Bug 2313110 (CVE-2024-46762)

Summary: CVE-2024-46762 kernel: xen: privcmd: Fix possible access to a freed kirqfd instance
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: 2313215    
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Description OSIDB Bzimport 2024-09-18 08:22:06 UTC 
In the Linux kernel, the following vulnerability has been resolved:

xen: privcmd: Fix possible access to a freed kirqfd instance

Nothing prevents simultaneous ioctl calls to privcmd_irqfd_assign() and
privcmd_irqfd_deassign(). If that happens, it is possible that a kirqfd
created and added to the irqfds_list by privcmd_irqfd_assign() may get
removed by another thread executing privcmd_irqfd_deassign(), while the
former is still using it after dropping the locks.

This can lead to a situation where an already freed kirqfd instance may
be accessed and cause kernel oops.

Use SRCU locking to prevent the same, as is done for the KVM
implementation for irqfds.
Comment 1 Michal Findra 2024-09-18 10:40:40 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024091843-CVE-2024-46762-6512@gregkh/T