by Kastro CVE-2021-47013
Linux Linux — net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send
Description · from the CVE record
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.
Affected
ProductAffectedFixed inSource
Linuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf – < c7f75d11fe72913d2619f97b2334b083cd7bb955c7f75d11fe72913d2619f97b2334b083cd7bb955CNA
Linuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf – < dc1b438a35773d030be0ee80d9c635c3e558a322dc1b438a35773d030be0ee80d9c635c3e558a322CNA
Linuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf – < 16d8c44be52e3650917736d45f5904384a9da83416d8c44be52e3650917736d45f5904384a9da834CNA
Linuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf – < 55fcdd1258faaecca74b91b88cc0921f9edd775d55fcdd1258faaecca74b91b88cc0921f9edd775dCNA
Linuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf – < 9dc373f74097edd0e35f3393d6248eda8d1ba99d9dc373f74097edd0e35f3393d6248eda8d1ba99dCNA
Linuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf – < 8c06f34785068b87e2b560534c77c163d6c6dca78c06f34785068b87e2b560534c77c163d6c6dca7CNA
Linuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf – < e407495ba6788a67d1bd41714158c079e340879be407495ba6788a67d1bd41714158c079e340879bCNA
Linuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf – < 6d72e7c767acbbdd44ebc7d89c6690b405b32b576d72e7c767acbbdd44ebc7d89c6690b405b32b57CNA
Linux4.94.9.269CNA
Scores by source
Linux (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: partial