The handle_dr function in arch/x86/kvm/vmx.c in the KVM subsystem in the Linux kernel before 2.6.31.1 does not properly verify the Current Privilege Level (CPL) before accessing a debug register, which allows guest OS users to cause a denial of service (trap) on the host OS via a crafted application.

From Red Hat Security Advisory 2010:0126 :

Updated kvm packages that fix two security issues and two 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.

KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux on AMD64 and Intel 64 systems. KVM is a Linux kernel module built for the standard Red Hat Enterprise Linux kernel.

A flaw was found in the way the x86 emulator loaded segment selectors (used for memory segmentation and protection) into segment registers.
In some guest system configurations, an unprivileged guest user could leverage this flaw to crash the guest or possibly escalate their privileges within the guest. (CVE-2010-0419)

The x86 emulator implementation was missing a check for the Current Privilege Level (CPL) while accessing debug registers. An unprivileged user in a guest could leverage this flaw to crash the guest.
(CVE-2009-3722)

This update also fixes the following bugs :

With Red Hat Enterprise Virtualization, the virtio_blk_dma_restart_bh() function was previously used to handle write errors; however, a bug fix provided by the RHSA-2009:1659 update meant that read errors would also have to be handled by this function.
The function was not updated for this, causing read errors to be resubmitted as writes. This caused guest image corruption in some cases.

Additionally, the return values of the bdrv_aio_write() and bdrv_aio_read() functions were ignored. If an immediate failure occurred in one of these functions, errors would be missed and the guest could hang or read corrupted data. (BZ#562776)

All KVM users should upgrade to these updated packages, which contain backported patches to resolve these issues. Note: The procedure in the Solution section must be performed before this update will take effect.

Updated kvm packages that fix two security issues and two 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.

KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux on AMD64 and Intel 64 systems. KVM is a Linux kernel module built for the standard Red Hat Enterprise Linux kernel.

A flaw was found in the way the x86 emulator loaded segment selectors (used for memory segmentation and protection) into segment registers.
In some guest system configurations, an unprivileged guest user could leverage this flaw to crash the guest or possibly escalate their privileges within the guest. (CVE-2010-0419)

The x86 emulator implementation was missing a check for the Current Privilege Level (CPL) while accessing debug registers. An unprivileged user in a guest could leverage this flaw to crash the guest.
(CVE-2009-3722)

This update also fixes the following bugs :

With Red Hat Enterprise Virtualization, the virtio_blk_dma_restart_bh() function was previously used to handle write errors; however, a bug fix provided by the RHSA-2009:1659 update meant that read errors would also have to be handled by this function.
The function was not updated for this, causing read errors to be resubmitted as writes. This caused guest image corruption in some cases.

Additionally, the return values of the bdrv_aio_write() and bdrv_aio_read() functions were ignored. If an immediate failure occurred in one of these functions, errors would be missed and the guest could hang or read corrupted data. (BZ#562776)

All KVM users should upgrade to these updated packages, which contain backported patches to resolve these issues. Note: The procedure in the Solution section must be performed before this update will take effect.

CVE-2009-3722 KVM: Check cpl before emulating debug register access

CVE-2010-0419 kvm: emulator privilege escalation segment selector check

A flaw was found in the way the x86 emulator loaded segment selectors (used for memory segmentation and protection) into segment registers.
In some guest system configurations, an unprivileged guest user could leverage this flaw to crash the guest or possibly escalate their privileges within the guest. (CVE-2010-0419)

The x86 emulator implementation was missing a check for the Current Privilege Level (CPL) while accessing debug registers. An unprivileged user in a guest could leverage this flaw to crash the guest.
(CVE-2009-3722)

This update also fixes the following bugs :

The return values of the bdrv_aio_write() and bdrv_aio_read() functions were ignored. If an immediate failure occurred in one of these functions, errors would be missed and the guest could hang or read corrupted data. (BZ#562776)

The following procedure must be performed before this update will take effect :

1) Stop all KVM guest virtual machines.

2) Either reboot the hypervisor machine or, as the root user, remove (using 'modprobe -r [module]') and reload (using 'modprobe [module]') all of the following modules which are currently running (determined using 'lsmod'): kvm, ksm, kvm-intel or kvm-amd.

3) Restart the KVM guest virtual machines.

Some vulnerabilities were discovered and corrected in the Linux 2.6 kernel :

fs/namei.c in Linux kernel 2.6.18 through 2.6.34 does not always follow NFS automount symlinks, which allows attackers to have an unknown impact, related to LOOKUP_FOLLOW. (CVE-2010-1088)

The tc_fill_tclass function in net/sched/sch_api.c in the tc subsystem in the Linux kernel 2.4.x before 2.4.37.6 and 2.6.x before 2.6.31-rc9 does not initialize certain (1) tcm__pad1 and (2) tcm__pad2 structure members, which might allow local users to obtain sensitive information from kernel memory via unspecified vectors. (CVE-2009-3228)

The do_pages_move function in mm/migrate.c in the Linux kernel before 2.6.33-rc7 does not validate node values, which allows local users to read arbitrary kernel memory locations, cause a denial of service (OOPS), and possibly have unspecified other impact by specifying a node that is not part of the kernel node set. (CVE-2010-0415)

The ATI Rage 128 (aka r128) driver in the Linux kernel before 2.6.31-git11 does not properly verify Concurrent Command Engine (CCE) state initialization, which allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly gain privileges via unspecified ioctl calls. (CVE-2009-3620)

The wake_futex_pi function in kernel/futex.c in the Linux kernel before 2.6.33-rc7 does not properly handle certain unlock operations for a Priority Inheritance (PI) futex, which allows local users to cause a denial of service (OOPS) and possibly have unspecified other impact via vectors involving modification of the futex value from user space. (CVE-2010-0622)

The kvm_arch_vcpu_ioctl_set_sregs function in the KVM in Linux kernel 2.6 before 2.6.30, when running on x86 systems, does not validate the page table root in a KVM_SET_SREGS call, which allows local users to cause a denial of service (crash or hang) via a crafted cr3 value, which triggers a NULL pointer dereference in the gfn_to_rmap function.
(CVE-2009-2287)

The handle_dr function in arch/x86/kvm/vmx.c in the KVM subsystem in the Linux kernel before 2.6.31.1 does not properly verify the Current Privilege Level (CPL) before accessing a debug register, which allows guest OS users to cause a denial of service (trap) on the host OS via a crafted application. (CVE-2009-3722)

The ext4_decode_error function in fs/ext4/super.c in the ext4 filesystem in the Linux kernel before 2.6.32 allows user-assisted remote attackers to cause a denial of service (NULL pointer dereference), and possibly have unspecified other impact, via a crafted read-only filesystem that lacks a journal. (CVE-2009-4308)

The eisa_eeprom_read function in the parisc isa-eeprom component (drivers/parisc/eisa_eeprom.c) in the Linux kernel before 2.6.31-rc6 allows local users to access restricted memory via a negative ppos argument, which bypasses a check that assumes that ppos is positive and causes an out-of-bounds read in the readb function.
(CVE-2009-2846)

Multiple buffer overflows in fs/nfsd/nfs4xdr.c in the XDR implementation in the NFS server in the Linux kernel before 2.6.34-rc6 allow remote attackers to cause a denial of service (panic) or possibly execute arbitrary code via a crafted NFSv4 compound WRITE request, related to the read_buf and nfsd4_decode_compound functions.
(CVE-2010-2521)

mm/shmem.c in the Linux kernel before 2.6.28-rc8, when strict overcommit is enabled and CONFIG_SECURITY is disabled, does not properly handle the export of shmemfs objects by knfsd, which allows attackers to cause a denial of service (NULL pointer dereference and knfsd crash) or possibly have unspecified other impact via unknown vectors. NOTE: this vulnerability exists because of an incomplete fix for CVE-2010-1643. (CVE-2008-7256)

The release_one_tty function in drivers/char/tty_io.c in the Linux kernel before 2.6.34-rc4 omits certain required calls to the put_pid function, which has unspecified impact and local attack vectors.
(CVE-2010-1162)

mm/shmem.c in the Linux kernel before 2.6.28-rc3, when strict overcommit is enabled, does not properly handle the export of shmemfs objects by knfsd, which allows attackers to cause a denial of service (NULL pointer dereference and knfsd crash) or possibly have unspecified other impact via unknown vectors. (CVE-2010-1643)

The sctp_process_unk_param function in net/sctp/sm_make_chunk.c in the Linux kernel 2.6.33.3 and earlier, when SCTP is enabled, allows remote attackers to cause a denial of service (system crash) via an SCTPChunkInit packet containing multiple invalid parameters that require a large amount of error data. (CVE-2010-1173)

The Transparent Inter-Process Communication (TIPC) functionality in Linux kernel 2.6.16-rc1 through 2.6.33, and possibly other versions, allows local users to cause a denial of service (kernel OOPS) by sending datagrams through AF_TIPC before entering network mode, which triggers a NULL pointer dereference. (CVE-2010-1187)

The sctp_process_unk_param function in net/sctp/sm_make_chunk.c in the Linux kernel 2.6.33.3 and earlier, when SCTP is enabled, allows remote attackers to cause a denial of service (system crash) via an SCTPChunkInit packet containing multiple invalid parameters that require a large amount of error data. (CVE-2010-1173)

fs/cifs/cifssmb.c in the CIFS implementation in the Linux kernel before 2.6.34-rc4 allows remote attackers to cause a denial of service (panic) via an SMB response packet with an invalid CountHigh value, as demonstrated by a response from an OS/2 server, related to the CIFSSMBWrite and CIFSSMBWrite2 functions. (CVE-2010-2248)

Buffer overflow in the ecryptfs_uid_hash macro in fs/ecryptfs/messaging.c in the eCryptfs subsystem in the Linux kernel before 2.6.35 might allow local users to gain privileges or cause a denial of service (system crash) via unspecified vectors.
(CVE-2010-2492)

The xfs_swapext function in fs/xfs/xfs_dfrag.c in the Linux kernel before 2.6.35 does not properly check the file descriptors passed to the SWAPEXT ioctl, which allows local users to leverage write access and obtain read access by swapping one file into another file.
(CVE-2010-2226)

The gfs2_dirent_find_space function in fs/gfs2/dir.c in the Linux kernel before 2.6.35 uses an incorrect size value in calculations associated with sentinel directory entries, which allows local users to cause a denial of service (NULL pointer dereference and panic) and possibly have unspecified other impact by renaming a file in a GFS2 filesystem, related to the gfs2_rename function in fs/gfs2/ops_inode.c. (CVE-2010-2798)

The do_anonymous_page function in mm/memory.c in the Linux kernel before 2.6.27.52, 2.6.32.x before 2.6.32.19, 2.6.34.x before 2.6.34.4, and 2.6.35.x before 2.6.35.2 does not properly separate the stack and the heap, which allows context-dependent attackers to execute arbitrary code by writing to the bottom page of a shared memory segment, as demonstrated by a memory-exhaustion attack against the X.Org X server. (CVE-2010-2240)

The drm_ioctl function in drivers/gpu/drm/drm_drv.c in the Direct Rendering Manager (DRM) subsystem in the Linux kernel before 2.6.27.53, 2.6.32.x before 2.6.32.21, 2.6.34.x before 2.6.34.6, and 2.6.35.x before 2.6.35.4 allows local users to obtain potentially sensitive information from kernel memory by requesting a large memory-allocation amount. (CVE-2010-2803)

Integer overflow in net/can/bcm.c in the Controller Area Network (CAN) implementation in the Linux kernel before 2.6.27.53, 2.6.32.x before 2.6.32.21, 2.6.34.x before 2.6.34.6, and 2.6.35.x before 2.6.35.4 allows attackers to execute arbitrary code or cause a denial of service (system crash) via crafted CAN traffic. (CVE-2010-2959)

Double free vulnerability in the snd_seq_oss_open function in sound/core/seq/oss/seq_oss_init.c in the Linux kernel before 2.6.36-rc4 might allow local users to cause a denial of service or possibly have unspecified other impact via an unsuccessful attempt to open the /dev/sequencer device. (CVE-2010-3080)

A vulnerability in Linux kernel caused by insecure allocation of user space memory when translating system call inputs to 64-bit. A stack pointer underflow can occur when using the compat_alloc_user_space method with an arbitrary length input. (CVE-2010-3081)

The IA32 system call emulation functionality in arch/x86/ia32/ia32entry.S in the Linux kernel before 2.6.36-rc4-git2 on the x86_64 platform does not zero extend the %eax register after the 32-bit entry path to ptrace is used, which allows local users to gain privileges by triggering an out-of-bounds access to the system call table using the %rax register. NOTE: this vulnerability exists because of a CVE-2007-4573 regression. (CVE-2010-3301)

To update your kernel, please follow the directions located at :

http://www.mandriva.com/en/security/kernelupdate

Several vulnerabilities have been discovered in kvm, a full virtualization system. The Common Vulnerabilities and Exposures project identifies the following problems :

  - CVE-2009-3638     It was discovered an Integer overflow in the     kvm_dev_ioctl_get_supported_cpuid function. This allows     local users to have an unspecified impact via a     KVM_GET_SUPPORTED_CPUID request to the     kvm_arch_dev_ioctl function.

  - CVE-2009-3722     It was discovered that the handle_dr function in the KVM     subsystem does not properly verify the Current Privilege     Level (CPL) before accessing a debug register, which     allows guest OS users to cause a denial of service     (trap) on the host OS via a crafted application.

  - CVE-2009-4031     It was discovered that the do_insn_fetch function in the     x86 emulator in the KVM subsystem tries to interpret     instructions that contain too many bytes to be valid,     which allows guest OS users to cause a denial of service     (increased scheduling latency) on the host OS via     unspecified manipulations related to SMP support.

It was discovered that the AX.25 network subsystem did not correctly check integer signedness in certain setsockopt calls. A local attacker could exploit this to crash the system, leading to a denial of service. Ubuntu 9.10 was not affected. (CVE-2009-2909)

Jan Beulich discovered that the kernel could leak register contents to 32-bit processes that were switched to 64-bit mode. A local attacker could run a specially crafted binary to read register values from an earlier process, leading to a loss of privacy. (CVE-2009-2910)

Dave Jones discovered that the gdth SCSI driver did not correctly validate array indexes in certain ioctl calls. A local attacker could exploit this to crash the system or gain elevated privileges.
(CVE-2009-3080)

Eric Dumazet and Jiri Pirko discovered that the TC and CLS subsystems would leak kernel memory via uninitialized structure members. A local attacker could exploit this to read several bytes of kernel memory, leading to a loss of privacy. (CVE-2009-3228, CVE-2009-3612)

Earl Chew discovered race conditions in pipe handling. A local attacker could exploit anonymous pipes via /proc/*/fd/ and crash the system or gain root privileges. (CVE-2009-3547)

Dave Jones and Francois Romieu discovered that the r8169 network driver could be made to leak kernel memory. A remote attacker could send a large number of jumbo frames until the system memory was exhausted, leading to a denial of service. Ubuntu 9.10 was not affected. (CVE-2009-3613).

Ben Hutchings discovered that the ATI Rage 128 video driver did not correctly validate initialization states. A local attacker could make specially crafted ioctl calls to crash the system or gain root privileges. (CVE-2009-3620)

Tomoki Sekiyama discovered that Unix sockets did not correctly verify namespaces. A local attacker could exploit this to cause a system hang, leading to a denial of service. (CVE-2009-3621)

J. Bruce Fields discovered that NFSv4 did not correctly use the credential cache. A local attacker using a mount with AUTH_NULL authentication could exploit this to crash the system or gain root privileges. Only Ubuntu 9.10 was affected. (CVE-2009-3623)

Alexander Zangerl discovered that the kernel keyring did not correctly reference count. A local attacker could issue a series of specially crafted keyring calls to crash the system or gain root privileges.
Only Ubuntu 9.10 was affected. (CVE-2009-3624)

David Wagner discovered that KVM did not correctly bounds-check CPUID entries. A local attacker could exploit this to crash the system or possibly gain elevated privileges. Ubuntu 6.06 and 9.10 were not affected. (CVE-2009-3638)

Avi Kivity discovered that KVM did not correctly check privileges when accessing debug registers. A local attacker could exploit this to crash a host system from within a guest system, leading to a denial of service. Ubuntu 6.06 and 9.10 were not affected. (CVE-2009-3722)

Philip Reisner discovered that the connector layer for uvesafb, pohmelfs, dst, and dm did not correctly check capabilties. A local attacker could exploit this to crash the system or gain elevated privileges. Ubuntu 6.06 was not affected. (CVE-2009-3725)

Trond Myklebust discovered that NFSv4 clients did not robustly verify attributes. A malicious remote NFSv4 server could exploit this to crash a client or gain root privileges. Ubuntu 9.10 was not affected.
(CVE-2009-3726)

Robin Getz discovered that NOMMU systems did not correctly validate NULL pointers in do_mmap_pgoff calls. A local attacker could attempt to allocate large amounts of memory to crash the system, leading to a denial of service. Only Ubuntu 6.06 and 9.10 were affected.
(CVE-2009-3888)

Joseph Malicki discovered that the MegaRAID SAS driver had world-writable option files. A local attacker could exploit these to disrupt the behavior of the controller, leading to a denial of service. (CVE-2009-3889, CVE-2009-3939)

Roel Kluin discovered that the Hisax ISDN driver did not correctly check the size of packets. A remote attacker could send specially crafted packets to cause a system crash, leading to a denial of service. (CVE-2009-4005)

Lennert Buytenhek discovered that certain 802.11 states were not handled correctly. A physically-proximate remote attacker could send specially crafted wireless traffic that would crash the system, leading to a denial of service. Only Ubuntu 9.10 was affected.
(CVE-2009-4026, CVE-2009-4027).

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.

ID	Name	Product	Family	Severity
68005	Oracle Linux 5 : kvm (ELSA-2010-0126)	Nessus	Oracle Linux Local Security Checks	high
63920	RHEL 5 : kvm (RHSA-2010:0126)	Nessus	Red Hat Local Security Checks	high
60740	Scientific Linux Security Update : kvm on SL5.4 x86_64	Nessus	Scientific Linux Local Security Checks	high
49795	Mandriva Linux Security Advisory : kernel (MDVSA-2010:198)	Nessus	Mandriva Local Security Checks	critical
49666	Mandriva Linux Security Advisory : kernel (MDVSA-2010:188)	Nessus	Mandriva Local Security Checks	critical
44969	CentOS 5 : kvm (CESA-2010:0126)	Nessus	CentOS Local Security Checks	high
44827	Debian DSA-1962-1 : kvm - several vulnerabilities	Nessus	Debian Local Security Checks	high
43026	Ubuntu 6.06 LTS / 8.04 LTS / 8.10 / 9.04 / 9.10 : linux, linux-source-2.6.15 vulnerabilities (USN-864-1)	Nessus	Ubuntu Local Security Checks	high

Detections

Analytics

CVE-2009-3722

high

Tenable Plugins

high

high

high

critical

critical

high

high

high