ID

VAR-201704-1397

CVE

CVE-2017-7895

TITLE

Linux Kernel of NFSv2/NFSv3 Vulnerability that triggers pointer arithmetic errors in server implementation

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-rt security and bug fix update Advisory ID: RHSA-2017:1616-01 Product: Red Hat Enterprise Linux Advisory URL: https://access.redhat.com/errata/RHSA-2017:1616 Issue date: 2017-06-28 CVE Names: CVE-2017-1000364 CVE-2017-2583 CVE-2017-6214 CVE-2017-7477 CVE-2017-7645 CVE-2017-7895 ===================================================================== 1. Summary: An update for kernel-rt is now available for Red Hat Enterprise Linux 7. 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 Realtime (v. 7) - noarch, x86_64 Red Hat Enterprise Linux for Real Time for NFV (v. 7) - noarch, x86_64 3. Description: The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements. Security Fix(es): * A flaw was found in the way memory was being allocated on the stack for user space binaries. If heap (or different memory region) and stack memory regions were adjacent to each other, an attacker could use this flaw to jump over the stack guard gap, cause controlled memory corruption on process stack or the adjacent memory region, and thus increase their privileges on the system. This is a kernel-side mitigation which increases the stack guard gap size from one page to 1 MiB to make successful exploitation of this issue more difficult. (CVE-2017-1000364, Important) * A flaw was found in the way Linux kernel allocates heap memory to build the scattergather list from a fragment list(skb_shinfo(skb)->frag_list) in the socket buffer(skb_buff). The heap overflow occurred if 'MAX_SKB_FRAGS + 1' parameter and 'NETIF_F_FRAGLIST' feature are both used together. A remote user or process could use this flaw to potentially escalate their privilege on a system. (CVE-2017-7477, Important) * The NFS2/3 RPC client could send long arguments to the NFS server. These encoded arguments are stored in an array of memory pages, and accessed using pointer variables. Arbitrarily long arguments could make these pointers point outside the array and cause an out-of-bounds memory access. A remote user or program could use this flaw to crash the kernel, resulting in denial of service. (CVE-2017-7895, Important) * Linux kernel built with the Kernel-based Virtual Machine (CONFIG_KVM) support was vulnerable to an incorrect segment selector(SS) value error. The error could occur while loading values into the SS register in long mode. A user or process inside a guest could use this flaw to crash the guest, resulting in DoS or potentially escalate their privileges inside the guest. (CVE-2017-2583, Moderate) * A flaw was found in the Linux kernel's handling of packets with the URG flag. Applications using the splice() and tcp_splice_read() functionality could allow a remote attacker to force the kernel to enter a condition in which it could loop indefinitely. (CVE-2017-6214, Moderate) Red Hat would like to thank Qualys Research Labs for reporting CVE-2017-1000364; Ari Kauppi for reporting CVE-2017-7895; and Xiaohan Zhang (Huawei Inc.) for reporting CVE-2017-2583. Bug Fix(es): * The kernel-rt packages have been upgraded to the 3.10.0-514.25.2 source tree, which provides a number of bug fixes over the previous version. (BZ#1452742) * Previously, a local lock acquisition around the ip_send_unicast_reply() function was incorrectly terminated. Consequently, a list corruption occurred that led to a kernel panic. This update adds locking functions around calls to ip_send_unicast_reply(). As a result, neither list corruption nor kernel panic occur under the described circumstances. (BZ#1455239) 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/): 1414735 - CVE-2017-2583 Kernel: Kvm: vmx/svm potential privilege escalation inside guest 1426542 - CVE-2017-6214 kernel: ipv4/tcp: Infinite loop in tcp_splice_read() 1443615 - CVE-2017-7645 kernel: nfsd: Incorrect handling of long RPC replies 1445207 - CVE-2017-7477 kernel: net: Heap overflow in skb_to_sgvec in macsec.c 1446103 - CVE-2017-7895 kernel: NFSv3 server does not properly handle payload bounds checking of WRITE requests 1452742 - kernel-rt: update to the RHEL7.3.z batch#6 source tree 1455239 - net: add back the missing serialization in ip_send_unicast_reply() [RT 7.3.z] 1461333 - CVE-2017-1000364 kernel: heap/stack gap jumping via unbounded stack allocations 6. Package List: Red Hat Enterprise Linux for Real Time for NFV (v. 7): Source: kernel-rt-3.10.0-514.26.1.rt56.442.el7.src.rpm noarch: kernel-rt-doc-3.10.0-514.26.1.rt56.442.el7.noarch.rpm x86_64: kernel-rt-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debug-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debug-debuginfo-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debug-devel-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debug-kvm-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debug-kvm-debuginfo-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debuginfo-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debuginfo-common-x86_64-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-devel-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-kvm-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-kvm-debuginfo-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-trace-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-trace-debuginfo-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-trace-devel-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-trace-kvm-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-trace-kvm-debuginfo-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm Red Hat Enterprise Linux Realtime (v. 7): Source: kernel-rt-3.10.0-514.26.1.rt56.442.el7.src.rpm noarch: kernel-rt-doc-3.10.0-514.26.1.rt56.442.el7.noarch.rpm x86_64: kernel-rt-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debug-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debug-debuginfo-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debug-devel-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debuginfo-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-debuginfo-common-x86_64-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-devel-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-trace-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-trace-debuginfo-3.10.0-514.26.1.rt56.442.el7.x86_64.rpm kernel-rt-trace-devel-3.10.0-514.26.1.rt56.442.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-2017-1000364 https://access.redhat.com/security/cve/CVE-2017-2583 https://access.redhat.com/security/cve/CVE-2017-6214 https://access.redhat.com/security/cve/CVE-2017-7477 https://access.redhat.com/security/cve/CVE-2017-7645 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 iD8DBQFZU/mtXlSAg2UNWIIRAhYIAJ42qRehY60kmV2FptsmEemr0sL35ACdG4mg VHOx6LYlrjxRBjx/wWE9z2A= =sI9J -----END PGP SIGNATURE----- -- RHSA-announce mailing list RHSA-announce@redhat.com https://www.redhat.com/mailman/listinfo/rhsa-announce . 7.2) - ppc64, ppc64le, x86_64 3. 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'. 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. 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. 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. =========================================================================== Ubuntu Security Notice USN-3312-2 June 07, 2017 linux-lts-xenial vulnerabilities =========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 14.04 LTS 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 16.04 LTS for Ubuntu 14.04 LTS. It was discovered that the netfilter netlink implementation in the Linux kernel did not properly validate batch messages. (CVE-2016-7917) Qian Zhang discovered a heap-based buffer overflow in the tipc_msg_build() function in the Linux kernel. (CVE-2016-8632) It was discovered that the keyring implementation in the Linux kernel in some situations did not prevent special internal keyrings from being joined by userspace keyrings. A privileged local attacker could use this to bypass module verification. A privileged local attacker could use this to execute arbitrary code. (CVE-2017-0605) Dmitry Vyukov discovered that KVM implementation in the Linux kernel improperly emulated the VMXON instruction. A local attacker in a guest OS could use this to cause a denial of service (memory consumption) in the host OS. (CVE-2017-6001) Eric Biggers discovered a memory leak in the keyring implementation in the Linux kernel. (CVE-2017-7472) Sabrina Dubroca discovered that the asynchronous cryptographic hash (ahash) implementation in the Linux kernel did not properly handle a full request queue. (CVE-2017-7645) Tommi Rantala and Brad Spengler discovered that the memory manager in the Linux kernel did not properly enforce the CONFIG_STRICT_DEVMEM protection mechanism. A local attacker with access to /dev/mem could use this to expose sensitive information or possibly execute arbitrary code. (CVE-2016-7913) Vlad Tsyrklevich discovered an integer overflow vulnerability in the VFIO PCI driver for the Linux kernel. A local attacker with access to a vfio PCI device file could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2016-9083, CVE-2016-9084) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 14.04 LTS: linux-image-4.4.0-79-generic 4.4.0-79.100~14.04.1 linux-image-4.4.0-79-generic-lpae 4.4.0-79.100~14.04.1 linux-image-4.4.0-79-lowlatency 4.4.0-79.100~14.04.1 linux-image-4.4.0-79-powerpc-e500mc 4.4.0-79.100~14.04.1 linux-image-4.4.0-79-powerpc-smp 4.4.0-79.100~14.04.1 linux-image-4.4.0-79-powerpc64-emb 4.4.0-79.100~14.04.1 linux-image-4.4.0-79-powerpc64-smp 4.4.0-79.100~14.04.1 linux-image-generic-lpae-lts-xenial 4.4.0.79.64 linux-image-generic-lts-xenial 4.4.0.79.64 linux-image-lowlatency-lts-xenial 4.4.0.79.64 linux-image-powerpc-e500mc-lts-xenial 4.4.0.79.64 linux-image-powerpc-smp-lts-xenial 4.4.0.79.64 linux-image-powerpc64-emb-lts-xenial 4.4.0.79.64 linux-image-powerpc64-smp-lts-xenial 4.4.0.79.64 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): * 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. 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