CVE-2026-98216 (GCVE-0-2026-98216)
Vulnerability from cvelistv5
Published
2026-10-06 08:44
Modified
2026-10-19 09:15
Severity ?
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: IB/hfi1: Fix the PIO_CRED credit-return mmap hfi1_file_mmap()'s PIO_CRED case must hand user space the single credit-return page that holds this context's entry. That page is the second or third page of the per-node credit-return allocation once the hardware send context index reaches 64 or 128, so the failure below is intermittent: when the entry lands on the first page the offset is zero and everything works. Two things are wrong. First, cr_page_offset is a byte offset but .va is a struct credit_return *, so adding it is pointer arithmetic and scales the offset by sizeof(struct credit_return) == 64. memvirt then lands 256 KiB or 512 KiB past a 10240-byte allocation. With an IOMMU translating, that address is inside the vmalloc range but in no vm_area, so dma_mmap_coherent() -> iommu_dma_mmap() finds no pages, vmalloc_to_pfn() returns page_to_pfn(NULL), and remap_pfn_range() installs a frame above MAXPHYADDR. The first user read then takes: psm2_ep_open_pr: Corrupted page table at address 7a14d007e000 PGD 800000013886a067 P4D 800000013886a067 PUD 13886b067 PMD 13886c067 PTE 800049168e911235 Oops: Bad pagetable: 000d [#1] SMP PTI Second, and still wrong once the arithmetic is corrected, dma_mmap_coherent() describes a whole coherent buffer and selects the page within it with vma->vm_pgoff. Offsetting cpu_addr has no effect: for a vmap'd allocation iommu_dma_mmap() uses cpu_addr only to locate the vm_area and then maps pages[vm_pgoff], which hfi1_file_mmap() has just set to 0. User space therefore always receives the first credit-return page, every credit read is for the wrong context, and send PIO stalls forever. Use the DMA API as intended: pass the base of the allocation with its full length and select the page with vm_pgoff. A separate length is needed because memlen must keep describing the VMA for the existing size check. The dma-direct path stays correct as well, since dma_direct_mmap() adds the same vm_pgoff to the base pfn. Tested on a Dell T7610 (Xeon E5-2650 v2, Intel IOMMU in DMA-FQ mode) against a Threadripper PRO 3995WX peer, both Omni-Path 100. Before this change psm2_ep_open() Oopses the kernel; with only the arithmetic corrected psm2_ep_open() succeeds but any transfer that uses send PIO hangs, PSM2_SDMA=2 (send PIO disabled) completing normally while PSM2_SDMA=0 (send PIO only) hangs every time. With this change send PIO, send DMA and the default mixed mode all work.
References
Impacted products
Vendor Product Version
Linux Linux Version: 1ec82317a1daac78c04b0c15af89018ccf9fa2b7
Version: 1ec82317a1daac78c04b0c15af89018ccf9fa2b7
Version: 1ec82317a1daac78c04b0c15af89018ccf9fa2b7
Version: 1ec82317a1daac78c04b0c15af89018ccf9fa2b7
Version: 1ec82317a1daac78c04b0c15af89018ccf9fa2b7
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/hw/hfi1/file_ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/hw/hfi1/file_ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.3"
            },
            {
              "lessThan": "6.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.54",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.158",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.112",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.54",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.8",
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nIB/hfi1: Fix the PIO_CRED credit-return mmap\n\nhfi1_file_mmap()\u0027s PIO_CRED case must hand user space the single\ncredit-return page that holds this context\u0027s entry.  That page is the\nsecond or third page of the per-node credit-return allocation once the\nhardware send context index reaches 64 or 128, so the failure below is\nintermittent: when the entry lands on the first page the offset is zero\nand everything works.\n\nTwo things are wrong.\n\nFirst, cr_page_offset is a byte offset but .va is a struct\ncredit_return *, so adding it is pointer arithmetic and scales the offset\nby sizeof(struct credit_return) == 64.  memvirt then lands 256 KiB or\n512 KiB past a 10240-byte allocation.  With an IOMMU translating, that\naddress is inside the vmalloc range but in no vm_area, so\ndma_mmap_coherent() -\u003e iommu_dma_mmap() finds no pages, vmalloc_to_pfn()\nreturns page_to_pfn(NULL), and remap_pfn_range() installs a frame above\nMAXPHYADDR.  The first user read then takes:\n\n  psm2_ep_open_pr: Corrupted page table at address 7a14d007e000\n  PGD 800000013886a067 P4D 800000013886a067 PUD 13886b067 PMD 13886c067\n                                            PTE 800049168e911235\n  Oops: Bad pagetable: 000d [#1] SMP PTI\n\nSecond, and still wrong once the arithmetic is corrected,\ndma_mmap_coherent() describes a whole coherent buffer and selects the\npage within it with vma-\u003evm_pgoff.  Offsetting cpu_addr has no effect:\nfor a vmap\u0027d allocation iommu_dma_mmap() uses cpu_addr only to locate the\nvm_area and then maps pages[vm_pgoff], which hfi1_file_mmap() has just\nset to 0.  User space therefore always receives the first credit-return\npage, every credit read is for the wrong context, and send PIO stalls\nforever.\n\nUse the DMA API as intended: pass the base of the allocation with its\nfull length and select the page with vm_pgoff.  A separate length is\nneeded because memlen must keep describing the VMA for the existing size\ncheck.  The dma-direct path stays correct as well, since dma_direct_mmap()\nadds the same vm_pgoff to the base pfn.\n\nTested on a Dell T7610 (Xeon E5-2650 v2, Intel IOMMU in DMA-FQ mode)\nagainst a Threadripper PRO 3995WX peer, both Omni-Path 100.  Before this\nchange psm2_ep_open() Oopses the kernel; with only the arithmetic\ncorrected psm2_ep_open() succeeds but any transfer that uses send PIO\nhangs, PSM2_SDMA=2 (send PIO disabled) completing normally while\nPSM2_SDMA=0 (send PIO only) hangs every time.  With this change send PIO,\nsend DMA and the default mixed mode all work."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bad mapping is created by hfi1_file_mmap() PIO_CRED case, reached by a local process via open() of the /dev/hfi1_N user cdev, the ASSIGN_CTXT ioctl and mmap() of the PIO_CRED token; no remote peer supplies any data to this path.\nAC:L - With IOMMU DMA translation (common on x86 servers), the pointer-scaled cr_page_offset deterministically sends memvirt 256/512 KiB past the credit-return buffer for send context index \u003e=64, and the attacker can raise the index by opening more contexts; the commit\u0027s reproducer oopses every time.\nPR:L - hfi1_user_devnode() creates the user device node with mode 0666 and hfi1_file_open() has no capability check, so any unprivileged local user on an Omni-Path node (e.g. a shared HPC node) can assign a context and issue the mmap.\nUI:N - The attacker triggers the faulty mapping and the faulting read entirely from their own process; no other user or administrator has to do anything.\nS:U - Both impacts stay within the host kernel\u0027s own authority: a kernel page or bogus PFN is mapped into a local process and the kernel oopses; no VM, IOMMU or sandbox boundary is crossed.\nC:H - If the out-of-range vmalloc address lands in a non-DMA-coherent vm_area, iommu_dma_mmap() falls back to vmalloc_to_pfn() and remap_pfn_range() exposes that kernel page to userspace read-only with no reference held, so the user can read unrelated kernel memory, even after it is freed and reused.\nI:N - The PIO_CRED VMA is read-only: VM_WRITE is rejected with -EPERM and VM_MAYWRITE is cleared, so the mis-mapped page cannot be written from userspace, and the bug gives no kernel write primitive.\nA:H - When the address falls in a vmalloc hole, page_to_pfn(NULL) installs a PTE for a frame above MAXPHYADDR and the first user read causes an \u0027Oops: Bad pagetable\u0027 kernel crash; even with the arithmetic fixed, mapping the wrong page leaves send PIO hung forever."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:15:47.022Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/535530bb2ea5254e1e9f55280143d262dd065204"
        },
        {
          "url": "https://git.kernel.org/stable/c/dcebe0b0bb080a25fe08011fd6b6e741f7912f01"
        },
        {
          "url": "https://git.kernel.org/stable/c/180752deb7270ad37394ab6ef7cf4978fad040b3"
        },
        {
          "url": "https://git.kernel.org/stable/c/bafeac9ce5d1ce5256bcf7e5702e831e9aaf419b"
        },
        {
          "url": "https://git.kernel.org/stable/c/62f0f34fbd2b2d5653d33d3b9d42fdcabb1c0101"
        }
      ],
      "title": "IB/hfi1: Fix the PIO_CRED credit-return mmap",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98216",
    "datePublished": "2026-10-06T08:44:52.288Z",
    "dateReserved": "2026-09-25T10:25:14.326Z",
    "dateUpdated": "2026-10-19T09:15:47.022Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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