Bug 2157270 (CVE-2023-0030) - CVE-2023-0030 kernel: Use after Free in nvkm_vmm_pfn_map
Summary: CVE-2023-0030 kernel: Use after Free in nvkm_vmm_pfn_map
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2023-0030
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2157041 2157271 2157272
Blocks: 2157079 2175316
TreeView+ depends on / blocked
 
Reported: 2023-01-01 14:31 UTC by Alex
Modified: 2023-04-02 22:46 UTC (History)
51 users (show)

Fixed In Version: Linux kernel 5.0-rc1
Doc Type: If docs needed, set a value
Doc Text:
A use-after-free flaw was found in the Linux kernel’s nouveau driver in how a user triggers a memory overflow that causes the nvkm_vma_tail function to fail. This flaw allows a local user to crash or potentially escalate their privileges on the system.
Clone Of:
Environment:
Last Closed: 2023-01-03 02:30:48 UTC


Attachments (Terms of Use)

Description Alex 2023-01-01 14:31:41 UTC
A vulnerability was found in kernel, where a use-after-frees in nouveau's nvkm_vmm_pfn_map() could happen.

Description of problem:
Here is a function call chain. 
nvkm_vmm_pfn_map->nvkm_vmm_pfn_split_merge->nvkm_vmm_node_split
If nvkm_vma_tail return NULL in nvkm_vmm_node_split, it will 
finally invoke nvkm_vmm_node_merge->nvkm_vmm_node_delete, which
will free the vma. However, nvkm_vmm_pfn_map didn't notice that.
It goes into next label and UAF happens

How reproducible:
This bug is hard to trigger. It requires nvkm_vma_tail return NULL,
which means kzalloc returns NULL.

Steps to Reproduce:
1.make a lot of memory allocation in Linux kernel so that to make 
kzalloc failed in nvkm_vma_tail 
2.UAF happens

Reference:
https://github.com/torvalds/linux/commit/729eba3355674f2d9524629b73683ba1d1cd3f10

Comment 1 Alex 2023-01-01 14:32:21 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-36 [bug 2157272]
Affects: fedora-37 [bug 2157271]

Comment 5 Product Security DevOps Team 2023-01-03 02:30:43 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2023-0030

Comment 6 Justin M. Forbes 2023-01-03 15:16:08 UTC
Not sure if this was backported to a 4.20 kernel for Fedora, but even if not, it was in 5.0 several years ago.  All currently supported Fedora releases have never shipped with an impacted kernel.


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