Bug 2320794 (CVE-2022-49004)

Summary: CVE-2022-49004 kernel: riscv: Sync efi page table's kernel mappings before switching
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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Description OSIDB Bzimport 2024-10-21 22:04:45 UTC 
In the Linux kernel, the following vulnerability has been resolved:

riscv: Sync efi page table's kernel mappings before switching

The EFI page table is initially created as a copy of the kernel page table.
With VMAP_STACK enabled, kernel stacks are allocated in the vmalloc area:
if the stack is allocated in a new PGD (one that was not present at the
moment of the efi page table creation or not synced in a previous vmalloc
fault), the kernel will take a trap when switching to the efi page table
when the vmalloc kernel stack is accessed, resulting in a kernel panic.

Fix that by updating the efi kernel mappings before switching to the efi
page table.
Comment 1 Avinash Hanwate 2024-10-22 04:58:56 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024102151-CVE-2022-49004-18ac@gregkh/T