Re: CVE-2024-47722: xen: use correct end address of kernel for conflict checking

Re: CVE-2024-47722: xen: use correct end address of kernel for conflict checking

[Juergen Gross]

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On 21.10.24 14:16, Greg Kroah-Hartman wrote:
> Description
> ===========
> 
> In the Linux kernel, the following vulnerability has been resolved:
> 
> xen: use correct end address of kernel for conflict checking
> 
> When running as a Xen PV dom0 the kernel is loaded by the hypervisor
> using a different memory map than that of the host. In order to
> minimize the required changes in the kernel, the kernel adapts its
> memory map to that of the host. In order to do that it is checking
> for conflicts of its load address with the host memory map.
> 
> Unfortunately the tested memory range does not include the .brk
> area, which might result in crashes or memory corruption when this
> area does conflict with the memory map of the host.
> 
> Fix the test by using the _end label instead of __bss_stop.
> 
> The Linux kernel CVE team has assigned CVE-2024-47722 to this issue.

I fail to see how an unprivileged user could cause any harm here.

This bug is affecting the guest only, so only the guest admin can cause
harm to the guest at will via a special kernel. IMHO nothing CVE-worthy
here.

So I'd like to ask for this CVE being revoked.


Juergen

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Re: CVE-2024-47722: xen: use correct end address of kernel for conflict checking

[Greg Kroah-Hartman]

On Mon, Oct 21, 2024 at 02:35:16PM +0200, Juergen Gross wrote:
> On 21.10.24 14:16, Greg Kroah-Hartman wrote:
> > Description
> > ===========
> > 
> > In the Linux kernel, the following vulnerability has been resolved:
> > 
> > xen: use correct end address of kernel for conflict checking
> > 
> > When running as a Xen PV dom0 the kernel is loaded by the hypervisor
> > using a different memory map than that of the host. In order to
> > minimize the required changes in the kernel, the kernel adapts its
> > memory map to that of the host. In order to do that it is checking
> > for conflicts of its load address with the host memory map.
> > 
> > Unfortunately the tested memory range does not include the .brk
> > area, which might result in crashes or memory corruption when this
> > area does conflict with the memory map of the host.
> > 
> > Fix the test by using the _end label instead of __bss_stop.
> > 
> > The Linux kernel CVE team has assigned CVE-2024-47722 to this issue.
> 
> I fail to see how an unprivileged user could cause any harm here.
> 
> This bug is affecting the guest only, so only the guest admin can cause
> harm to the guest at will via a special kernel. IMHO nothing CVE-worthy
> here.

Ah, I thought this could affect the host, sorry about that.

> So I'd like to ask for this CVE being revoked.

Now revoked!

thanks for the review.

greg k-h