In the Linux kernel, the following vulnerability has been resolved:
dma-direct: return struct page from dma_direct_alloc_from_pool()
Commit 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool
helper") changed dma_direct_alloc_from_pool() to return the CPU address
from dma_alloc_from_pool(). That fits dma_direct_alloc(), but
dma_direct_alloc_pages() also uses the helper and expects a struct page *.
Fix this by making dma_direct_alloc_from_pool() return the struct page *
again, and pass the CPU address back through an out-parameter for the
dma_direct_alloc() caller.
CVSS Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 8.8
AV:A - dma_direct_alloc_pages() takes the buggy pool path from dma_alloc_noncoherent(GFP_ATOMIC) in ath11k_peer_rx_tid_setup(), which runs when a same-LAN WiFi peer associates or starts a Block Ack. On SEV/TDX/CCA guests and SME hosts, force_dma_unencrypted() is true, so a wireless attacker reaches the type confusion without a wired/Internet service.
AC:L - The peer fully controls association and ADDBA, so the GFP_ATOMIC dma_alloc_pages() call is deterministic with no race to win. Confidential-computing dma-direct (atomic decrypted pool, no IOMMU) is the scored deployment, not an uninfluenced memory layout or rare extra config.
PR:N - ath11k peer/TID setup and the cdns3 gadget GFP_ATOMIC dma_alloc_noncoherent() path run in kernel interrupt/softirq context with no host account, capability, or user-namespace check. An unauthenticated WiFi peer (or USB gadget host) is sufficient.
UI:N - Peer creation and Block Ack setup are 802.11 protocol operations. Once the interface is up as an AP/hotspot or an already-associated STA, exploitation needs no victim mount, open, or other interactive step.
S:U - The allocator returns a CPU virtual address as a struct page *, corrupting page and DMA bookkeeping in the same kernel. This is not a VM escape, IOMMU bypass, or host/guest confidential-computing boundary crossing.
C:H - Callers treat the kernel VA as a struct page, so page_to_virt/page_address/page_to_pfn compute wrong addresses and dma_mmap_pages() can remap a bogus PFN into userspace. That type confusion is an arbitrary kernel-memory disclosure primitive.
I:H - sg_set_page, page_address stores, dma_set_encrypted(), and dma_free_contiguous() then operate on the fake page pointer, writing, re-encrypting, or freeing the wrong memory. That is an arbitrary kernel write/free primitive usable for control-flow hijack.
A:H - Interpreting a DMA pool virtual address as a struct page * causes invalid vmemmap/page-flag accesses and buddy frees, which oops or panic the kernel even when not fully turned into a stable read/write primitive.
| Attack Vector |
Adjacent Network |
Scope |
Unchanged |
| Attack Complexity |
Low |
Confidentiality Impact |
High |
| Privileges Required |
None |
Integrity Impact |
High |
| User Interaction |
None |
Availability Impact |
High |
AV:A - dma_direct_alloc_pages() takes the buggy pool path from dma_alloc_noncoherent(GFP_ATOMIC) in ath11k_peer_rx_tid_setup(), which runs when a same-LAN WiFi peer associates or starts a Block Ack. On SEV/TDX/CCA guests and SME hosts, force_dma_unencrypted() is true, so a wireless attacker reaches the type confusion without a wired/Internet service.
AC:L - The peer fully controls association and ADDBA, so the GFP_ATOMIC dma_alloc_pages() call is deterministic with no race to win. Confidential-computing dma-direct (atomic decrypted pool, no IOMMU) is the scored deployment, not an uninfluenced memory layout or rare extra config.
PR:N - ath11k peer/TID setup and the cdns3 gadget GFP_ATOMIC dma_alloc_noncoherent() path run in kernel interrupt/softirq context with no host account, capability, or user-namespace check. An unauthenticated WiFi peer (or USB gadget host) is sufficient.
UI:N - Peer creation and Block Ack setup are 802.11 protocol operations. Once the interface is up as an AP/hotspot or an already-associated STA, exploitation needs no victim mount, open, or other interactive step.
S:U - The allocator returns a CPU virtual address as a struct page *, corrupting page and DMA bookkeeping in the same kernel. This is not a VM escape, IOMMU bypass, or host/guest confidential-computing boundary crossing.
C:H - Callers treat the kernel VA as a struct page, so page_to_virt/page_address/page_to_pfn compute wrong addresses and dma_mmap_pages() can remap a bogus PFN into userspace. That type confusion is an arbitrary kernel-memory disclosure primitive.
I:H - sg_set_page, page_address stores, dma_set_encrypted(), and dma_free_contiguous() then operate on the fake page pointer, writing, re-encrypting, or freeing the wrong memory. That is an arbitrary kernel write/free primitive usable for control-flow hijack.
A:H - Interpreting a DMA pool virtual address as a struct page * causes invalid vmemmap/page-flag accesses and buddy frees, which oops or panic the kernel even when not fully turned into a stable read/write primitive.
CVSS 3.1