The Xen hypervisor block backend driver for Linux kernel 2.6.18, when running on a 64-bit host with a 32-bit paravirtualized guest, allows local privileged users in the guest OS to cause a denial of service (host OS crash) via a request that specifies a large number of blocks.

The remote Oracle Linux 5 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2008-0233 advisory.

    - Update: [fs] fix race condition in dnotify (Alexander Viro ) [439758] {CVE-2008-1375}
    - Update: [xen] ia64: ftp stress test fixes between HVM/Dom0 (Tetsu Yamamoto ) [427400] {CVE-2008-1619}
    - Update: [fs] fix race condition in dnotify (Alexander Viro ) [439758] {CVE-2008-1375}
    - [fs] fix race condition in dnotify (Alexander Viro ) [439758] {CVE-2008-1375}
    - [x86] clear df flag for signal handlers (Jason Baron ) [437316] {CVE-2008-1367}
    - [xen] ia64: ftp stress test fixes between HVM/Dom0 (Tetsu Yamamoto ) [427400] {CVE-2008-1619}
    - [xen] ia64: fix ssm_i emulation barrier and vdso pv (Tetsu Yamamoto ) [427400] {CVE-2008-1619}

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

These updated packages fix the following security issues :

  - the absence of a protection mechanism when attempting to     access a critical section of code has been found in the     Linux kernel open file descriptors control mechanism,     fcntl. This could allow a local unprivileged user to     simultaneously execute code, which would otherwise be     protected against parallel execution. As well, a race     condition when handling locks in the Linux kernel fcntl     functionality, may have allowed a process belonging to a     local unprivileged user to gain re-ordered access to the     descriptor table. (CVE-2008-1669, Important)

  - a possible hypervisor panic was found in the Linux     kernel. A privileged user of a fully virtualized guest     could initiate a stress-test File Transfer Protocol     (FTP) transfer between the guest and the hypervisor,     possibly leading to hypervisor panic. (CVE-2008-1619,     Important)

  - the absence of a protection mechanism when attempting to     access a critical section of code, as well as a race     condition, have been found in the Linux kernel file     system event notifier, dnotify. This could allow a local     unprivileged user to get inconsistent data, or to send     arbitrary signals to arbitrary system processes.
    (CVE-2008-1375, Important)

  - when accessing kernel memory locations, certain Linux     kernel drivers registering a fault handler did not     perform required range checks. A local unprivileged user     could use this flaw to gain read or write access to     arbitrary kernel memory, or possibly cause a kernel     crash. (CVE-2008-0007, Important)

  - the absence of sanity-checks was found in the hypervisor     block backend driver, when running 32-bit     paravirtualized guests on a 64-bit host. The number of     blocks to be processed per one request from guest to     host, or vice-versa, was not checked for its maximum     value, which could have allowed a local privileged user     of the guest operating system to cause a denial of     service. (CVE-2007-5498, Important)

  - it was discovered that the Linux kernel handled string     operations in the opposite way to the GNU Compiler     Collection (GCC). This could allow a local unprivileged     user to cause memory corruption. (CVE-2008-1367, Low)

As well, these updated packages fix the following bugs :

  - on IBM System z architectures, when running QIOASSIST     enabled QDIO devices in an IBM z/VM environment, the     output queue stalled under heavy load. This caused     network performance to degrade, possibly causing network     hangs and outages.

  - multiple buffer overflows were discovered in the neofb     video driver. It was not possible for an unprivileged     user to exploit these issues, and as such, they have not     been handled as security issues.

  - when running Microsoft Windows in a HVM, a bug in     vmalloc/vfree caused network performance to degrade.

  - on certain architectures, a bug in the libATA sata_nv     driver may have caused infinite reboots, and an 'ata1:
    CPB flags CMD err flags 0x11' error.

  - repeatedly hot-plugging a PCI Express card may have     caused 'Bad DLLP' errors.

  - a NULL pointer dereference in NFS, which may have caused     applications to crash, has been resolved.

  - when attempting to kexec reboot, either manually or via     a panic-triggered kdump, the Unisys ES7000/one hanged     after rebooting in the new kernel, after printing the     'Memory: 32839688k/33685504k available' line.

Updated kernel packages that fix various security issues and several bugs are now available for Red Hat Enterprise Linux 5.

This update has been rated as having important security impact by the Red Hat Security Response Team.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

These updated packages fix the following security issues :

* the absence of a protection mechanism when attempting to access a critical section of code has been found in the Linux kernel open file descriptors control mechanism, fcntl. This could allow a local unprivileged user to simultaneously execute code, which would otherwise be protected against parallel execution. As well, a race condition when handling locks in the Linux kernel fcntl functionality, may have allowed a process belonging to a local unprivileged user to gain re-ordered access to the descriptor table. (CVE-2008-1669, Important)

* a possible hypervisor panic was found in the Linux kernel. A privileged user of a fully virtualized guest could initiate a stress-test File Transfer Protocol (FTP) transfer between the guest and the hypervisor, possibly leading to hypervisor panic.
(CVE-2008-1619, Important)

* the absence of a protection mechanism when attempting to access a critical section of code, as well as a race condition, have been found in the Linux kernel file system event notifier, dnotify. This could allow a local unprivileged user to get inconsistent data, or to send arbitrary signals to arbitrary system processes. (CVE-2008-1375, Important)

Red Hat would like to thank Nick Piggin for responsibly disclosing the following issue :

* when accessing kernel memory locations, certain Linux kernel drivers registering a fault handler did not perform required range checks. A local unprivileged user could use this flaw to gain read or write access to arbitrary kernel memory, or possibly cause a kernel crash.
(CVE-2008-0007, Important)

* the absence of sanity-checks was found in the hypervisor block backend driver, when running 32-bit paravirtualized guests on a 64-bit host. The number of blocks to be processed per one request from guest to host, or vice-versa, was not checked for its maximum value, which could have allowed a local privileged user of the guest operating system to cause a denial of service. (CVE-2007-5498, Important)

* it was discovered that the Linux kernel handled string operations in the opposite way to the GNU Compiler Collection (GCC). This could allow a local unprivileged user to cause memory corruption.
(CVE-2008-1367, Low)

As well, these updated packages fix the following bugs :

* on IBM System z architectures, when running QIOASSIST enabled QDIO devices in an IBM z/VM environment, the output queue stalled under heavy load. This caused network performance to degrade, possibly causing network hangs and outages.

* multiple buffer overflows were discovered in the neofb video driver.
It was not possible for an unprivileged user to exploit these issues, and as such, they have not been handled as security issues.

* when running Microsoft Windows in a HVM, a bug in vmalloc/vfree caused network performance to degrade.

* on certain architectures, a bug in the libATA sata_nv driver may have caused infinite reboots, and an 'ata1: CPB flags CMD err flags 0x11' error.

* repeatedly hot-plugging a PCI Express card may have caused 'Bad DLLP' errors.

* a NULL pointer dereference in NFS, which may have caused applications to crash, has been resolved.

* when attempting to kexec reboot, either manually or via a panic-triggered kdump, the Unisys ES7000/one hanged after rebooting in the new kernel, after printing the 'Memory: 32839688k/33685504k available' line.

Red Hat Enterprise Linux 5 users are advised to upgrade to these updated packages, which contain backported patches to resolve these issues.

It was discovered that the Xen hypervisor block driver did not correctly validate requests. A user with root privileges in a guest OS could make a malicious IO request with a large number of blocks that would crash the host OS, leading to a denial of service. This only affected Ubuntu 7.10. (CVE-2007-5498)

It was discovered the the i915 video driver did not correctly validate memory addresses. A local attacker could exploit this to remap memory that could cause a system crash, leading to a denial of service. This issue did not affect Ubuntu 6.06 and was previous fixed for Ubuntu 7.10 and 8.04 in USN-659-1. Ubuntu 8.10 has now been corrected as well. (CVE-2008-3831)

David Watson discovered that the kernel did not correctly strip permissions when creating files in setgid directories. A local user could exploit this to gain additional group privileges. This issue only affected Ubuntu 6.06. (CVE-2008-4210)

Olaf Kirch and Miklos Szeredi discovered that the Linux kernel did not correctly reject the 'append' flag when handling file splice requests.
A local attacker could bypass append mode and make changes to arbitrary locations in a file. This issue only affected Ubuntu 7.10 and 8.04. (CVE-2008-4554)

It was discovered that the SCTP stack did not correctly handle INIT-ACK. A remote user could exploit this by sending specially crafted SCTP traffic which would trigger a crash in the system, leading to a denial of service. This issue did not affect Ubuntu 8.10.
(CVE-2008-4576)

It was discovered that the SCTP stack did not correctly handle bad packet lengths. A remote user could exploit this by sending specially crafted SCTP traffic which would trigger a crash in the system, leading to a denial of service. This issue did not affect Ubuntu 8.10.
(CVE-2008-4618)

Eric Sesterhenn discovered multiple flaws in the HFS+ filesystem. If a local user or automated system were tricked into mounting a malicious HFS+ filesystem, the system could crash, leading to a denial of service. (CVE-2008-4933, CVE-2008-4934, CVE-2008-5025)

It was discovered that the Unix Socket handler did not correctly process the SCM_RIGHTS message. A local attacker could make a malicious socket request that would crash the system, leading to a denial of service. (CVE-2008-5029)

It was discovered that the driver for simple i2c audio interfaces did not correctly validate certain function pointers. A local user could exploit this to gain root privileges or crash the system, leading to a denial of service. (CVE-2008-5033).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote CentOS system is missing a security update which has been documented in Red Hat advisory RHSA-2008-0233.

ID	Name	Product	Family	Severity
67683	Oracle Linux 5 : kernel (ELSA-2008-0233)	Nessus	Oracle Linux Local Security Checks	high
60395	Scientific Linux Security Update : kernel on SL5.x i386/x86_64	Nessus	Scientific Linux Local Security Checks	high
43681	CentOS 5 : kernel (CESA-2008:0233)	Nessus	CentOS Local Security Checks	high
37683	Ubuntu 6.06 LTS / 7.10 / 8.04 LTS / 8.10 : linux, linux-source-2.6.15/22 vulnerabilities (USN-679-1)	Nessus	Ubuntu Local Security Checks	high
32161	RHEL 5 : kernel (RHSA-2008:0233)	Nessus	Red Hat Local Security Checks	high
801450	CentOS RHSA-2008-0233 Security Check	Log Correlation Engine	Generic	high

Detections

Analytics

CVE-2007-5498

medium

Tenable Plugins

high

high

high

high

high

high