diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-system-cpu | 1 | ||||
| -rw-r--r-- | Documentation/admin-guide/hw-vuln/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst | 149 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 20 | ||||
| -rw-r--r-- | arch/x86/include/asm/cpufeatures.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/msr-index.h | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 106 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 56 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/cpu.h | 1 | ||||
| -rw-r--r-- | drivers/base/cpu.c | 8 | ||||
| -rw-r--r-- | kernel/events/uprobes.c | 16 |
11 files changed, 349 insertions, 15 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 77caf3ef82d3..b555df825447 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -486,6 +486,7 @@ What: /sys/devices/system/cpu/vulnerabilities /sys/devices/system/cpu/vulnerabilities/spec_store_bypass /sys/devices/system/cpu/vulnerabilities/l1tf /sys/devices/system/cpu/vulnerabilities/mds + /sys/devices/system/cpu/vulnerabilities/srbds /sys/devices/system/cpu/vulnerabilities/tsx_async_abort /sys/devices/system/cpu/vulnerabilities/itlb_multihit Date: January 2018 diff --git a/Documentation/admin-guide/hw-vuln/index.rst b/Documentation/admin-guide/hw-vuln/index.rst index 0795e3c2643f..ca4dbdd9016d 100644 --- a/Documentation/admin-guide/hw-vuln/index.rst +++ b/Documentation/admin-guide/hw-vuln/index.rst @@ -14,3 +14,4 @@ are configurable at compile, boot or run time. mds tsx_async_abort multihit.rst + special-register-buffer-data-sampling.rst diff --git a/Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst b/Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst new file mode 100644 index 000000000000..47b1b3afac99 --- /dev/null +++ b/Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst @@ -0,0 +1,149 @@ +.. SPDX-License-Identifier: GPL-2.0 + +SRBDS - Special Register Buffer Data Sampling +============================================= + +SRBDS is a hardware vulnerability that allows MDS :doc:`mds` techniques to +infer values returned from special register accesses. Special register +accesses are accesses to off core registers. According to Intel's evaluation, +the special register reads that have a security expectation of privacy are +RDRAND, RDSEED and SGX EGETKEY. + +When RDRAND, RDSEED and EGETKEY instructions are used, the data is moved +to the core through the special register mechanism that is susceptible +to MDS attacks. + +Affected processors +-------------------- +Core models (desktop, mobile, Xeon-E3) that implement RDRAND and/or RDSEED may +be affected. + +A processor is affected by SRBDS if its Family_Model and stepping is +in the following list, with the exception of the listed processors +exporting MDS_NO while Intel TSX is available yet not enabled. The +latter class of processors are only affected when Intel TSX is enabled +by software using TSX_CTRL_MSR otherwise they are not affected. + + ============= ============ ======== + common name Family_Model Stepping + ============= ============ ======== + IvyBridge 06_3AH All + + Haswell 06_3CH All + Haswell_L 06_45H All + Haswell_G 06_46H All + + Broadwell_G 06_47H All + Broadwell 06_3DH All + + Skylake_L 06_4EH All + Skylake 06_5EH All + + Kabylake_L 06_8EH <= 0xC + Kabylake 06_9EH <= 0xD + ============= ============ ======== + +Related CVEs +------------ + +The following CVE entry is related to this SRBDS issue: + + ============== ===== ===================================== + CVE-2020-0543 SRBDS Special Register Buffer Data Sampling + ============== ===== ===================================== + +Attack scenarios +---------------- +An unprivileged user can extract values returned from RDRAND and RDSEED +executed on another core or sibling thread using MDS techniques. + + +Mitigation mechanism +------------------- +Intel will release microcode updates that modify the RDRAND, RDSEED, and +EGETKEY instructions to overwrite secret special register data in the shared +staging buffer before the secret data can be accessed by another logical +processor. + +During execution of the RDRAND, RDSEED, or EGETKEY instructions, off-core +accesses from other logical processors will be delayed until the special +register read is complete and the secret data in the shared staging buffer is +overwritten. + +This has three effects on performance: + +#. RDRAND, RDSEED, or EGETKEY instructions have higher latency. + +#. Executing RDRAND at the same time on multiple logical processors will be + serialized, resulting in an overall reduction in the maximum RDRAND + bandwidth. + +#. Executing RDRAND, RDSEED or EGETKEY will delay memory accesses from other + logical processors that miss their core caches, with an impact similar to + legacy locked cache-line-split accesses. + +The microcode updates provide an opt-out mechanism (RNGDS_MITG_DIS) to disable +the mitigation for RDRAND and RDSEED instructions executed outside of Intel +Software Guard Extensions (Intel SGX) enclaves. On logical processors that +disable the mitigation using this opt-out mechanism, RDRAND and RDSEED do not +take longer to execute and do not impact performance of sibling logical +processors memory accesses. The opt-out mechanism does not affect Intel SGX +enclaves (including execution of RDRAND or RDSEED inside an enclave, as well +as EGETKEY execution). + +IA32_MCU_OPT_CTRL MSR Definition +-------------------------------- +Along with the mitigation for this issue, Intel added a new thread-scope +IA32_MCU_OPT_CTRL MSR, (address 0x123). The presence of this MSR and +RNGDS_MITG_DIS (bit 0) is enumerated by CPUID.(EAX=07H,ECX=0).EDX[SRBDS_CTRL = +9]==1. This MSR is introduced through the microcode update. + +Setting IA32_MCU_OPT_CTRL[0] (RNGDS_MITG_DIS) to 1 for a logical processor +disables the mitigation for RDRAND and RDSEED executed outside of an Intel SGX +enclave on that logical processor. Opting out of the mitigation for a +particular logical processor does not affect the RDRAND and RDSEED mitigations +for other logical processors. + +Note that inside of an Intel SGX enclave, the mitigation is applied regardless +of the value of RNGDS_MITG_DS. + +Mitigation control on the kernel command line +--------------------------------------------- +The kernel command line allows control over the SRBDS mitigation at boot time +with the option "srbds=". The option for this is: + + ============= ============================================================= + off This option disables SRBDS mitigation for RDRAND and RDSEED on + affected platforms. + ============= ============================================================= + +SRBDS System Information +----------------------- +The Linux kernel provides vulnerability status information through sysfs. For +SRBDS this can be accessed by the following sysfs file: +/sys/devices/system/cpu/vulnerabilities/srbds + +The possible values contained in this file are: + + ============================== ============================================= + Not affected Processor not vulnerable + Vulnerable Processor vulnerable and mitigation disabled + Vulnerable: No microcode Processor vulnerable and microcode is missing + mitigation + Mitigation: Microcode Processor is vulnerable and mitigation is in + effect. + Mitigation: TSX disabled Processor is only vulnerable when TSX is + enabled while this system was booted with TSX + disabled. + Unknown: Dependent on + hypervisor status Running on virtual guest processor that is + affected but with no way to know if host + processor is mitigated or vulnerable. + ============================== ============================================= + +SRBDS Default mitigation +------------------------ +This new microcode serializes processor access during execution of RDRAND, +RDSEED ensures that the shared buffer is overwritten before it is released for +reuse. Use the "srbds=off" kernel command line to disable the mitigation for +RDRAND and RDSEED. diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 746030ae3b12..fb95fad81c79 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4837,6 +4837,26 @@ the kernel will oops in either "warn" or "fatal" mode. + srbds= [X86,INTEL] + Control the Special Register Buffer Data Sampling + (SRBDS) mitigation. + + Certain CPUs are vulnerable to an MDS-like + exploit which can leak bits from the random + number generator. + + By default, this issue is mitigated by + microcode. However, the microcode fix can cause + the RDRAND and RDSEED instructions to become + much slower. Among other effects, this will + result in reduced throughput from /dev/urandom. + + The microcode mitigation can be disabled with + the following option: + + off: Disable mitigation and remove + performance impact to RDRAND and RDSEED + srcutree.counter_wrap_check [KNL] Specifies how frequently to check for grace-period sequence counter wrap for the diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index db189945e9b0..02dabc9e77b0 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -362,6 +362,7 @@ #define X86_FEATURE_AVX512_4FMAPS (18*32+ 3) /* AVX-512 Multiply Accumulation Single precision */ #define X86_FEATURE_FSRM (18*32+ 4) /* Fast Short Rep Mov */ #define X86_FEATURE_AVX512_VP2INTERSECT (18*32+ 8) /* AVX-512 Intersect for D/Q */ +#define X86_FEATURE_SRBDS_CTRL (18*32+ 9) /* "" SRBDS mitigation MSR available */ #define X86_FEATURE_MD_CLEAR (18*32+10) /* VERW clears CPU buffers */ #define X86_FEATURE_TSX_FORCE_ABORT (18*32+13) /* "" TSX_FORCE_ABORT */ #define X86_FEATURE_PCONFIG (18*32+18) /* Intel PCONFIG */ @@ -407,5 +408,6 @@ #define X86_BUG_SWAPGS X86_BUG(21) /* CPU is affected by speculation through SWAPGS */ #define X86_BUG_TAA X86_BUG(22) /* CPU is affected by TSX Async Abort(TAA) */ #define X86_BUG_ITLB_MULTIHIT X86_BUG(23) /* CPU may incur MCE during certain page attribute changes */ +#define X86_BUG_SRBDS X86_BUG(24) /* CPU may leak RNG bits if not mitigated */ #endif /* _ASM_X86_CPUFEATURES_H */ diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index ef452b817f44..e8370e64a155 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -128,6 +128,10 @@ #define TSX_CTRL_RTM_DISABLE BIT(0) /* Disable RTM feature */ #define TSX_CTRL_CPUID_CLEAR BIT(1) /* Disable TSX enumeration */ +/* SRBDS support */ +#define MSR_IA32_MCU_OPT_CTRL 0x00000123 +#define RNGDS_MITG_DIS BIT(0) + #define MSR_IA32_SYSENTER_CS 0x00000174 #define MSR_IA32_SYSENTER_ESP 0x00000175 #define MSR_IA32_SYSENTER_EIP 0x00000176 diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index c901b086bbdb..b6f887be440c 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -41,6 +41,7 @@ static void __init l1tf_select_mitigation(void); static void __init mds_select_mitigation(void); static void __init mds_print_mitigation(void); static void __init taa_select_mitigation(void); +static void __init srbds_select_mitigation(void); /* The base value of the SPEC_CTRL MSR that always has to be preserved. */ u64 x86_spec_ctrl_base; @@ -108,6 +109,7 @@ void __init check_bugs(void) l1tf_select_mitigation(); mds_select_mitigation(); taa_select_mitigation(); + srbds_select_mitigation(); /* * As MDS and TAA mitigations are inter-related, print MDS @@ -398,6 +400,97 @@ static int __init tsx_async_abort_parse_cmdline(char *str) early_param("tsx_async_abort", tsx_async_abort_parse_cmdline); #undef pr_fmt +#define pr_fmt(fmt) "SRBDS: " fmt + +enum srbds_mitigations { + SRBDS_MITIGATION_OFF, + SRBDS_MITIGATION_UCODE_NEEDED, + SRBDS_MITIGATION_FULL, + SRBDS_MITIGATION_TSX_OFF, + SRBDS_MITIGATION_HYPERVISOR, +}; + +static enum srbds_mitigations srbds_mitigation __ro_after_init = SRBDS_MITIGATION_FULL; + +static const char * const srbds_strings[] = { + [SRBDS_MITIGATION_OFF] = "Vulnerable", + [SRBDS_MITIGATION_UCODE_NEEDED] = "Vulnerable: No microcode", + [SRBDS_MITIGATION_FULL] = "Mitigation: Microcode", + [SRBDS_MITIGATION_TSX_OFF] = "Mitigation: TSX disabled", + [SRBDS_MITIGATION_HYPERVISOR] = "Unknown: Dependent on hypervisor status", +}; + +static bool srbds_off; + +void update_srbds_msr(void) +{ + u64 mcu_ctrl; + + if (!boot_cpu_has_bug(X86_BUG_SRBDS)) + return; + + if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) + return; + + if (srbds_mitigation == SRBDS_MITIGATION_UCODE_NEEDED) + return; + + rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl); + + switch (srbds_mitigation) { + case SRBDS_MITIGATION_OFF: + case SRBDS_MITIGATION_TSX_OFF: + mcu_ctrl |= RNGDS_MITG_DIS; + break; + case SRBDS_MITIGATION_FULL: + mcu_ctrl &= ~RNGDS_MITG_DIS; + break; + default: + break; + } + + wrmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl); +} + +static void __init srbds_select_mitigation(void) +{ + u64 ia32_cap; + + if (!boot_cpu_has_bug(X86_BUG_SRBDS)) + return; + + /* + * Check to see if this is one of the MDS_NO systems supporting + * TSX that are only exposed to SRBDS when TSX is enabled. + */ + ia32_cap = x86_read_arch_cap_msr(); + if ((ia32_cap & ARCH_CAP_MDS_NO) && !boot_cpu_has(X86_FEATURE_RTM)) + srbds_mitigation = SRBDS_MITIGATION_TSX_OFF; + else if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) + srbds_mitigation = SRBDS_MITIGATION_HYPERVISOR; + else if (!boot_cpu_has(X86_FEATURE_SRBDS_CTRL)) + srbds_mitigation = SRBDS_MITIGATION_UCODE_NEEDED; + else if (cpu_mitigations_off() || srbds_off) + srbds_mitigation = SRBDS_MITIGATION_OFF; + + update_srbds_msr(); + pr_info("%s\n", srbds_strings[srbds_mitigation]); +} + +static int __init srbds_parse_cmdline(char *str) +{ + if (!str) + return -EINVAL; + + if (!boot_cpu_has_bug(X86_BUG_SRBDS)) + return 0; + + srbds_off = !strcmp(str, "off"); + return 0; +} +early_param("srbds", srbds_parse_cmdline); + +#undef pr_fmt #define pr_fmt(fmt) "Spectre V1 : " fmt enum spectre_v1_mitigation { @@ -1528,6 +1621,11 @@ static char *ibpb_state(void) return ""; } +static ssize_t srbds_show_state(char *buf) +{ + return sprintf(buf, "%s\n", srbds_strings[srbds_mitigation]); +} + static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr, char *buf, unsigned int bug) { @@ -1572,6 +1670,9 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr case X86_BUG_ITLB_MULTIHIT: return itlb_multihit_show_state(buf); + case X86_BUG_SRBDS: + return srbds_show_state(buf); + default: break; } @@ -1618,4 +1719,9 @@ ssize_t cpu_show_itlb_multihit(struct device *dev, struct device_attribute *attr { return cpu_show_common(dev, attr, buf, X86_BUG_ITLB_MULTIHIT); } + +ssize_t cpu_show_srbds(struct device *dev, struct device_attribute *attr, char *buf) +{ + return cpu_show_common(dev, attr, buf, X86_BUG_SRBDS); +} #endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index b367df8f54e7..8be042df12c3 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1073,9 +1073,30 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = { {} }; -static bool __init cpu_matches(unsigned long which) +#define VULNBL_INTEL_STEPPINGS(model, steppings, issues) \ + X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(INTEL, 6, \ + INTEL_FAM6_##model, steppings, \ + X86_FEATURE_ANY, issues) + +#define SRBDS BIT(0) + +static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = { + VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS), + VULNBL_INTEL_STEPPINGS(HASWELL, X86_STEPPING_ANY, SRBDS), + VULNBL_INTEL_STEPPINGS(HASWELL_L, X86_STEPPING_ANY, SRBDS), + VULNBL_INTEL_STEPPINGS(HASWELL_G, X86_STEPPING_ANY, SRBDS), + VULNBL_INTEL_STEPPINGS(BROADWELL_G, X86_STEPPING_ANY, SRBDS), + VULNBL_INTEL_STEPPINGS(BROADWELL, X86_STEPPING_ANY, SRBDS), + VULNBL_INTEL_STEPPINGS(SKYLAKE_L, X86_STEPPING_ANY, SRBDS), + VULNBL_INTEL_STEPPINGS(SKYLAKE, X86_STEPPING_ANY, SRBDS), + VULNBL_INTEL_STEPPINGS(KABYLAKE_L, X86_STEPPINGS(0x0, 0xC), SRBDS), + VULNBL_INTEL_STEPPINGS(KABYLAKE, X86_STEPPINGS(0x0, 0xD), SRBDS), + {} +}; + +static bool __init cpu_matches(const struct x86_cpu_id *table, unsigned long which) { - const struct x86_cpu_id *m = x86_match_cpu(cpu_vuln_whitelist); + const struct x86_cpu_id *m = x86_match_cpu(table); return m && !!(m->driver_data & which); } @@ -1095,31 +1116,34 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) u64 ia32_cap = x86_read_arch_cap_msr(); /* Set ITLB_MULTIHIT bug if cpu is not in the whitelist and not mitigated */ - if (!cpu_matches(NO_ITLB_MULTIHIT) && !(ia32_cap & ARCH_CAP_PSCHANGE_MC_NO)) + if (!cpu_matches(cpu_vuln_whitelist, NO_ITLB_MULTIHIT) && + !(ia32_cap & ARCH_CAP_PSCHANGE_MC_NO)) setup_force_cpu_bug(X86_BUG_ITLB_MULTIHIT); - if (cpu_matches(NO_SPECULATION)) + if (cpu_matches(cpu_vuln_whitelist, NO_SPECULATION)) return; setup_force_cpu_bug(X86_BUG_SPECTRE_V1); - if (!cpu_matches(NO_SPECTRE_V2)) + if (!cpu_matches(cpu_vuln_whitelist, NO_SPECTRE_V2)) setup_force_cpu_bug(X86_BUG_SPECTRE_V2); - if (!cpu_matches(NO_SSB) && !(ia32_cap & ARCH_CAP_SSB_NO) && + if (!cpu_matches(cpu_vuln_whitelist, NO_SSB) && + !(ia32_cap & ARCH_CAP_SSB_NO) && !cpu_has(c, X86_FEATURE_AMD_SSB_NO)) setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS); if (ia32_cap & ARCH_CAP_IBRS_ALL) setup_force_cpu_cap(X86_FEATURE_IBRS_ENHANCED); - if (!cpu_matches(NO_MDS) && !(ia32_cap & ARCH_CAP_MDS_NO)) { + if (!cpu_matches(cpu_vuln_whitelist, NO_MDS) && + !(ia32_cap & ARCH_CAP_MDS_NO)) { setup_force_cpu_bug(X86_BUG_MDS); - if (cpu_matches(MSBDS_ONLY)) + if (cpu_matches(cpu_vuln_whitelist, MSBDS_ONLY)) setup_force_cpu_bug(X86_BUG_MSBDS_ONLY); } - if (!cpu_matches(NO_SWAPGS)) + if (!cpu_matches(cpu_vuln_whitelist, NO_SWAPGS)) setup_force_cpu_bug(X86_BUG_SWAPGS); /* @@ -1137,7 +1161,16 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) (ia32_cap & ARCH_CAP_TSX_CTRL_MSR))) setup_force_cpu_bug(X86_BUG_TAA); - if (cpu_matches(NO_MELTDOWN)) + /* + * SRBDS affects CPUs which support RDRAND or RDSEED and are listed + * in the vulnerability blacklist. + */ + if ((cpu_has(c, X86_FEATURE_RDRAND) || + cpu_has(c, X86_FEATURE_RDSEED)) && + cpu_matches(cpu_vuln_blacklist, SRBDS)) + setup_force_cpu_bug(X86_BUG_SRBDS); + + if (cpu_matches(cpu_vuln_whitelist, NO_MELTDOWN)) return; /* Rogue Data Cache Load? No! */ @@ -1146,7 +1179,7 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN); - if (cpu_matches(NO_L1TF)) + if (cpu_matches(cpu_vuln_whitelist, NO_L1TF)) return; setup_force_cpu_bug(X86_BUG_L1TF); @@ -1574,6 +1607,7 @@ void identify_secondary_cpu(struct cpuinfo_x86 *c) mtrr_ap_init(); validate_apic_and_package_id(c); x86_spec_ctrl_setup_ap(); + update_srbds_msr(); } static __init int setup_noclflush(char *arg) diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h index 37fdefd14f28..fb538fccd24c 100644 --- a/arch/x86/kernel/cpu/cpu.h +++ b/arch/x86/kernel/cpu/cpu.h @@ -77,6 +77,7 @@ extern void detect_ht(struct cpuinfo_x86 *c); unsigned int aperfmperf_get_khz(int cpu); extern void x86_spec_ctrl_setup_ap(void); +extern void update_srbds_msr(void); extern u64 x86_read_arch_cap_msr(void); diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 9a1c00fbbaef..d2136ab9b14a 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -562,6 +562,12 @@ ssize_t __weak cpu_show_itlb_multihit(struct device *dev, return sprintf(buf, "Not affected\n"); } +ssize_t __weak cpu_show_srbds(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "Not affected\n"); +} + static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL); static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL); static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL); @@ -570,6 +576,7 @@ static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL); static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL); static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL); static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL); +static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL); static struct attribute *cpu_root_vulnerabilities_attrs[] = { &dev_attr_meltdown.attr, @@ -580,6 +587,7 @@ static struct attribute *cpu_root_vulnerabilities_attrs[] = { &dev_attr_mds.attr, &dev_attr_tsx_async_abort.attr, &dev_attr_itlb_multihit.attr, + &dev_attr_srbds.attr, NULL }; diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 4f4993dcf17a..bb0862873dba 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -861,10 +861,6 @@ static int prepare_uprobe(struct uprobe *uprobe, struct file *file, if (ret) goto out; - /* uprobe_write_opcode() assumes we don't cross page boundary */ - BUG_ON((uprobe->offset & ~PAGE_MASK) + - UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); - smp_wmb(); /* pairs with the smp_rmb() in handle_swbp() */ set_bit(UPROBE_COPY_INSN, &uprobe->flags); @@ -1160,6 +1156,15 @@ static int __uprobe_register(struct inode *inode, loff_t offset, if (offset > i_size_read(inode)) return -EINVAL; + /* + * This ensures that copy_from_page(), copy_to_page() and + * __update_ref_ctr() can't cross page boundary. + */ + if (!IS_ALIGNED(offset, UPROBE_SWBP_INSN_SIZE)) + return -EINVAL; + if (!IS_ALIGNED(ref_ctr_offset, sizeof(short))) + return -EINVAL; + retry: uprobe = alloc_uprobe(inode, offset, ref_ctr_offset); if (!uprobe) @@ -2008,6 +2013,9 @@ static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr) uprobe_opcode_t opcode; int result; + if (WARN_ON_ONCE(!IS_ALIGNED(vaddr, UPROBE_SWBP_INSN_SIZE))) + return -EINVAL; + pagefault_disable(); result = __get_user(opcode, (uprobe_opcode_t __user *)vaddr); pagefault_enable(); |