b43: Drop packets that we are not able to encrypt

We must not transmit packets we're not able to encrypt.

This fixes a bug where in a tiny timeframe after machine resume
packets can get sent unencrypted and might leak information.

This also fixes three small resource leakages I spotted while fixing
the security problem. Properly deallocate the DMA slots in any DMA
allocation error path.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 21 deletions

diff --git a/drivers/net/wireless/b43/xmit.c b/drivers/net/wireless/b43/xmit.c
index 7de2814d527e..7caa26eb4105 100644
--- a/drivers/net/wireless/b43/xmit.c
+++ b/drivers/net/wireless/b43/xmit.c
@@ -178,12 +178,12 @@ static u8 b43_calc_fallback_rate(u8 bitrate)
 }
 
 /* Generate a TX data header. */
-void b43_generate_txhdr(struct b43_wldev *dev,
-                        u8 *_txhdr,
-                        const unsigned char *fragment_data,
-                        unsigned int fragment_len,
-                        const struct ieee80211_tx_control *txctl,
-                        u16 cookie)
+int b43_generate_txhdr(struct b43_wldev *dev,
+                       u8 *_txhdr,
+                       const unsigned char *fragment_data,
+                       unsigned int fragment_len,
+                       const struct ieee80211_tx_control *txctl,
+                       u16 cookie)
 {
         struct b43_txhdr *txhdr = (struct b43_txhdr *)_txhdr;
         const struct b43_phy *phy = &dev->phy;
@@ -238,22 +238,27 @@ void b43_generate_txhdr(struct b43_wldev *dev,
                 B43_WARN_ON(key_idx >= dev->max_nr_keys);
                 key = &(dev->key[key_idx]);
 
-                if (likely(key->keyconf)) {
-                        /* This key is valid. Use it for encryption. */
-
-                        /* Hardware appends ICV. */
-                        plcp_fragment_len += txctl->icv_len;
-
-                        key_idx = b43_kidx_to_fw(dev, key_idx);
-                        mac_ctl |= (key_idx << B43_TXH_MAC_KEYIDX_SHIFT) &
-                                   B43_TXH_MAC_KEYIDX;
-                        mac_ctl |= (key->algorithm << B43_TXH_MAC_KEYALG_SHIFT) &
-                                   B43_TXH_MAC_KEYALG;
-                        wlhdr_len = ieee80211_get_hdrlen(fctl);
-                        iv_len = min((size_t) txctl->iv_len,
-                                     ARRAY_SIZE(txhdr->iv));
-                        memcpy(txhdr->iv, ((u8 *) wlhdr) + wlhdr_len, iv_len);
+                if (unlikely(!key->keyconf)) {
+                        /* This key is invalid. This might only happen
+                         * in a short timeframe after machine resume before
+                         * we were able to reconfigure keys.
+                         * Drop this packet completely. Do not transmit it
+                         * unencrypted to avoid leaking information. */
+                        return -ENOKEY;
                 }
+
+                /* Hardware appends ICV. */
+                plcp_fragment_len += txctl->icv_len;
+
+                key_idx = b43_kidx_to_fw(dev, key_idx);
+                mac_ctl |= (key_idx << B43_TXH_MAC_KEYIDX_SHIFT) &
+                           B43_TXH_MAC_KEYIDX;
+                mac_ctl |= (key->algorithm << B43_TXH_MAC_KEYALG_SHIFT) &
+                           B43_TXH_MAC_KEYALG;
+                wlhdr_len = ieee80211_get_hdrlen(fctl);
+                iv_len = min((size_t) txctl->iv_len,
+                             ARRAY_SIZE(txhdr->iv));
+                memcpy(txhdr->iv, ((u8 *) wlhdr) + wlhdr_len, iv_len);
         }
         if (b43_is_old_txhdr_format(dev)) {
                 b43_generate_plcp_hdr((struct b43_plcp_hdr4 *)(&txhdr->old_format.plcp),
@@ -411,6 +416,7 @@ void b43_generate_txhdr(struct b43_wldev *dev,
         txhdr->phy_ctl = cpu_to_le16(phy_ctl);
         txhdr->extra_ft = extra_ft;
 
+        return 0;
 }
 
 static s8 b43_rssi_postprocess(struct b43_wldev *dev,