CVE-2021-47152 Information

Description

In the Linux kernel the following vulnerability has been resolved:

mptcp: fix data stream corruption

Maxim reported several issues when forcing a TCP transparent proxy to use the MPTCP protocol for the inbound connections. He also provided a clean reproducer.

The problem boils down to ‘mptcp_frag_can_collapse_to()’ assuming that only MPTCP will use the given page_frag.

If others - e.g. the plain TCP protocol - allocate page fragments we can end-up re-using already allocated memory for mptcp_data_frag.

Fix the issue ensuring that the to-be-expanded data fragment is located at the current page frag end.

v1 -> v2:

• added missing fixes tag (Mat)

Reference

https://git.kernel.org/stable/c/3267a061096efc91eda52c2a0c61ba76e46e4b34 https://git.kernel.org/stable/c/18e7f0580da15cac1e79d73683ada5a9e70980f8 https://git.kernel.org/stable/c/29249eac5225429b898f278230a6ca2baa1ae154