powerpc/47x: Fix 47x syscall return crash

{
  "id": "05e27e4000f262315245e68ef98190b9d2400e9a04b9849836f367c0b537980c",
  "url": "https://osv.dev/vulnerability/CVE-2023-52499",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "powerpc/47x: Fix 47x syscall return crash",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: powerpc/47x: Fix 47x syscall return crash Eddie reported that newer kernels were crashing during boot on his 476 FSP2 system: kernel tried to execute user page (b7ee2000) - exploit attempt? (uid: 0) BUG: Unable to handle kernel instruction fetch Faulting instruction address: 0xb7ee2000 Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=4K FSP-2 Modules linked in: CPU: 0 PID: 61 Comm: mount Not tainted 6.1.55-d23900f.ppcnf-fsp2 #1 Hardware name: ibm,fsp2 476fpe 0x7ff520c0 FSP-2 NIP: b7ee2000 LR: 8c008000 CTR: 00000000 REGS: bffebd83 TRAP: 0400 Not tainted (6.1.55-d23900f.ppcnf-fs p2) MSR: 00000030 CR: 00001000 XER: 20000000 GPR00: c00110ac bffebe63 bffebe7e bffebe88 8c008000 00001000 00000d12 b7ee2000 GPR08: 00000033 00000000 00000000 c139df10 48224824 1016c314 10160000 00000000 GPR16: 10160000 10160000 00000008 00000000 10160000 00000000 10160000 1017f5b0 GPR24: 1017fa50 1017f4f0 1017fa50 1017f740 1017f630 00000000 00000000 1017f4f0 NIP [b7ee2000] 0xb7ee2000 LR [8c008000] 0x8c008000 Call Trace: Instruction dump: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX ---[ end trace 0000000000000000 ]--- The problem is in ret_from_syscall where the check for icache_44x_need_flush is done. When the flush is needed the code jumps out-of-line to do the flush, and then intends to jump back to continue the syscall return",
    "evidence": "osv:CVE-2023-52499",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.137",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.59",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.5.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2023-52499",
      "aliases": [
        "CVE-2023-52499"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "6f76a01173ccaa363739f913394d4e138d92d718"
                },
                {
                  "fixed": "29017ab1a539101d9c7bec63cc13a019f97b2820"
                },
                {
                  "fixed": "8ac2689502f986a46f4221e239d4ff2897f1ccb3"
                },
                {
                  "fixed": "70f6756ad96dd70177dddcfac2fe4bd4bb320746"
                },
                {
                  "fixed": "f0eee815babed70a749d2496a7678be5b45b4c14"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-52499.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.12.0"
                },
                {
                  "fixed": "5.15.137"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.59"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.5.8"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-52499.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.405243471Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/29017ab1a539101d9c7bec63cc13a019f97b2820",
        "https://git.kernel.org/stable/c/70f6756ad96dd70177dddcfac2fe4bd4bb320746",
        "https://git.kernel.org/stable/c/8ac2689502f986a46f4221e239d4ff2897f1ccb3",
        "https://git.kernel.org/stable/c/f0eee815babed70a749d2496a7678be5b45b4c14",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/52xxx/CVE-2023-52499.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-52499",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/52xxx/CVE-2023-52499.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-52499",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 519643,
  "published_at": "2024-03-02T21:52:15.268+00:00"
}