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authorSara Sharon <sara.sharon@intel.com>2018-08-29 08:57:02 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-10-10 08:54:19 +0200
commit9a5d353908db44d639108dee9fe05c0a8803b572 (patch)
tree780bfc0a530093dd758e95cb3735236c487ea2d7 /net
parent79448960e3d701f498accd3aa493c5e0851c639c (diff)
mac80211: avoid kernel panic when building AMSDU from non-linear SKB
[ 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>
Diffstat (limited to 'net')
-rw-r--r--net/mac80211/tx.c38
1 files changed, 21 insertions, 17 deletions
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index ccb65f18df5d..2064234500cf 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3022,27 +3022,18 @@ void ieee80211_clear_fast_xmit(struct sta_info *sta)
}
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(struct ieee80211_sub_if_data *sdata,
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(struct ieee80211_sub_if_data *sdata,
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(struct ieee80211_sub_if_data *sdata,
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(struct ieee80211_sub_if_data *sdata,
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;