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HistoryJan 04, 2018 - 12:19 p.m.

Security update for the Linux Kernel (important)


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The SUSE Linux Enterprise 12 SP2 kernel was updated to receive various
security and bugfixes.

This update adds mitigations for various side channel attacks against
modern CPUs that could disclose content of otherwise unreadable memory

  • CVE-2017-5753 / "SpecŧreAttack": Local attackers on systems with modern
    CPUs featuring deep instruction pipelining could use attacker
    controllable speculative execution over code patterns in the Linux
    Kernel to leak content from otherwise not readable memory in the same
    address space, allowing retrieval of passwords, cryptographic keys and
    other secrets.

    This problem is mitigated by adding speculative fencing on affected code
    paths throughout the Linux kernel.

  • CVE-2017-5715 / "SpectreAttack": Local attackers on systems with modern
    CPUs featuring branch prediction could use mispredicted branches to
    speculatively execute code patterns that in turn could be made to leak
    other non-readable content in the same address space, an attack similar
    to CVE-2017-5753.

    This problem is mitigated by disabling predictive branches, depending
    on CPU architecture either by firmware updates and/or fixes in the
    user-kernel privilege boundaries.

    Please also check with your CPU / Hardware vendor on updated firmware
    or BIOS images regarding this issue.

    As this feature can have a performance impact, it can be disabled using
    the "nospec" kernel commandline option.

  • CVE-2017-5754 / "MeltdownAttack": Local attackers on systems with modern
    CPUs featuring deep instruction pipelining could use code patterns in
    userspace to speculative executive code that would read
    otherwise read protected memory, an attack similar to CVE-2017-5753.

    This problem is mitigated by unmapping the Linux Kernel from the user
    address space during user code execution, following a approach called
    "KAISER". The terms used here are "KAISER" / "Kernel Address Isolation"
    and "PTI" / "Page Table Isolation".

    Note that this is only done on affected platforms.

    This feature can be enabled / disabled by the "pti=[on|off|auto]" or
    "nopti" commandline options.

Also the following unrelated security bugs were fixed:

  • CVE-2017-17806: The HMAC implementation (crypto/hmac.c) in the Linux
    kernel did not validate that the underlying cryptographic hash algorithm
    is unkeyed, allowing a local attacker able to use the AF_ALG-based hash
    interface (CONFIG_CRYPTO_USER_API_HASH) and the SHA-3 hash algorithm
    (CONFIG_CRYPTO_SHA3) to cause a kernel stack buffer overflow by
    executing a crafted sequence of system calls that encounter a missing
    SHA-3 initialization (bnc#1073874).
  • CVE-2017-17805: The Salsa20 encryption algorithm in the Linux kernel did
    not correctly handle zero-length inputs, allowing a local attacker able
    to use the AF_ALG-based skcipher interface
    (CONFIG_CRYPTO_USER_API_SKCIPHER) to cause a denial of service
    (uninitialized-memory free and kernel crash) or have unspecified other
    impact by executing a crafted sequence of system calls that use the
    blkcipher_walk API. Both the generic implementation
    (crypto/salsa20_generic.c) and x86 implementation
    (arch/x86/crypto/salsa20_glue.c) of Salsa20 were vulnerable

The following non-security bugs were fixed:

  • Add undefine _unique_build_ids (bsc#964063)
  • Always sign validate_negotiate_info reqs (bsc#1071009, fate#324404).
  • apei / ERST: Fix missing error handling in erst_reader() (bsc#1072556).
  • arm: Hide finish_arch_post_lock_switch() from modules (bsc#1068032).
  • autofs: fix careless error in recent commit (bnc#1012382 bsc#1065180).
  • bpf: prevent speculative execution in eBPF interpreter (bnc#1068032).
  • carl9170: prevent speculative execution (bnc#1068032).
  • Check cmdline_find_option() retval properly and use boot_cpu_has().
  • cw1200: prevent speculative execution (bnc#1068032).
  • e1000e: Avoid receiver overrun interrupt bursts (bsc#969470 FATE#319819).
  • e1000e: Fix e1000_check_for_copper_link_ich8lan return value
  • Fix leak of validate_negotiate_info resp (bsc#1071009, fate#324404).
  • Fix NULL pointer deref in SMB2_tcon() (bsc#1071009, fate#324404).
  • Fix validate_negotiate_info uninitialized mem (bsc#1071009, fate#324404).
  • fs: prevent speculative execution (bnc#1068032).
  • genwqe: Take R/W permissions into account when dealing with memory pages
  • ibmvnic: Include header descriptor support for ARP packets (bsc#1073912).
  • ibmvnic: Increase maximum number of RX/TX queues (bsc#1073912).
  • ipv6: prevent speculative execution (bnc#1068032).
  • kaiser: add "nokaiser" boot option, using ALTERNATIVE.
  • kaiser: align addition to x86/mm/Makefile.
  • kaiser: asm/tlbflush.h handle noPGE at lower level.
  • kaiser: cleanups while trying for gold link.
  • kaiser: Disable on Xen PV.
  • kaiser: do not set _PAGE_NX on pgd_none.
  • kaiser: drop is_atomic arg to kaiser_pagetable_walk().
  • kaiser: enhanced by kernel and user PCIDs.
  • kaiser: ENOMEM if kaiser_pagetable_walk() NULL.
  • kaiser: fix build and FIXME in alloc_ldt_struct().
  • kaiser: fix perf crashes.
  • kaiser: fix regs to do_nmi() ifndef CONFIG_KAISER.
  • kaiser: fix unlikely error in alloc_ldt_struct().
  • kaiser: KAISER depends on SMP.
  • kaiser: kaiser_flush_tlb_on_return_to_user() check PCID.
  • kaiser: kaiser_remove_mapping() move along the pgd.
  • kaiser: Kernel Address Isolation.
  • kaiser: load_new_mm_cr3() let SWITCH_USER_CR3 flush.
  • kaiser: load_new_mm_cr3() let SWITCH_USER_CR3 flush user.
  • kaiser: name that 0x1000 KAISER_SHADOW_PGD_OFFSET.
  • kaiser: paranoid_entry pass cr3 need to paranoid_exit.
  • kaiser: PCID 0 for kernel and 128 for user.
  • kaiser: _pgd_alloc() without __GFP_REPEAT to avoid stalls.
  • kaiser: stack map PAGE_SIZE at THREAD_SIZE-PAGE_SIZE.
  • kaiser: tidied up asm/kaiser.h somewhat.
  • kaiser: tidied up kaiser_add/remove_mapping slightly.
  • kaiser: use ALTERNATIVE instead of x86_cr3_pcid_noflush.
  • kaiser: vmstat show NR_KAISERTABLE as nr_overhead.
  • kaiser: x86_cr3_pcid_noflush and x86_cr3_pcid_user.
  • kvm: SVM: Do not intercept new speculative control MSRs (bsc#1068032).
  • kvm: x86: Add speculative control CPUID support for guests (bsc#1068032).
  • locking/barriers: introduce new memory barrier gmb() (bnc#1068032).
  • mm/mmu_context, sched/core: Fix mmu_context.h assumption (bsc#1068032).
  • net: mpls: prevent speculative execution (bnc#1068032).
  • nfs: revalidate "." etc correctly on "open" (bsc#1068951).
  • nfs: revalidate "." etc correctly on "open" (git-fixes). Fix References
  • nfsv4: always set NFS_LOCK_LOST when a lock is lost (bsc#1068951).
  • p54: prevent speculative execution (bnc#1068032).
  • powerpc/barrier: add gmb.
  • powerpc: Secure memory rfi flush (bsc#1068032).
  • ptrace: Add a new thread access check (bsc#1068032).
  • qla2xxx: prevent speculative execution (bnc#1068032).
  • Redo encryption backport to fix pkt signing (bsc#1071009, fate#324404).
  • s390: add ppa to system call and program check path (bsc#1068032).
  • s390: introduce CPU alternatives.
  • s390: introduce CPU alternatives (bsc#1068032).
  • s390/spinlock: add gmb memory barrier
  • s390/spinlock: add gmb memory barrier (bsc#1068032).
  • s390/spinlock: add ppa to system call path Signoff the s390 patches.
  • sched/core: Add switch_mm_irqs_off() and use it in the scheduler
  • sched/core: Idle_task_exit() shouldn’t use switch_mm_irqs_off()
  • scsi_dh_alua: skip RTPG for devices only supporting active/optimized
  • scsi_scan: Exit loop if TUR to LUN0 fails with 0x05/0x25 (bsc#1063043).
    This is specific to FUJITSU ETERNUS_DX* targets. They can return
    "Illegal Request - Logical unit not supported" and processing should
    leave the timeout loop in this case.
  • scsi: ses: check return code from ses_recv_diag() (bsc#1039616).
  • scsi: ses: Fixup error message ‘failed to get diagnostic page
    0xffffffea’ (bsc#1039616).
  • scsi: ses: Fix wrong page error (bsc#1039616).
  • scsi: ses: make page2 support optional (bsc#1039616).
  • Thermal/int340x: prevent speculative execution (bnc#1068032).
  • udf: prevent speculative execution (bnc#1068032).
  • Update config files: enable KAISER.
  • usb: host: fix incorrect updating of offset (bsc#1047487).
  • userns: prevent speculative execution (bnc#1068032).
  • uvcvideo: prevent speculative execution (bnc#1068032).
  • vxlan: correctly handle ipv6.disable module parameter (bsc#1072962).
  • x86/boot: Add early cmdline parsing for options with arguments.
  • x86/CPU/AMD: Add speculative control support for AMD (bsc#1068032).
  • x86/CPU/AMD: Make the LFENCE instruction serialized (bsc#1068032).
  • x86/CPU/AMD: Remove now unused definition of MFENCE_RDTSC feature
  • x86/CPU: Check speculation control CPUID bit (bsc#1068032).
  • x86/enter: Add macros to set/clear IBRS and set IBPB (bsc#1068032).
  • x86/entry: Add a function to overwrite the RSB (bsc#1068032).
  • x86/entry: Stuff RSB for entry to kernel for non-SMEP platform
  • x86/entry: Use IBRS on entry to kernel space (bsc#1068032).
  • x86/feature: Enable the x86 feature to control Speculation (bsc#1068032).
  • x86/idle: Disable IBRS when offlining a CPU and re-enable on wakeup
  • x86/idle: Toggle IBRS when going idle (bsc#1068032).
  • x86/kaiser: Check boottime cmdline params.
  • x86/kaiser: Move feature detection up (bsc#1068032).
  • x86/kaiser: Reenable PARAVIRT.
  • x86/kaiser: Rename and simplify X86_FEATURE_KAISER handling.
  • x86/kvm: Add MSR_IA32_SPEC_CTRL and MSR_IA32_PRED_CMD to kvm
  • x86/kvm: Flush IBP when switching VMs (bsc#1068032).
  • x86/kvm: Pad RSB on VM transition (bsc#1068032).
  • x86/kvm: Toggle IBRS on VM entry and exit (bsc#1068032).
  • x86/mm/64: Fix reboot interaction with CR4.PCIDE (bsc#1068032).
  • x86/mm: Add a ‘noinvpcid’ boot option to turn off INVPCID (bsc#1068032).
  • x86/mm: Add INVPCID helpers (bsc#1068032).
  • x86/mm: Add the ‘nopcid’ boot option to turn off PCID (bsc#1068032).
  • x86/mm: Build arch/x86/mm/tlb.c even on !SMP (bsc#1068032).
  • x86/mm: Enable CR4.PCIDE on supported systems (bsc#1068032).
  • x86/mm: Fix INVPCID asm constraint (bsc#1068032).
  • x86/mm: If INVPCID is available, use it to flush global mappings
  • x86/mm: Make flush_tlb_mm_range() more predictable (bsc#1068032).
  • x86/mm: Only set IBPB when the new thread cannot ptrace current thread
  • x86/mm: Reimplement flush_tlb_page() using flush_tlb_mm_range()
  • x86/mm: Remove flush_tlb() and flush_tlb_current_task() (bsc#1068032).
  • x86/mm: Remove the UP asm/tlbflush.h code, always use the (formerly) SMP
    code (bsc#1068032).
  • x86/mm, sched/core: Turn off IRQs in switch_mm() (bsc#1068032).
  • x86/mm, sched/core: Uninline switch_mm() (bsc#1068032).
  • x86/mm: Set IBPB upon context switch (bsc#1068032).
  • x86/MSR: Move native_*msr(… u64) to msr.h (bsc#1068032).
  • x86/paravirt: Dont patch flush_tlb_single (bsc#1068032).
  • x86/spec: Add IBRS control functions (bsc#1068032).
  • x86/spec: Add "nospec" chicken bit (bsc#1068032).
  • x86/spec: Check CPUID direclty post microcode reload to support IBPB
    feature (bsc#1068032).
  • x86/spec_ctrl: Add an Indirect Branch Predictor barrier (bsc#1068032).
  • x86/spec_ctrl: Check whether IBPB is enabled before using it
  • x86/spec_ctrl: Check whether IBRS is enabled before using it
  • x86/svm: Add code to clear registers on VM exit (bsc#1068032).
  • x86/svm: Clobber the RSB on VM exit (bsc#1068032).
  • x86/svm: Set IBPB when running a different VCPU (bsc#1068032).
  • x86/svm: Set IBRS value on VM entry and exit (bsc#1068032).