Several local and remote vulnerabilities have been discovered in the Linux kernel that may lead to a denial of service or the execution of arbitrary code. The Common Vulnerabilities and Exposures project identifies the following problems :

  - CVE-2005-3359     Franz Filz discovered that some socket calls permit     causing inconsistent reference counts on loadable     modules, which allows local users to cause a denial of     service.

  - CVE-2006-0038     'Solar Designer' discovered that arithmetic computations     in netfilter's do_replace() function can lead to a     buffer overflow and the execution of arbitrary code.
    However, the operation requires CAP_NET_ADMIN     privileges, which is only an issue in virtualization     systems or fine grained access control systems.

  - CVE-2006-0039     'Solar Designer' discovered a race condition in     netfilter's do_add_counters() function, which allows     information disclosure of kernel memory by exploiting a     race condition. Likewise, it requires CAP_NET_ADMIN     privileges. 

  - CVE-2006-0456     David Howells discovered that the s390 assembly version     of the strnlen_user() function incorrectly returns some     string size values.

  - CVE-2006-0554     It was discovered that the ftruncate() function of XFS     can expose unallocated blocks, which allows information     disclosure of previously deleted files.

  - CVE-2006-0555     It was discovered that some NFS file operations on     handles mounted with O_DIRECT can force the kernel into     a crash.

  - CVE-2006-0557     It was discovered that the code to configure memory     policies allows tricking the kernel into a crash, thus     allowing denial of service.

  - CVE-2006-0558     It was discovered by Cliff Wickman that perfmon for the     IA64 architecture allows users to trigger a BUG()     assert, which allows denial of service.

  - CVE-2006-0741     Intel EM64T systems were discovered to be susceptible to     a local DoS due to an endless recursive fault related to     a bad ELF entry address.

  - CVE-2006-0742     Alan and Gareth discovered that the ia64 platform had an     incorrectly declared die_if_kernel() function as 'does     never return' which could be exploited by a local     attacker resulting in a kernel crash.

  - CVE-2006-0744     The Linux kernel did not properly handle uncanonical     return addresses on Intel EM64T CPUs, reporting     exceptions in the SYSRET instead of the next     instruction, causing the kernel exception handler to run     on the user stack with the wrong GS. This may result in     a DoS due to a local user changing the frames.

  - CVE-2006-1056     AMD64 machines (and other 7th and 8th generation     AuthenticAMD processors) were found to be vulnerable to     sensitive information leakage, due to how they handle     saving and restoring the FOP, FIP, and FDP x87 registers     in FXSAVE/FXRSTOR when an exception is pending. This     allows a process to determine portions of the state of     floating point instructions of other processes.

  - CVE-2006-1242     Marco Ivaldi discovered that there was an unintended     information disclosure allowing remote attackers to     bypass protections against Idle Scans (nmap -sI) by     abusing the ID field of IP packets and bypassing the     zero IP ID in DF packet countermeasure. This was a     result of the ip_push_pending_frames function improperly     incremented the IP ID field when sending a RST after     receiving unsolicited TCP SYN-ACK packets.

  - CVE-2006-1368     Shaun Tancheff discovered a buffer overflow (boundary     condition error) in the USB Gadget RNDIS implementation     allowing remote attackers to cause a DoS. While creating     a reply message, the driver allocated memory for the     reply data, but not for the reply structure. The kernel     fails to properly bounds-check user-supplied data before     copying it to an insufficiently sized memory buffer.
    Attackers could crash the system, or possibly execute     arbitrary machine code.

  - CVE-2006-1523     Oleg Nesterov reported an unsafe BUG_ON call in signal.c     which was introduced by RCU signal handling. The BUG_ON     code is protected by siglock while the code in     switch_exit_pids() uses tasklist_lock. It may be     possible for local users to exploit this to initiate a     denial of service attack (DoS).

  - CVE-2006-1524     Hugh Dickins discovered an issue in the madvise_remove()     function wherein file and mmap restrictions are not     followed, allowing local users to bypass IPC permissions     and replace portions of readonly tmpfs files with     zeroes.

  - CVE-2006-1525     Alexandra Kossovsky reported a NULL pointer dereference     condition in ip_route_input() that can be triggered by a     local user by requesting a route for a multicast IP     address, resulting in a denial of service (panic).

  - CVE-2006-1857     Vlad Yasevich reported a data validation issue in the     SCTP subsystem that may allow a remote user to overflow     a buffer using a badly formatted HB-ACK chunk, resulting     in a denial of service.

  - CVE-2006-1858     Vlad Yasevich reported a bug in the bounds checking code     in the SCTP subsystem that may allow a remote attacker     to trigger a denial of service attack when rounded     parameter lengths are used to calculate parameter     lengths instead of the actual values.

  - CVE-2006-1863     Mark Mosely discovered that chroots residing on an CIFS     share can be escaped with specially crafted 'cd'     sequences.

  - CVE-2006-1864     Mark Mosely discovered that chroots residing on an SMB     share can be escaped with specially crafted 'cd'     sequences.

  - CVE-2006-2271     The 'Mu security team' discovered that carefully crafted     ECNE chunks can cause a kernel crash by accessing     incorrect state stable entries in the SCTP networking     subsystem, which allows denial of service.

  - CVE-2006-2272     The 'Mu security team' discovered that fragmented SCTP     control chunks can trigger kernel panics, which allows     for denial of service attacks.

  - CVE-2006-2274     It was discovered that SCTP packets with two initial     bundled data packets can lead to infinite recursion,     which allows for denial of service attacks.

A number of vulnerabilities were discovered and corrected in the Linux 2.6 kernel :

Prior to Linux kernel 2.6.16.5, the kernel does not properly handle uncanonical return addresses on Intel EM64T CPUs which causes the kernel exception handler to run on the user stack with the wrong GS (CVE-2006-0744).

The selinux_ptrace logic hooks in SELinux for 2.6.6 allow local users with ptrace permissions to change the tracer SID to an SID of another process (CVE-2006-1052).

Prior to 2.6.16, the ip_push_pending_frames function increments the IP ID field when sending a RST after receiving unsolicited TCP SYN-ACK packets, which allows a remote attacker to conduct an idle scan attack, bypassing any intended protection against such an attack (CVE-2006-1242).

In kernel 2.6.16.1 and some earlier versions, the sys_add_key function in the keyring code allows local users to cause a DoS (OOPS) via keyctl requests that add a key to a user key instead of a keyring key, causing an invalid dereference (CVE-2006-1522).

Prior to 2.6.16.8, the ip_route_input function allows local users to cause a DoS (panic) via a request for a route for a multicast IP address, which triggers a null dereference (CVE-2006-1525).

Prior to 2.6.16.13, the SCTP-netfilter code allows remote attackers to cause a DoS (infinite loop) via unknown vectors that cause an invalid SCTP chunk size to be processed (CVE-2006-1527).

Prior to 2.6.16, local users can bypass IPC permissions and modify a read-only attachment of shared memory by using mprotect to give write permission to the attachment (CVE-2006-2071).

Prior to 2.6.17, the ECNE chunk handling in SCTP (lksctp) allows remote attackers to cause a DoS (kernel panic) via an unexpected chucnk when the session is in CLOSED state (CVE-2006-2271).

Prior to 2.6.17, SCTP (lksctp) allows remote attacker to cause a DoS (kernel panic) via incoming IP fragmented COOKIE_ECHO and HEARTBEAT SCTP control chunks (CVE-2006-2272).

In addition to these security fixes, other fixes have been included such as :

  - fix a scheduler deadlock

    - Yenta oops fix

    - ftdi_sio: adds support for iPlus devices

    - enable kprobes on i386 and x86_64

    - avoid a panic on bind mount of autofs owned directory

    - fix a kernel OOPs when booting with 'console=ttyUSB0'       but without a USB-serial dongle plugged in

  - make dm-mirror not issue invalid resync requests

    - fix media change detection on scsi removable devices

    - add support for the realtek 8168 chipset

    - update hfsplus driver to 2.6.16 state

    - backport 'Gilgal' support from e1000 7.0.33

    - selected ACPI video fixes

    - update 3w-9xxx to 2.26.02.005 (9550SX support)

    - fix a deadlock in the ext2 filesystem

    - fix usbserial use-after-free bug

    - add i945GM DRI support

    - S3 resume fixes

    - add ECS PF22 hda model support

    - SMP suspend

    - CPU hotplug

    - miscellaneous AGP fixes

    - added sata-suspend patch for 2.6.12 for Napa platform

The provided packages are patched to fix these vulnerabilities. All users are encouraged to upgrade to these updated kernels.

As well, updated mkinitrd and bootsplash packages are provided to fix minor issues; users should upgrade both packages prior to installing a new kernel.

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

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

The sys_mbind() function did not properly verify the validity of the 'maxnod' argument. A local user could exploit this to trigger a buffer overflow, which caused a kernel crash. (CVE-2006-0557)

The SELinux module did not correctly handle the tracer SID when a process was already being traced. A local attacker could exploit this to cause a kernel crash. (CVE-2006-1052)

Al Viro discovered a local Denial of Service in the sysfs write buffer handling. By writing a block with a length exactly equal to the processor's page size to any writable file in /sys, a local attacker could cause a kernel crash. (CVE-2006-1055)

John Blackwood discovered a race condition with single-step debugging multiple processes at the same time. A local attacker could exploit this to crash the system. This only affects the amd64 platform.
(CVE-2006-1066)

Marco Ivaldi discovered a flaw in the handling of the ID number of IP packets. This number was incremented after receiving unsolicited TCP SYN-ACK packets. A remote attacker could exploit this to conduct port scans with the 'Idle scan' method (nmap -sI), which bypassed intended port scan protections. (CVE-2006-1242)

Pavel Kankovsky discovered that the getsockopt() function, when called with an SO_ORIGINAL_DST argument, does not properly clear the returned structure, so that a random piece of kernel memory is exposed to the user. This could potentially reveal sensitive data like passwords or encryption keys. (CVE-2006-1343)

A buffer overflow was discovered in the USB Gadget RNDIS implementation. While creating a reply message, the driver did not allocate enough memory for the reply structure. A remote attacker could exploit this to cause a kernel crash. (CVE-2006-1368)

Alexandra Kossovsky discovered an invalid memory access in the ip_route_input() function. By using the 'ip' command in a particular way to retrieve multicast routes, a local attacker could exploit this to crash the kernel. (CVE-2006-1525).

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.

This update includes a number of security issues that have been fixed upstream over the last week or so.

i386/x86-64: Fix x87 information leak between processes (CVE-2006-1056) ip_route_input panic fix (CVE-2006-1525) fix MADV_REMOVE vulnerability (CVE-2006-1524) shmat: stop mprotect from giving write permission to a readonly attachment (CVE-2006-1524) Fix MPBL0010 driver insecure sysfs permissions x86_64: When user could have changed RIP always force IRET (CVE-2006-0744) Fix RCU signal handling Keys: Fix oops when adding key to non-keyring (CVE-2006-1522) sysfs: zero terminate sysfs write buffers (CVE-2006-1055)

It also includes various other fixes from the -stable tree. Full changelogs are available from :

http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.9 http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.8 http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.7 http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.6 http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.5 http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.4 http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.3 http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.2

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

Several local and remote vulnerabilities have been discovered in the Linux kernel that may lead to a denial of service or the execution of arbitrary code. The Common Vulnerabilities and Exposures project identifies the following problems :

  - CVE-2006-0038     'Solar Designer' discovered that arithmetic computations     in netfilter's do_replace() function can lead to a     buffer overflow and the execution of arbitrary code.
    However, the operation requires CAP_NET_ADMIN     privileges, which is only an issue in virtualization     systems or fine grained access control systems.

  - CVE-2006-0039     'Solar Designer' discovered a race condition in     netfilter's do_add_counters() function, which allows     information disclosure of kernel memory by exploiting a     race condition. Like CVE-2006-0038, it requires     CAP_NET_ADMIN privileges.

  - CVE-2006-0741     Intel EM64T systems were discovered to be susceptible to     a local DoS due to an endless recursive fault related to     a bad ELF entry address.

  - CVE-2006-0742     Incorrectly declared die_if_kernel() function as 'does     never return' which could be exploited by a local     attacker resulting in a kernel crash.

  - CVE-2006-1056     AMD64 machines (and other 7th and 8th generation     AuthenticAMD processors) were found to be vulnerable to     sensitive information leakage, due to how they handle     saving and restoring the FOP, FIP, and FDP x87 registers     in FXSAVE/FXRSTOR when an exception is pending. This     allows a process to determine portions of the state of     floating point instructions of other processes.

  - CVE-2006-1242     Marco Ivaldi discovered that there was an unintended     information disclosure allowing remote attackers to     bypass protections against Idle Scans (nmap -sI) by     abusing the ID field of IP packets and bypassing the     zero IP ID in DF packet countermeasure. This was a     result of the ip_push_pending_frames function improperly     incremented the IP ID field when sending a RST after     receiving unsolicited TCP SYN-ACK packets.

  - CVE-2006-1343     Pavel Kankovsky reported the existence of a potential     information leak resulting from the failure to     initialize sin.sin_zero in the IPv4 socket code.

  - CVE-2006-1368     Shaun Tancheff discovered a buffer overflow (boundary     condition error) in the USB Gadget RNDIS implementation     allowing remote attackers to cause a DoS. While creating     a reply message, the driver allocated memory for the     reply data, but not for the reply structure. The kernel     fails to properly bounds-check user-supplied data before     copying it to an insufficiently sized memory buffer.
    Attackers could crash the system, or possibly execute     arbitrary machine code.

  - CVE-2006-1524     Hugh Dickins discovered an issue in the madvise_remove()     function wherein file and mmap restrictions are not     followed, allowing local users to bypass IPC permissions     and replace portions of readonly tmpfs files with     zeroes.

  - CVE-2006-1525     Alexandra Kossovsky reported a NULL pointer dereference     condition in ip_route_input() that can be triggered by a     local user by requesting a route for a multicast IP     address, resulting in a denial of service (panic).

  - CVE-2006-1857     Vlad Yasevich reported a data validation issue in the     SCTP subsystem that may allow a remote user to overflow     a buffer using a badly formatted HB-ACK chunk, resulting     in a denial of service.

  - CVE-2006-1858     Vlad Yasevich reported a bug in the bounds checking code     in the SCTP subsystem that may allow a remote attacker     to trigger a denial of service attack when rounded     parameter lengths are used to calculate parameter     lengths instead of the actual values.

  - CVE-2006-1864     Mark Mosely discovered that chroots residing on an SMB     share can be escaped with specially crafted 'cd'     sequences.

  - CVE-2006-2271     The 'Mu security team' discovered that carefully crafted     ECNE chunks can cause a kernel crash by accessing     incorrect state stable entries in the SCTP networking     subsystem, which allows denial of service.

  - CVE-2006-2272     The 'Mu security team' discovered that fragmented SCTP     control chunks can trigger kernel panics, which allows     for denial of service attacks.

  - CVE-2006-2274     It was discovered that SCTP packets with two initial     bundled data packets can lead to infinite recursion,     which allows for denial of service attacks.

Updated kernel packages that fix several security issues in the Red Hat Enterprise Linux 4 kernel are now available.

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

The Linux kernel handles the basic functions of the operating system.

These new kernel packages contain fixes for the security issues described below :

* a flaw in the IPv6 implementation that allowed a local user to cause a denial of service (infinite loop and crash) (CVE-2005-2973, important)

* a flaw in the bridge implementation that allowed a remote user to cause forwarding of spoofed packets via poisoning of the forwarding table with already dropped frames (CVE-2005-3272, moderate)

* a flaw in the atm module that allowed a local user to cause a denial of service (panic) via certain socket calls (CVE-2005-3359, important)

* a flaw in the NFS client implementation that allowed a local user to cause a denial of service (panic) via O_DIRECT writes (CVE-2006-0555, important)

* a difference in 'sysretq' operation of EM64T (as opposed to Opteron) processors that allowed a local user to cause a denial of service (crash) upon return from certain system calls (CVE-2006-0741 and CVE-2006-0744, important)

* a flaw in the keyring implementation that allowed a local user to cause a denial of service (OOPS) (CVE-2006-1522, important)

* a flaw in IP routing implementation that allowed a local user to cause a denial of service (panic) via a request for a route for a multicast IP (CVE-2006-1525, important)

* a flaw in the SCTP-netfilter implementation that allowed a remote user to cause a denial of service (infinite loop) (CVE-2006-1527, important)

* a flaw in the sg driver that allowed a local user to cause a denial of service (crash) via a dio transfer to memory mapped (mmap) IO space (CVE-2006-1528, important)

* a flaw in the threading implementation that allowed a local user to cause a denial of service (panic) (CVE-2006-1855, important)

* two missing LSM hooks that allowed a local user to bypass the LSM by using readv() or writev() (CVE-2006-1856, moderate)

* a flaw in the virtual memory implementation that allowed local user to cause a denial of service (panic) by using the lsof command (CVE-2006-1862, important)

* a directory traversal vulnerability in smbfs that allowed a local user to escape chroot restrictions for an SMB-mounted filesystem via '..\\' sequences (CVE-2006-1864, moderate)

* a flaw in the ECNE chunk handling of SCTP that allowed a remote user to cause a denial of service (panic) (CVE-2006-2271, moderate)

* a flaw in the handling of COOKIE_ECHO and HEARTBEAT control chunks of SCTP that allowed a remote user to cause a denial of service (panic) (CVE-2006-2272, moderate)

* a flaw in the handling of DATA fragments of SCTP that allowed a remote user to cause a denial of service (infinite recursion and crash) (CVE-2006-2274, moderate)

All Red Hat Enterprise Linux 4 users are advised to upgrade their kernels to the packages associated with their machine architectures and configurations as listed in this erratum.

The remote CentOS system is missing a security update which has been documented in Red Hat advisory RHSA-2006-0493.

ID	Name	Product	Family	Published	Updated	Severity
22645	Debian DSA-1103-1 : kernel-source-2.6.8 - several vulnerabilities	Nessus	Debian Local Security Checks	10/14/2006	1/4/2021	critical
21575	Mandrake Linux Security Advisory : kernel (MDKSA-2006:086)	Nessus	Mandriva Local Security Checks	5/19/2006	1/6/2021	high
21375	Ubuntu 5.04 / 5.10 : linux-source-2.6.10, linux-source-2.6.12 vulnerabilities (USN-281-1)	Nessus	Ubuntu Local Security Checks	5/13/2006	1/19/2021	critical
21253	Fedora Core 4 : kernel-2.6.16-1.2096_FC4 (2006-423)	Nessus	Fedora Local Security Checks	4/21/2006	1/11/2021	medium
22639	Debian DSA-1097-1 : kernel-source-2.4.27 - several vulnerabilities	Nessus	Debian Local Security Checks	10/14/2006	1/4/2021	critical
21592	RHEL 4 : kernel (RHSA-2006:0493)	Nessus	Red Hat Local Security Checks	5/24/2006	1/14/2021	high
21997	CentOS 4 : kernel (CESA-2006:0493)	Nessus	CentOS Local Security Checks	7/5/2006	1/4/2021	high
801418	CentOS RHSA-2006-0493 Security Check	Log Correlation Engine	Generic			high

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