{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2024-35871",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "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."
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
                    }
                ]
            }
        ]
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "Linux",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "Linux",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_affected": "<",
                                            "version_name": "7db91e57a0ac",
                                            "version_value": "9abc3e6f1116"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "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"
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                                                    {
                                                        "version": "6.8.5",
                                                        "lessThanOrEqual": "6.8.*",
                                                        "status": "unaffected",
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                                                    {
                                                        "version": "6.9",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "original_commit_for_fix"
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                                                "defaultStatus": "affected"
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    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/9abc3e6f1116adb7a2d4fbb8ce20c37916976bf5",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/9abc3e6f1116adb7a2d4fbb8ce20c37916976bf5"
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                "url": "https://git.kernel.org/stable/c/dff6072124f6df77bfd36951fbd88565746980ef",
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                "name": "https://git.kernel.org/stable/c/dff6072124f6df77bfd36951fbd88565746980ef"
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                "url": "https://git.kernel.org/stable/c/f6583444d7e78dae750798552b65a2519ff3ca84",
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                "name": "https://git.kernel.org/stable/c/f6583444d7e78dae750798552b65a2519ff3ca84"
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                "url": "https://git.kernel.org/stable/c/00effef72c98294edb1efa87ffa0f6cfb61b36a4",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/00effef72c98294edb1efa87ffa0f6cfb61b36a4"
            },
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                "url": "https://git.kernel.org/stable/c/d8dcba0691b8e42bddb61aab201e4d918a08e5d9",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/d8dcba0691b8e42bddb61aab201e4d918a08e5d9"
            },
            {
                "url": "https://git.kernel.org/stable/c/d14fa1fcf69db9d070e75f1c4425211fa619dfc8",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/d14fa1fcf69db9d070e75f1c4425211fa619dfc8"
            },
            {
                "url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html",
                "refsource": "MISC",
                "name": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
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