CVE-2021-47013

In the Linux kernel, the following vulnerability has been resolved: net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send In emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(..,skb,..). If some error happens in emac_tx_fill_tpd(), the skb will be freed via dev_kfree_skb(skb) in error branch of emac_tx_fill_tpd(). But the freed skb is still used via skb->len by netdev_sent_queue(,skb->len). As i observed that emac_tx_fill_tpd() haven't modified the value of skb->len, thus my patch assigns skb->len to 'len' before the possible free and use 'len' instead of skb->len later.

• linux linux kernel (>= 4.9 < 4.9.269) • linux linux kernel (>= 4.10 < 4.14.233) • linux linux kernel (>= 4.15 < 4.19.191) • linux linux kernel (>= 4.20 < 5.4.119) • linux linux kernel (>= 5.5 < 5.10.37) • linux linux kernel (>= 5.11 < 5.11.21) • linux linux kernel (>= 5.12 < 5.12.4)