swiotlb: use the adjusted address for the highmem page lookup

Summary

In the Linux kernel, the following vulnerability has been resolved: swiotlb: use the adjusted address for the highmem page lookup swiotlb_bounce() reads the page frame number from the slot's recorded orig_addr, then advances orig_addr by tlb_offset to reach the address the caller asked about. The highmem branch mixes the two: the offset within the page comes from the adjusted address, the page from the value before it. Once the adjustment crosses a page boundary the pair no longer describes one location, and the whole copy lands one page below the intended one for a positive tlb_offset, one above for a negative one. DMA_FROM_DEVICE writes the device data over the wrong page and leaves the intended one stale, DMA_TO_DEVICE feeds the device from a page the mapping may not cover. Partial syncs through dma_sync_single_range_for_*() are what make tlb_offset non-zero. The branch test is picked the same way, so a slot recorded in lowmem can be adjusted into highmem and the lowmem path then hands a highmem address to phys_to_virt(). Take both from orig_addr once it is final and keep pfn in the branch that uses it. PhysHighMem() asks the question straight from the address, as dma-debug already does.

Timeline

1. Oct 6, 2026, 8:45 AM UTCCVE published
2. Oct 19, 2026, 9:16 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 5f89468e2f060031cd89fd4287298e0eaf246bf6 · fixed in 6e53b4d6afbde626255805d438cabb1cac482445; From 5f89468e2f060031cd89fd4287298e0eaf246bf6 · fixed in aa4709813b29db89f2307f968db5d24925dcdeb1; From 5f89468e2f060031cd89fd4287298e0eaf246bf6 · fixed in 0219b72f5c209732b2f03a8cc0d7240b5e428a99; From 5f89468e2f060031cd89fd4287298e0eaf246bf6 · fixed in b7d7914a9ae3097e63d113007e4fb44d33d515b1; From 5.10.47 · fixed in 5.11; From 5.12.14 · fixed in 5.13

• Linux Linux

  5.13

• KernelLinux

  From 5.13.0 · fixed in 6.12.112; From 6.13.0 · fixed in 6.18.54; From 6.19.0 · fixed in 7.2.8

References 4