{"cve":"CVE-2026-46325","nvd":{"published":"2026-06-09T14:16:42.177","modified":"2026-10-21T13:19:06.677","status":"Modified","description":"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 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/","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-190"],"references":["https://git.kernel.org/stable/c/12985e5915a0b8354796efadaaeb201eed115377","https://git.kernel.org/stable/c/2a585a08a43c568ed6e9f27a97fd3d95106b9e68","https://git.kernel.org/stable/c/409c2c5508f3d30627bea576f8676de523cb906e","https://git.kernel.org/stable/c/836f6c13c9674027793f720be3f15ecd2b90b6ca","https://git.kernel.org/stable/c/e327021bd73b134c18167e2cd2a52eb5597fcba6"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-46325","score":0.0045,"percentile":0.38792,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}