Bug 2320455 (CVE-2024-49864)

Summary: CVE-2024-49864 kernel: rxrpc: Fix a race between socket set up and I/O thread creation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Bug Depends On: 2320813    
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Description OSIDB Bzimport 2024-10-21 19:03:09 UTC 
In the Linux kernel, the following vulnerability has been resolved:

rxrpc: Fix a race between socket set up and I/O thread creation

In rxrpc_open_socket(), it sets up the socket and then sets up the I/O
thread that will handle it.  This is a problem, however, as there's a gap
between the two phases in which a packet may come into rxrpc_encap_rcv()
from the UDP packet but we oops when trying to wake the not-yet created I/O
thread.

As a quick fix, just make rxrpc_encap_rcv() discard the packet if there's
no I/O thread yet.

A better, but more intrusive fix would perhaps be to rearrange things such
that the socket creation is done by the I/O thread.
Comment 1 Robb Gatica 2024-10-21 22:35:20 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024102113-CVE-2024-49864-5158@gregkh/T