{"id":"CVE-2026-46325","title":"RDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE\n\nThe current implementation incorrectly handles memory regions (MRs) with\npage sizes different from t…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 592627ccbdff0ec6fff00fc761142a76db750dd4 < 409c2c5508f3d30627bea576f8676de523cb906e","Linux >= 592627ccbdff0ec6fff00fc761142a76db750dd4 < 836f6c13c9674027793f720be3f15ecd2b90b6ca","Linux >= 592627ccbdff0ec6fff00fc761142a76db750dd4 < 12985e5915a0b8354796efadaaeb201eed115377","Linux 0e443760b8b7b1e6723f4408afa056b2bc4fea12","Linux >= 6.2.3 < 6.3","Linux 6.3"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T15:22:12.775005Z"},"published":"2026-06-09","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:31:17.256Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-46325","references":[{"url":"https://git.kernel.org/stable/c/409c2c5508f3d30627bea576f8676de523cb906e"},{"url":"https://git.kernel.org/stable/c/836f6c13c9674027793f720be3f15ecd2b90b6ca"},{"url":"https://git.kernel.org/stable/c/12985e5915a0b8354796efadaaeb201eed115377"}],"tags":["cve.org"],"epss":0.00347,"epssPercentile":0.26703,"ingestedAt":"2026-10-16T17:24:46.717Z","slug":"CVE-2026-46325","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE\n\nThe current implementation incorrectly handles memory regions (MRs) with\npage sizes different from the system PAGE_SIZE. The core issue is that\nrxe_set_page() is called with mr->page_size step increments, but the\npage_list stores individual struct page pointers, each representing\nPAGE_SIZE of memory.\n\nib_sg_to_page() has ensured that when i>=1 either\na) SG[i-1].dma_end and SG[i].dma_addr are contiguous\nor\nb) SG[i-1].dma_end and SG[i].dma_addr are mr->page_size aligned.\n\nThis leads to incorrect iova-to-va conversion in scenarios:\n\n1) page_size < PAGE_SIZE (e.g., MR: 4K, system: 64K):\n   ibmr->iova = 0x181800\n   sg[0]: dma_addr=0x181800, len=0x800\n   sg[1]: dma_addr=0x173000, len=0x1000\n\n   Access iova = 0x181800 + 0x810 = 0x182010\n   Expected VA: 0x173010 (second SG, offset 0x10)\n   Before fix:\n     - index = (0x182010 >> 12) - (0x181800 >> 12) = 1\n     - page_offset = 0x182010 & 0xFFF = 0x10\n     - xarray[1] stores system page base 0x170000\n     - Resulting VA: 0x170000 + 0x10 = 0x170010 (wrong)\n\n2) page_size > PAGE_SIZE (e.g., MR: 64K, system: 4K):\n   ibmr->iova = 0x18f800\n   sg[0]: dma_addr=0x18f800, len=0x800\n   sg[1]: dma_addr=0x170000, len=0x1000\n\n   Access iova = 0x18f800 + 0x810 = 0x190010\n   Expected VA: 0x170010 (second SG, offset 0x10)\n   Before fix:\n     - index = (0x190010 >> 16) - (0x18f800 >> 16) = 1\n     - page_offset = 0x190010 & 0xFFFF = 0x10\n     - xarray[1] stores system page for dma_addr 0x170000\n     - Resulting VA: system page of 0x170000 + 0x10 = 0x170010 (wrong)\n\nYi Zhang reported a kernel panic[1] years ago related to this defect.\n\nSolution:\n1. Replace xarray with pre-allocated rxe_mr_page array for sequential\n   indexing (all MR page indices are contiguous)\n2. Each rxe_mr_page stores both struct page* and offset within the\n   system page\n3. Handle MR page_size != PAGE_SIZE relationships:\n   - page_size > PAGE_SIZE: Split MR pages into multiple system pages\n   - page_size <= PAGE_SIZE: Store offset within system page\n4. Add boundary checks and compatibility validation\n\nThis ensures correct iova-to-va conversion regardless of MR page size\nand system PAGE_SIZE relationship, while improving performance through\narray-based sequential access.\n\nTests on 4K and 64K PAGE_SIZE hosts:\n- rdma-core/pytests\n  $ ./build/bin/run_tests.py  --dev eth0_rxe\n- blktest:\n  $ TIMEOUT=30 QUICK_RUN=1 USE_RXE=1 NVMET_TRTYPES=rdma ./check nvme srp rnbd\n\n[1] https://lore.kernel.org/all/CAHj4cs9XRqE25jyVw9rj9YugffLn5+f=1znaBEnu1usLOciD+g@mail.gmail.com/T/\n\n## Affected\n\n- `Linux >= 592627ccbdff0ec6fff00fc761142a76db750dd4 < 409c2c5508f3d30627bea576f8676de523cb906e`\n- `Linux >= 592627ccbdff0ec6fff00fc761142a76db750dd4 < 836f6c13c9674027793f720be3f15ecd2b90b6ca`\n- `Linux >= 592627ccbdff0ec6fff00fc761142a76db750dd4 < 12985e5915a0b8354796efadaaeb201eed115377`\n- `Linux 0e443760b8b7b1e6723f4408afa056b2bc4fea12`\n- `Linux >= 6.2.3 < 6.3`\n- `Linux 6.3`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}