Bug 2324856 (CVE-2024-50260)

Summary: CVE-2024-50260 kernel: sock_map: fix a NULL pointer dereference in sock_map_link_update_prog()
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: 2325076    
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Description OSIDB Bzimport 2024-11-09 11:01:31 UTC 
In the Linux kernel, the following vulnerability has been resolved:

sock_map: fix a NULL pointer dereference in sock_map_link_update_prog()

The following race condition could trigger a NULL pointer dereference:

sock_map_link_detach():		sock_map_link_update_prog():
   mutex_lock(&sockmap_mutex);
   ...
   sockmap_link->map = NULL;
   mutex_unlock(&sockmap_mutex);
   				   mutex_lock(&sockmap_mutex);
				   ...
				   sock_map_prog_link_lookup(sockmap_link->map);
				   mutex_unlock(&sockmap_mutex);
   <continue>

Fix it by adding a NULL pointer check. In this specific case, it makes
no sense to update a link which is being released.
Comment 1 Avinash Hanwate 2024-11-11 04:14:03 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024110940-CVE-2024-50260-db68@gregkh/T