{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nriscv: process: Fix kernel gp leakage\n\nchildregs represents the registers which are active for the new thread\nin user context. For a kernel thread, childregs->gp is never used since\nthe kernel gp is not touched by switch_to. For a user mode helper, the\ngp value can be observed in user space after execve or possibly by other\nmeans.\n\n[From the email thread]\n\nThe /* Kernel thread */ comment is somewhat inaccurate in that it is also used\nfor user_mode_helper threads, which exec a user process, e.g. /sbin/init or\nwhen /proc/sys/kernel/core_pattern is a pipe. Such threads do not have\nPF_KTHREAD set and are valid targets for ptrace etc. even before they exec.\n\nchildregs is the *user* context during syscall execution and it is observable\nfrom userspace in at least five ways:\n\n1. kernel_execve does not currently clear integer registers, so the starting\n   register state for PID 1 and other user processes started by the kernel has\n   sp = user stack, gp = kernel __global_pointer$, all other integer registers\n   zeroed by the memset in the patch comment.\n\n   This is a bug in its own right, but I'm unwilling to bet that it is the only\n   way to exploit the issue addressed by this patch.\n\n2. ptrace(PTRACE_GETREGSET): you can PTRACE_ATTACH to a user_mode_helper thread\n   before it execs, but ptrace requires SIGSTOP to be delivered which can only\n   happen at user/kernel boundaries.\n\n3. /proc/*/task/*/syscall: this is perfectly happy to read pt_regs for\n   user_mode_helpers before the exec completes, but gp is not one of the\n   registers it returns.\n\n4. PERF_SAMPLE_REGS_USER: LOCKDOWN_PERF normally prevents access to kernel\n   addresses via PERF_SAMPLE_REGS_INTR, but due to this bug kernel addresses\n   are also exposed via PERF_SAMPLE_REGS_USER which is permitted under\n   LOCKDOWN_PERF. I have not attempted to write exploit code.\n\n5. Much of the tracing infrastructure allows access to user registers. I have\n   not attempted to determine which forms of tracing allow access to user\n   registers without already allowing access to kernel registers."
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "arch/riscv/kernel/process.c"
               ],
               "versions": [
                  {
                     "version": "7db91e57a0ac",
                     "lessThan": "9abc3e6f1116",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "7db91e57a0ac",
                     "lessThan": "dff6072124f6",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "7db91e57a0ac",
                     "lessThan": "f6583444d7e7",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "7db91e57a0ac",
                     "lessThan": "00effef72c98",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "7db91e57a0ac",
                     "lessThan": "d8dcba0691b8",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "7db91e57a0ac",
                     "lessThan": "d14fa1fcf69d",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "arch/riscv/kernel/process.c"
               ],
               "versions": [
                  {
                     "version": "4.15",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "4.15",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.10.216",
                     "lessThanOrEqual": "5.10.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.15.154",
                     "lessThanOrEqual": "5.15.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.1.85",
                     "lessThanOrEqual": "6.1.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.6.26",
                     "lessThanOrEqual": "6.6.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.8.5",
                     "lessThanOrEqual": "6.8.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.9",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/9abc3e6f1116adb7a2d4fbb8ce20c37916976bf5"
            },
            {
               "url": "https://git.kernel.org/stable/c/dff6072124f6df77bfd36951fbd88565746980ef"
            },
            {
               "url": "https://git.kernel.org/stable/c/f6583444d7e78dae750798552b65a2519ff3ca84"
            },
            {
               "url": "https://git.kernel.org/stable/c/00effef72c98294edb1efa87ffa0f6cfb61b36a4"
            },
            {
               "url": "https://git.kernel.org/stable/c/d8dcba0691b8e42bddb61aab201e4d918a08e5d9"
            },
            {
               "url": "https://git.kernel.org/stable/c/d14fa1fcf69db9d070e75f1c4425211fa619dfc8"
            }
         ],
         "title": "riscv: process: Fix kernel gp leakage",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2024-35871",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}