The Linux kernel 2.6.24 and 2.6.25 before 2.6.25.9 allows local users to cause a denial of service (memory consumption) via a large number of calls to the get_user_pages function, which lacks a ZERO_PAGE optimization and results in allocation of "useless newly zeroed pages."

From Red Hat Security Advisory 2008:0957 :

Updated kernel packages that resolve several security issues and fix various 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.

[Updated 12th November 2008] The original packages distributed with this errata had a bug which prevented the Xen kernel booting on older hardware. We have updated the packages to correct this bug.

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

* the Xen implementation did not prevent applications running in a para-virtualized guest from modifying CR4 TSC. This could cause a local denial of service. (CVE-2007-5907, Important)

* Tavis Ormandy reported missing boundary checks in the Virtual Dynamic Shared Objects (vDSO) implementation. This could allow a local unprivileged user to cause a denial of service or escalate privileges.
(CVE-2008-3527, Important)

* the do_truncate() and generic_file_splice_write() functions did not clear the setuid and setgid bits. This could allow a local unprivileged user to obtain access to privileged information.
(CVE-2008-4210, CVE-2008-3833, Important)

* a flaw was found in the Linux kernel splice implementation. This could cause a local denial of service when there is a certain failure in the add_to_page_cache_lru() function. (CVE-2008-4302, Important)

* a flaw was found in the Linux kernel when running on AMD64 systems.
During a context switch, EFLAGS were being neither saved nor restored.
This could allow a local unprivileged user to cause a denial of service. (CVE-2006-5755, Low)

* a flaw was found in the Linux kernel virtual memory implementation.
This could allow a local unprivileged user to cause a denial of service. (CVE-2008-2372, Low)

* an integer overflow was discovered in the Linux kernel Datagram Congestion Control Protocol (DCCP) implementation. This could allow a remote attacker to cause a denial of service. By default, remote DCCP is blocked by SELinux. (CVE-2008-3276, Low)

In addition, these updated packages fix the following bugs :

* random32() seeding has been improved.

* in a multi-core environment, a race between the QP async event-handler and the destro_qp() function could occur. This led to unpredictable results during invalid memory access, which could lead to a kernel crash.

* a format string was omitted in the call to the request_module() function.

* a stack overflow caused by an infinite recursion bug in the binfmt_misc kernel module was corrected.

* the ata_scsi_rbuf_get() and ata_scsi_rbuf_put() functions now check for scatterlist usage before calling kmap_atomic().

* a sentinel NUL byte was added to the device_write() function to ensure that lspace.name is NUL-terminated.

* in the character device driver, a range_is_allowed() check was added to the read_mem() and write_mem() functions. It was possible for an illegitimate application to bypass these checks, and access /dev/mem beyond the 1M limit by calling mmap_mem() instead. Also, the parameters of range_is_allowed() were changed to cleanly handle greater than 32-bits of physical address on 32-bit architectures.

* some of the newer Nehalem-based systems declare their CPU DSDT entries as type 'Alias'. During boot, this caused an 'Error attaching device data' message to be logged.

* the evtchn event channel device lacked locks and memory barriers.
This has led to xenstore becoming unresponsive on the Itanium(r) architecture.

* sending of gratuitous ARP packets in the Xen frontend network driver is now delayed until the backend signals that its carrier status has been processed by the stack.

* on forcedeth devices, whenever setting ethtool parameters for link speed, the device could stop receiving interrupts.

* the CIFS 'forcedirectio' option did not allow text to be appended to files.

* the gettimeofday() function returned a backwards time on Intel(r) 64.

* residual-count corrections during UNDERRUN handling were added to the qla2xxx driver.

* the fix for a small quirk was removed for certain Adaptec controllers for which it caused problems.

* the 'xm trigger init' command caused a domain panic if a userland application was running on a guest on the Intel(r) 64 architecture.

Users of kernel should upgrade to these updated packages, which contain backported patches to correct these issues.

- the Xen implementation did not prevent applications     running in a para-virtualized guest from modifying CR4     TSC. This could cause a local denial of service.
    (CVE-2007-5907, Important)

  - Tavis Ormandy reported missing boundary checks in the     Virtual Dynamic Shared Objects (vDSO) implementation.
    This could allow a local unprivileged user to cause a     denial of service or escalate privileges.
    (CVE-2008-3527, Important)

  - the do_truncate() and generic_file_splice_write()     functions did not clear the setuid and setgid bits. This     could allow a local unprivileged user to obtain access     to privileged information. (CVE-2008-4210,     CVE-2008-3833, Important)

  - a flaw was found in the Linux kernel splice     implementation. This could cause a local denial of     service when there is a certain failure in the     add_to_page_cache_lru() function. (CVE-2008-4302,     Important)

  - a flaw was found in the Linux kernel when running on     AMD64 systems. During a context switch, EFLAGS were     being neither saved nor restored. This could allow a     local unprivileged user to cause a denial of service.
    (CVE-2006-5755, Low)

  - a flaw was found in the Linux kernel virtual memory     implementation. This could allow a local unprivileged     user to cause a denial of service. (CVE-2008-2372, Low)

  - an integer overflow was discovered in the Linux kernel     Datagram Congestion Control Protocol (DCCP)     implementation. This could allow a remote attacker to     cause a denial of service. By default, remote DCCP is     blocked by SELinux. (CVE-2008-3276, Low)

In addition, these updated packages fix the following bugs :

  - random32() seeding has been improved.

  - in a multi-core environment, a race between the QP async     event-handler and the destro_qp() function could occur.
    This led to unpredictable results during invalid memory     access, which could lead to a kernel crash.

  - a format string was omitted in the call to the     request_module() function.

  - a stack overflow caused by an infinite recursion bug in     the binfmt_misc kernel module was corrected.

  - the ata_scsi_rbuf_get() and ata_scsi_rbuf_put()     functions now check for scatterlist usage before calling     kmap_atomic().

  - a sentinel NUL byte was added to the device_write()     function to ensure that lspace.name is NUL-terminated.

  - in the character device driver, a range_is_allowed()     check was added to the read_mem() and write_mem()     functions. It was possible for an illegitimate     application to bypass these checks, and access /dev/mem     beyond the 1M limit by calling mmap_mem() instead. Also,     the parameters of range_is_allowed() were changed to     cleanly handle greater than 32-bits of physical address     on 32-bit architectures.

  - some of the newer Nehalem-based systems declare their     CPU DSDT entries as type 'Alias'. During boot, this     caused an 'Error attaching device data' message to be     logged.

  - the evtchn event channel device lacked locks and memory     barriers. This has led to xenstore becoming unresponsive     on the Itanium&reg; architecture.

  - sending of gratuitous ARP packets in the Xen frontend     network driver is now delayed until the backend signals     that its carrier status has been processed by the stack.

  - on forcedeth devices, whenever setting ethtool     parameters for link speed, the device could stop     receiving interrupts.

  - the CIFS 'forcedirectio' option did not allow text to be     appended to files.

  - the gettimeofday() function returned a backwards time on     Intel&reg; 64.

  - residual-count corrections during UNDERRUN handling were     added to the qla2xxx driver.

  - the fix for a small quirk was removed for certain     Adaptec controllers for which it caused problems.

  - the 'xm trigger init' command caused a domain panic if a     userland application was running on a guest on the     Intel&reg; 64 architecture.

This is a respin of the previous kernel update, which got retracted due to an IDE-CDROM regression, where any IDE CDROM access would hang or crash the system. Only this problem was fixed additionally.

This kernel update fixes the following security problems :

  - On x86_64 a denial of service attack could be used by     local attackers to immediately panic / crash the     machine. (CVE-2008-1615)

  - Fixed a SMP ordering problem in fcntl_setlk could     potentially allow local attackers to execute code by     timing file locking. (CVE-2008-1669)

  - Fixed a resource starvation problem in the handling of     ZERO mmap pages. (CVE-2008-2372)

  - The asn1 implementation in (a) the Linux kernel, as used     in the cifs and ip_nat_snmp_basic modules does not     properly validate length values during decoding of ASN.1     BER data, which allows remote attackers to cause a     denial of service (crash) or execute arbitrary code via     (1) a length greater than the working buffer, which can     lead to an unspecified overflow; (2) an oid length of     zero, which can lead to an off-by-one error; or (3) an     indefinite length for a primitive encoding.
    (CVE-2008-1673)

  - Various tty / serial devices did not check     functionpointers for NULL before calling them, leading     to potential crashes or code execution. The devices     affected are usually only accessible by the root user     though. (CVE-2008-2812)

  - A missing permission check in mount changing was added     which could have been used by local attackers to change     the mountdirectory. (CVE-2008-2931)

Additionally a very large number of bugs was fixed. Details can be found in the RPM changelog of the included packages.

OCFS2 has been upgraded to the 1.4.1 release :

  - Endian fixes

  - Use slab caches for DLM objects

  - Export DLM state info to debugfs

  - Avoid ENOSPC in rare conditions when free inodes are     reserved by other nodes

  - Error handling fix in ocfs2_start_walk_page_trans()

  - Cleanup lockres printing

  - Allow merging of extents

  - Fix to allow changing permissions of symlinks

  - Merged local fixes upstream (no code change)

Updated kernel packages that resolve several security issues and fix various 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.

[Updated 12th November 2008] The original packages distributed with this errata had a bug which prevented the Xen kernel booting on older hardware. We have updated the packages to correct this bug.

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

* the Xen implementation did not prevent applications running in a para-virtualized guest from modifying CR4 TSC. This could cause a local denial of service. (CVE-2007-5907, Important)

* Tavis Ormandy reported missing boundary checks in the Virtual Dynamic Shared Objects (vDSO) implementation. This could allow a local unprivileged user to cause a denial of service or escalate privileges.
(CVE-2008-3527, Important)

* the do_truncate() and generic_file_splice_write() functions did not clear the setuid and setgid bits. This could allow a local unprivileged user to obtain access to privileged information.
(CVE-2008-4210, CVE-2008-3833, Important)

* a flaw was found in the Linux kernel splice implementation. This could cause a local denial of service when there is a certain failure in the add_to_page_cache_lru() function. (CVE-2008-4302, Important)

* a flaw was found in the Linux kernel when running on AMD64 systems.
During a context switch, EFLAGS were being neither saved nor restored.
This could allow a local unprivileged user to cause a denial of service. (CVE-2006-5755, Low)

* a flaw was found in the Linux kernel virtual memory implementation.
This could allow a local unprivileged user to cause a denial of service. (CVE-2008-2372, Low)

* an integer overflow was discovered in the Linux kernel Datagram Congestion Control Protocol (DCCP) implementation. This could allow a remote attacker to cause a denial of service. By default, remote DCCP is blocked by SELinux. (CVE-2008-3276, Low)

In addition, these updated packages fix the following bugs :

* random32() seeding has been improved.

* in a multi-core environment, a race between the QP async event-handler and the destro_qp() function could occur. This led to unpredictable results during invalid memory access, which could lead to a kernel crash.

* a format string was omitted in the call to the request_module() function.

* a stack overflow caused by an infinite recursion bug in the binfmt_misc kernel module was corrected.

* the ata_scsi_rbuf_get() and ata_scsi_rbuf_put() functions now check for scatterlist usage before calling kmap_atomic().

* a sentinel NUL byte was added to the device_write() function to ensure that lspace.name is NUL-terminated.

* in the character device driver, a range_is_allowed() check was added to the read_mem() and write_mem() functions. It was possible for an illegitimate application to bypass these checks, and access /dev/mem beyond the 1M limit by calling mmap_mem() instead. Also, the parameters of range_is_allowed() were changed to cleanly handle greater than 32-bits of physical address on 32-bit architectures.

* some of the newer Nehalem-based systems declare their CPU DSDT entries as type 'Alias'. During boot, this caused an 'Error attaching device data' message to be logged.

* the evtchn event channel device lacked locks and memory barriers.
This has led to xenstore becoming unresponsive on the Itanium(r) architecture.

* sending of gratuitous ARP packets in the Xen frontend network driver is now delayed until the backend signals that its carrier status has been processed by the stack.

* on forcedeth devices, whenever setting ethtool parameters for link speed, the device could stop receiving interrupts.

* the CIFS 'forcedirectio' option did not allow text to be appended to files.

* the gettimeofday() function returned a backwards time on Intel(r) 64.

* residual-count corrections during UNDERRUN handling were added to the qla2xxx driver.

* the fix for a small quirk was removed for certain Adaptec controllers for which it caused problems.

* the 'xm trigger init' command caused a domain panic if a userland application was running on a guest on the Intel(r) 64 architecture.

Users of kernel should upgrade to these updated packages, which contain backported patches to correct these issues.

The openSUSE 11.0 kernel was updated to 2.6.25.9.

It fixes two security problems: CVE-2008-2372: A resource starvation issue within mmap was fixed, which could have been used by local attackers to hang the machine.

CVE-2008-2826: A integer overflow in SCTP was fixed, which might have been used by remote attackers to crash the machine or potentially execute code.

The update also has lots of other bugfixes that are listed in the RPM changelog.

It was discovered that the direct-IO subsystem did not correctly validate certain structures. A local attacker could exploit this to cause a system crash, leading to a denial of service. (CVE-2007-6716)

It was discovered that the disabling of the ZERO_PAGE optimization could lead to large memory consumption. A local attacker could exploit this to allocate all available memory, leading to a denial of service.
(CVE-2008-2372)

It was discovered that the Datagram Congestion Control Protocol (DCCP) did not correctly validate its arguments. If DCCP was in use, a remote attacker could send specially crafted network traffic and cause a system crash, leading to a denial of service. (CVE-2008-3276)

It was discovered that the SBNI WAN driver did not correctly check for the NET_ADMIN capability. A malicious local root user lacking CAP_NET_ADMIN would be able to change the WAN device configuration, leading to a denial of service. (CVE-2008-3525)

It was discovered that the Stream Control Transmission Protocol (SCTP) did not correctly validate the key length in the SCTP_AUTH_KEY option.
If SCTP is in use, a remote attacker could send specially crafted network traffic that would crash the system, leading to a denial of service. (CVE-2008-3526)

It was discovered that the tmpfs implementation did not correctly handle certain sequences of inode operations. A local attacker could exploit this to crash the system, leading to a denial of service.
(CVE-2008-3534)

It was discovered that the readv/writev functions did not correctly handle certain sequences of file operations. A local attacker could exploit this to crash the system, leading to a denial of service.
(CVE-2008-3535)

It was discovered that SCTP did not correctly validate its userspace arguments. A local attacker could call certain sctp_* functions with malicious options and cause a system crash, leading to a denial of service. (CVE-2008-3792, CVE-2008-4113, CVE-2008-4445)

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.
(CVE-2008-3831)

Johann Dahm and David Richter discovered that NFSv4 did not correctly handle certain file ACLs. If NFSv4 is in use, a local attacker could create a malicious ACL that could cause a system crash, leading to a denial of service. (CVE-2008-3915).

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-2008-0957.

ID	Name	Product	Family	Severity
67758	Oracle Linux 5 : kernel (ELSA-2008-0957)	Nessus	Oracle Linux Local Security Checks	high
60488	Scientific Linux Security Update : kernel on SL5.x i386/x86_64	Nessus	Scientific Linux Local Security Checks	high
59129	SuSE 10 Security Update : Linux kernel (ZYPP Patch Number 5477)	Nessus	SuSE Local Security Checks	critical
43713	CentOS 5 : kernel (CESA-2008:0957)	Nessus	CentOS Local Security Checks	high
41533	SuSE 10 Security Update : Linux kernel (ZYPP Patch Number 5473)	Nessus	SuSE Local Security Checks	critical
40007	openSUSE Security Update : kernel (kernel-67)	Nessus	SuSE Local Security Checks	medium
36681	Ubuntu 6.06 LTS / 7.10 / 8.04 LTS : linux, linux-source-2.6.15/22 vulnerabilities (USN-659-1)	Nessus	Ubuntu Local Security Checks	high
34690	RHEL 5 : kernel (RHSA-2008:0957)	Nessus	Red Hat Local Security Checks	high
801458	CentOS RHSA-2008-0957 Security Check	Log Correlation Engine	Generic	high

Detections

Analytics

CVE-2008-2372

medium

Tenable Plugins

high

high

critical

high

critical

medium

high

high

high