4.14-stable review patch. If anyone has any objections, please let me know.
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From: Sara Sharon sara.sharon@intel.com
[ Upstream commit 166ac9d55b0ab70b644e429be1f217fe8393cbd7 ]
When building building AMSDU from non-linear SKB, we hit a kernel panic when trying to push the padding to the tail. Instead, put the padding at the head of the next subframe. This also fixes the A-MSDU subframes to not have the padding accounted in the length field and not have pad at all for the last subframe, both required by the spec.
Fixes: 6e0456b54545 ("mac80211: add A-MSDU tx support") Signed-off-by: Sara Sharon sara.sharon@intel.com Reviewed-by: Lorenzo Bianconi lorenzo.bianconi@redhat.com Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mac80211/tx.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-)
--- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -3022,27 +3022,18 @@ void ieee80211_clear_fast_xmit(struct st }
static bool ieee80211_amsdu_realloc_pad(struct ieee80211_local *local, - struct sk_buff *skb, int headroom, - int *subframe_len) + struct sk_buff *skb, int headroom) { - int amsdu_len = *subframe_len + sizeof(struct ethhdr); - int padding = (4 - amsdu_len) & 3; - - if (skb_headroom(skb) < headroom || skb_tailroom(skb) < padding) { + if (skb_headroom(skb) < headroom) { I802_DEBUG_INC(local->tx_expand_skb_head);
- if (pskb_expand_head(skb, headroom, padding, GFP_ATOMIC)) { + if (pskb_expand_head(skb, headroom, 0, GFP_ATOMIC)) { wiphy_debug(local->hw.wiphy, "failed to reallocate TX buffer\n"); return false; } }
- if (padding) { - *subframe_len += padding; - skb_put_zero(skb, padding); - } - return true; }
@@ -3066,8 +3057,7 @@ static bool ieee80211_amsdu_prepare_head if (info->control.flags & IEEE80211_TX_CTRL_AMSDU) return true;
- if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(*amsdu_hdr), - &subframe_len)) + if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(*amsdu_hdr))) return false;
data = skb_push(skb, sizeof(*amsdu_hdr)); @@ -3133,7 +3123,8 @@ static bool ieee80211_amsdu_aggregate(st void *data; bool ret = false; unsigned int orig_len; - int n = 1, nfrags; + int n = 1, nfrags, pad = 0; + u16 hdrlen;
if (!ieee80211_hw_check(&local->hw, TX_AMSDU)) return false; @@ -3184,8 +3175,19 @@ static bool ieee80211_amsdu_aggregate(st if (max_frags && nfrags > max_frags) goto out;
- if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(rfc1042_header) + 2, - &subframe_len)) + /* + * Pad out the previous subframe to a multiple of 4 by adding the + * padding to the next one, that's being added. Note that head->len + * is the length of the full A-MSDU, but that works since each time + * we add a new subframe we pad out the previous one to a multiple + * of 4 and thus it no longer matters in the next round. + */ + hdrlen = fast_tx->hdr_len - sizeof(rfc1042_header); + if ((head->len - hdrlen) & 3) + pad = 4 - ((head->len - hdrlen) & 3); + + if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(rfc1042_header) + + 2 + pad)) goto out;
ret = true; @@ -3197,6 +3199,8 @@ static bool ieee80211_amsdu_aggregate(st memcpy(data, &len, 2); memcpy(data + 2, rfc1042_header, sizeof(rfc1042_header));
+ memset(skb_push(skb, pad), 0, pad); + head->len += skb->len; head->data_len += skb->len; *frag_tail = skb;