forked from Minki/linux
x86/bugs: Report Intel retbleed vulnerability
Skylake suffers from RSB underflow speculation issues; report this vulnerability and it's mitigation (spectre_v2=ibrs). [jpoimboe: cleanups, eibrs] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
This commit is contained in:
Peter Zijlstra
Borislav Petkov
parent
166115c08a
commit
6ad0ad2bf8
@ -93,6 +93,7 @@
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#define MSR_IA32_ARCH_CAPABILITIES 0x0000010a
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#define ARCH_CAP_RDCL_NO BIT(0) /* Not susceptible to Meltdown */
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#define ARCH_CAP_IBRS_ALL BIT(1) /* Enhanced IBRS support */
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#define ARCH_CAP_RSBA BIT(2) /* RET may use alternative branch predictors */
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#define ARCH_CAP_SKIP_VMENTRY_L1DFLUSH BIT(3) /* Skip L1D flush on vmentry */
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#define ARCH_CAP_SSB_NO BIT(4) /*
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* Not susceptible to Speculative Store Bypass
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@ -790,12 +790,17 @@ static int __init nospectre_v1_cmdline(char *str)
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}
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early_param("nospectre_v1", nospectre_v1_cmdline);
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static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =
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SPECTRE_V2_NONE;
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#undef pr_fmt
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#define pr_fmt(fmt) "RETBleed: " fmt
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enum retbleed_mitigation {
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RETBLEED_MITIGATION_NONE,
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RETBLEED_MITIGATION_UNRET,
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RETBLEED_MITIGATION_IBRS,
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RETBLEED_MITIGATION_EIBRS,
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};
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enum retbleed_mitigation_cmd {
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@ -807,6 +812,8 @@ enum retbleed_mitigation_cmd {
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const char * const retbleed_strings[] = {
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[RETBLEED_MITIGATION_NONE] = "Vulnerable",
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[RETBLEED_MITIGATION_UNRET] = "Mitigation: untrained return thunk",
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[RETBLEED_MITIGATION_IBRS] = "Mitigation: IBRS",
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[RETBLEED_MITIGATION_EIBRS] = "Mitigation: Enhanced IBRS",
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};
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static enum retbleed_mitigation retbleed_mitigation __ro_after_init =
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@ -849,6 +856,7 @@ early_param("retbleed", retbleed_parse_cmdline);
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#define RETBLEED_UNTRAIN_MSG "WARNING: BTB untrained return thunk mitigation is only effective on AMD/Hygon!\n"
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#define RETBLEED_COMPILER_MSG "WARNING: kernel not compiled with RETPOLINE or -mfunction-return capable compiler!\n"
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#define RETBLEED_INTEL_MSG "WARNING: Spectre v2 mitigation leaves CPU vulnerable to RETBleed attacks, data leaks possible!\n"
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static void __init retbleed_select_mitigation(void)
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{
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@ -865,12 +873,15 @@ static void __init retbleed_select_mitigation(void)
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case RETBLEED_CMD_AUTO:
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default:
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if (!boot_cpu_has_bug(X86_BUG_RETBLEED))
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break;
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if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
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boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
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retbleed_mitigation = RETBLEED_MITIGATION_UNRET;
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/*
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* The Intel mitigation (IBRS) was already selected in
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* spectre_v2_select_mitigation().
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*/
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break;
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}
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@ -900,15 +911,31 @@ static void __init retbleed_select_mitigation(void)
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break;
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}
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/*
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* Let IBRS trump all on Intel without affecting the effects of the
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* retbleed= cmdline option.
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*/
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if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) {
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switch (spectre_v2_enabled) {
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case SPECTRE_V2_IBRS:
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retbleed_mitigation = RETBLEED_MITIGATION_IBRS;
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break;
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case SPECTRE_V2_EIBRS:
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case SPECTRE_V2_EIBRS_RETPOLINE:
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case SPECTRE_V2_EIBRS_LFENCE:
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retbleed_mitigation = RETBLEED_MITIGATION_EIBRS;
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break;
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default:
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pr_err(RETBLEED_INTEL_MSG);
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}
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}
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pr_info("%s\n", retbleed_strings[retbleed_mitigation]);
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}
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#undef pr_fmt
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#define pr_fmt(fmt) "Spectre V2 : " fmt
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static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =
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SPECTRE_V2_NONE;
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static enum spectre_v2_user_mitigation spectre_v2_user_stibp __ro_after_init =
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SPECTRE_V2_USER_NONE;
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static enum spectre_v2_user_mitigation spectre_v2_user_ibpb __ro_after_init =
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@ -1237,24 +1237,24 @@ static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
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VULNBL_INTEL_STEPPINGS(BROADWELL_G, X86_STEPPING_ANY, SRBDS),
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VULNBL_INTEL_STEPPINGS(BROADWELL_X, X86_STEPPING_ANY, MMIO),
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VULNBL_INTEL_STEPPINGS(BROADWELL, X86_STEPPING_ANY, SRBDS),
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VULNBL_INTEL_STEPPINGS(SKYLAKE_L, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO),
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VULNBL_INTEL_STEPPINGS(SKYLAKE_L, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO | RETBLEED),
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VULNBL_INTEL_STEPPINGS(SKYLAKE_L, X86_STEPPING_ANY, SRBDS),
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VULNBL_INTEL_STEPPINGS(SKYLAKE_X, BIT(3) | BIT(4) | BIT(6) |
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BIT(7) | BIT(0xB), MMIO),
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VULNBL_INTEL_STEPPINGS(SKYLAKE, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO),
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BIT(7) | BIT(0xB), MMIO | RETBLEED),
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VULNBL_INTEL_STEPPINGS(SKYLAKE, X86_STEPPINGS(0x3, 0x3), SRBDS | MMIO | RETBLEED),
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VULNBL_INTEL_STEPPINGS(SKYLAKE, X86_STEPPING_ANY, SRBDS),
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VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPINGS(0x9, 0xC), SRBDS | MMIO),
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VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPINGS(0x9, 0xC), SRBDS | MMIO | RETBLEED),
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VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPINGS(0x0, 0x8), SRBDS),
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VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPINGS(0x9, 0xD), SRBDS | MMIO),
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VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPINGS(0x9, 0xD), SRBDS | MMIO | RETBLEED),
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VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPINGS(0x0, 0x8), SRBDS),
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VULNBL_INTEL_STEPPINGS(ICELAKE_L, X86_STEPPINGS(0x5, 0x5), MMIO | MMIO_SBDS),
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VULNBL_INTEL_STEPPINGS(ICELAKE_L, X86_STEPPINGS(0x5, 0x5), MMIO | MMIO_SBDS | RETBLEED),
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VULNBL_INTEL_STEPPINGS(ICELAKE_D, X86_STEPPINGS(0x1, 0x1), MMIO),
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VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPINGS(0x4, 0x6), MMIO),
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VULNBL_INTEL_STEPPINGS(COMETLAKE, BIT(2) | BIT(3) | BIT(5), MMIO | MMIO_SBDS),
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VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
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VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x0), MMIO),
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VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
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VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPINGS(0x1, 0x1), MMIO),
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VULNBL_INTEL_STEPPINGS(COMETLAKE, BIT(2) | BIT(3) | BIT(5), MMIO | MMIO_SBDS | RETBLEED),
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VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS | RETBLEED),
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VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x0), MMIO | RETBLEED),
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VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS | RETBLEED),
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VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPINGS(0x1, 0x1), MMIO | RETBLEED),
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VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
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VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_D, X86_STEPPING_ANY, MMIO),
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VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPINGS(0x0, 0x0), MMIO | MMIO_SBDS),
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@ -1364,7 +1364,7 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
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!arch_cap_mmio_immune(ia32_cap))
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setup_force_cpu_bug(X86_BUG_MMIO_STALE_DATA);
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if (cpu_matches(cpu_vuln_blacklist, RETBLEED))
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if ((cpu_matches(cpu_vuln_blacklist, RETBLEED) || (ia32_cap & ARCH_CAP_RSBA)))
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setup_force_cpu_bug(X86_BUG_RETBLEED);
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if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN))
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