From 5e3033e2f50a224b7bb4d398bd9ae7ba8ed40c7a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?St=C3=A9phane=20Lesimple?= Date: Thu, 2 Apr 2026 19:55:25 +0200 Subject: [PATCH] enh: CVE-2022-40982 (Downfall) overhaul & Spectre V2 enhancements Downfall: - added `--kernel-config` support for all three Kconfig variants seen over all kernel versions up to now - added `--kernel-map` support for `gds_select_mitigation` in `System.map` - fixed the `--sysfs-only` mode - added verbose information about remediation when `--explain` is used - implemented `--paranoid mode`, requiring `GDS_MITIGATION_LOCKED` so that mitigation can't be disabled at runtime - fixed offline mode (was wrongly looking at the system `dmesg`) - better microcode status reporting (enabled, disabled, unsupported, unknown) - fixed unknown (EOL) AVX-capable Intel family 6 CPUs now defaulting to affected - fixed 2 missing known affected CPU models: INTEL_FAM6_SKYLAKE_L and INTEL_FAM6_SKYLAKE - fixed case when we're running in a VM and the hypervisor doesn't let us read the MSR Spectre V2: - fix: affected_cpu: added Centaur family 7 (CentaurHauls) and Zhaoxin family 7 (Shanghai) as immune - fix: added Centaur family 5 (CentaurHauls) and NSC family 5 (Geode by NSC) to is_cpu_specex_free() - enh: offline mode: added detection logic by probing System.map and Kconfig --- src/libs/200_cpu_affected.sh | 23 +++- src/libs/210_cpu_detect.sh | 7 ++ src/vulns/CVE-2017-5715.sh | 74 +++++++++++-- src/vulns/CVE-2022-40982.sh | 198 +++++++++++++++++++++++++++++------ 4 files changed, 256 insertions(+), 46 deletions(-) diff --git a/src/libs/200_cpu_affected.sh b/src/libs/200_cpu_affected.sh index 7206a39..77ff111 100644 --- a/src/libs/200_cpu_affected.sh +++ b/src/libs/200_cpu_affected.sh @@ -126,6 +126,14 @@ is_cpu_affected() { pr_debug "is_cpu_affected: cpu not affected by Special Register Buffer Data Sampling" fi + # NO_SPECTRE_V2: Centaur family 7 and Zhaoxin family 7 are immune to Spectre V2 + # kernel commit 1e41a766c98b (v5.6-rc1): added NO_SPECTRE_V2 exemption + # Zhaoxin vendor_id is " Shanghai " in cpuinfo (parsed as "Shanghai" by awk) + if { [ "$cpu_vendor" = "CentaurHauls" ] || [ "$cpu_vendor" = "Shanghai" ]; } && [ "$cpu_family" = 7 ]; then + _infer_immune variant2 + pr_debug "is_cpu_affected: Centaur/Zhaoxin family 7 immune to Spectre V2 (NO_SPECTRE_V2)" + fi + if is_cpu_specex_free; then _set_immune variant1 _set_immune variant2 @@ -222,9 +230,12 @@ is_cpu_affected() { pr_debug "is_cpu_affected: downfall: not affected (GDS_NO)" _set_immune downfall elif [ "$cpu_family" = 6 ]; then - # list from https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=64094e7e3118aff4b0be8ff713c242303e139834 + # model blacklist from the kernel (arch/x86/kernel/cpu/common.c cpu_vuln_blacklist): + # 8974eb588283 (initial list) + c9f4c45c8ec3 (added Skylake/Skylake_L client) set -u - if [ "$cpu_model" = "$INTEL_FAM6_SKYLAKE_X" ] || + if [ "$cpu_model" = "$INTEL_FAM6_SKYLAKE_L" ] || + [ "$cpu_model" = "$INTEL_FAM6_SKYLAKE" ] || + [ "$cpu_model" = "$INTEL_FAM6_SKYLAKE_X" ] || [ "$cpu_model" = "$INTEL_FAM6_KABYLAKE_L" ] || [ "$cpu_model" = "$INTEL_FAM6_KABYLAKE" ] || [ "$cpu_model" = "$INTEL_FAM6_ICELAKE_L" ] || @@ -239,10 +250,12 @@ is_cpu_affected() { _set_vuln downfall elif [ "$cap_avx2" = 0 ] && [ "$cap_avx512" = 0 ]; then pr_debug "is_cpu_affected: downfall: no avx; immune" + _infer_immune downfall else - # old Intel CPU (not in their DB), not listed as being affected by the Linux kernel, - # but with AVX2 or AVX512: unclear for now - pr_debug "is_cpu_affected: downfall: unclear, defaulting to non-affected for now" + # Intel family 6 CPU with AVX2 or AVX512, not in the known-affected list + # and GDS_NO not set: assume affected (whitelist principle) + pr_debug "is_cpu_affected: downfall: unknown AVX-capable CPU, defaulting to affected" + _infer_vuln downfall fi set +u fi diff --git a/src/libs/210_cpu_detect.sh b/src/libs/210_cpu_detect.sh index 2e0a637..13111dc 100644 --- a/src/libs/210_cpu_detect.sh +++ b/src/libs/210_cpu_detect.sh @@ -27,6 +27,13 @@ is_cpu_specex_free() { return 0 fi fi + # Centaur family 5 and NSC family 5 are also non-speculative + if [ "$cpu_vendor" = "CentaurHauls" ] && [ "$cpu_family" = 5 ]; then + return 0 + fi + if [ "$cpu_vendor" = "Geode by NSC" ] && [ "$cpu_family" = 5 ]; then + return 0 + fi [ "$cpu_family" = 4 ] && return 0 return 1 } diff --git a/src/vulns/CVE-2017-5715.sh b/src/vulns/CVE-2017-5715.sh index c911a39..8f59f4a 100644 --- a/src/vulns/CVE-2017-5715.sh +++ b/src/vulns/CVE-2017-5715.sh @@ -1,14 +1,12 @@ # vim: set ts=4 sw=4 sts=4 et: -################### -# SPECTRE 2 SECTION +############################### +# CVE-2017-5715, Spectre V2, Branch Target Injection -# CVE-2017-5715 Spectre Variant 2 (branch target injection) - entry point # Sets: vulnstatus check_CVE_2017_5715() { check_cve 'CVE-2017-5715' } -# CVE-2017-5715 Spectre Variant 2 (branch target injection) - Linux mitigation check # Sets: g_ibrs_can_tell, g_ibrs_supported, g_ibrs_enabled, g_ibrs_fw_enabled, # g_ibpb_can_tell, g_ibpb_supported, g_ibpb_enabled, g_specex_knob_dir check_CVE_2017_5715_linux() { @@ -208,6 +206,43 @@ check_CVE_2017_5715_linux() { # rocky9 (RHEL 9, kernel 5.14): matches mainline. Semicolons, BHI, all fields. # rocky10 (RHEL 10, kernel 6.12): matches mainline. # + # + # --- Kconfig symbols --- + # 76b043848fd2 (v4.15-rc8): CONFIG_RETPOLINE + # f43b9876e857 (v5.19-rc7): CONFIG_CPU_IBRS_ENTRY (kernel IBRS on entry) + # aefb2f2e619b (v6.9-rc1): renamed CONFIG_RETPOLINE => CONFIG_MITIGATION_RETPOLINE + # 1da8d2172ce5 (v6.9-rc1): renamed CONFIG_CPU_IBRS_ENTRY => CONFIG_MITIGATION_IBRS_ENTRY + # ec9404e40e8f (v6.9-rc4): CONFIG_SPECTRE_BHI_ON / CONFIG_SPECTRE_BHI_OFF + # 4f511739c54b (v6.9-rc4): replaced by CONFIG_MITIGATION_SPECTRE_BHI + # 72c70f480a70 (v6.12-rc1): CONFIG_MITIGATION_SPECTRE_V2 (top-level on/off) + # 8754e67ad4ac (v6.15-rc7): CONFIG_MITIGATION_ITS (indirect target selection) + # stable 5.4.y-6.6.y: CONFIG_RETPOLINE (pre-rename) + # stable 6.12.y: CONFIG_MITIGATION_RETPOLINE, CONFIG_MITIGATION_SPECTRE_V2 + # + # --- kernel functions (for $opt_map / System.map) --- + # da285121560e (v4.15-rc8): spectre_v2_select_mitigation(), + # spectre_v2_parse_cmdline(), nospectre_v2_parse_cmdline() + # 20ffa1caecca (v4.16-rc1): spectre_v2_module_string(), retpoline_module_ok() + # a8f76ae41cd6 (v4.20-rc5): spectre_v2_user_select_mitigation(), + # spectre_v2_user_parse_cmdline() + # 7c693f54c873 (v5.19-rc7): spectre_v2_in_ibrs_mode(), spectre_v2_in_eibrs_mode() + # 44a3918c8245 (v5.17-rc8): spectre_v2_show_state() + # 480e803dacf8 (v6.16-rc1): split into spectre_v2_select_mitigation() + + # spectre_v2_apply_mitigation() + spectre_v2_update_mitigation() + + # spectre_v2_user_apply_mitigation() + spectre_v2_user_update_mitigation() + # + # --- CPU affection logic (for is_cpu_affected) --- + # X86_BUG_SPECTRE_V2 is set for ALL x86 CPUs except: + # - CPUs matching NO_SPECULATION: family 4 (all vendors), Centaur/Intel/NSC/Vortex + # family 5, Intel Atom Bonnell/Saltwell + # - CPUs matching NO_SPECTRE_V2: Centaur family 7, Zhaoxin family 7 + # 99c6fa2511d8 (v4.15-rc8): unconditional for all x86 CPUs + # 1e41a766c98b (v5.6-rc1): added NO_SPECTRE_V2 exemption for Centaur/Zhaoxin + # 98c7a713db91 (v6.15-rc1): added X86_BUG_SPECTRE_V2_USER as separate bit + # No MSR/CPUID immunity bits — purely whitelist-based. + # vendor scope: all x86 vendors affected (Intel, AMD, Hygon, etc.) + # except Centaur family 7 and Zhaoxin family 7. + # # all messages start with either "Not affected", "Mitigation", or "Vulnerable" fi if [ "$opt_sysfs_only" != 1 ]; then @@ -332,6 +367,19 @@ check_CVE_2017_5715_linux() { if grep -q spec_ctrl "$opt_map"; then g_ibrs_supported="found spec_ctrl in symbols file" pr_debug "ibrs: found '*spec_ctrl*' symbol in $opt_map" + elif grep -q -e spectre_v2_select_mitigation -e spectre_v2_apply_mitigation "$opt_map"; then + # spectre_v2_select_mitigation exists since v4.15; split into + # spectre_v2_select_mitigation + spectre_v2_apply_mitigation in v6.16 + g_ibrs_supported="found spectre_v2 mitigation function in symbols file" + pr_debug "ibrs: found spectre_v2_*_mitigation symbol in $opt_map" + fi + fi + # CONFIG_CPU_IBRS_ENTRY (v5.19) / CONFIG_MITIGATION_IBRS_ENTRY (v6.9): kernel IBRS on entry + if [ -z "$g_ibrs_supported" ] && [ -n "$opt_config" ] && [ -r "$opt_config" ]; then + g_ibrs_can_tell=1 + if grep -q '^CONFIG_\(CPU_\|MITIGATION_\)IBRS_ENTRY=y' "$opt_config"; then + g_ibrs_supported="CONFIG_CPU_IBRS_ENTRY/CONFIG_MITIGATION_IBRS_ENTRY found in kernel config" + pr_debug "ibrs: found IBRS entry config option in $opt_config" fi fi # recent (4.15) vanilla kernels have IBPB but not IBRS, and without the debugfs tunables of Red Hat @@ -579,7 +627,7 @@ check_CVE_2017_5715_linux() { rsb_filling=0 if [ "$opt_live" = 1 ] && [ "$opt_no_sysfs" != 1 ]; then # if we're live and we aren't denied looking into /sys, let's do it - if echo "$msg" | grep -qw RSB; then + if echo "$ret_sys_interface_check_fullmsg" | grep -qw RSB; then rsb_filling=1 pstatus green YES fi @@ -679,6 +727,11 @@ check_CVE_2017_5715_linux() { *) pstatus yellow UNKNOWN ;; esac + # --- SMT state (used in STIBP inference and verdict) --- + is_cpu_smt_enabled + smt_enabled=$? + # smt_enabled: 0=enabled, 1=disabled, 2=unknown + # --- v2_stibp_status --- pr_info_nol " * STIBP status: " if [ -n "$ret_sys_interface_check_fullmsg" ]; then @@ -821,11 +874,6 @@ check_CVE_2017_5715_linux() { fi fi - # --- SMT state (used in verdict) --- - is_cpu_smt_enabled - smt_enabled=$? - # smt_enabled: 0=enabled, 1=disabled, 2=unknown - elif [ "$sys_interface_available" = 0 ]; then # we have no sysfs but were asked to use it only! msg="/sys vulnerability interface use forced, but it's not available!" @@ -840,6 +888,8 @@ check_CVE_2017_5715_linux() { # --- own logic using Phase 2 variables --- # Helper: collect caveats for the verdict message _v2_caveats='' + # Append a caveat string to the _v2_caveats list + # Callers: check_CVE_2017_5715_linux (eIBRS, IBRS, retpoline verdict paths) _v2_add_caveat() { _v2_caveats="${_v2_caveats:+$_v2_caveats; }$1"; } # ARM branch predictor hardening (unchanged) @@ -1107,6 +1157,9 @@ check_CVE_2017_5715_linux() { pvulnstatus "$cve" OK "offline mode: kernel supports IBRS + IBPB to mitigate the vulnerability" elif [ "$cap_ibrs_all" = 1 ] || [ "$cap_autoibrs" = 1 ]; then pvulnstatus "$cve" OK "offline mode: CPU supports Enhanced / Automatic IBRS" + # CONFIG_MITIGATION_SPECTRE_V2 (v6.12+): top-level on/off for all Spectre V2 mitigations + elif [ -n "$opt_config" ] && [ -r "$opt_config" ] && grep -q '^CONFIG_MITIGATION_SPECTRE_V2=y' "$opt_config"; then + pvulnstatus "$cve" OK "offline mode: kernel has Spectre V2 mitigation framework enabled (CONFIG_MITIGATION_SPECTRE_V2)" elif [ "$g_ibrs_can_tell" != 1 ]; then pvulnstatus "$cve" UNK "offline mode: not enough information" explain "Re-run this script with root privileges, and give it the kernel image (--kernel), the kernel configuration (--config) and the System.map file (--map) corresponding to the kernel you would like to inspect." @@ -1137,7 +1190,6 @@ check_CVE_2017_5715_linux() { fi } -# CVE-2017-5715 Spectre Variant 2 (branch target injection) - BSD mitigation check # Sets: vulnstatus check_CVE_2017_5715_bsd() { local ibrs_disabled ibrs_active retpoline nb_thunks diff --git a/src/vulns/CVE-2022-40982.sh b/src/vulns/CVE-2022-40982.sh index 5a07460..0c61467 100644 --- a/src/vulns/CVE-2022-40982.sh +++ b/src/vulns/CVE-2022-40982.sh @@ -17,22 +17,132 @@ check_CVE_2022_40982_linux() { if sys_interface_check "$VULN_SYSFS_BASE/gather_data_sampling"; then # this kernel has the /sys interface, trust it over everything sys_interface_available=1 + # + # Kernel source inventory for gather_data_sampling (GDS/Downfall) + # + # --- sysfs messages --- + # all versions: + # "Not affected" (cpu_show_common, pre-existing) + # + # --- mainline --- + # 8974eb588283 (v6.5-rc6, initial GDS sysfs): + # "Vulnerable" (GDS_MITIGATION_OFF) + # "Vulnerable: No microcode" (GDS_MITIGATION_UCODE_NEEDED) + # "Mitigation: Microcode" (GDS_MITIGATION_FULL) + # "Mitigation: Microcode (locked)" (GDS_MITIGATION_FULL_LOCKED) + # "Unknown: Dependent on hypervisor status" (GDS_MITIGATION_HYPERVISOR) + # 553a5c03e90a (v6.5-rc6, added force option): + # "Mitigation: AVX disabled, no microcode" (GDS_MITIGATION_FORCE) + # 53cf5797f114 (v6.5-rc6, added CONFIG_GDS_FORCE_MITIGATION): + # no string changes; default becomes FORCE when Kconfig enabled + # 81ac7e5d7417 (v6.5-rc6, KVM GDS_NO plumbing): + # no string changes + # be83e809ca67 (v6.9-rc1, Kconfig rename): + # no string changes; CONFIG_GDS_FORCE_MITIGATION => CONFIG_MITIGATION_GDS_FORCE + # 03267a534bb3 (v6.12-rc1, removed force Kconfig): + # no string changes; CONFIG_MITIGATION_GDS_FORCE removed + # 225f2bd064c3 (v6.12-rc1, added on/off Kconfig): + # no string changes; added CONFIG_MITIGATION_GDS (default y) + # 9dcad2fb31bd (v6.16-rc1, restructured select/apply): + # no string changes; added GDS_MITIGATION_AUTO (internal, resolved before display) + # split gds_select_mitigation() + gds_apply_mitigation() + # d4932a1b148b (v6.17-rc3, bug fix): + # no string changes; CPUs without ARCH_CAP_GDS_CTRL were incorrectly classified + # as OFF ("Vulnerable") instead of UCODE_NEEDED ("Vulnerable: No microcode"), + # and locked-mitigation detection was skipped. + # NOT backported to any stable or RHEL branch as of 2026-04. + # + # --- stable backports --- + # 5.4.y, 5.10.y, 5.15.y, 6.1.y, 6.6.y: same 7 strings as mainline. + # use CONFIG_GDS_FORCE_MITIGATION; no GDS_MITIGATION_AUTO enum; + # missing d4932a1b148b bug fix (UCODE_NEEDED vs OFF misclassification). + # 6.12.y: same 7 strings as mainline. + # uses CONFIG_MITIGATION_GDS; no GDS_MITIGATION_AUTO enum; + # missing d4932a1b148b bug fix. + # + # --- RHEL/CentOS --- + # centos7 (3.10), rocky8 (4.18): same 7 strings; CONFIG_GDS_FORCE_MITIGATION. + # centos7 uses sprintf (not sysfs_emit) and __read_mostly. + # rocky9 (5.14): same 7 strings; CONFIG_MITIGATION_GDS (skipped FORCE rename). + # rocky10 (6.12): same 7 strings; CONFIG_MITIGATION_GDS; has gds_apply_mitigation(). + # + # --- Kconfig symbols --- + # 53cf5797f114 (v6.5-rc6): CONFIG_GDS_FORCE_MITIGATION (default n) + # be83e809ca67 (v6.9-rc1): renamed to CONFIG_MITIGATION_GDS_FORCE + # 03267a534bb3 (v6.12-rc1): CONFIG_MITIGATION_GDS_FORCE removed + # 225f2bd064c3 (v6.12-rc1): CONFIG_MITIGATION_GDS (default y) + # vendor kernels: rocky9 uses CONFIG_MITIGATION_GDS on 5.14-based kernel + # + # --- kernel functions (for $opt_map / System.map) --- + # 8974eb588283 (v6.5-rc6): gds_select_mitigation(), update_gds_msr(), + # gds_parse_cmdline(), gds_show_state() + # 81ac7e5d7417 (v6.5-rc6): gds_ucode_mitigated() (exported for KVM) + # 9dcad2fb31bd (v6.16-rc1): split into gds_select_mitigation() + gds_apply_mitigation() + # stable 5.4.y-6.12.y: same 5 functions (no gds_apply_mitigation) + # rocky10 (6.12): has gds_apply_mitigation() + # + # --- CPU affection logic (for is_cpu_affected) --- + # X86_BUG_GDS is set when ALL three conditions are true: + # 1. CPU matches model blacklist (cpu_vuln_blacklist[] in common.c) + # 2. ARCH_CAP_GDS_NO (bit 26 of IA32_ARCH_CAPABILITIES) is NOT set + # 3. X86_FEATURE_AVX is present (GATHER instructions require AVX) + # 8974eb588283 (v6.5-rc6, initial model list): + # Intel: SKYLAKE_X, KABYLAKE_L, KABYLAKE, ICELAKE_L, ICELAKE_D, + # ICELAKE_X, COMETLAKE, COMETLAKE_L, TIGERLAKE_L, TIGERLAKE, + # ROCKETLAKE (all steppings) + # c9f4c45c8ec3 (v6.5-rc6, added missing client Skylake): + # Intel: + SKYLAKE_L, SKYLAKE + # 159013a7ca18 (v6.10-rc1, ITS stepping splits): + # no GDS model changes; some entries split by stepping for ITS but + # GDS flag remains on all stepping ranges for these models + # immunity: ARCH_CAP_GDS_NO (bit 26 of IA32_ARCH_CAPABILITIES) + # feature dependency: requires AVX (if AVX absent, CPU is immune) + # vendor scope: Intel only + # + # all messages start with either "Not affected", "Vulnerable", "Mitigation", + # or "Unknown" status=$ret_sys_interface_check_status + # Override: when the kernel says "Unknown: Dependent on hypervisor status", it + # gave up because it's running as a VM guest and can't read MCU_OPT_CTRL. + # We can often do better: the hypervisor may have exposed GDS_NO or GDS_CTRL + # to us via ARCH_CAPABILITIES, so let our own Phase 2 checks take over. + if echo "$ret_sys_interface_check_fullmsg" | grep -qi 'Dependent on hypervisor'; then + status=UNK + fi fi if [ "$opt_sysfs_only" != 1 ]; then pr_info_nol "* GDS is mitigated by microcode: " if [ "$cap_gds_ctrl" = 1 ] && [ "$cap_gds_mitg_dis" = 0 ]; then pstatus green OK "microcode mitigation is supported and enabled" + elif [ "$cap_gds_ctrl" = 1 ] && [ "$cap_gds_mitg_dis" = 1 ]; then + pstatus yellow NO "microcode mitigation is supported but disabled" + elif [ "$cap_gds_ctrl" = 0 ]; then + pstatus yellow NO "microcode doesn't support GDS mitigation" else - pstatus yellow NO + pstatus yellow UNKNOWN "couldn't read MSR for GDS capability" fi + pr_info_nol "* Kernel supports software mitigation by disabling AVX: " + kernel_gds='' + kernel_gds_err='' if [ -n "$g_kernel_err" ]; then kernel_gds_err="$g_kernel_err" elif grep -q 'gather_data_sampling' "$g_kernel"; then kernel_gds="found gather_data_sampling in kernel image" fi + if [ -z "$kernel_gds" ] && [ -r "$opt_config" ]; then + if grep -q '^CONFIG_GDS_FORCE_MITIGATION=y' "$opt_config" || + grep -q '^CONFIG_MITIGATION_GDS_FORCE=y' "$opt_config" || + grep -q '^CONFIG_MITIGATION_GDS=y' "$opt_config"; then + kernel_gds="GDS mitigation config option found enabled in kernel config" + fi + fi + if [ -z "$kernel_gds" ] && [ -n "$opt_map" ]; then + if grep -q 'gds_select_mitigation' "$opt_map"; then + kernel_gds="found gds_select_mitigation in System.map" + fi + fi if [ -n "$kernel_gds" ]; then pstatus green YES "$kernel_gds" elif [ -n "$kernel_gds_err" ]; then @@ -44,30 +154,34 @@ check_CVE_2022_40982_linux() { if [ -n "$kernel_gds" ]; then pr_info_nol "* Kernel has disabled AVX as a mitigation: " - # Check dmesg message to see whether AVX has been disabled - dmesg_grep 'Microcode update needed! Disabling AVX as mitigation' - dmesgret=$? - if [ "$dmesgret" -eq 0 ]; then - kernel_avx_disabled="AVX disabled by the kernel (dmesg)" - pstatus green YES "$kernel_avx_disabled" - elif [ "$cap_avx2" = 0 ]; then - # Find out by ourselves - # cpuinfo says we don't have AVX2, query - # the CPU directly about AVX2 support - read_cpuid 0x7 0x0 "$EBX" 5 1 1 - ret=$? - if [ "$ret" -eq "$READ_CPUID_RET_OK" ]; then - kernel_avx_disabled="AVX disabled by the kernel (cpuid)" + if [ "$opt_live" = 1 ]; then + # Check dmesg message to see whether AVX has been disabled + dmesg_grep 'Microcode update needed! Disabling AVX as mitigation' + dmesgret=$? + if [ "$dmesgret" -eq 0 ]; then + kernel_avx_disabled="AVX disabled by the kernel (dmesg)" pstatus green YES "$kernel_avx_disabled" - elif [ "$ret" -eq "$READ_CPUID_RET_KO" ]; then - pstatus yellow NO "CPU doesn't support AVX" - elif [ "$dmesgret" -eq 2 ]; then - pstatus yellow UNKNOWN "dmesg truncated, can't tell whether mitigation is active, please reboot and relaunch this script" + elif [ "$cap_avx2" = 0 ]; then + # Find out by ourselves + # cpuinfo says we don't have AVX2, query + # the CPU directly about AVX2 support + read_cpuid 0x7 0x0 "$EBX" 5 1 1 + ret=$? + if [ "$ret" -eq "$READ_CPUID_RET_OK" ]; then + kernel_avx_disabled="AVX disabled by the kernel (cpuid)" + pstatus green YES "$kernel_avx_disabled" + elif [ "$ret" -eq "$READ_CPUID_RET_KO" ]; then + pstatus yellow NO "CPU doesn't support AVX" + elif [ "$dmesgret" -eq 2 ]; then + pstatus yellow UNKNOWN "dmesg truncated, can't tell whether mitigation is active, please reboot and relaunch this script" + else + pstatus yellow UNKNOWN "No sign of mitigation in dmesg and couldn't read cpuid info" + fi else - pstatus yellow UNKNOWN "No sign of mitigation in dmesg and couldn't read cpuid info" + pstatus yellow NO "AVX support is enabled" fi else - pstatus yellow NO "AVX support is enabled" + pstatus blue N/A "not testable in offline mode" fi fi @@ -82,16 +196,40 @@ check_CVE_2022_40982_linux() { pvulnstatus "$cve" OK "your CPU vendor reported your CPU model as not affected" elif [ -z "$msg" ]; then # if msg is empty, sysfs check didn't fill it, rely on our own test - if [ "$cap_gds_ctrl" = 1 ] && [ "$cap_gds_mitg_dis" = 0 ]; then - pvulnstatus "$cve" OK "Your microcode is up to date and mitigation is enabled" - elif [ "$cap_gds_ctrl" = 1 ] && [ "$cap_gds_mitg_dis" = 1 ]; then - pvulnstatus "$cve" VULN "Your microcode is up to date but mitigation is disabled" - elif [ -z "$kernel_gds" ]; then - pvulnstatus "$cve" VULN "Your microcode doesn't mitigate the vulnerability, and your kernel doesn't support mitigation" - elif [ -z "$kernel_avx_disabled" ]; then - pvulnstatus "$cve" VULN "Your microcode doesn't mitigate the vulnerability, your kernel support the mitigation but the script did not detect AVX as disabled by the kernel" + if [ "$opt_sysfs_only" != 1 ]; then + if [ "$cap_gds_ctrl" = 1 ] && [ "$cap_gds_mitg_dis" = 0 ]; then + if [ "$opt_paranoid" = 1 ] && [ "$cap_gds_mitg_lock" != 1 ]; then + pvulnstatus "$cve" VULN "Microcode mitigation is enabled but not locked" + explain "In paranoid mode, the GDS mitigation must be locked to prevent a privileged attacker\n " \ + "(e.g. in a guest VM) from disabling it. Check your firmware/BIOS for an option to lock the\n " \ + "GDS mitigation, or update your microcode." + else + pvulnstatus "$cve" OK "Your microcode is up to date and mitigation is enabled" + fi + elif [ "$cap_gds_ctrl" = 1 ] && [ "$cap_gds_mitg_dis" = 1 ]; then + pvulnstatus "$cve" VULN "Your microcode is up to date but mitigation is disabled" + explain "The GDS mitigation has been explicitly disabled (gather_data_sampling=off or mitigations=off).\n " \ + "Remove the kernel parameter to re-enable it." + elif [ "$sys_interface_available" = 1 ] && + echo "$ret_sys_interface_check_fullmsg" | grep -qi 'Dependent on hypervisor'; then + # We're in a VM guest, the kernel gave up, and we couldn't read the + # GDS MSR bits either (cap_gds_ctrl != 1). We genuinely can't tell. + pvulnstatus "$cve" UNK "Running in a VM, mitigation depends on the hypervisor" + explain "This system is running as a virtual machine guest. GDS mitigation must be handled by\n " \ + "the host hypervisor. Contact your VM/cloud provider to verify that GDS is mitigated on the host." + elif [ -z "$kernel_gds" ]; then + pvulnstatus "$cve" VULN "Your microcode doesn't mitigate the vulnerability, and your kernel doesn't support mitigation" + explain "Update both your CPU microcode (via BIOS/firmware update from your OEM) and your kernel\n " \ + "to a version that supports GDS mitigation (Linux 6.5+, or check if your distro has a backport)." + elif [ -z "$kernel_avx_disabled" ]; then + pvulnstatus "$cve" VULN "Your microcode doesn't mitigate the vulnerability, your kernel supports the mitigation but AVX was not disabled" + explain "Update your CPU microcode (via BIOS/firmware update from your OEM). If no microcode update\n " \ + "is available, use gather_data_sampling=force on the kernel command line to disable AVX as a workaround." + else + pvulnstatus "$cve" OK "Your microcode doesn't mitigate the vulnerability, but your kernel has disabled AVX support" + fi else - pvulnstatus "$cve" OK "Your microcode doesn't mitigate the vulnerability, but your kernel has disabled AVX support" + pvulnstatus "$cve" "$status" "$ret_sys_interface_check_fullmsg" fi else pvulnstatus "$cve" "$status" "$msg"