Messages in this thread | | | Date | Mon, 26 Feb 2024 16:25:09 +0100 | From | Michal Hocko <> | Subject | Re: CVE-2023-52451: powerpc/pseries/memhp: Fix access beyond end of drmem array |
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On Mon 26-02-24 16:06:51, Greg KH wrote: > On Mon, Feb 26, 2024 at 03:52:11PM +0100, Michal Hocko wrote: > > On Thu 22-02-24 17:21:58, Greg KH wrote: > > > Description > > > =========== > > > > > > In the Linux kernel, the following vulnerability has been resolved: > > > > > > powerpc/pseries/memhp: Fix access beyond end of drmem array > > > > > > dlpar_memory_remove_by_index() may access beyond the bounds of the > > > drmem lmb array when the LMB lookup fails to match an entry with the > > > given DRC index. When the search fails, the cursor is left pointing to > > > &drmem_info->lmbs[drmem_info->n_lmbs], which is one element past the > > > last valid entry in the array. The debug message at the end of the > > > function then dereferences this pointer: > > > > > > pr_debug("Failed to hot-remove memory at %llx\n", > > > lmb->base_addr); > > > > While this is a reasonable fix and the stable material it is really > > unclear to me why it has gained a CVE. Memory hotplug is a privileged > > operation. Could you clarify please? > > As you know, history has shown us that accessing out of your allocated > memory can cause problems, and we can not assume use-cases, as we don't > know how everyone uses our codebase, so marking places where we fix > out-of-bound memory accesses is resolving a weakness in the codebase, > hence a CVE assignment.
Does that mean that any potentially incorrect input provided by an admin is considered CVE now? I guess we would need to ban interfaces like /dev/mem and many others.
> If your systems are not vulnerable to this specific issue, wonderful, no > need to take it, but why wouldn't you want to take a fix that resolves a > known weakness?
I have explicitly said, the fix is reasonable. I just do not see a point to mark it as CVE. I fail to see any thread model where this would matter as it would require untrusted privileged actor to trigger it AFAICS. I am happy to be proven wrong here.
-- Michal Hocko SUSE Labs
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