ID

VAR-201704-1397

CVE

CVE-2017-7895

TITLE

Linux Kernel CVE-2017-7895 Multiple Security Bypass Vulnerabilities

DESCRIPTION

The NFSv2 and NFSv3 server implementations in the Linux kernel through 4.10.13 lack certain checks for the end of a buffer, which allows remote attackers to trigger pointer-arithmetic errors or possibly have unspecified other impact via crafted requests, related to fs/nfsd/nfs3xdr.c and fs/nfsd/nfsxdr.c. Linux Kernel is prone to multiple security-bypass vulnerabilities. Attackers can exploit these issues to bypass certain security restrictions and perform unauthorized actions. This may aid in further attacks. -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ===================================================================== Red Hat Security Advisory Synopsis: Important: kernel security and bug fix update Advisory ID: RHSA-2017:1766-01 Product: Red Hat Enterprise Linux Advisory URL: https://access.redhat.com/errata/RHSA-2017:1766 Issue date: 2017-07-18 CVE Names: CVE-2017-7895 ===================================================================== 1. Summary: An update for kernel is now available for Red Hat Enterprise Linux 7.2 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. 2. Relevant releases/architectures: Red Hat Enterprise Linux ComputeNode EUS (v. 7.2) - noarch, x86_64 Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.2) - x86_64 Red Hat Enterprise Linux Server EUS (v. 7.2) - noarch, ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Server Optional EUS (v. 7.2) - ppc64, ppc64le, x86_64 3. (CVE-2017-7895, Important) Red Hat would like to thank Ari Kauppi for reporting this issue. Bug Fix(es): * Previously, a race condition between Linux kernel module error handling and kprobe registration code existed in the Linux kernel. The protection that was applied during module error handling code could be overridden by kprobe registration code before the module was deallocated. Consequently, the mapped page could be freed and become not 'writable'. When this page was later accessed, a page fault occurred, which led to a kernel panic. This update fixes the race condition, and the kernel no longer panics due to this bug. (BZ#1454683) * Due to a race with another NFS mount, the nfs41_walk_client_list() function previously established a lease on the nfs_client pointer before the check for trunking was finished. This update ensures the processes follow the correct order and the race no longer occurs in this scenario. (BZ#1447383) * If a duplicate IPv6 address or an issue setting an address was present in the net/ipv6/addrconf.c file, a race condition occurred that could cause an IFP refcount leak. Attempts to unregister a netdevice then produced "Unregister Netdevice Failed" error messages. The provided patch fixes this bug, and race conditions no longer occur in this situation. (BZ#1449103) * Previously, subtracting from vCPU threads could cause a steal_time overflow on QEMU live migration. This update makes sure steal_time accumulation to vCPU entry time is moved before copying steal_time data to QEMU guest, thus fixing this bug. (BZ#1274919) 4. Solution: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. 5. Bugs fixed (https://bugzilla.redhat.com/): 1446103 - CVE-2017-7895 kernel: NFSv3 server does not properly handle payload bounds checking of WRITE requests 6. Package List: Red Hat Enterprise Linux ComputeNode EUS (v. 7.2): Source: kernel-3.10.0-327.58.1.el7.src.rpm noarch: kernel-abi-whitelists-3.10.0-327.58.1.el7.noarch.rpm kernel-doc-3.10.0-327.58.1.el7.noarch.rpm x86_64: kernel-3.10.0-327.58.1.el7.x86_64.rpm kernel-debug-3.10.0-327.58.1.el7.x86_64.rpm kernel-debug-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-debug-devel-3.10.0-327.58.1.el7.x86_64.rpm kernel-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-debuginfo-common-x86_64-3.10.0-327.58.1.el7.x86_64.rpm kernel-devel-3.10.0-327.58.1.el7.x86_64.rpm kernel-headers-3.10.0-327.58.1.el7.x86_64.rpm kernel-tools-3.10.0-327.58.1.el7.x86_64.rpm kernel-tools-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-tools-libs-3.10.0-327.58.1.el7.x86_64.rpm perf-3.10.0-327.58.1.el7.x86_64.rpm perf-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm python-perf-3.10.0-327.58.1.el7.x86_64.rpm python-perf-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.2): x86_64: kernel-debug-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-debuginfo-common-x86_64-3.10.0-327.58.1.el7.x86_64.rpm kernel-tools-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-tools-libs-devel-3.10.0-327.58.1.el7.x86_64.rpm perf-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm python-perf-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm Red Hat Enterprise Linux Server EUS (v. 7.2): Source: kernel-3.10.0-327.58.1.el7.src.rpm noarch: kernel-abi-whitelists-3.10.0-327.58.1.el7.noarch.rpm kernel-doc-3.10.0-327.58.1.el7.noarch.rpm ppc64: kernel-3.10.0-327.58.1.el7.ppc64.rpm kernel-bootwrapper-3.10.0-327.58.1.el7.ppc64.rpm kernel-debug-3.10.0-327.58.1.el7.ppc64.rpm kernel-debug-debuginfo-3.10.0-327.58.1.el7.ppc64.rpm kernel-debug-devel-3.10.0-327.58.1.el7.ppc64.rpm kernel-debuginfo-3.10.0-327.58.1.el7.ppc64.rpm kernel-debuginfo-common-ppc64-3.10.0-327.58.1.el7.ppc64.rpm kernel-devel-3.10.0-327.58.1.el7.ppc64.rpm kernel-headers-3.10.0-327.58.1.el7.ppc64.rpm kernel-tools-3.10.0-327.58.1.el7.ppc64.rpm kernel-tools-debuginfo-3.10.0-327.58.1.el7.ppc64.rpm kernel-tools-libs-3.10.0-327.58.1.el7.ppc64.rpm perf-3.10.0-327.58.1.el7.ppc64.rpm perf-debuginfo-3.10.0-327.58.1.el7.ppc64.rpm python-perf-3.10.0-327.58.1.el7.ppc64.rpm python-perf-debuginfo-3.10.0-327.58.1.el7.ppc64.rpm ppc64le: kernel-3.10.0-327.58.1.el7.ppc64le.rpm kernel-bootwrapper-3.10.0-327.58.1.el7.ppc64le.rpm kernel-debug-3.10.0-327.58.1.el7.ppc64le.rpm kernel-debug-debuginfo-3.10.0-327.58.1.el7.ppc64le.rpm kernel-debuginfo-3.10.0-327.58.1.el7.ppc64le.rpm kernel-debuginfo-common-ppc64le-3.10.0-327.58.1.el7.ppc64le.rpm kernel-devel-3.10.0-327.58.1.el7.ppc64le.rpm kernel-headers-3.10.0-327.58.1.el7.ppc64le.rpm kernel-tools-3.10.0-327.58.1.el7.ppc64le.rpm kernel-tools-debuginfo-3.10.0-327.58.1.el7.ppc64le.rpm kernel-tools-libs-3.10.0-327.58.1.el7.ppc64le.rpm perf-3.10.0-327.58.1.el7.ppc64le.rpm perf-debuginfo-3.10.0-327.58.1.el7.ppc64le.rpm python-perf-3.10.0-327.58.1.el7.ppc64le.rpm python-perf-debuginfo-3.10.0-327.58.1.el7.ppc64le.rpm s390x: kernel-3.10.0-327.58.1.el7.s390x.rpm kernel-debug-3.10.0-327.58.1.el7.s390x.rpm kernel-debug-debuginfo-3.10.0-327.58.1.el7.s390x.rpm kernel-debug-devel-3.10.0-327.58.1.el7.s390x.rpm kernel-debuginfo-3.10.0-327.58.1.el7.s390x.rpm kernel-debuginfo-common-s390x-3.10.0-327.58.1.el7.s390x.rpm kernel-devel-3.10.0-327.58.1.el7.s390x.rpm kernel-headers-3.10.0-327.58.1.el7.s390x.rpm kernel-kdump-3.10.0-327.58.1.el7.s390x.rpm kernel-kdump-debuginfo-3.10.0-327.58.1.el7.s390x.rpm kernel-kdump-devel-3.10.0-327.58.1.el7.s390x.rpm perf-3.10.0-327.58.1.el7.s390x.rpm perf-debuginfo-3.10.0-327.58.1.el7.s390x.rpm python-perf-3.10.0-327.58.1.el7.s390x.rpm python-perf-debuginfo-3.10.0-327.58.1.el7.s390x.rpm x86_64: kernel-3.10.0-327.58.1.el7.x86_64.rpm kernel-debug-3.10.0-327.58.1.el7.x86_64.rpm kernel-debug-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-debug-devel-3.10.0-327.58.1.el7.x86_64.rpm kernel-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-debuginfo-common-x86_64-3.10.0-327.58.1.el7.x86_64.rpm kernel-devel-3.10.0-327.58.1.el7.x86_64.rpm kernel-headers-3.10.0-327.58.1.el7.x86_64.rpm kernel-tools-3.10.0-327.58.1.el7.x86_64.rpm kernel-tools-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-tools-libs-3.10.0-327.58.1.el7.x86_64.rpm perf-3.10.0-327.58.1.el7.x86_64.rpm perf-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm python-perf-3.10.0-327.58.1.el7.x86_64.rpm python-perf-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm Red Hat Enterprise Linux Server Optional EUS (v. 7.2): ppc64: kernel-debug-debuginfo-3.10.0-327.58.1.el7.ppc64.rpm kernel-debuginfo-3.10.0-327.58.1.el7.ppc64.rpm kernel-debuginfo-common-ppc64-3.10.0-327.58.1.el7.ppc64.rpm kernel-tools-debuginfo-3.10.0-327.58.1.el7.ppc64.rpm kernel-tools-libs-devel-3.10.0-327.58.1.el7.ppc64.rpm perf-debuginfo-3.10.0-327.58.1.el7.ppc64.rpm python-perf-debuginfo-3.10.0-327.58.1.el7.ppc64.rpm ppc64le: kernel-debug-debuginfo-3.10.0-327.58.1.el7.ppc64le.rpm kernel-debug-devel-3.10.0-327.58.1.el7.ppc64le.rpm kernel-debuginfo-3.10.0-327.58.1.el7.ppc64le.rpm kernel-debuginfo-common-ppc64le-3.10.0-327.58.1.el7.ppc64le.rpm kernel-tools-debuginfo-3.10.0-327.58.1.el7.ppc64le.rpm kernel-tools-libs-devel-3.10.0-327.58.1.el7.ppc64le.rpm perf-debuginfo-3.10.0-327.58.1.el7.ppc64le.rpm python-perf-debuginfo-3.10.0-327.58.1.el7.ppc64le.rpm x86_64: kernel-debug-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-debuginfo-common-x86_64-3.10.0-327.58.1.el7.x86_64.rpm kernel-tools-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm kernel-tools-libs-devel-3.10.0-327.58.1.el7.x86_64.rpm perf-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm python-perf-debuginfo-3.10.0-327.58.1.el7.x86_64.rpm These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from https://access.redhat.com/security/team/key/ 7. References: https://access.redhat.com/security/cve/CVE-2017-7895 https://access.redhat.com/security/updates/classification/#important 8. Contact: The Red Hat security contact is <secalert@redhat.com>. More contact details at https://access.redhat.com/security/team/contact/ Copyright 2017 Red Hat, Inc. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iD8DBQFZbgajXlSAg2UNWIIRAo1QAJ9rG97XUIz7In2HjQDuGu4IRp8o9wCeJS0L NpOEganfCD0pWxGZs1k7yac= =22kx -----END PGP SIGNATURE----- -- RHSA-announce mailing list RHSA-announce@redhat.com https://www.redhat.com/mailman/listinfo/rhsa-announce . 6.6) - noarch, x86_64 3. 6.2) - x86_64 3. On systems with the stack protection feature enabled in the kernel (CONFIG_CC_STACKPROTECTOR=y, which is enabled on all architectures other than s390x and ppc64[le]), an unauthenticated attacker able to initiate a connection to a system via Bluetooth could use this flaw to crash the system. Due to the nature of the stack protection feature, code execution cannot be fully ruled out, although we believe it is unlikely. Bug Fix(es): * Previously, while the MAP_GROWSDOWN flag was set, writing to the memory which was mapped with the mmap system call failed with the SIGBUS signal. This update fixes memory management in the Linux kernel by backporting an upstream patch that enlarges the stack guard page gap. As a result, mmap now works as expected under the described circumstances. (BZ#1474720) 4. CVE-2017-7487 Li Qiang reported a reference counter leak in the ipxitf_ioctl function which may result into a use-after-free vulnerability, triggerable when a IPX interface is configured. CVE-2017-7645 Tuomas Haanpaa and Matti Kamunen from Synopsys Ltd discovered that the NFSv2 and NFSv3 server implementations are vulnerable to an out-of-bounds memory access issue while processing arbitrarily long arguments sent by NFSv2/NFSv3 PRC clients, leading to a denial of service. A remote attacker with write access to a NFS mount can take advantage of this flaw to read chunks of arbitrary memory from both kernel-space and user-space. CVE-2017-8064 Arnd Bergmann found that the DVB-USB core misused the device logging system, resulting in a use-after-free vulnerability, with unknown security impact. CVE-2017-8925 Johan Hovold found a reference counter leak in the omninet USB serial driver, resulting in a use-after-free vulnerability. This can be triggered by a local user permitted to open tty devices. CVE-2017-9074 Andrey Konovalov reported that the IPv6 fragmentation implementation could read beyond the end of a packet buffer. CVE-2017-9075 Andrey Konovalov reported that the SCTP/IPv6 implementation wrongly initialised address lists on connected sockets, resulting in a use-after-free vulnerability, a similar issue to CVE-2017-8890. This can be triggered by any local user. CVE-2017-9076 / CVE-2017-9077 Cong Wang found that the TCP/IPv6 and DCCP/IPv6 implementations wrongly initialised address lists on connected sockets, a similar issue to CVE-2017-9075. CVE-2017-9242 Andrey Konovalov reported a packet buffer overrun in the IPv6 implementation. CVE-2017-1000364 The Qualys Research Labs discovered that the size of the stack guard page is not sufficiently large. The stack-pointer can jump over the guard-page and moving from the stack into another memory region without accessing the guard-page. In this case no page-fault exception is raised and the stack extends into the other memory region. An attacker can exploit this flaw for privilege escalation. The default stack gap protection is set to 256 pages and can be configured via the stack_guard_gap kernel parameter on the kernel command line. Further details can be found at https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt For the oldstable distribution (jessie), these problems have been fixed in version 3.16.43-2+deb8u1. For the stable distribution (stretch), these problems have been fixed in version 4.9.30-2+deb9u1 or earlier versions before the stretch release. Bug Fix(es): * If a VFC port became unmapped in the VIOS, it sometimes did not respond with a CRQ init complete following the H_REG_CRQ() call. As a consequence, scsi_block_requests were called until the init complete occurred. If not, I/O requests were hung. The provided patch ensures the host action stays set to IBMVFC_HOST_ACTION_TGT_DEL so that all rports are moved into devloss state unless an init complete is received. (BZ#1460210) 4. ========================================================================== Ubuntu Security Notice USN-3360-2 July 21, 2017 linux-lts-trusty vulnerabilities ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 12.04 ESM Summary: Several security issues were fixed in the Linux kernel. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 14.04 LTS for Ubuntu 12.04 ESM. It was discovered that the Linux kernel did not properly initialize a Wake- on-Lan data structure. A local attacker could use this to expose sensitive information (kernel memory). A local attacker could use this to expose sensitive information. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2015-8955) It was discovered that the SCSI generic (sg) driver in the Linux kernel contained a double-free vulnerability. A local attacker could use this to cause a denial of service (system crash). A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2015-8963) Tilman Schmidt and Sasha Levin discovered a use-after-free condition in the TTY implementation in the Linux kernel. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2015-8964) It was discovered that the fcntl64() system call in the Linux kernel did not properly set memory limits when returning on 32-bit ARM processors. A local attacker could use this to gain administrative privileges. (CVE-2015-8966) It was discovered that the system call table for ARM 64-bit processors in the Linux kernel was not write-protected. An attacker could use this in conjunction with another kernel vulnerability to execute arbitrary code. (CVE-2015-8967) It was discovered that the generic SCSI block layer in the Linux kernel did not properly restrict write operations in certain situations. A local attacker could use this to cause a denial of service (system crash) or possibly gain administrative privileges. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2017-1000380) Li Qiang discovered that the DRM driver for VMware Virtual GPUs in the Linux kernel did not properly validate some ioctl arguments. A local attacker could use this to cause a denial of service (system crash). (CVE-2017-7895) It was discovered that an integer underflow existed in the Edgeport USB Serial Converter device driver of the Linux kernel. An attacker with physical access could use this to expose sensitive information (kernel memory). (CVE-2017-8924) It was discovered that the USB ZyXEL omni.net LCD PLUS driver in the Linux kernel did not properly perform reference counting. A local attacker could use this to cause a denial of service (tty exhaustion). (CVE-2017-8925) Andrey Konovalov discovered an IPv6 out-of-bounds read error in the Linux kernel's IPv6 stack. (CVE-2017-9074) Murray McAllister discovered that the DRM driver for VMware Virtual GPUs in the Linux kernel did not properly initialize memory. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2017-9605) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 12.04 ESM: linux-image-3.13.0-125-generic 3.13.0-125.174~precise1 linux-image-3.13.0-125-generic-lpae 3.13.0-125.174~precise1 linux-image-generic-lpae-lts-trusty 3.13.0.125.116 linux-image-generic-lts-trusty 3.13.0.125.116 After a standard system update you need to reboot your computer to make all the necessary changes. ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well. Bug Fix(es): * When upgrading to kernel with the fix for stack guard flaw, a crash could occur in Java Virtual Machine (JVM) environments, which attempted to implement their own stack guard page. With this update, the underlying source code has been fixed to consider the PROT_NONE mapping as a part of the stack, and the crash in JVM no longer occurs under the described circumstances. (BZ#1472671) 4

AFFECTED PRODUCTS