CVE-2022-49393 (GCVE-0-2022-49393)
Vulnerability from cvelistv5
Published
2025-02-26 02:11
Modified
2026-08-05 08:55
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: misc: fastrpc: fix list iterator in fastrpc_req_mem_unmap_impl This is another instance of incorrect use of list iterator and checking it for NULL. The list iterator value 'map' will *always* be set and non-NULL by list_for_each_entry(), so it is incorrect to assume that the iterator value will be NULL if the list is empty (in this case, the check 'if (!map) {' will always be false and never exit as expected). To fix the bug, use a new variable 'iter' as the list iterator, while use the original variable 'map' as a dedicated pointer to point to the found element. Without this patch, Kernel crashes with below trace: Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000ffff7fb03750 ... Call trace: fastrpc_map_create+0x70/0x290 [fastrpc] fastrpc_req_mem_map+0xf0/0x2dc [fastrpc] fastrpc_device_ioctl+0x138/0xc60 [fastrpc] __arm64_sys_ioctl+0xa8/0xec invoke_syscall+0x48/0x114 el0_svc_common.constprop.0+0xd4/0xfc do_el0_svc+0x28/0x90 el0_svc+0x3c/0x130 el0t_64_sync_handler+0xa4/0x130 el0t_64_sync+0x18c/0x190 Code: 14000016 f94000a5 eb05029f 54000260 (b94018a6) ---[ end trace 0000000000000000 ]---
References
Impacted products
Vendor Product Version
Linux Linux Version: 5c1b97c7d7b736e6439af4f43a65837bc72f56c1
Version: 5c1b97c7d7b736e6439af4f43a65837bc72f56c1
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/misc/fastrpc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2d12905aad462383f4e7a5fdb024d2b7ae2d10cf",
              "status": "affected",
              "version": "5c1b97c7d7b736e6439af4f43a65837bc72f56c1",
              "versionType": "git"
            },
            {
              "lessThan": "c5c07c5958cf0c9af6e76813e6de15d42ee49822",
              "status": "affected",
              "version": "5c1b97c7d7b736e6439af4f43a65837bc72f56c1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/misc/fastrpc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.18"
            },
            {
              "lessThan": "5.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.18.*",
              "status": "unaffected",
              "version": "5.18.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.19",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.18.3",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.19",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmisc: fastrpc: fix list iterator in fastrpc_req_mem_unmap_impl\n\nThis is another instance of incorrect use of list iterator and\nchecking it for NULL.\n\nThe list iterator value \u0027map\u0027 will *always* be set and non-NULL\nby list_for_each_entry(), so it is incorrect to assume that the\niterator value will be NULL if the list is empty (in this case, the\ncheck \u0027if (!map) {\u0027 will always be false and never exit as expected).\n\nTo fix the bug, use a new variable \u0027iter\u0027 as the list iterator,\nwhile use the original variable \u0027map\u0027 as a dedicated pointer to\npoint to the found element.\n\nWithout this patch, Kernel crashes with below trace:\n\nUnable to handle kernel access to user memory outside uaccess routines\n at virtual address 0000ffff7fb03750\n...\nCall trace:\n fastrpc_map_create+0x70/0x290 [fastrpc]\n fastrpc_req_mem_map+0xf0/0x2dc [fastrpc]\n fastrpc_device_ioctl+0x138/0xc60 [fastrpc]\n __arm64_sys_ioctl+0xa8/0xec\n invoke_syscall+0x48/0x114\n el0_svc_common.constprop.0+0xd4/0xfc\n do_el0_svc+0x28/0x90\n el0_svc+0x3c/0x130\n el0t_64_sync_handler+0xa4/0x130\n el0t_64_sync+0x18c/0x190\nCode: 14000016 f94000a5 eb05029f 54000260 (b94018a6)\n---[ end trace 0000000000000000 ]---"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached via FASTRPC_IOCTL_MEM_UNMAP (and the MEM_MAP copy_to_user failure cleanup) on the local /dev/fastrpc-* misc device ioctl path, not via network or adjacent protocols.\nAC:L - An attacker who can open the device can populate fl-\u003emaps and then issue MEM_UNMAP with a non-matching fd/vaddr (or force the MEM_MAP cleanup path), reliably taking the bad iterator path with no race or victim-controlled timing.\nPR:L - fastrpc_device_open and the MEM_MAP/MEM_UNMAP ioctls have no capability checks; on Qualcomm/Android deployments unprivileged apps can obtain FastRPC device access (directly or via DSP HAL FD passing), so only low local privileges are required.\nUI:N - Exploitation requires no victim action; the attacker triggers the vulnerable ioctl sequence themselves once they have the device file descriptor.\nS:U - Impact is kernel memory corruption / privilege escalation within the host Linux kernel authority; it does not by itself cross a VM, IOMMU, or other separate security boundary.\nC:H - The failed lookup leaves map as a type-confused pointer into fastrpc_user, then reads forged map fields and can drive fastrpc_free_map/kfree on that object, yielding heap corruption that can be leveraged for arbitrary kernel read under the required uncertainty rule.\nI:H - Calling fastrpc_map_put on the bogus map can invoke fastrpc_free_map and kfree an interior pointer into the fastrpc_user allocation, producing heap metadata corruption exploitable for arbitrary write / control-flow hijacking.\nA:H - The commit documents a kernel oops from corrupted pointer dereference (userspace address used as a kernel pointer), so availability impact is a full kernel crash."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:55:00.985Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2d12905aad462383f4e7a5fdb024d2b7ae2d10cf"
        },
        {
          "url": "https://git.kernel.org/stable/c/c5c07c5958cf0c9af6e76813e6de15d42ee49822"
        }
      ],
      "title": "misc: fastrpc: fix list iterator in fastrpc_req_mem_unmap_impl",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2022-49393",
    "datePublished": "2025-02-26T02:11:24.730Z",
    "dateReserved": "2025-02-26T02:08:31.562Z",
    "dateUpdated": "2026-08-05T08:55:00.985Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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