Use After Free Affecting kernel-rt package, versions <0:4.18.0-553.5.1.rt7.346.el8_10
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Test your applications- Snyk ID SNYK-CENTOS8-KERNELRT-6337981
- published 29 Feb 2024
- disclosed 28 Feb 2024
Introduced: 28 Feb 2024
CVE-2021-47013 Open this link in a new tabHow to fix?
Upgrade Centos:8 kernel-rt to version 0:4.18.0-553.5.1.rt7.346.el8_10 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-rt package and not the kernel-rt package as distributed by Centos.
See How to fix? for Centos:8 relevant fixed versions and status.
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.
References
- https://access.redhat.com/security/cve/CVE-2021-47013
- https://git.kernel.org/stable/c/16d8c44be52e3650917736d45f5904384a9da834
- https://git.kernel.org/stable/c/55fcdd1258faaecca74b91b88cc0921f9edd775d
- https://git.kernel.org/stable/c/6d72e7c767acbbdd44ebc7d89c6690b405b32b57
- https://git.kernel.org/stable/c/8c06f34785068b87e2b560534c77c163d6c6dca7
- https://git.kernel.org/stable/c/9dc373f74097edd0e35f3393d6248eda8d1ba99d
- https://git.kernel.org/stable/c/c7f75d11fe72913d2619f97b2334b083cd7bb955
- https://git.kernel.org/stable/c/dc1b438a35773d030be0ee80d9c635c3e558a322
- https://git.kernel.org/stable/c/e407495ba6788a67d1bd41714158c079e340879b