From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> commit 11e7a91994c29da96d847f676be023da6a2c1359 upstream. The problem is that we always copy a minimum of ETH_ZLEN (60) bytes from skb->data even when skb->len is less than ETH_ZLEN so it leads to a read overflow. The fix is to pad skb->data to at least ETH_ZLEN bytes. Cc: <stable@xxxxxxxxxxxxxxx> Reported-by: Hu Jiahui <kirin.say@xxxxxxxxx> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200527184830.GA1164846@mwanda Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/cisco/airo.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/drivers/net/wireless/cisco/airo.c +++ b/drivers/net/wireless/cisco/airo.c @@ -1925,6 +1925,10 @@ static netdev_tx_t mpi_start_xmit(struct airo_print_err(dev->name, "%s: skb == NULL!",__func__); return NETDEV_TX_OK; } + if (skb_padto(skb, ETH_ZLEN)) { + dev->stats.tx_dropped++; + return NETDEV_TX_OK; + } npacks = skb_queue_len (&ai->txq); if (npacks >= MAXTXQ - 1) { @@ -2127,6 +2131,10 @@ static netdev_tx_t airo_start_xmit(struc airo_print_err(dev->name, "%s: skb == NULL!", __func__); return NETDEV_TX_OK; } + if (skb_padto(skb, ETH_ZLEN)) { + dev->stats.tx_dropped++; + return NETDEV_TX_OK; + } /* Find a vacant FID */ for( i = 0; i < MAX_FIDS / 2 && (fids[i] & 0xffff0000); i++ ); @@ -2201,6 +2209,10 @@ static netdev_tx_t airo_start_xmit11(str airo_print_err(dev->name, "%s: skb == NULL!", __func__); return NETDEV_TX_OK; } + if (skb_padto(skb, ETH_ZLEN)) { + dev->stats.tx_dropped++; + return NETDEV_TX_OK; + } /* Find a vacant FID */ for( i = MAX_FIDS / 2; i < MAX_FIDS && (fids[i] & 0xffff0000); i++ );
