep->data) {
@@ -3258,7 +3257,7 @@ static void hfa384x_usbin_rx(struct wlandevice *wlandev, struct sk_buff *skb)
 
        switch (status) {
        case 0:
-               fc = le16_to_cpu(usbin->rxfrm.desc.frame_control);
+               fc = le16_to_cpu(usbin->rxfrm.desc.hdr.frame_control);
 
                /* If exclude and we receive an unencrypted, drop it */
                if ((wlandev->hostwep & HOSTWEP_EXCLUDEUNENCRYPTED) &&
@@ -3278,7 +3277,7 @@ static void hfa384x_usbin_rx(struct wlandevice *wlandev, struct sk_buff *skb)
                 * with an "overlapping" copy
                 */
                memmove(skb_push(skb, hdrlen),
-                       &usbin->rxfrm.desc.frame_control, hdrlen);
+                       &usbin->rxfrm.desc.hdr, hdrlen);
 
                skb->dev = wlandev->netdev;
 
@@ -3356,7 +3355,7 @@ static void hfa384x_int_rxmonitor(struct wlandevice *wlandev,
 
        /* Remember the status, time, and data_len fields are in host order */
        /* Figure out how big the frame is */
-       fc = le16_to_cpu(rxdesc->frame_control);
+       fc = le16_to_cpu(rxdesc->hdr.frame_control);
        hdrlen = p80211_headerlen(fc);
        datalen = le16_to_cpu(rxdesc->data_len);
 
@@ -3404,7 +3403,7 @@ static void hfa384x_int_rxmonitor(struct wlandevice *wlandev,
        /* Copy the 802.11 header to the skb
         * (ctl frames may be less than a full header)
         */
-       skb_put_data(skb, &rxdesc->frame_control, hdrlen);
+       skb_put_data(skb, &rxdesc->hdr.frame_control, hdrlen);
 
        /* If any, copy the data from the card to the skb */
        if (datalen > 0) {

diff --git a/drivers/staging/wlan-ng/p80211conv.c b/drivers/staging/wlan-ng/p80211conv.c
index 0b3ba03..59b25ca 100644 (file)
--- a/drivers/staging/wlan-ng/p80211conv.c
+++ b/drivers/staging/wlan-ng/p80211conv.c
@@ -175,21 +175,21 @@ int skb_ether_to_p80211(struct wlandevice *wlandev, u32 ethconv,
 
        switch (wlandev->macmode) {
        case WLAN_MACMODE_IBSS_STA:
-               memcpy(p80211_hdr->a1, &e_hdr.daddr, ETH_ALEN);
-               memcpy(p80211_hdr->a2, wlandev->netdev->dev_addr, ETH_ALEN);
-               memcpy(p80211_hdr->a3, wlandev->bssid, ETH_ALEN);
+               memcpy(p80211_hdr->address1, &e_hdr.daddr, ETH_ALEN);
+               memcpy(p80211_hdr->address2, wlandev->netdev->dev_addr, ETH_ALEN);
+               memcpy(p80211_hdr->address3, wlandev->bssid, ETH_ALEN);
                break;
        case WLAN_MACMODE_ESS_STA:
                fc |= cpu_to_le16(WLAN_SET_FC_TODS(1));
-               memcpy(p80211_hdr->a1, wlandev->bssid, ETH_ALEN);
-               memcpy(p80211_hdr->a2, wlandev->netdev->dev_addr, ETH_ALEN);
-               memcpy(p80211_hdr->a3, &e_hdr.daddr, ETH_ALEN);
+               memcpy(p80211_hdr->address1, wlandev->bssid, ETH_ALEN);
+               memcpy(p80211_hdr->address2, wlandev->netdev->dev_addr, ETH_ALEN);
+               memcpy(p80211_hdr->address3, &e_hdr.daddr, ETH_ALEN);
                break;
        case WLAN_MACMODE_ESS_AP:
                fc |= cpu_to_le16(WLAN_SET_FC_FROMDS(1));
-               memcpy(p80211_hdr->a1, &e_hdr.daddr, ETH_ALEN);
-               memcpy(p80211_hdr->a2, wlandev->bssid, ETH_ALEN);
-               memcpy(p80211_hdr->a3, &e_hdr.saddr, ETH_ALEN);
+               memcpy(p80211_hdr->address1, &e_hdr.daddr, ETH_ALEN);
+               memcpy(p80211_hdr->address2, wlandev->bssid, ETH_ALEN);
+               memcpy(p80211_hdr->address3, &e_hdr.saddr, ETH_ALEN);
                break;
        default:
                netdev_err(wlandev->netdev,
@@ -222,9 +222,9 @@ int skb_ether_to_p80211(struct wlandevice *wlandev, u32 ethconv,
 
        /*      skb->nh.raw = skb->data; */
 
-       p80211_hdr->fc = fc;
-       p80211_hdr->dur = 0;
-       p80211_hdr->seq = 0;
+       p80211_hdr->frame_control = fc;
+       p80211_hdr->duration_id = 0;
+       p80211_hdr->sequence_control = 0;
 
        return 0;
 }
@@ -294,18 +294,18 @@ int skb_p80211_to_ether(struct wlandevice *wlandev, u32 ethconv,
        w_hdr = (struct p80211_hdr *)skb->data;
 
        /* setup some vars for convenience */
-       fc = le16_to_cpu(w_hdr->fc);
+       fc = le16_to_cpu(w_hdr->frame_control);
        if ((WLAN_GET_FC_TODS(fc) == 0) && (WLAN_GET_FC_FROMDS(fc) == 0)) {
-               ether_addr_copy(daddr, w_hdr->a1);
-               ether_addr_copy(saddr, w_hdr->a2);
+               ether_addr_copy(daddr, w_hdr->address1);
+               ether_addr_copy(saddr, w_hdr->address2);
        } else if ((WLAN_GET_FC_TODS(fc) == 0) &&
                   (WLAN_GET_FC_FROMDS(fc) == 1)) {
-               ether_addr_copy(daddr, w_hdr->a1);
-               ether_addr_copy(saddr, w_hdr->a3);
+               ether_addr_copy(daddr, w_hdr->address1);
+               ether_addr_copy(saddr, w_hdr->address3);
        } else if ((WLAN_GET_FC_TODS(fc) == 1) &&
                   (WLAN_GET_FC_FROMDS(fc) == 0)) {
-               ether_addr_copy(daddr, w_hdr->a3);
-               ether_addr_copy(saddr, w_hdr->a2);
+               ether_addr_copy(daddr, w_hdr->address3);
+               ether_addr_copy(saddr, w_hdr->address2);
        } else {
                payload_offset = WLAN_HDR_A4_LEN;
                if (payload_length < WLAN_HDR_A4_LEN - WLAN_HDR_A3_LEN) {
@@ -313,8 +313,8 @@ int skb_p80211_to_ether(struct wlandevice *wlandev, u32 ethconv,
                        return 1;
                }
                payload_length -= (WLAN_HDR_A4_LEN - WLAN_HDR_A3_LEN);
-               ether_addr_copy(daddr, w_hdr->a3);
-               ether_addr_copy(saddr, w_hdr->a4);
+               ether_addr_copy(daddr, w_hdr->address3);
+               ether_addr_copy(saddr, w_hdr->address4);
        }
 
        /* perform de-wep if necessary.. */

diff --git a/drivers/staging/wlan-ng/p80211hdr.h b/drivers/staging/wlan-ng/p80211hdr.h
index 93dd8ff..dd1fb99 100644 (file)
--- a/drivers/staging/wlan-ng/p80211hdr.h
+++ b/drivers/staging/wlan-ng/p80211hdr.h
@@ -149,13 +149,13 @@
 /* Generic 802.11 Header types */
 
 struct p80211_hdr {
-       u16 fc;
-       u16 dur;
-       u8 a1[ETH_ALEN];
-       u8 a2[ETH_ALEN];
-       u8 a3[ETH_ALEN];
-       u16 seq;
-       u8 a4[ETH_ALEN];
+       u16     frame_control;
+       u16     duration_id;
+       u8      address1[ETH_ALEN];
+       u8      address2[ETH_ALEN];
+       u8      address3[ETH_ALEN];
+       u16     sequence_control;
+       u8      address4[ETH_ALEN];
 } __packed;
 
 /* Frame and header length macros */

diff --git a/drivers/staging/wlan-ng/p80211netdev.c b/drivers/staging/wlan-ng/p80211netdev.c
index 3a4cc0b..0905602 100644 (file)
--- a/drivers/staging/wlan-ng/p80211netdev.c
+++ b/drivers/staging/wlan-ng/p80211netdev.c
@@ -238,7 +238,7 @@ static int p80211_convert_to_ether(struct wlandevice *wlandev,
        struct p80211_hdr *hdr;
 
        hdr = (struct p80211_hdr *)skb->data;
-       if (p80211_rx_typedrop(wlandev, le16_to_cpu(hdr->fc)))
+       if (p80211_rx_typedrop(wlandev, le16_to_cpu(hdr->frame_control)))
                return CONV_TO_ETHER_SKIPPED;
 
        /* perform mcast filtering: allow my local address through but reject
@@ -246,8 +246,8 @@ static int p80211_convert_to_ether(struct wlandevice *wlandev,
         */
        if (wlandev->netdev->flags & IFF_ALLMULTI) {
                if (!ether_addr_equal_unaligned(wlandev->netdev->dev_addr,
-                                               hdr->a1)) {
-                       if (!is_multicast_ether_addr(hdr->a1))
+                                               hdr->address1)) {
+                       if (!is_multicast_ether_addr(hdr->address1))
                                return CONV_TO_ETHER_SKIPPED;
                }
        }

diff --git a/drivers/staging/wlan-ng/prism2sta.c b/drivers/staging/wlan-ng/prism2sta.c
index 1f9ba26..f67b740 100644 (file)
--- a/drivers/staging/wlan-ng/prism2sta.c
+++ b/drivers/staging/wlan-ng/prism2sta.c
@@ -250,7 +250,7 @@ static int prism2sta_txframe(struct wlandevice *wlandev, struct sk_buff *skb,
        /* If necessary, set the 802.11 WEP bit */
        if ((wlandev->hostwep & (HOSTWEP_PRIVACYINVOKED | HOSTWEP_ENCRYPT)) ==
            HOSTWEP_PRIVACYINVOKED) {
-               p80211_hdr->fc |= cpu_to_le16(WLAN_SET_FC_ISWEP(1));
+               p80211_hdr->frame_control |= cpu_to_le16(WLAN_SET_FC_ISWEP(1));
        }
 
        return hfa384x_drvr_txframe(hw, skb, p80211_hdr, p80211_wep);