CVE-2021-47013

Summary

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 Software

VendorProductVersion RangeStatus
LinuxLinuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf < c7f75d11fe72913d2619f97b2334b083cd7bb955affected
LinuxLinuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf < dc1b438a35773d030be0ee80d9c635c3e558a322affected
LinuxLinuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf < 16d8c44be52e3650917736d45f5904384a9da834affected
LinuxLinuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf < 55fcdd1258faaecca74b91b88cc0921f9edd775daffected
LinuxLinuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf < 9dc373f74097edd0e35f3393d6248eda8d1ba99daffected
LinuxLinuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf < 8c06f34785068b87e2b560534c77c163d6c6dca7affected
LinuxLinuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf < e407495ba6788a67d1bd41714158c079e340879baffected
LinuxLinuxb9b17debc69d27cd55e21ee51a5ba7fc50a426cf < 6d72e7c767acbbdd44ebc7d89c6690b405b32b57affected
LinuxLinux4.9affected
LinuxLinux0 < 4.9unaffected
LinuxLinux4.9.269 <= 4.9.*unaffected
LinuxLinux4.14.233 <= 4.14.*unaffected
LinuxLinux4.19.191 <= 4.19.*unaffected
LinuxLinux5.4.119 <= 5.4.*unaffected
LinuxLinux5.10.37 <= 5.10.*unaffected
LinuxLinux5.11.21 <= 5.11.*unaffected
LinuxLinux5.12.4 <= 5.12.*unaffected
LinuxLinux5.13 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References