CVE-2024-45009

In the Linux kernel, the following vulnerability has been resolved:

mptcp: pm: only decrement add_addr_accepted for MPJ req

Adding the following warning …

WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)

… before decrementing the add_addr_accepted counter helped to find a bug when running the remove single subflow subtest from the mptcp_join.sh selftest.

Removing a subflow endpoint will first trigger a RM_ADDR, then the subflow closure. Before this patch, and upon the reception of the RM_ADDR, the other peer will then try to decrement this add_addr_accepted. Thats not correct because the attached subflows have not been created upon the reception of an ADD_ADDR.

A way to solve that is to decrement the counter only if the attached subflow was an MP_JOIN to a remote id that was not 0, and initiated by the host receiving the RM_ADDR.

Affected Software

References

• https://git.kernel.org/stable/c/1c1f721375989579e46741f59523e39ec9b2a9bd
• https://git.kernel.org/stable/c/2060f1efab370b496c4903b840844ecaff324c3c
• https://git.kernel.org/stable/c/35b31f5549ede4070566b949781e83495906b43d
• https://git.kernel.org/stable/c/85b866e4c4e63a1d7afb58f1e24273caad03d0b7
• https://git.kernel.org/stable/c/d20bf2c96d7ffd171299b32f562f70e5bf5dc608